Been having inconsistency problems with my RWS 52 for some time now. It seems like it may have started in the spring when I noted the stock screws were extremely loose (like two or three complete turns before they contacted anything). Since then, I've just not been able to get any kind of decent groups. Yesterday I sat down and tried 10 pellets with each combination of 'ratcheted down tight' and 'just snug' at about 13 yards (about as much as I can do in the basement). I should probably preface by saying that the velocities weren't very consistent either, but seem quite solid now since I replaced the breech seal a couple of weeks ago. At any rate, I found:
1) both screws really tight - worst group - around 3/4" wide 13/16" high and 1" spread.
2) rear screw tight, front just snug - a little better 11/16" wide 1/2" high about 11/16" spread.
3) both screws just snug - 7/16" wide a/2" high 5/8" spread
4) front screw tight, rear one just snug - 9/16" wide 1/2" high and 9/16" spread.
I also observe that the first two groups (with rear screw really tight) seem to pull the POI about 1/2". So my analysis is that the 52 really likes the rear stock screw 'just snug' but not really tight and is relatively insensitive to the state of the front screw.
I'm wondering if anyone else has any observations on the subject.
mine seems to prefer both bolts well tightened, but you might have something in your observation about the rear bolt which i never felt was up to the job, its been about 18 years since i did my tests but it rings a bell, i replaced both bolts with standard counter sunk bolts, the (metal) trigger guard hole was counter sunk a bit deeper and the front washer just lightly, gun gives me clover leafs at 40 metres when i do my bit and means i only need 1 size of Allen/hex key to remove the stock.
front m6 x 25mm (standard 1mm thread)
rear m6 x 40mm /20mm thread length (standard 1mm thread)
around the same time i bedded the gun just in the area immediately around the bolt holes with as far as i can remember epoxy loaded with talc
the ME method, bed the action to the wood stock and use 1 size allen/hex screws, you then a solid platform and the misses (flyers) are on YOU not the air rifle
Nice test you have there!
I know that, on really high level, some marksmen experiment with stockscrew torque on their matchrifles.
I have no experience with that though, just screw them in tight.(some rifles with loctite)
Some rifles dó have a specific order to tighten the bolts though..