Maybe this 1878 scene involved use by Selous of a pair of 4-bore single-barrel, percussion muzzleloaders:



I am guessing this illustration of an 1880 scene is near the beginning of the career of Selous's .461 Gibbs No. 1 Farquharson:


Selous (front seated) leader of H Troops of Bulawayo Field Force, Matabeleland, 1890s.
This might have been about 1893 near the end of Selous's use of the Gibbs rifle:



Selous gave up on the .461 Gibbs No. 1 Farquharson when it got lost in shipping prior to an 1895 safari.
It might have been a replacement .461 Gibbs No. 2 by then.
Selous did lose at least one of his .461 Gibbs No. 1 rifles to murderous thieves in Africa, early on in his career.
Records of the Gibbs Farquharson rifle were mostly lost in the WWII Nazi bombings of England.
His last Gibbs had served him well from pre-1880 to about 1895 when "TSA-of-the-day" baggage handlers lost/stole it!
Rather than buy another one, not being a wealthy man, he borrowed a .303 Lee-Metford rifle, smokeless at last!
He had written of the .303's usefulness since 1893, but 1895 was his first trip to Africa with it. He never went back to Gibbs or BP.

In 1899 he ordered his first of three H&H falling block rifles. That first one was chambered for the ".256 Dutch" according to Wal Winfer.
See it shoot in the video here:

https://www.youtube.com/watch?v=-Uo5Ziaxhow



Selous's ".256 Dutch" aka 6.5x53R Dutch Mannlicher of 1893 aka ".256 Mannlicher with rim":
I cannot find a chamber reamer drawing for it.
It might have been very similar to the CIP 6.5x54 Mannlicher-Schonauer,
which has a long, leade-only throat of 0.8327" length and leade semi-angle of 0*34'08".
That is nicely coned up at the breech, circa 1903.

That 6.5x54 MS is the one Karamojo Bell used on elephant.

.264-cal/160-grainer at 2300 fps, sectional density 0.328
.458/480-grainer at 2300 fps, sectional density = 0.327
Both are absolutely gentlemanly.

.458/500-grainer at 2300 fps, sectional density = 0.341
Not so gentlemanly, but easily done with a .458 WIN LongCOL, more easily (lower pressure) than with a .458 Lott.

Rip ...

Ha!
There is a Canadian collector who is said to own a "Selous Personal Rifle."
It is a side-safety Farquharson-Metford by George C. Gibbs chambered in .461 Gibbs No. 2,
Rifle serial number: 16876
Action no.: 815
Frame no.: 302
Metford barrel no.: 1777

It has Selous side plates and an oval escutcheon engraved "F.C.S." in the style of other original Gibbs rifles.

So is this the last Gibbs rifle Selous owned? Lost by the baggage handlers?

His early writings bragged on the .461 Gibbs No. 1, the cartridge case differing from the No. 2 only by having a neck not quite so long.
.461 Gibbs No. 1: 2.35" case length, bottle-necked.
.461 Gibbs No. 2: 2.76" case length, bottle-necked.
All neck-length difference only: 0.41"

Selous's "Lion Load": .461/360-grain hollow-point, lead bullet with 90 grains of BP

Selous's "Elephant Load": .461/540-grain hard-cast-lead bullet with 75 grains of BP.

The .461 Gibbs No. 2 upped the ante slightly:

360-grainer with 100 grains BP, an "Express Load" with MV about 1700 fps.
Probably very close to what Selous used for lion.
10 grains less BP in the shorter case would be about same pressure and velocity.

570-grainer with 90 grains of BP gave about 1350 fps.
Likewise, probably very close to same velocity as the 540-grainer in the shorter cartridge.

Why have such a long neck then?
Another reason for the very long neck of the bottle-necked .461 Gibbs No. 2?
Wal Winfer:
"The longer case neck also enabled the shorter 480 grain military bullet to be held up near the rifling.
This was important to the military target shooter when a smaller powder charge was loaded,
for he was left with enough neck length to position his wads at the base of the bullet.
The writer has read that Gibbs claimed the long neck as an improvement, for without it,
the wads would fall into the body of the necked case.
Gibbs inference was that this was the main reason for the new design --
others suggest that the longer necked case was specifically to enable more powder to be used
behind the 360 grain bullet, perhaps both are correct."

For Nostalgia purpose, with the .458 WIN:

I will substitute the .458/350-grain TSX at over 1000 fps faster and call it the "Selous Lion Load Warp Three."
The .458/300-grain TSX at 2900 fps is "Warp Four."
My backorder of those has shipped from MidwayUSA.

480-grainers of hard-cast lead or DGX/DGS: Tropical duplication of original .450 NE ballistics,
or slowpoke military target loads.

540-grain hard-cast lead: 1400 fps with AA-5744
or 2150 fps with AA-2460.

Modern, non-sentimental loads:
400-gr GSC HV at 2500 fps
450-gr North Forks and Barnes TSX at 2400 fps.
500-grain Barnes TSX at 2300 fps.

Rip ...

I got into reloading and fucking about with guns by the time I was 15 and I am now 71, so have done a bit of animal killing. I have had most stuff from 218 Bee to the 460 Wby and several of each. Three 460s for example.

If I was to look back I think one of my standouts for performance, fun and just plain satisfaction were 458 M70s with 400 grain Speer and either 70 grains of 4064 or 3031 which did 2000 nd 2100 respectively.

It is hard to explain but with 2000-2100 f/s and doing a lot of shooting you soon on the first day "get onto them". On big kangaroos, pigs and goats I had much same "shots to hits" ratio with the 458/400 Speer as I did with the 270.

For whatever reason, for me velocities up to 2400 or so the gun seems to have some feel. You just seem to get hold over correct. At higher velocities things, at least for me change. I have used the 308 with 130 Speer Hollow points at 2950 and the 270 with 110 Sierras at 3300 and over the course of a week or 10 days the 270 was the clear winner. However, not so when compared to the 458/400 Speer.

I am sure there are a lot of shooters out there who would not even think of owning a 458 but if they did they might really like it. Those 400 grainers at 2000-2100 with what re low pressure loads are very good to shoot and very mild muzzle blast and easy on scopes. I suspect the lower pressure loads don't give the scope the big belt in the first few inches of bullet travel. Similar to a 460 loaded back to 2300 plus is easier on scopes than the 450 Ackley with maximum loads to get the 2300 plus.

Personally, if I was getting a 458 again the standard length would do me and for a simple reason. I would much rather a loaded back 460 to equal maximum loads from 458 Lott or 450 Ackley. The 460 loaded back to 2300 or so with 500 grainers has that same feel as a big V8 manual, just does it so easy.

Mike,

Thanks for supporting THE MISSION.
Your .458/400-grain 'RooBuster load is quite tropical.

I would prefer a .458/400-grainer at 2400 fps in a SAAMI .458 WIN, reduced from the usual 2550 fps in the .458 WIN LongCOL ... but I repeat myself.



Rip ...

Starting load for a .458 WIN LongCOL by Saint Finn:

Here is an illustration by sambarman338 for a discussion on scoping a rifle that kicks a little, like a .458 WIN:

Sorry to interrupt the Selous mood, RIP, but I've been asked on occasion to explain the problem I see with the erector-tube springs in modern scopes, and, since they are most likely to give problems with the 458 Winchester Magnum and bigger calibres, I can think of no better place to air the matter than here.

So, that is a not-to-scale 'drawing' of an erector tube cross section, in the centralised position found when a scope is mounted correctly. The rectangles at 12 and 3 o'clock represent the turret screws, while the line drawing at 7.30 is a basic flat spring attached to the erector tube and bearing longitudinally against the outer tube.

The image has gone a fraction out of round and the proportions are a bit Weaver patent (US 2,949,816) but, considering the use now of 30mm tubes to give more reticle movement, not utterly ridiculous.

Though I finally managed to get that LibreOffice file into Imgur, doing it again for the subsequent pics is not working. So, until I manage to send some more to RIP please consider the following as a little homework.

Knowing the four-inch-long erector tube weighing two or more ounces is hinged by a gimbal at the ocular end, what will be the effect on the spring fastened to the inner tube: 1) if wound to the maximum elevation (possibly to the bottom), whereby the spring might be completely compressed; and 2) what will be the effect on the spring under heavy recoil, oblivious of the screws' positions?

Shazam!
If that is just a flat spring
with one end of it attached to the erector tube,
and the other end of the spring pressing outward against the main scope tube,
it depends on which direction the outward end of the spring is pointing.
If that outward end is pointing toward the objective end of the scope, then recoil forces would tend to flatten it away from the outer tube wall and let loose of the erector tube, so reticle would scurry about with each shot.
If the outward end of the spring is pointing back toward the ocular end of the scope, then recoil would tend to increase the tension in the spring, better holding the reticle in place.
How am I doing?

And how about this: The limited range of adjustment in the Nikon Prostaff P3 Shotgun 3-9x40 is only 55 MOA of windage and 55 MOA of elevation.
That is small compared to many scopes.
Does that make it better at holding zero in recoil?

And here is that picture of Finn Aagaard's old "Best Quality" .425 WR re-barreled to .458 WIN, a great way to improve a .425 WR:



Rip ...

The spring can go either way, RIP. Weaver's patent showed in under the erector tube, which may cushion the tube from whacking against the outer scope, but that is less damaging than crashing into the screws coming back, anyway.

Swaro's at least appears to extend out from the erector tube, which as you say, should twist it less than the other way.

Yes, less is more in zero adjustment. Someone criticised the old B. Nickel scopes for only having about 20-MoA movement but, in reticle-movement, even that is more than you should ever want.

Pictures of a Weaver versus a Swaro spring placement?

Tropical Loads with AA-2460 in .458 WIN with 24" barrel:
400-grainer: 80.0 grains AA-2460 >>> 2452 fps <<< 52,746 psi
450-grainer: 77.0
500-grainer: 74.0 gr AA-2460 >>> 2192 fps <<< 52,864 psi
550-grainer: 71.0
600-grainer: 68.0

Well, I have the Weaver patent drawing somewhere, but the easiest way to get it might be just to google the number US2,949,816 ...

They show PDFs of both the patent and drawings and it goes back to 1956 so is hopefully beyond copyright.

Swaro used to show both kinds of spring on their website but I can't find the flat one anymore. There is a picture in my book, of course. The Z6 springs can be seen here:

https://huntforever.org/2018/0...-inside-that-counts/

Paul,

quote:

US2,949,816

I now have the Weaver as a pdf for study.
Know of any Swarovski drawings/photos?
I can't remember if there is one in your book, might have to go look ... Yes, now see your comments about that.

Rip ...

I get right into this stuff in explanation of the second and third drawing, so, as they say in the classics: Release the Cracken!

The older Burris Scopes were advertised to have "dual springs" to resist the effects of recoil. I have several of them. I also have one Posi Loc 1.5x5 that essential locks the Erector tube in place once zeroed. I have it on my 458WM. I had a Konus 2.5 shotgun scope on it for the past 5 years and shot lot's of 480 grain cast loads. Great little scope. Etched Reticle.

With scopes, I reckon if you have very accurate rifles AND they are frequently tested on paper off a bench rest and fire lots of shots then anything above 375 and you are on your own.

Here is a re-run of the Burris ad from 1999 when they sure looked better than either Leupold or Nikon.
But the increased mass of the internals would increase inertial tendencies to wander.
Maybe they better have two flat springs instead of one, and Posi-Lock.

quote:

Originally posted by Mike McGuire:
With scopes, I reckon if you have very accurate rifles AND they are frequently tested on paper off a bench rest and fire lots of shots then anything above 375 and you are on your own.

Maybe that 2.5x20mm Leupold Ultralight survives best because it is so light, 6.5 ounces.
I am hoping the Leupold 6x36mm Compact is tough too, only 8.5 ounces.
A standard Leupold 6X stood up to Mitch Carter's .577 Tyrannosaur. It was about 10.3 ounces IIRC.

Rip ...

The Weaver erector tube spring is ingenious and might be the strongest system of all.
It is like a long piece of spring-tempered, heavy-gauge wire folded to make a cradle under the front of the erector tube,
and then two legs run along the underside of the erector tube, bowing out as with flat springs, about 90-degrees apart, so they respectively oppose the elevation and windage adjustments.
Then at the rear/ocular end, each leg of the spring gets poked into a hole in the side of the erector tube, to anchor the spring solidly to the erector tube.
Apparently a heavy yoke runs along the top of the erector tube, and has an articulated attachment to the outer scope tube at the rear/ocular end.

Swarovski from sambarman338's book:

Pictures from the Swarovski link above:





The inside of a Swarovski riflescope is a rugged balance of minute parts, all working in concert to help you get your shot where you want it to go and retain the zero so you can repeat that shot again and again. In order to do that,
Swarovski developed unique retention spring systems that combine precision and durability housed in a 30mm or 1-inch tube. After years of research and development, Swarovski realized that the internal parts of its scopes need to be tailored for the optics’ primary purpose. The approach has culminated in the five series of riflescopes currently available in Swarovski’s catalog.

The Z5 5-25×52 from Swarovski one of the Professional Hunter series.
Spring retention systems are quite possibly the most critical element in the inner workings of a scope. They serve to hold the erector tube tight inside the main tube during the firing sequence and to hold the erector tube precisely while making click adjustments for windage and elevation while sighting in.

The Z3 Series was Swarovski’s entre into the American market. Swarovski changed the tube size to a 1-inch tube versus the European 30mm standard to accommodate the availability of rings at that time. The Z3 scopes use a traditional U-shaped leaf spring retention system spaced exactly diagonally between the windage and elevation turrets. This keeps a constant pressure against the turrets to make the adjustment process as accurate as possible. The Z3 Series adjustments are in 1/4 MOA clicks.

The Z5, Z6(i) and Z8i Series – also known as the Professional Hunter Series — feature a patented four-point coil spring system that is a marked improvement over the traditional leaf spring system. Mounted on the ocular end of the erector tube, the coil springs are stiffened to enable more precise adjustments. In addition, the coil springs provide shock absorption for the scope under recoil. When the rifle is fired, the springs compress and absorb the shock that would affect the other internal components. This series also provides the best optical quality at the lightest weight.

The long range X5(i) features the most sophisticated spring retention systems of any of the Swarovski scope series. Designed primarily as a long range competition target scope, the X5(i) is also experiencing popularity with mountain hunters who tend to encounter 500-yard-plus shots on a regular basis.


Swarovski’s X5i 3.5-18x50mm Long-range scope
The unique design of the X5(i) utilizes a spring retention system in conjunction with a retention lever to keep equal pressure against the erector tube. At the ocular end of the erector tube, a highly polished ball and socket section minimizes friction. According to Swarovski’s Rob Lancellotti, “The lever and positioning spring is designed for repeatability of precision long range shooting normally associated with match or tactical competition. The system keeps the internal works from wearing out or becoming mushy with continued use.”

While the technology is starting to crossover from the competition arena to hunting applications, there are still the ethical and moral considerations as to what constitutes a clean shot for each hunter. “For most hunters, 400 yards is a long shot,” Lancellotti explains, “and for sheep hunters especially, that range can extend due to the nature of the habitat and the challenges of mountain hunting. We at Swarovski are firm believers in getting as close as possible to achieve a clean and humane shot. Our scopes are not a substitute for ethical hunting practices.”

Readjusting the coil spring system.
The X5(i) is engineered for long range and long wear. Its oversized turrets contain stainless steel components designed for repetitive dialing, and the main tube is 30 percent thicker for more durability; but bulking up the scope for longer life creates a trade off in the form of more weight. That’s something to consider if your long range hunt will have you trudging up and down mountains where an extra pound can be torture by the end of the day.

Through years of research and development, Swarovski has expanded its hunting optics line to cover virtually all hunting and shooting sports needs and is continuing to innovate and redefine the standard for sports optics worldwide.–Randy Gibbs

The recoil diagram from sambarman338's book,
this time with some context around it:

Thanks RIP, Mike and Fury.

The single springs* shown in the Burris graphic look every bit as weedy as the ones I drew - drawings showing what might happen to such things should be forthcoming* (now in place, below).

Yes, Mike, extra springs can be used and that makes sense to me. I'll keep my conclusions until after the other drawings come and are discussed.

Sorry my drawings of erector tubes turned out a bit crappy. I expected the stuck-on text at least to be seamless but the printer's scanner found all the shadows. The 'curved hinge point' is usually a gimbal these days but lacking any solid barriers to the tube moving back and forward, even gimbals can give up eventually.

*PS written here later on 21/08, after I had posted my graphics and come back to digest these ones, to keep the comments near the posts concerned. One thing I notice, looking at the springs in the Burris ad is that they are all pretty square looking, unlike the Nightforce or Swarovski ones, thus more likely to hang up on the outside tube ...

quote:

Originally posted by RIP:

quote:

Originally posted by Mike McGuire:
With scopes, I reckon if you have very accurate rifles AND they are frequently tested on paper off a bench rest and fire lots of shots then anything above 375 and you are on your own.

Maybe that 2.5x20mm Leupold Ultralight survives best because it is so light, 6.5 ounces.
I am hoping the Leupold 6x36mm Compact is tough too, only 8.5 ounces.
A standard Leupold 6X stood up to Mitch Carter's .577 Tyrannosaur. It was about 10.3 ounces IIRC.

Rip ...

My guess is a light small scope (I am excluding mount considerations and heavy scope) with scaling down then if all else is equal less chance of lenses becoming loose in their mounting.

You can put the springs from a Mack semi in the scope but you still have to deal with the lens mounting or whatever you would call it.

One thing I have proven and simple physics supports it and that is a bigger case capacity loaded back to equally maximum ballistics from a small case will be easier on a scope and mounts. If a 460 is load back to 2300/500s with 4350, then if you could chronograph the load when the bullet was 2 or 3 inches up the barrel the 450 Ackley would be going faster even though both are 2300 at muzzle.

Actually there are plenty of scopes in use that do have a problem but the rifle is not spot on for accuracy and you get compensating errors. Put the same scope on super accurate 6mm/06 and you might get 3 in a hole and 3 flyers but the other blokes rifle just shows a larger open group.

Actually this thread could become an AR reference thread. Apart form the 458 Bs 458 Lott stuff, we have cast bullets, paper patch, powder coating bullets, scopes etc. and fucking etc.

If someone wants to know something the answer will be probably be on this thread

Paul,

May be my crappy scanner.
I convert a PDF file to JPEG by printing the PDF to paper and then scanning the paper print to JPEG.
Here are your other two drawings.
Have at 'em Perfessor:

quote:

Originally posted by Mike McGuire:
One thing I have proven and simple physics supports it and that is a bigger case capacity loaded back to equally maximum ballistics from a small case will be easier on a scope and mounts. If a 460 is load back to 2300/500s with 4350, then if you could chronograph the load when the bullet was 2 or 3 inches up the barrel the 450 Ackley would be going faster even though both are 2300 at muzzle.

About like a 450-grain TSX at 2450 fps in the .458 WIN LongCOL with AA-2230 and 25" barrel,
versus same bullet at same velocity in the .450 Dakota with XYZ-1234 powder and 25" barrel?
I will have to do the recoil calculations and get back to you.
Then it will be a matter of sorting the fly specks out of the pepper, regarding scope survival,
if the .458 WIN load actually has a lower recoil energy and slower recoil velocity in the same weight rifle.

Rip ...

quote:

Originally posted by RIP:

quote:

Originally posted by Mike McGuire:
One thing I have proven and simple physics supports it and that is a bigger case capacity loaded back to equally maximum ballistics from a small case will be easier on a scope and mounts. If a 460 is load back to 2300/500s with 4350, then if you could chronograph the load when the bullet was 2 or 3 inches up the barrel the 450 Ackley would be going faster even though both are 2300 at muzzle.

About like a 450-grain TSX at 2450 fps in the .458 WIN LongCOL with AA-2230 and 25" barrel,
versus same bullet at same velocity in the .450 Dakota with XYZ-1234 powder and 25" barrel?
I will have to do the recoil calculations and get back to you.
Then it will be a matter of sorting the fly specks out of the pepper, regarding scope survival,
if the .458 WIN load actually has a lower recoil energy and slower recoil velocity in the same weight rifle.

Rip ...

Ron,

The velocity the rifle gets to in recoil is not the main issue. The scope gets two big belts. One is initial bullet acceleration and then when the bullet clears the muzzle and the gases accelerate up to maybe 6000 f/s plus.

quote:

Originally posted by RIP:
Paul,

May be my crappy scanner.
I convert a PDF file to JPEG by printing the PDF to paper and then scanning the paper print to JPEG.
Here are your other two drawings.
Have at 'em Perfessor:

Thanks very much RIP, you've done well with my clumsy graphics.

So, Fig. 1 represents the position of the front of an erector tube when a scope has been well mounted; Fig. 2 an erector tube when the elevation has been wound to one extreme, perhaps for a long shot (depending on scope geometry) or just badly mounted - it also represents the tube and spring situation after the first impulse of heavy recoil; Fig. 3 perhaps represents a more-likely position when elevation is taken to the edge for an extreme-range shot.

As RIP brought out, the flat spring may extend from the front, back under the tube or out into the vacant scope ahead. In either position, unless superbly made to slip across the outer tube, it is likely hang up at some point and be twisted as in Fig. 2, as well as compressed when the rifle is fired. Hanging up when being adjusted is also a problem and is the likely reason some scopes fail to move consistently when the knobs are turned.

Fig. 3 shows the position of the front of erector tube if the elevation screw is turned out, which may be the most likely position when the shot is raised for extreme distances. Though the spring will not be under constant compression and lateral twisting as in Fig. 2, the shock to it upon discharge may be even more harmful, as it will be thrust into something like that Fig.-2 position and released every time.

To try to avoid the twisting aspect of this trauma at least, makers employ various means of helping the loose end of the spring to skate across the inner surface of the scope's outer tube. Nightforce tumbles its springs for days on end to remove rough edges, Leupold has a double-bias spring made of copper-beryllium alloy (which I suspect is a greasy metal that helps it slide), while Swarovski has two takes on it. On the cheaper Z3 models the spring has a hemispherical knob on the end to reduce friction; the Z5 and Z6 models replace the flat spring with four helical springs behind the hingeing provision at the ocular end. Swaro fudges the purpose of these springs, though, saying they are meant to cushion against the tremendous recoil-inertia forces that are unleashed by heavy recoil. This they do, of course, but less in the longitudinal way the coils' alignment suggests than their cutting the Gordian knot of the flat-spring problem.

Fig. 2 and Fig. 3 also show another problem extreme adjustments may bring to a scope - pushing the erector tube past the sweet spot on the windage screw. This may cause the zero to move laterally as well as up. When extreme adjustment is achieved by turning the elevation screw out, recoil may damage the erector tube by scraping it past the windage screw and slamming it against what remains exposed of the elevation screw on the second recoil pulse, as the rifle is arrested by the shooter's shoulder.

Paul,
Is not the front of the erector tube down for a long range scope adjustment, thus causing shooter to raise the bore of the rifle up to be on target?
Are you checking to see if we are awake?
Otherwise you are making a lot of good sense and your pictures are indeed worth a thousand words each.
And all I can think of is any scope is doomed on a hard kicker.
Best to have a backup scope or two or three,
and brush up on the iron sights, that are questionably more rugged.
From the Brownells catalog:





Rip ...

quote:

Originally posted by Mike McGuire:

quote:

Originally posted by RIP:

quote:

Originally posted by Mike McGuire:
One thing I have proven and simple physics supports it and that is a bigger case capacity loaded back to equally maximum ballistics from a small case will be easier on a scope and mounts. If a 460 is load back to 2300/500s with 4350, then if you could chronograph the load when the bullet was 2 or 3 inches up the barrel the 450 Ackley would be going faster even though both are 2300 at muzzle.

About like a 450-grain TSX at 2450 fps in the .458 WIN LongCOL with AA-2230 and 25" barrel,
versus same bullet at same velocity in the .450 Dakota with XYZ-1234 powder and 25" barrel?
I will have to do the recoil calculations and get back to you.
Then it will be a matter of sorting the fly specks out of the pepper, regarding scope survival,
if the .458 WIN load actually has a lower recoil energy and slower recoil velocity in the same weight rifle.

Rip ...

Ron,

The velocity the rifle gets to in recoil is not the main issue. The scope gets two big belts. One is initial bullet acceleration and then when the bullet clears the muzzle and the gases accelerate up to maybe 6000 f/s plus.

Well there is the fly poop in the pepper!
Faster powder giving a faster initial acceleration, harder on scopes.
OK.

10# .450 Dakota with 25" barrel, 102.0 grains of H4350, 450-grain bullet, MV 2450 fps
Recoil KE = 79.4 ft-lbs
Recoil vel. = 22.6 fps

10# .458 WIN LongCOL with 25" barrel, 82.0 grains of AA-2230, 450-grain bullet, MV 2450 fps
Recoil KE = 70.2 ft-lbs ... 12% less
Recoil vel. = 21.3 fps ... 6% less

Anyway, less likely to damage scope on forehead of shooter, therefore possibly overall easier on scopes.



Rip ...

quote:

Originally posted by RIP:
Paul,
Is not the front of the erector tube down for a long range scope adjustment, thus causing shooter to raise the bore of the rifle up to be on target?
Are you checking to see if we are awake?
Otherwise you are making a lot of good sense and your pictures are indeed worth a thousand words each.
And all I can think of is any scope is doomed on a hard kicker.
Best to have a backup scope or two or three,
and brush up on the iron sights, that are questionably more rugged.
From the Brownells catalog:





Rip ...

A good question, RIP, but my experience with Pecars taught me that no longer do I know or think I know.

With old reticle-movement scopes, if you raise your aim for long distance, the post will move lower in your field of view - but then the Nickel and old Pecar reticle assemblies I've seen were upside-down in the scope. That would reverse the extreme range movement, meaning the reticle would move up. The picture I've got of a Pecar Champion reticle, however, shows it right way up. The Champion has a constantly centred reticle but, bar for a restrictive field stop in the same focal plane, is otherwise analogous with reticle-movement types, having a fixed erector set.

The only conventional image-movement scopes I've pulled to bits have just had cross-hairs and duplex reticles with no discernible top or bottom, so who knows?

sambarman338

I had a tool made up to tighten the lens assembly on the objective of Pecars (reticle movers). Of course that did not allow me to control where the lens is cemented/glued in to it surround. Since that was the only lens in front of the reticle it is the only lens that matters. Lenses behind the reticle if moved will move both reticle and image together so no change in point of impact.

quote:

Originally posted by Mike McGuire:
sambarman338

I had a tool made up to tighten the lens assembly on the objective of Pecars (reticle movers). Of course that did not allow me to control where the lens is cemented/glued in to it surround. Since that was the only lens in front of the reticle it is the only lens that matters. Lenses behind the reticle if moved will move both reticle and image together so no change in point of impact.

Mike,
Is that like a spanner to tighten the ring holding the rubber gasket in front of the objective lens?

My latest mischief on the Gunsmithing forum:



Rip ...

quote:

Originally posted by RIP:

quote:

Originally posted by Mike McGuire:
sambarman338

I had a tool made up to tighten the lens assembly on the objective of Pecars (reticle movers). Of course that did not allow me to control where the lens is cemented/glued in to it surround. Since that was the only lens in front of the reticle it is the only lens that matters. Lenses behind the reticle if moved will move both reticle and image together so no change in point of impact.

Mike,
Is that like a spanner to tighten the ring holding the rubber gasket in front of the objective lens?

Ron,

From memory there were two slots on the objective lens. A gunsmith widened the slots and made a tool that fitted into the slot so you could say it was like a spanner.

In those days in Australia the Pecar (and also the Kahles) were the scope for the good gear. We could also get Pecars refinished etc. as in bluing as remember they were a steel scope. Back in those days if you have a few bob to spend the Sako in 270 and a 6X Pecar was the go. On the ^x the flat top picket reticule covered about 1 inch at 100 yards. We used to put the top of the post right on the bottom of a 1 inch square and so the bullets were cutting the top of the square. For long range hold over some blokes had the scopes mounted upside down. You could adjust them as they had knobs to adjust.

It used to be my understanding that those slots in the front of the objective were to adjust parallax (cf. the knurled objective rings on some big scopes).

I had a parallax problem on one of my Pecars but did not try to fix it myself. I sent it to an optical firm in Marrickville, NSW, but they were unable to improve it, either. It could be I was lining the scope up on things closer than the adjusted distance (100-metres?), of course. I fixed the practical aspect by upholstering a leather cheek piece to get my face up off the military comb to the height of the Weaver mounts, which may have been higher than ideal, for some reason of the gunsmith's.

I have tried to turn that objective assembly on other scopes without luck, though, so it may be the slots were meant for assembly only and, as Mike suggested, the lens(es) were cemented in place at that time.

quote:

Originally posted by sambarman338:
It used to be my understanding that those slots in the front of the objective were to adjust parallax (cf. the knurled objective rings on some big scopes).

Yes, that is part of the deal as when the front is loosened you can screw the lens in or out. Of course it also lock the objective in place.

As a side note, on some cheaper scopes like Tasco the optical centre is well away from the mechanical centre. This can come in handy when the scope/mounts alignment with the bore is a fuck up. The front lens assembly is loosened and the lens housing rotated a bit and this can change the point of impact a lot and with some fiddling overcome the scope/mount alignment problem.

PS,

You are not actually by loosening dealing with lens cement/glue. That is for housing the lens in the metal. That is what I mentioned to Ron earlier about small scopes and the objective lens will be stronger in the cementing/gluing.

Of course with image moving it is not just the objective that is in front of the reticle. Movement of any lens in front of the reticle changes point if impact. Lenses behind the reticle if moved will move the reticle and aiming point together so no change in point of impact.

You can demonstrate that very easily by loosening the eye piece and look through the scope while you wobble it.

I think that turning the scope around to get the reticle in the centre was just a way to make sure the scope was mounted right after someone had fiddled with the knobs.

Getting the reticle centred is a wise place to start, to save optical problems and running out of clicks, but the usual method I hear of now is to count the clicks from end to end then wind back half way.

quote:

Originally posted by sambarman338:
I think that turning the scope around to get the reticle in the centre was just a way to make sure the scope was mounted right after someone had fiddled with the knobs.

Getting the reticle centred is a wise place to start, to save optical problems and running out of clicks, but the usual method I hear of now is to count the clicks from end to end then wind back half way.

No, I am talking about where the scope/mount alignment to the bore is fucked so aa centred scope will be way off.

And I am not talking about rotating the scope but rotating the front lens and in particular cheaper scope where the optical centre does not match the actual physical centre of the lens.