I have a Bushmaster 20" V-Match that will not feed reliably.I have shot this gun 2-3 times never had a problem before.It will feed ok for about 5-6 shots then it will stop. Looking thru the ejection port you can see the round has fed about half way out of the mag and stops.I have tried 5 diffrent mags that work flawless in my other guns.I swapped bolts no help.I put this upper on another bushy lower same thing happens. Ammo used was Winchester white box,Federal xm-193 and UMC.The gun was clean and lubricated when I tried it.If anybody has any ideas I would greatly appreciate any help.Thanks Jake

On the jammed round, is the bolt tight against the back of the round when the bolt comes to rest, or is the ammo case left with a little movement between the barrel/bolt face?

Also, does the bolt come to rest behind the round being feed or is the bolt on top of the round?

Jam with gap between the back of the round and bolt means the bolt/firing pin got bound on the hammer.

Jam with the bolt tight against the back of the case means the mag catch needs to be tightened up on turn. This will hold the mag tighter in the mag well and keeps the mag front from being pushed downward.

Jam with the bolt on top of the round means the rifle short stroked and you may have a loose carrier key that needs to be tightened.

Dano the bolt is behind the round but I didn't notice if there was a space between them.Tomorrow I am going to strip the gun down again and see If I can find something I missed.Thanks for the tips JAKE