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I jumped on the bandwagon a few moths ago. Had a spare complete Stag lower. Decided to buy a dedicated ST-22 22LR upper. First 500 rounds of Federal bulk ran like butter, Decided to try other brands of ammo due to shortage locally. Nothing but federal copper plated would feed reliably. That was a bummer. Read the polishing thread on AR15.com but didn't work for me. Looked at the problem my self. My findings were that ammo (copper and/or lead) with bands would get stuck on the feeding ramp of the barrel not due to it being dirty and or at a high angle but there seemed to be a slight sharp edge where the ramp was machined instead of a rounded ramp lead into the chamber. I decided to file the ramp with a small round file. Now it eats any type of ammo. Gone through 3k rounds without a single FTF.
These are my findings,
As far as I can tell the problem is not in the collar. Looks like the collar only plays a role when the round is first stripped from the magazine. Then the barrel ramp together with the upper wall of the barrel help feed the round.
This shows what im describing in the barrel feed ramp having a sharp edge (please excuse the pre-school sketch)
A little difficult to take close up pictures but this shows what i filed, and what it looks like.
Side view with inset
These are the rounds that show the jamming. Clearly the bands are visible that would catch the edge. Also the bend it would create from the bolt's force when the jam would occur
As far as i can tell the bolt would strip the round, the round bands would catch the barrel lip, with the feed angle the tip of the round was already in contact with the top wall of the barrel, the bolt still in forward motion and the round already jammed, it would bend the round, and a FTF was present.
Just providing my 2 cents worth of knowledge.
These are my findings,
As far as I can tell the problem is not in the collar. Looks like the collar only plays a role when the round is first stripped from the magazine. Then the barrel ramp together with the upper wall of the barrel help feed the round.
This shows what im describing in the barrel feed ramp having a sharp edge (please excuse the pre-school sketch)
A little difficult to take close up pictures but this shows what i filed, and what it looks like.
Side view with inset
These are the rounds that show the jamming. Clearly the bands are visible that would catch the edge. Also the bend it would create from the bolt's force when the jam would occur
As far as i can tell the bolt would strip the round, the round bands would catch the barrel lip, with the feed angle the tip of the round was already in contact with the top wall of the barrel, the bolt still in forward motion and the round already jammed, it would bend the round, and a FTF was present.
Just providing my 2 cents worth of knowledge.
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