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Poodleshooter
January 17, 2011, 03:04 PM
I have a Marlin 925 .22lr bolt action (box magazine fed) that was performing rather poorly at distance (2" groups at 50yds with good ammo and a good scope, well mounted).
The stock didn't touch the barrel at the forend, but it did touch at random points through the length of the barrel. The forend also appeared to be slightly uneven, though it didn't directly contact the forearm of the stock. The rifle attaches in two points: a dovetailed pillar w/screw that is mounted on the barrel about 1" forward of the receiver, and a screw in front of the triggerguard/behind the magazine which attaches to the receiver.
I relieved the barrel channel back to the receiver, so that I could easily get 2+ dollar bills all the way back to the pillar, then I bedded the barrel to about 2" forward of the receiver (around the pillar, but not into the pillar well,as it is a good tight fit already). I also bedded the lip that impacts the front of the receiver, making it a bit tighter than before, but still leaving enough room to remove the action. I didn't bed the tang or any of the rear of the receiver, as it seems to be a very good fit already since I relieved the barrel channel and bedding only raised it to about the original level.
Trouble is, groups haven't improved, and I seem to have even more random fliers than before. I tried shimming the barrel, but that only resulted in diagonal stringing because I couldn't get the shim pressure centered. Should I bed the barrel out further, or just bed the entire barrel? Bed the tang even though it still seems a good fit?
The annoying thing is that when torqued down good, the rifle seems very snug in its bedding. I'm guessing that I might need more support forward of the barrel lug?

publius
January 17, 2011, 05:24 PM
Have you tried different ammo? Spring for a box of the "good stuff" like Eley just to see what the gun is capable of. Try asking the guys at rimfirecentral.com. they are the .22 experts

Poodleshooter
January 17, 2011, 08:21 PM
Already tried over there,but haven't gotten too many answers.
I ran this thing with CCI Mini-mags, Subsonic and even Standard velocity. Standard Velocity gave maybe 1.5" groups at 50yds.

Don't get me wrong, it still shoots 7 rounds into a ragged hole with all shots touching at 25yds...it's just that it's a ragged elongated hole, and that it isn't cutting the mustard at 50yds.

Poodleshooter
January 20, 2011, 04:15 PM
Rebedded further under the barrel as well as the front of the action and shot groups of about 1.3" at 50yds with good ammo (CCI Standard and Federal Gold Medal) at 50yds. Cheap ammo runs about 1.8" now, roughly where the good ammo shot before. Not the best, but it did reduce the flier and cold bore problem, making it more consistent from cold to hot and unfouled to fouled. Oh well. It's not an Anschutz I guess.
The thing that drives me nuts is that my dad's Anschutz isn't even fully floated, has an inconsistent barrel channel,but still shoots wonderfully. It's German made voodoo I think....

thickstrings
January 21, 2011, 04:32 PM
Try some different torque settings on the take down screws....Tighter....looser... you could also try a piece of inner tube under the barrel near the front of the stock, try various places, move it up and back till you find the sweet spot...same for the screws..

highvel
January 21, 2011, 05:44 PM
How does the muzzle crown look? Any dings or marks of any kind?
As far as ammo goes; my rifle shows a very large accuracy difference between manufactures. I tried many until I found what it liked.

Poodleshooter
January 24, 2011, 03:07 PM
The crown is clean-no nicks or gouges even under close inspection.
I tried varying torque. Best accuracy was with all screws quite tight. A loosened rear screw only led to diagonal groups with significant horizontal dispersion as well. Both screws loosened opened groups up in general, as did loosening the front (barrel mounted pillar) screw. Tightening down both screws gives tighter groups,but with random fliers and sometimes multiple group centers.
It's shooting better with the barrel partially bedded. Now I'm curious if I should just bed the whole barrel.

I noticed that accuracy is best with warm ammo,right out of the car. That seems to really keep group size down.

I've tried many,many types of ammo:
Fed Champion 510b
Fed Lightning 510
Fed Gold Medal- good accuracy
Fed Automatch AM22- good accuracy
Rem Target
Rem Subsonic
Rem Goldens
Winchester Wildcats
Winchester Dynapoints (old white box)
Winchester Subsonic
Winchester T22
Winchester Super Speed HP and SP- (good 100yd accuracy,oddly enough.)
CCI Minimags (HP and solids)
CCI Standard Velocity- good accuracy
Aguila SE subsonic