on AR's, what are light primer strikes and/or not locking back signs of?

[Cannonman]

Playing around with an adjustable block and started to get either light primer strikes or the bold not locking back after the last round. What should I be looking for as a cause?

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[quneur]

Light primer strikes would be either the spring set in the fire control group or the primer itself. Make sure the spring to the hammer wasn't put in backwards, a common mistake. Or the springs are aftermarket.

If shooting reloads, the primer used could be magnum primers which may have a thicker cup (from what I hear). Or it could be just the ammo itself.

More experienced people here could chime in better on the lock back issue. Heavier buffer? Bolt issue? Mag issue?

 

[arrowshooter]

Failed to hold back before or after adjusting the adjustable gas block. Generally it means not enough gas getting into the system, so you would need to open up the gas block.

 

[Cannonman]

Failed to hold back before or after adjusting the adjustable gas block. Generally it means not enough gas getting into the system, so you would need to open up the gas block.

Hope to try this today. BTW, do .308's make decent boat anchors?

 

[3MTA3]

Quick question - is the adjustable gas block new to the system? Did everything work correctly before?

 

[powermad]

Quick question - is the adjustable gas block new to the system? Did everything work correctly before?

It would be easier to follow if all the info was in one thread with updates on this.

If I have been following the bread crumbs right this is a complete 18" .308 upper from Aero correct?
Misaligned gas block fixed and such.
Using a .308 carbine action on an 18" rifle length gas system.

Did you get a .308 Rifle action and try it yet?
I would match the action with the upper before fiddling around with an adjustable gas block.

Start with what is known to the manufacturer to work and go from there.
Aero doesn't sell a complete M5 rifle with a carbine action and rifle gas system for a reason.
They have a recipe so to speak, just follow it and don't change it.

This will work, isn't drastically expensive and in stock.

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[Member 5605]

I need a photo of the light hammer strike.
Me things it's not a light hammer strike but a floating pin strike.

 

[HB of CJ]

Floating firing pin strike marks with the AR platform are considered normal. Another reason why to use ONLY military spec HARD primers. Looks like just a tiny peck mark on the primer. Remember to remember that you are always just a random slam fire away. Ore doubling. Or sometimes tripling. Not good. Stay safe.

I think but do not know the failure to hold back the bolt carrier group after the last shot could be mag spec concerns but not likely. Make sure the bolt stop group is correct. Probably your problem is something to do with the gas block regulator not allowing enough gas. Curious what your AR10 barrel. gas port diameter is.

Have fun. Remember the hand loading rules with the 7.62x51 in the AR platform.

 

[powermad]

Curious what your AR10 barrel. gas port diameter is.

.080" from this thread. https://www.northwestfirearms.com/threads/gas-block-which-one.363723/

 

[oa98pistol512]

I adjust gas block till it locks open then open it 2 clicks more or a quarter turn on set screw type adjustable gas blocks. If you change weight of bullet etc it might need to be tuned again for that particular ammo..

 

[titsonritz]

I need a photo of the light hammer strike.
Me things it's not a light hammer strike but a floating pin strike.

The difference is a floating pin stike occurs when the BCG returns to battery and is normal. A light hammer strike occurs when the trigger in pulled and no bang or intermittent bangs, indicating something is wrong. The vast majority of time on a new build that translates to a backwards hammer spring.

 

[arrowshooter]

If in fact honest to goodness light strike, or failure to fire, is happening, remember to keep your muzzle down range for a few seconds after the failure just to be sure that a hang fire does not occur. Just in case you have never heard the term "hang fire" the best way I can describe it is like a muzzle loader, you pull the trigger and you hear the click then the boom.