91-30 sniper will not group

My buddy and I pocked up a pair of rebuilt 91-30 snipers, both from the same guy, at Tulsa gun show last year. both looked teal good with all matching (typical forced) numbers and matching-to-each-other scopes and mounts. We each grabbed one at random. Been playing with lead loads, mainly for easier recoil.
Mine keyholed at 50 yards with .309 bullets, his was good. So I figured I got screwed a little. But then his scope fell apart, so all shooting waited while he got a new one, ended up with a Chinese. Installed it using the original mount, itjust looked a whole lot better. Had to use shims, the Chinese tube is a hair smaller diameter.
Got a bunch of new bullets from .311 to .314, loaded them all 14 gns. Unique and back to the range. Results were weird, to say the least. Mine likes the .314 the best, giving up groups at 200 yards in the 2 to 3 inch neighborhood. So I don't feel bad no more!
His however, not so good. Every bullet tried, from.309 to .314, gave the same results- lousy! Groups at 100 yards were from 1 to 2 FEET diameter, all from a sand bag.
-scope mount screws are tight.
-action screws are tight.
- shimmed the foreend, putting a little up pressure at the end of the barrel.
- tried my loads.
-we both shot it.
-bore is bright.
-no obvious crown issues, looks exactly like mine, both are original, not back-bored or recrowned in any way.
Did not try using iron sights or military ammo yet, ran out of time and shoulders, but will.
So- what else should we look at? The obvious suspect is the Chinese scope, but I can't come up with a rationale that makes sense, the cross hairs don't seem to move on their own.
Is it possessed?

Try factory ammo to calibrate your rifles. Then if they don't group there might be something wrong. Pistol powder might work well for cast loads but I wouldn't be using it for jackets. If they haven't been slugged to the bore, they'll be loose...probably...and you won't hit a flock of barns.

As for the Chinese scope that doesn't fit, it's not the right scope for the mount so how can it be tight and group? No wonder the group is huge.

Iron sights seem like the first fall back. Surely capable of generating 2-3 MOA groups, better with good eyes. If it shoots better with the irons than with the scope, then...

Nice one Jim will have to remember a flock of Barns sorta matches my "Could have done better with a handful of Wheat"......:rofl:

Bob,
Something worth trying and never fails, before you lose the will to live, and we have all been there, is a basic bore sight.
Get it on the paper at say 25 metres first and then you know where you are and progress out from there.
Good Luck

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(typical forced) numbers and matching-to-each-other scopes and mounts

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that could be the problem right there. that sounds like one of the cheaper, put-together-for-the-collector's-market snipers. those aren't always accurate as they weren't originally snipers.

Sounds like a parallax issue to me. Is the new scope a repro PU or some other design? It may be the fault of the Chinese scope but I have all ideas the problem was caused by having to shim the scope to fit the mount. If just part of the scope tube was shimmed achieve good clamping pressure it could be stressing the scope and possibly even bending or crushing the tube a bit. It's important that the rings make even contact with the tube. The PU mount normally has plenty of take up to compensate for slight manufacturing tolerances in scope tube diameters but if shimming is necessary use thinner shims that will allow them to fit the whole circumference of the tube, align the end gaps with those of the mount clamps and lightly tap the clamp while tightening the screws.
Also what actually went wrong with the original scope that ''fell apart''?

A couple of good ideas were brought up, like using iron sights and factory ammo. Tried that, no improvement, but at least eliminated the scope, mounts and shims as culprits. Took it out today in 95 degree heat and 20 mph crosswinds, repeated the iron sights and surplus ammo drill to get a baseline group, which still was in the minute-of-barn door group, and then fixed it. All is well now, with .314" bullets it groups 2-3 " at 100 yards, still gonna need a little tweaking but things are looking up. Ran out of ammo, had to quit.
Oh yeah, the fix. We all missed the obvious simple thing to look at- check the barrel bedding. Russians didn't believe in using steel bushings around the action screws, so the old russian wood was kinda squashed down a bit. A whole bunch, actually!
Ended up having to shim the receiver almost 80 thou before the barrel would not contact the fore end channel. Still have to fine-tune the shims, like adjusting which one or both gets more or less thickness, but all that'l take is more ammo.
As a side note, to answer the last question, the original scope came apart internally, looks like a lens broke. At any rate, unuseable. The theory is that it broke due to using a Lead Sled, which tends to transmit the recoil forces directly to the rifle and scope, not to the shooter. Either that or it was just the scope's time.

There is a guy on gunboards that is fixing PU scopes for $50-70, including parts.

I would get some Extra Match ammo and if it does not group well with that I would keep working on the shims, barrel wrap and barrel floating(the barrel should be without contact with wood). The only contact point that typically works is under the front band, where the wrap should be. The old Soviet techniques for fitting the stock still work. There are a lot of places the metal should not be tightly fitted to the wood, including the tang, scope mount base, etc..