New build trouble.. light primer strikes

[sid]

Soo I got my ar15 together and started sighting it in.. good news is 24gr Varget with 77gr SMK work great with it!

The bad news, I had light primer strikes, every 5th shot. With different types of ammo.

My other rifle ran the same ammo without trouble.

I measured the fired cases, the light primer cases and fresh reloads, it all looked good so I don't think I have a chamber issue.

The lower is my sbr lower with larue trigger and it's runs great with my 300bo.the stock is however new and havent shot it with the 300bo.

I think I have a problem with bolt bounce, I noticed that the new upper is very violent, and I have more gas blowback than my other rifles.

Should I get an adjustable gasblock, or look at a heavier buffer?

What's y'all's opinion?

 

[eklarsen]

First, I would shoot it without the can and verify all works well. The reason is you stating you have light primer strikes, check to ensure you didn't put the hammer spring in backwards, really common issue. Then to shoot the 300BO with a can you will likely need both, an adjustable gas block for sure and then next step is heavier buffer.

 

[sid]

i double checked the hammer spring after i read about it, but it is correct.

i will try it without the can.

ps the buffer im using weights 3.1oz , i checked all the buffers i had laying around, and they are all 3.1 or lighter, my other cheap precision rifle has a rifle buffer, and it weights 5.something oz so i will put that one in this rifle and see how it goes

 

[nn8734]

Sounds like excessive back pressure, common when using a can on a rifle without a gas port diameter sized with suppressed usage in mind....def get an adjustable gas block and tune it such that ejection pattern is between 3-4 o’clock. That should solve the problem without needing to change your buffer.

if you still want to slow bolt speed or mitigate felt recoil, your buffer should be able to be taken apart and re-weighted; if so it’s cheaper than spending money on another one.