Does adding a scope to a previously regulated double rifle tend to cause the barrels to converge more quickly or further out? Is there a general rule?

I'd guess the extra weight would cause the recoil impulse to slow, making the bullets leave the barrel earlier on the arc, and therefore crossing closer. But maybe the weight being added in the back near the pivot point makes the front end move more and has the opposite affect. Anybody know?

quote:

Originally posted by skl1:
Does adding a scope to a previously regulated double rifle tend to cause the barrels to converge more quickly or further out? Is there a general rule?

I'd guess the extra weight would cause the recoil impulse to slow, making the bullets leave the barrel earlier on the arc, and therefore crossing closer. But maybe the weight being added in the back near the pivot point makes the front end move more and has the opposite affect. Anybody know?

In most cases, in a side by side double barrel, the addition of a scope on a double rifle will totally destroy the regulation of the
double rifle, especially in a side by side double.
........................ MacD37

Mac,

Where do the barrels group after the scope is added? Do they cross early or do they cross later?

My only two doubles shoot the same with QD scope on or off.

Very limited sample, but I like they way the guns shoot.

I remember reading that "Every double rifle is a law unto itself"

Indeed Ramrod. GENERALLY speaking the bigger the bore(recoil) the less susceptible they are to changes in the gun effecting regulation.

Add a scope. If you find the regulation changes too much and you don’t load your own ammo, a lighter weight red dot(yes…I know) might be an option.

Thanks, guys. How about the opposite? If the rifle was regulated for a scope, does it tend to shoot okay when the QD mount is pulled off and it's shot with the irons?

The answer to both is yes, no, and maybe.

To know for sure one has to shoot it with both sighting options.

quote:

Originally posted by skl1:
Does adding a scope to a previously regulated double rifle tend to cause the barrels to converge more quickly or further out? Is there a general rule?

I'd guess the extra weight would cause the recoil impulse to slow, making the bullets leave the barrel earlier on the arc, and therefore crossing closer. But maybe the weight being added in the back near the pivot point makes the front end move more and has the opposite affect. Anybody know?

How long is a piece of string?

The answer will be dependent on the individual rifle, the individual scope, and specific load. I had one hell of a time getting my Chapuis 9.3x74R to shoot both barrels to regulation with a 1.25x4 Trijicon mounted. It took 11 load combinations before finding a suitable load but once I had that one load, it's good out past 200 yards with either barrel.

Exactly; and 340 said it; each DR is a unique individual. Some will not care about the scope being put on it. Some will. I have seen it both ways, and when it doesn't' like it, it is not just shooting to a different place; the added weight will cause the bullets to cross because it slows down the recoil cycle. Flip.
Or not. Come on over and I can show you examples of ones that I put scopes on that did not make any difference at all. Most notably a Krieghoff 9.3, 450-400, and a Chapuis 9.3. Unlike TW, this later one with adjustable barrels, shot into one inch with or without the scope, and I never touched the adjustment feature. But I have had other ones that acted as his did.
So, the rule is, there are no rules.
This topic has been discussed here many times.
And others that the scope affected them so badly that I just use iron sights.
Now, I found that a small red dot sight does not affect them because they don't weigh anything.

As dpcd said, "So, the rule is, there are no rules." And that is correct when thinking within the box of double rifles and scopes. However...

think out of the box as I did. I wanted a scope on one double rifle, a .450-400 3" for the majority of my hunting. The scope has QD claw mounts and I thought I was stuck with accuracy with the scope mounted or not mounted--not both.

So, this is what I did. The rifle shot well with open sights--2" or better at 50 yards. When I mounted the scope accuracy went to hell. So, I sighted in the scope for the left barrel only which is the barrel I shoot first and have done so for 30+ years. What I have is an accurate scope sighted single shot rifle. I don't worry about the right barrel as at scope distances a quick second shot is not needed. When the scope is removed the rifle shoots as accurately as it always did.

This compromise worked for me, anyway,
Cal

My Rodda 450/400J shoots right at 2.5" @ 50 yds. with irons. I put a 1x4 Leupold in some Kimber double lever rings and it shot close to ten inchs! The good part is, like Cal, I shoot the left barrel first, and the groups it would shoot left bbl only, at 100 yds amazed me 1-1/2"! I ended up with the best of both worlds when I took Rusty's advice and removed the scope and put a Burris Fastfire 3 red dot on it using an aluminum weaver base, total weight might have been 4 ounces for both, and found that it did not affect the groups at all and gave my ageing eyes the assist needed to shoot accurately again. You never know till you try! Lee.

When I put a scope on my Merkel 470 there was no difference

The Heym and Chapuis rifles seem to come ready for scope installs. I often wondered if they made sure those rifles were regulated with both options but I somehow doubt that. Any owners of those care to weigh in on that assumption?

Much of this confusion is "regulation" and "sight in" is two different paths..regulation is the melting to two barrel to the same POI with wire and solder.

"sighting in" is moving the POI to zero with the sights. Ive seen many doubles that shot well with a detachable scope and irons, by most makers
although, if the vibes of the barrels are interfered with some change is possible but fixable with load work. but you can change things to hell and back by changing brands or loads of ammo.

the double rifle has nothing to do with bolt actions etc, it is said to be in a mystic world of its own, mostly horse hockey such as you must pull the front trigger first, don't shoot monolithic bullets, don't shoot 4831 and on an on witchcraft..

quote:

Originally posted by bghntr416:
The Heym and Chapuis rifles seem to come ready for scope installs. I often wondered if they made sure those rifles were regulated with both options but I somehow doubt that. Any owners of those care to weigh in on that assumption?

See here: http://forums.accuratereloadin...711069962#8711069962

If interested, you can search on AR for a more fully described story of getting my Chapius to regulate with the scope attached. In short, it was tedious but I got both barrels to shoot to regulation with the scope after 11 load combos.

The interesting thing is all the other 10 loads that were all over the place with the scope attached, shot perfectly about 1/2 of an inch apart at 50 yards with open sights. And the load that I finally developed for the scope, also shot great with the scope off.

That rifle digests just about any load combo you feed it with open sights, but will only shoot 1 specific load with the scope.

My Jeffery 303 with Talley dovetails cut in the rib shoots 2” or less at 100 meters with a 1-4x Leupold and hasn’t had any irregular results from it . I think all rifles are different.

My 405 double has similar Talley cuts in the rear rib and it makes for a very low sighting view! Same view as through the standing leaf !
Therefore, the same cheek placement for the shooter.

I just don't get it..Ive owned 3 doubles in my lifetime that came with scopes in QD claws and one with Talleys..In each case the scopes shot 3 to 7,5 inches away from the iron iron sights regulation..

The scopes in each case had elevation and windage adjustments so I made correct adjustments and the scopes shot to the iron sight zero?? plus my 3" high sight in..

Have we redesigned the system??

quote:

Originally posted by Atkinson:
I just don't get it..Ive owned 3 doubles in my lifetime that came with scopes in QD claws and one with Talleys..In each case the scopes shot 3 to 7,5 inches away from the iron iron sights regulation..

The scopes in each case had elevation and windage adjustments so I made correct adjustments and the scopes shot to the iron sight zero?? plus my 3" high sight in..

Have we redesigned the system??

I don't think you understand the problem Ray.

On my 9.3x74, for instance, shooting TSX bullets with the scope off, the L and R barrel printed about 1" apart at 25 yards and for the most part, level with L on the left and R on the right.

Put the scope on, same load, same distance and the R barrel would print 4" high and about 6" left with the L barrel printing at 5" low and 4" to the right ... crossing badly and spreading vertically.

Take the scope off, same load, same distance, and the two barrels are back to 1" apart and level with the R on the right and the L on the left.

That's not a scenario one can simply adjust the crosshairs on the scope for. This is a regulation problem, not a sighted in problem. At least not if you want to be able to shoot both barrels and not just have a scoped single shot using only one barrel sighted into the scope.

Anytime you change the weight of a DR you run the risk of affecting the regulation. Restocking will often do it, or even significantly shortening a stock. Adding scopes and mounts are going to effect muzzle flip. I do not know if it is predictable to any degree. There are a lot of factors. Maybe Aaron would know that.

Todd,
of course but does that not apply to any gun, bolt or auto or what ever, some guns are better and some worse..

The thing one has to allow for with a double is it will never shoot better than its WORSE BARREL..That has to be determined before anything else and on the benchrest without going into long drawn out conversations..

Ive seen more than a few Butch Searcy rifles that shoot both irons and QD scopes to the same POI? He does than during the regulation process if Im not mistakn

In addition to changing the weight of the rifle, your face position (relative to irons or scope) can have an impact how the rifle recoils, and - in turn - how it shoots.

For example, I've been doing load work for a 450-400 with CEB Raptors, and I've got the new load shooting under 2" at 100 yds with open sights... but the barrels are crossing.

However, same load, same rifle with the red dot (which sits higher on the rifle and raises my face up off of the stock comb), UN-crosses the group at 100 (still under 2".)

Does it matter? Not at all... but it does go to show how sensitive the recoil is to regulation.

quote:

Originally posted by new_guy:
In addition to changing the weight of the rifle, your face position (relative to irons or scope) can have an impact how the rifle recoils, and - in turn - how it shoots.

For example, I've been doing load work for a 450-400 with CEB Raptors, and I've got the new load shooting under 2" at 100 yds with open sights... but the barrels are crossing.

However, same load, same rifle with the red dot (which sits higher on the rifle and raises my face up off of the stock comb), UN-crosses the group at 100 (still under 2".)

Does it matter? Not at all... but it does go to show how sensitive the recoil is to regulation.

Chris, that rifle of mine I've been describing is the one I had when you and I were in Idaho a few years back. We shot on their buffalo charge simulator if you'll remember and I filmed some of your clients taking your course.

Todd,
I got 7 second places at that shoot and nary a trophy! that was sometime back, Jim Brockman and I attended it, may have been the first or second dunno? I misunderstood and had to shoot with irons in the scope shoots, but had a great day..

New Guy, when your barrels first cross, back off one grain to zero has been my experience in most cases over the years rarely 2 grs as I recall....With a double I usually stop when Im sighted in and have a good group with a game load..I don't tinker with them like I do with a repeater..I try not to let the POI cross as the follow up shots are spreading as the range lengthens..

One should start by shooting groups with one barrel then the other to determine which barrel is the most accurate and most sighted in to zero at whatever range your working on..All you can expect is for any double to shoot as good as he worst barrel, so that is your goal with irons and scope hopefully..

quote:

Originally posted by Atkinson:
New Guy, when your barrels first cross, back off one grain

Ray - read my original post again... you're not tracking.

Todd - Have you shot the rifle at 100?

Not that it would necessarily get any better, but I wouldn't base much off of results at 25-yards.

quote:

Originally posted by skl1:
Mac,

Where do the barrels group after the scope is added? Do they cross early or do they cross later?

In most cases, the rifle will shoot in just about any direction from the regular group without the scope. Some can be re-regulated to shoot properly with the scope, but that is expensive. The weight of the scope and bases along with the height above the barrels is a factor.
Some times one is lucky and doesn't have a problem, especially if the addition is very light. One thing to seems to cause less problem is the addition of one of the little battery operated pistol sights the weigh only about six ounces and look like a little TV mounted just in front of the joint of the barrels, and the breach.
In my opinion, for what that is worth, the only way I would put one of those on my doubles is because I'm loosing my sight because of age and macular degeneration. 99 percent of the sight is gone in the right eye, so that I am going to have to learn to shoot left handed or quite shooting my double rifles all together.
I have a fairly large collection of side by side double rifles, and over/under combination rifle/shotguns,and side by side cape-guns.

quote:

Originally posted by new_guy:
Todd - Have you shot the rifle at 100?

Not that it would necessarily get any better, but I wouldn't base much off of results at 25-yards.

For sure. It was crossing off paper at 50 yards. But I worked and worked at the reloading bench and got it sorted out.

I've taken quite a bit of game with it now over 200 yards, from either barrel.

I asked one of our regulators today, and he said that a rifle regulated with a scope will tend to cross when the scope is removed (this is my personal experience also.)

We also calculated that he's regulated nearly 700 doubles (only counting those that were 375 or larger.) So he's a pretty reliable source.

Ive had 3 Searcys a 470, and two 450-400-3" and a couple of English guns..they all were very acccurate, and the 470 Scearcy was the rifle that butch won the nationals with..He traded me out of it after that with a super nice 450-400, both of the 450-400s shot close together and enough to satisfy me, it took a lot of this and than at the loading bench but one shot zero at 50 with irons and the other shot an inch high with the scope, groups were One inch with one barrel and 1.6 with the other and with a scope it shot 3.5 high..

The other shot high also with the scope with a 5 inch group with both irons and scope, I think there is a pattern here in that they shot high or low and within the pattern of the gun laterally?? I got by with this gun but because of the accuracy factor, I used it as it came because it was a 5" gun to start with magnified the problem, but I got by using it out of the box both irons and scope...

I just have a hard time with all the real or imagined problems with doubles, it comes across as black magic, witchcraft, Ive kept a list of such problems over the years..

IMO very few double rifle gunsmiths are good at regulation, Butch is the best, David Yale was good, and the one just outside of Vegas some time ago and last but not least is Rick Stickley, Im just talking about regulation only, not capabilities gunsmithing or personality's..

I recall being brutally scolded on AR over taking exception to the claim that 4831 created a double ignition and wrecked double rifles and that Barnes and GS custom Monolithics split the bores on doubles..All of which was baloney trying to impress all with their knowledge or lack thereof. The double is just another firearm that's a tad more complicated, once understood its the cream of the crop for DG in a tight situation, overall its not very practical IMO..

OK, Ive had my fun, bottom line? Hunting game in Africa with a scoped double or simply scoping a double is akin to incest and child molestation, its just not done old chap!