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300 Blackout Help...Bolt not always locking back
1/8/2012 10:02:20 PM
16" CMMG BBL Carbine gas port
JP adjustible gas block-WIDE OPEN
So i just built this thing and I love it but for some reason it will not lock back with certain loads.
Not the mags
Re-did the gas block already just to make sure..It's good to go
tried my JP low mass buffer and a standard rifle buffer...no difference
Not the loads... my buddy have the same setup except the stock, i got an A2 and he has a Vltor IMOD. the same loads lock back fine in his
200gr subsonic(unsuppressed) cycle fine and lock back in his..cycle but wont lock in mine...
180gr full power same situation cycle but will not lock in mine..perfect in his
125gr SMK full power cycle and lock in mine and his
Maybe the recoil spring? If it is should i go with a reduced power or + power? What Gives
Not my first rodeo, built plenty but i never had one fight me this bad
EDIT: Not the bolt either....Brand new bushmaster BCG.....Rings are good and key is tight
JP adjustible gas block-WIDE OPEN
So i just built this thing and I love it but for some reason it will not lock back with certain loads.
Not the mags
Re-did the gas block already just to make sure..It's good to go
tried my JP low mass buffer and a standard rifle buffer...no difference
Not the loads... my buddy have the same setup except the stock, i got an A2 and he has a Vltor IMOD. the same loads lock back fine in his
200gr subsonic(unsuppressed) cycle fine and lock back in his..cycle but wont lock in mine...
180gr full power same situation cycle but will not lock in mine..perfect in his
125gr SMK full power cycle and lock in mine and his
Maybe the recoil spring? If it is should i go with a reduced power or + power? What Gives
Not my first rodeo, built plenty but i never had one fight me this bad
EDIT: Not the bolt either....Brand new bushmaster BCG.....Rings are good and key is tight
1/9/2012 3:01:53 PM
Check your spent case to make sure that the ammo is not going over pressure with your chamber.
If the primers look ok, then get CMMG on the line to have them open your barrel gas port. With the adjustable gas tube, you want to have a wide open setting for when shooting the sub sonic ammo, then close the tube down for the higher dwell pressures with super sonic ammo.
But as a side note, standard gas block and the barrel suppressed, would dare to bank that you would not have these problem since a suppressor increases back bore pressure, which increases the pressure through the gas system as well.
If the primers look ok, then get CMMG on the line to have them open your barrel gas port. With the adjustable gas tube, you want to have a wide open setting for when shooting the sub sonic ammo, then close the tube down for the higher dwell pressures with super sonic ammo.
But as a side note, standard gas block and the barrel suppressed, would dare to bank that you would not have these problem since a suppressor increases back bore pressure, which increases the pressure through the gas system as well.
