If a double is regulated with a scope in place, can you assume that you will not change regulation if a similar weight scope is swapped out for the existing scope? Thanks in advance.

If mounted in the same rings and weighing the same it will rarely change the regulation!

It is common to have a spare scope for a rifle in case one goes bad, or for two different purposes. One fore general hunting and say one that is illuminated for sitting a blind for Lion or leopard over bait! On a double rifle as long as the two scopes are pre-zeroed in the same type and height rings, and weight the same you should be OK.

......................................................................

I'm no expert on doubles but, I have a pretty solid background on "other" scoped long guns. I'd have to say that any changes would affect impact. There are other factors involved than just the weight of a scope. Even if multiple scopes (weighing the same) are sighted to ONE particular rifle each scope would have their slight differences and "act" differently (parallax, eye relief etc included) I'd go as far as saying even with 2 of the exact same brand and model of scopes impact would change. Then, go and factor in any differences with the mounts or rings. Depending on the distance and the accuracy you're looking for..... It may be acceptable.

weight of a scope seems a little out there if that causes a shift then why not the size of the hand that holds the rifle

quote:

Originally posted by FLGrizzy:
I'm no expert on doubles but, I have a pretty solid background on "other" scoped long guns. I'd have to say that any changes would affect impact. There are other factors involved than just the weight of a scope. Even if multiple scopes (weighing the same) are sighted to ONE particular rifle each scope would have their slight differences and "act" differently (parallax, eye relief etc included) I'd go as far as saying even with 2 of the exact same brand and model of scopes impact would change. Then, go and factor in any differences with the mounts or rings. Depending on the distance and the accuracy you're looking for..... It may be acceptable.

All this is certainly correct, if one uses standard bases! However to have interchangeability that works one must have quality quick detach rings and bases that return to zero every time.

Both scopes are to be placed in it’s own set of identical rings, and each for the QD bases, and each pre-zeroed on the rifle. I have done this on several rifles, and it has always worked perfectly! My rifles all had the older Warne QD rings and bases done on both bolt rifles and double rifles! However you are correct done the way you describe! The POI will definitely change when changing scopes, and will have to be zeroed before the rifle can be used! Here we are not talking about a 300 yd double rifle , we are discussing scoping a hunting big bore double rifle in this thread, but I have an FN Mauser with the same QD mounts with a 3-9X40mm scope mounted, and a 1.3-4X30mm with a German No4 post and crosshair reticle illuminated scope in the same QD Warne rings, The 3-9 is sighted in 1.5 in high at 100 yds, and the 1.3 sighted in dead on at 50 yds for shooting over bait, or set at 1.3 power for following up wounded buffalo in fading light . These two scopes interchange perfectly, and return to zero every time.

The only place where the weight, and height of the scope makes a difference is on a side by side double rifle because it effects the UP and to the SIDE muzzle flip for regulation. The OP wants to just change scopes, and is concerned about it changing the regulation. In his case he intends zeroing the new scope, and in that case if the scope is the same height and weight it will not change the regulation, but will need to be zeroed.

I'm with Mac - but have just one scoped double to base my opinion upon.

Verney-Carron SxS in 375Fl built with Recknagel swing off mount bases. Two different scopes of similar size and weight in Recknagel mounts, each sighted in separately - both shoot to same POA however many times I switch between them with no change in where bullets from the L or R barrel land.

I have two different scopes fitted to my 9,4x74R double rifle, a 2.5 to 8 Leupold and a 1.5 to6x Swarovski.

I notice no difference in regulation when switdchig between the two.

Also I have double rifle drillings in 308 and in 9,3x74R. I have scopes and red dots fitted to them, and again notice no difference in regulation when switching between the different optics.

quote:

Originally posted by bwananelson:
weight of a scope seems a little out there if that causes a shift then why not the size of the hand that holds the rifle

Bwana, The weight of the scope combined with the height does effect regulation to a degree because the barrels recoil UP and AWAY from the other barrel during the BARREL TIME. The extra weight retards to upward movement, and the height causes excess torque which retards the angle away from the other barrel.

Im sure you already know what the words BARREL TIME means, but others may not! BARREL TIME is the time it takes the bullet to reach and exit the muzzle. BARREL TIME is a very important part of the regulation process. To explain the process that causes a double rifle to regulate!

If one looks through the bores of a pair of double rifle barrels, with the sights lined up on the aiming point of a target place at the distance engraved on the rear sight of the barrels, what you will see is; The RIGHT barrel will be looking at a point on the target that is LOW and LEFT of the point of aim. The LEFT barrel will be looking at a point that is LOW and RIGHT of the point of aim. When the rifle is fired with a regulating load and with nothing to retard the movement of the barrels, and the speed is correct of the bullet the bullet will exit the muzzle exactly pointing to the place on the target where the sights were pointing when the trigger was pulled. This is the case with each barrel, the Barrel time making both barrels regulate into a composite group on the target. Any weight added will retard the rise, and the torque caused by the upward to the side movement height will retard the angle of UP and AWAY from the other barrel to a greater degree as the height gets higher!

As to the weight of the hand effecting the way the rifle regulates it certainly does, but most adult hands aer about the same, and the rifle was regulated with that average weight involved. Additionally, most double rifles were regulated with iron sights, and so when adding a scope and bases and rings one has to be careful how much weight, and how high his choice will be. The smaller amount of change in weight and height he can find the less it will effect the way the rifle shoots.

SO! Weight and height will effect the regulation, MORE or LESS depending on the amount of weight and Height.

I hope any of this is at least as clear a Mississippi mud!

For some rifle cartridges barrel time and recoil timing can be altered by using different rate powders, sometimes even while maintaining the same or very similar MV velocity. I have done this in my DR.

Has anyone tried to make a rifle shoot well with a scope by altering powder choice?

JPK

I have only had one experience with this, and it did not turn out well. Butch Searcy regulated my 450/400 classic to shoot with iron sights and with a Leupold VX-2 1-4X scope. This rifle literally shoots the width of the barrels at 100 yards, and it has consistently been the most accurate double I own. When I tried switching scopes over to a Leupold VX-3 1.5-5x, my super accurate double was now printing 2 shots that were 3" apart and crossing at 50 yards. I could not believe it, but it was true. When I put the old VX-2 back on the rifle, accuracy returned to 2 shots almost touching at 50 yards and a spread of a little more than an inch at 100 yards. This is the last time I messed around with switching scopes on doubles!

quote:

Originally posted by JPK:
For some rifle cartridges barrel time and recoil timing can be altered by using different rate powders, sometimes even while maintaining the same or very similar MV velocity. I have done this in my DR.

Has anyone tried to make a rifle shoot well with a scope by altering powder choice?

JPK

JPK, Todd Williams has a Chapuis 9.3X74R double that was super accurate with the iron sights. He mounted a 1.1-4 Trijicon illuminated scope in the QD rings and bases that came with the rifle. He burned a lot of powder, wasted a lot of bullets before finding a load the would shoot well with both irons and the scope! So it can be done, but sometimes it is not an easy task, as Todd found out.

Some times it simply doesn’t work without a new physical re-regulation. In most cases if a new rifle is ordered with both scope and irons the maker will request the scope you intend using. He will then regulate the rifle with the scope attached, and then file the irons to match the regulation after the scope is removed.

Even then if the new owner changes scopes to one that weighs more than the one the rifle was regulated with it will effect the regulation to some extent. It may not be much, or as Subsailor found on his Searcy, a lot!

It seems the faster the cartridge used is the more touchy the regulation is. A simple change of a bullet shape or hardness in a double with a fast cartridge, will sometimes totally send regulation out the door, while a larger bore, with slower bullets, heavier weight of rifle it’s self will be less bothered!

Double rifles can be a real bitch at times!
.....................................................................

Mac,

"Anyone" can replace irons and file them in, it is getting the barrels to shoot to the same poa with both the scope and the irons that is the tricky part.

I have not had any problems finding a couple of different loads and different bullets to shoot to regulation using different powders. I have for my Thys, for example, three 500gr Woodleigh solids loads that shoot to regulation, plus their slightly different versions for the softs, the slowest about 110fps slower than the fastest, and the other in the middle. Then I have two 450 NF FN loads, with about a 20fps difference, the faster one 90fps faster than the fastest 500 load, and then my 350gr 75% Rule load, which I haven't chorographed.

As you mention, it's the changing rifle weight, in particular the changing effective barrel weight that makes making rifle shoot the same ammo well with and without a scope a challenge.

You mention that Todd managed to experiment with different powders (and bullets) to find a load that shot well with and without a scope, and that was the info I was looking for.

Thanks,

JPK

Both my 9,3x74R Chapuis, and of course my British 450/400 3 1/4 were regulated with out a scope mounted.

I have detected no difference in regulation after mounting the scopes.

While I have killed several deer, my biggest ever, several pigs, and 2 bears with the iron sights,on the Chapuis, after using it scoped, I quickly realized how much more useful the rifle was with the scope.

Like wise I used the 450/400 for several years with its iron sights, taking deer, several pigs, 2 caribou in Alaska, and a bear in Montana, I had it scoped for my wife to use in Zim on her cape buff. I used the 400 to take a bull elephant and a couple of buffalo with the iron sights, and used it scoped to take my lion.

Looking back, the ONLY mistake I have made with double rifles, was NOT having the 450/400 scoped the day I bought it.

I think every double under 450/400 should be scoped.

On doubles bigger than 400, if you have difficulty with iron sights, then put a Docter Optic, or a Trijicon red dot on it.

I could be wrong but(i doubt it) all my resources tell me that a scope should not change anything.Perhaps the basics in shooting have not been mastered and one is putting the errors on the scope.It seems to me if a scope could change POI it would do so on a bolt as well and we know how ridiculous that notion is.

On a double , scopes are mounted on the barrels, on a bolt gun, mounted on the action. There is a big difference between the 2 . I have no experience with scopes on doubles, but I think the weight of the scope and mount could effect POI / regulation.

Nick

I have never in my life heard that weight on a barrel will effect POI.

"Ignored post by shootaway"
Whatever shootawhey is saying above is most likely the opposite of reality.

Yep, physics is undeniable, as Mac says.
I forgot about how much a scope of different weight and/or height of rings, and even the length of the scope, can affect the POI of a double rifle.
If a double rifle had been regulated for one sighting setup and then was switched to another,
there will be changes in POI.
The lighter the double rifle, and the bigger the change in sighting apparatus (weight, height, length), then the bigger that change in POI is going to be.

A master double rifle shooter is similar to a "shooting ballerina on ice skates" that shootawhey thinks he is.
Angular momentum effects.

Of course, unlike shootawhey, the master double rifle shooter wears no tutu or shooting helmet.

Lessee, if a CSMC RBL Professional was regulated for a heavier 30mm-tubed Nightforce variable-power scope,
that extra weight will retard the upward and outward movement of the muzzles in recoil,
more than will the 6.5 ounce Leupold Ultralight I am using.
My Right and Left POIs will be diverged and high compared to what happens with the heavier scope.
Hey! I am going to find out the weight of scope Tony Galazan was using before I got hold of his RBL ...
Done: A 1-4x24mm Nightforce weighing 17 ounces!!!
That was more than a half-pound extra at regulation time.
I can ease my search for a regulation load with round balls by using a heavier scope:
A 30mm-tubed 1-pounder in Talley rings.
All kinds of possibilities here!



That will reduce the horizontal divergence between the two barrels' POIs.
It will also decrease the elevation, but that is easily dialed back in with scope.
The dispersion in each barrel by itself may be my poor shooting, or poor consistency in powder burn.
There is a lot of unburnt Blue Dot left in the barrels, despite a consistent roll crimp holding the round ball.
A CCI 209 M primer will replace the standard primer, and a thin nitro card will go over the powder, and under the first gas seal.

Some re-regulation may yet be in order, to get the Right and Left barrels matching vertically.

Rip,what are you doing over here in the DR section? You have never shot a DR
Commenting on things you know nothing about as usual.

It is a point of honor for me to ignore contents of shootawhey posts. I only know they happened by the one-liners starting with "Ignored post by shootaway."
Ditto zombiekiller and Trax.

However, if any other member thinks shootawhey has posted anything of merit or with any truth to it,
I will be happy to disabuse them of anything from inside the shooting helmet of shootawhey.

quote:

Originally posted by shootaway:
I could be wrong but(i doubt it) all my resources tell me that a scope should not change anything.Perhaps the basics in shooting have not been mastered and one is putting the errors on the scope.It seems to me if a scope could change POI it would do so on a bolt as well and we know how ridiculous that notion is.

Numbnuts:
Yes, you are, indeed wrong. Again.
It is time you learned the difference in POI between a double rifle (with barrels set at a slight convergence) and a single barrel rifle of any action style.
Remember, lest it slip your mind, you are very new to the world of double rifles and have only limited experience with one low priced double. That is fine as it is, but you seem to attack those that have been shooting double for decades, have, or have had, many--perhaps dozens, and of the finest English makes. Oh, I forgot, they are all garbage except yours.
Grow up. You are giving all those above the 49th parallel a bad reputation.
Cal

quote:

Originally posted by N E 450 No2:
Both my 9,3x74R Chapuis, and of course my British 450/400 3 1/4 were regulated with out a scope mounted.

I have detected no difference in regulation after mounting the scopes.

Tony, one of these days we really do need to hit the range together, since we don't live that far apart and all. I'll bring my Chapuis 9.3X74R and a handful of 286gr TSX loads. We'll shoot them with the scope off ... it will shoot exactly to the regulation target at 50 yards, then put the scope on and try again ... they will cross off the paper at 50 yards!! Then we can move to the CEB's, using IMR 4831. Without the scope, it will shoot them to regulation again. Put the scope on and they will shoot 12" apart at 50 yards! Then shoot the same CEBs with IMR 4064 and a pinch of Dacron filler. Without the scope, they will shoot to regulation; with the scope, they will shoot to regulation as well! Strange behavior indeed, especially the last load that shoots to regulation in either configuration.

It took me 14 load combinations of bullets and powders to finally get a load that would shoot to regulation with the scope mounted on that rifle. There must be significant differences in the way each individual rifle is built. I remember you stating yours was not affected at all by mounting the scope. Mine? Well, I almost gave up on it completely before getting it to shoot correctly as I refused to set the right barrel to the scope and forget about it being a double unless using the irons. I came close to seriously "loosing my religion" on that rifle! But now that it's sorted out, it shoots quite well at range. In 2012, I took a couple of plains game past 100 yards including a Grysbok at 125 and a Warthog at 150. I thought that was pretty much the limit but this past year, 2013, while attempting to get an impala for leopard bait, we spooked a herd of impala several times. I was faced with a 263 yard shot which I pulled off with one shot with the bullet striking just in front of the shoulder blade at the base of the neck. One of these days, I'll get around to posting that little video clip but I just haven't found the proper context in which to present it, other than a simple killshot clip ... something I really prefer to not post.

quote:

Originally posted by shootaway:
I could be wrong but(i doubt it) all my resources tell me that a scope should not change anything.Perhaps the basics in shooting have not been mastered and one is putting the errors on the scope.It seems to me if a scope could change POI it would do so on a bolt as well and we know how ridiculous that notion is.

Ummm. Yeah ... you ARE wrong! But what else is new?

quote:

Originally posted by Todd Williams:

quote:

Originally posted by N E 450 No2:
Both my 9,3x74R Chapuis, and of course my British 450/400 3 1/4 were regulated with out a scope mounted.

I have detected no difference in regulation after mounting the scopes.

Tony, one of these days we really do need to hit the range together, since we don't live that far apart and all. I'll bring my Chapuis 9.3X74R and a handful of 286gr TSX loads. We'll shoot them with the scope off ... it will shoot exactly to the regulation target at 50 yards, then put the scope on and try again ... they will cross off the paper at 50 yards!! Then we can move to the CEB's, using IMR 4831. Without the scope, it will shoot them to regulation again. Put the scope on and they will shoot 12" apart at 50 yards! Then shoot the same CEBs with IMR 4064 and a pinch of Dacron filler. Without the scope, they will shoot to regulation; with the scope, they will shoot to regulation as well! Strange behavior indeed, especially the last load that shoots to regulation in either configuration.

It took me 14 load combinations of bullets and powders to finally get a load that would shoot to regulation with the scope mounted on that rifle. There must be significant differences in the way each individual rifle is built. I remember you stating yours was not affected at all by mounting the scope. Mine? Well, I almost gave up on it completely before getting it to shoot correctly as I refused to set the right barrel to the scope and forget about it being a double unless using the irons. I came close to seriously "loosing my religion" on that rifle! But now that it's sorted out, it shoots quite well at range. In 2012, I took a couple of plains game past 100 yards including a Grysbok at 125 and a Warthog at 150. I thought that was pretty much the limit but this past year, 2013, while attempting to get an impala for leopard bait, we spooked a herd of impala several times. I was faced with a 263 yard shot which I pulled off with one shot with the bullet striking just in front of the shoulder blade at the base of the neck. One of these days, I'll get around to posting that little video clip but I just haven't found the proper context in which to present it, other than a simple killshot clip ... something I really prefer to not post.

One thing you can be sure of and that is that each DR is a law unto itself.

Regarding the differences between your rifle and 450 No2 Nitro Express's, his was regulated with the 14th load. Yours was regulated with the first load!

JPK

My Chapuis came from the factory regulated with RWS 293gr TUG.

However I use 65 gr of IMR 4831 with the 286 Woodleigh Softs and Solids, Nosler Partitions, and the 285 gr Hawks with the .035 jacket.

They all hit close enough together to use the same sight setting for all.

Inside 100 yards on deer and pigs, I also use 232 Norma Vulcan, 286gr Alaska and S&B 286gr bullets as well.

My longest shots were a coyote at 287 yards, kneeling, I hit him with a Woodleigh Soft with the right barrel and then with a Nosler Partition with the left. It was filmed, Mac was there and saw the shots. I used the Leupold 2.5 to 8 scope.

In Zim I shot a kudu at a little over 300 yards,again filmed. This time I used the Swarovski 1.5 to 6 scope.

I will say that I had shot the double a "little bit" at 200 and 300 yards in practice...

These loads do not cross, in fact at 300 yards the right and left barrel shoot a bit wider than at 100.

Edited to replace the typo of IMR3831 powder with the proper IMR 4831.

what about the little micro red dot,long range and double rifle dont seem to go together. i want a double to get close to be right up there , yes you decrease your odds but then ask for your scoped rifle

quote:

Originally posted by bwananelson:
what about the little micro red dot,long range and double rifle dont seem to go together. i want a double to get close to be right up there , yes you decrease your odds but then ask for your scoped rifle

BwanaN you are of course correct in that assessment of the main reason the double rifle came about in the first place. However In the case of real double rifle nuts, they want to do all their hunting with double rifles. I happen to be one of those who hunts almost exclusively with double rifles. That is not because I don't have viable dangerous game bolt rifles, I do, but simply want to hunt with doubles.

Because of that mindset,in many cases a scope in quality quick detach rings and bases is a very useful thing to have.

I want both quality irons, and a scope in quality quick detach rings and bases on all my bolt rifles that are chambered for big game cartridges, and that is the way mine are set up. The difference that most folks do not understand is, on a bolt or single, shot the scope is the primary sight, and the irons are back-up, while on the double rifle the irons are the primary and the scope is the back-up or special purpose sight. I have never understood the absolute objection to having a scope on a double rifle. The makers have offered them as long as they have been available.

There are times when the light is failing or you spot a buffalo or lion in thick cover where bush covers most of the animal. even if you can see small sticks in the way, once you look over Iron sights those small sticks disappear from sight. A quick detaching of a scope will let you pin point a clearing in the bush to hit the vitals. Then if you want to take a lion or leopard over bait with one of your doubles, a scope is accentual. Of course you could just go against you desire to take those two animals with your double, and shoot them with a scoped single shot or bolt rifle. I'd rather them with my double rifles.

IMO, a scope or a red dot like a Docter sight on a double rifle simply makes sense!

Then we get down to MY case, I'm going to have to mount scopes and red dots on all my doubles because I have developed Macular degeneration in my right eye, and I am right handed. With a 1-5 power scope or a Docter optic sight I can still shoot all my double rifle which are right handed rifles, byt shooting with both eyes open so the binocular effect wil work because I can still see the illuminated dot with my right eye, but not detail. The binocular effect will superimpose the dot, and the left eye detail in a composite field of view.

Even with good vision, anyone who has used a low powered scope with illuminated dot or a Docter sight will tell you that even in bright sunlight those sights are faster than irons! That is the reason Ivan Carter put a Docter Optic sight on his 600NE Heym double rifle! I believe that is enough proof of the value of optical sights on a double rifle, one could ask for! He uses that thing on elephant that is in his face distance!
.....................................................................

quote:

Originally posted by MacD37:

quote:

Originally posted by bwananelson:
what about the little micro red dot,long range and double rifle dont seem to go together. i want a double to get close to be right up there , yes you decrease your odds but then ask for your scoped rifle

BwanaN you of course correct in that assessment of the main reason the double rifle came about in the first place. However In the case of real double rifle nuts, they want to do all their hunting with double rifles. I happen to be one of those who hunts almost exclusively with double rifles. That is not because I don't have viable dangerous game bolt rifles, I do, but simply want to hunt with doubles.

Because of that mindset,in many cases a scope in quality quick detach rings and bases is a very useful thing to have.

I want both quality irons, and a scope in quality quick detach rings and bases on all my bolt rifles that are chambered for big game cartridges, and that is the way mine are set up. The difference that most folks the do not understand is on a bolt or single shot the scope is the primary sight, and the irons are back-up, while on the double rifle the irons are the primary and the scope is the back-up. I have never understood the absolute objection to having a scope on a double rifle. There are times when the light is failing or you spot a buffalo or lion in thick cover where bush covers most of the animal. even if you can see small sticks in the way, once you look over Iron sights those small sticks disappear from sight. A quick detaching of a scope will let you pin point a clearing in the bush to hit the vitals. Then if you want to take a lion or leopard over bait with one of your doubles, a scope is accentual. Of course you could just go against you desire to take those two animals with your double, and shoot them with a scoped single shot or bolt rifle. I'd rather them with my double rifles.

IMO, a scope or a red dot like a Docter sight on a double rifle simply makes sense!

Then we get down to MY case, I'm going to have to mount scopes and red dots on all my doubles because I have developed Macular degeneration in my right eye, and I am right handed. With a 1-5 power scope or a Docter sight I can still shoot all my double rifle which are right handed rifles, byt shooting with both eyes open so the binocular effect wil work because I can still see the illuminated dot with my right eye, but not detail. The binocular effect will superimpose the dot, and the left eye detail in a composite field of view.

Even with good vision, anyone who has used a low powered scope with illuminated dot or a Docter sight will tell you that even in bright sunlight those sights are faster than irons! That is the reason Ivan Carter put a Docter Optic sight on his 600NE Heym double rifle! I believe that is enough proof of the value of optical sights on a double rifle, one could ask for! He uses that thing on elephant that is in his face distance!
.....................................................................

Good point Mac. I'm a double rifle nut as well and currently desire to do all of my African hunting with a double rifle. Deer and pigs back home to a large extent as well.

To BwanaNelson's comment, I think it's more of an accurate statement to say "Big Bore" rifles and long distances don't go together more so than simply painting with a broad brush and saying "Double Rifles" and long distance don't go together. Of course, if one is shooting a rifle and ammo combination that isn't properly matched, and the barrels are crossing at some point, that will certainly limit one's distance shooting. But if the ammo is properly matched to the rifle's regulation, meaning the center of the right barrel's groups and the center of the left barrel's groups are equal to the spread between the barrels themselves, why would one be limited on range? Specifically, that's what I had so much trouble with in getting my Chapuis 9.3x74R property sorted out. I could have easily just called it a 50 yard gun with open sights, or treated it like a single shot and sighted in the right barrel, saving the left for the occasion when I detach the scope. But the effort eventually paid off. I've gone ahead and pulled a couple of shots with that rifle from my 2013 elephant bull / leopard hunt and posted them below. All three of these shots were in excess of 100 yards with the warthog being the closest at about 120 or so. The little baboon was about 160 yards, and then of course, the impala was later lasered at 263 with my rangefinder. As long as I can keep the rifle shooting in this manner, I'll probably continue to rely on the double, double rifle safari battery. One exception being that since having my CZ properly repaired by Wayne at AHR in 2012, I'm really ready to put that gun to use on a buffalo again. I may take it instead of the VC 500NE this year to Moz. Haven't decided yet.

Here is the video:

http://www.youtube.com/watch?v...Y6A&feature=youtu.be

Interesting and impressiv Todd. I understand that I just have to start excercising with my Heym 9,3x74R ... picking it up tomorrow

Mounting the new Schmidt & Bender 1-8x24 Red Dot on top of it !

Maybe told you before, but the new VC will also have a red dot Doctor mounted - I think that Kebco Ken has the same feature !

Good shooting Todd.
What scope on your VC 9.3x74R?

OK, having only "low" Talley 30mm rings on hand, the larger ocular would not allow room for a thumb tip to work the action lever.
So I changed scope for a 7.5-ounce-heavier 1-inch, as an experiment. Went from this 6.5 ounce scope ...



... to this 14.0 ounce scope (Nikon Monarch 1-4x20mm) in same rings, total weight of scope and rings is 1 pound 2 ounces:



If that is not enough weight difference to converge the diverged POI's of the RBL,
then I can get higher Talley rings and more weight,
much, much more weight if Talley makes 34mm rings ...

Slightly off topic but you posted the pic. That PM II is a long range scope. The big diameter tube allows enough internal movement to make big elevation changes. So, I am wondering, what is the caliber of that rifle?

quote:

Originally posted by Grenadier:
Slightly off topic but you posted the pic. That PM II is a long range scope. The big diameter tube allows enough internal movement to make big elevation changes. So, I am wondering, what is the caliber of that rifle?

Sir,
It is a 12.7x68mm Magnum aka "The 49-bore of 2010" aka "49-10."
Less cryptically, it is a .500/.338 Lapua Magnum Improved, capable of long range accuracy:



Sorry you asked now?
Actually the scope is so bulky and heavy that I can only justify using it on a 50 BMG, .416 Barrett or a Dakota Longbow .338 Lapua Magnum. The "S&B 4-16x50mm PM II Scope Mounting" picture above is a misadventure, a joke.
The scope and mounting contraption shown add 3.5 pounds, or 56 ounces, to the rifle weight.
That will require re-regulation for sure if I get it welded onto the RBL.
Weighing more than half the weight of the RBL 20-bore, it might make those loads cross that were diverged with the 6.5 ounce scope.

RIP, my scope is a Trijicon 1.25x4 mounted in Recknagel swivel quick disconnect mounts. Always goes right back to zero. Post and red triangle reticle.

quote:

Originally posted by Todd Williams:
RIP, my scope is a Trijicon 1.25x4 mounted in Recknagel swivel quick disconnect mounts. Always goes right back to zero. Post and red triangle reticle.

Thanks.
That is an 11-ounce scope on my scales.
That one works very well on your DR, obviously,
but probably too light to converge the diverged without more velocity of my load,
or re-regulation of my toy ... to be continued ...

quote:

Originally posted by Kynoch:
If a double is regulated with a scope in place, can you assume that you will not change regulation if a similar weight scope is swapped out for the existing scope? Thanks in advance.

You really can't be sure what will happen until you actually fit up the new scope and try it.
Some doubles are very sensitive to changes like that. Others are not so bad.

My only experience with doubles is with a couple of smaller bores (.30-06 and 9.3x74R...ignoring the .45-70 Baikal), so take the following for what it's worth.

I find my Shootaway-inspired shooting helmet essential for accurate field use of these guns. I have installed two screw-eyes on the helmet, one on each side, more or less at the temples. For the SxS gun, a hole is drilled and tapped through the barrel wall on each side of the muzzles (Vice-grips work well for this), about an inch from the end. Another screw eye is fixed and Loctited into each of these holes (careful dremel work inside the muzzle removes any interior projections) and a length of aircraft cable is attached from the left-muzzle screw-eye to the left-temple screw-eye, and another on the right side in similar fashion. The length of these cables is critical and must be adjusted by trial and error to allow the shooter to apply varying tension towards the left or right by slight motions of the head. My latest refinement includes a turnbuckle in the centre of each cable, allowing for minute changes to be made in each cable length to allow for such variables as alterations in hairstyle or shifts in the Earth's magnetic field. Someone with the steely-eyed determination and strength of character displayed by Shootaway could probably effect the necessary changes merely by flexing the jaw muscles on the appropriate side.

This system works! With practice, you can easily and instantly adapt for changes in scope weight, alterations in grip or stance, different bullet weights, different velocities, altitude, Coriolis effects...the possibilities are endless! A quick snap on the cable at the exact moment of firing even allows shooting around corners!

I am still working on the modifications required to use this system on my OU gun...so far, one cable from the top barrel going to the forehead of the helmet, and a second cable from the bottom barrel to a fixture on my belt buckle has shown some promising results...but of course, now it's starting to look silly...

An unexpected and happy side-effect is the fact that a short length of copper wire can be attached to each cable, and the loose end then held clamped between the teeth. As long as this copper wire is held in contact with fillings or dental work, I find that it greatly improves the quality of the signal that I periodically receive from the Home Planet. Shootaway, they are asking about you, since you apparently aren't reporting in regularly...have you gone rogue?

Ah ha! So that is how shootawhey makes it matter not how heavy a dumbbell he duct-tapes to the barrels of his DR.
No change in POI by proper regulating tension on the cables from shooting helmet to muzzles!

The 14-ounce scope did not make much difference compared to the 6.5-ounce scope,
though it did tighten things up a little.
6.5-ounce composite about 7" X 4".
14-ounce composite about 5" x 2".
3 shots from each barrel in each trial "pattern."
Less diverged with the heavier scope.
So I am going to try a 20-ounce scope with the same round ball load,
still with no changes in the regulation via the RBL muzzle contraption.

After this, I am going to pick the scope I like best and commence to regulatin'.

6.5-ounce scope and target:





14-ounce scope and target:


I may be at fault for the odd spread on this target, either my shooting or the round ball loads I am still perfecting.
But adding the extra 7.5 ounces of scope weight did bring the composite for the two barrels together a little.



20-ounce scope, target pending:



It seems that the little red-dot optics that weigh a fraction of an ounce, and little more with the mountings,
ought to have little effect on a DR that was regulated for open/express sights.

If I "scope" my Merkel 470 NE, it will be with something like the

which weighs 0.5 ounce dry!!!
http://www.trijicon.com/na_en/...?whats_newID=news_61


BTW, the 20-ounce scope is a Sightron SIII 1-7x24mm, illuminated dot reticle (red or green by pushbutton).
The extra-high, non-detachable Talley 30mm rings have their work cut out for them, containing this foot-long scope.
Scope plus rings: 24 ounces.

I'm sure a lot of these impact problems with changing scopes on doubles and with bolt guns stems more from ring and base fit more so than the scope itself..
Keeping in mind a double is designed for two fast shots at very short range, such changes seldom effect its use and mostly go unnoticed, not withstanding the fact that some mighty fancy shooting can be accomplished at up to even 200 yards if one knows his double gun, his limits, and can manage his loads.

On a QD set of rings and bases fit to a bolt gun, I have found surface grinding the action to be square with the world, and hand fitting the bases to full contact much the way that you inlet wood. Attaching the bases permently with silver solder or ? certainly is a plus) then keeping the levers in the same position (I like straight up) by positioning them in a certain way or even installing a stop to keep them returned the the same "tightness" makes for very close return to zero each time..

Just sticking them on a gun and screwing them in tight, may or may not be condusive to exact return to zero and I know a lot of folks that if they get 2 or 3 inches close to zero they are happy as a church mouse..

There are 3 inch groups and there are 3 inch groups..string up and down can effect trajectory, and side ways isn't what I like..A clover leave is condusive to good results IMO..

I would not find stringing an acceptable group pattern on any QD unit..The closer to exact return to zero the better and the group pattern is a important. I have a couple of rifles that return to exact zero everytime and sometimes with a load change, but changing loads means you need to check that load out by firing a group and takeing the scope off and on between each firing. I shoot for a 2 or 3 inch "clover leaf group" patterned group if I can get ...With the great European Claw Mounts I expect even better results on return.

By in large the best grouping with any rifle will be with a permenent ridged set up, but it shouldn't be by much if your QD are installed properly...

Just my 2 cents.

Maybe I just get rid of the scopes altogether and find that a sabot load that was crossing with scope sight now shoots parallel with open express sights ... if only the sabot loads were consistent enough to pattern well.
Nah, I'll stick with 20-bore round balls, 330-grainers at about 1600 fps.
Might have to re-regulate for that with iron sights afterall.

Or maybe regulate it for one of those half-ounce red-dot sights and use both open sights or red-dot battery power,
and have a 6.5-pounder instead of an 8-pounder.
Yeh! That is the ticket.
Lessee, I gotta back that screw-in wedge out and squeeze the barrels tighter together at the muzzle ...



JB Weld the whole shebang in place when I get it right for round ball & red dot.

Dre-Mel! Dre-Mel! Dre-Mel!