308 brand new Aero precision lower and upper bot upper complete built lower.

[Dr1620]

Hi guys my name is David and I'm just checking out there to see if any of you guys can help me. I bought a new 308 Upper from Aero precision and I built a lower also Aero precision and have a bolt carrier group and charging handle Aero precision.

My issue is I bought 147 grain PMC and every single case I put through it gets jammed either from the tail or straight up on the neck. I read someone else's issues with the 308 also doing the same thing and they said 168 grain fix their problem, so I went and bought 168 grain to see how it work. The first two rounds ejected perfectly but then I start again the same jams again. I ended up getting five clean injections out of the 20 rounds I purchased of the 168.

I'm curious if I'm either under gas or over gas which I wouldn't really think so seeing how it's brand new upper built by Aero precision. Maybe it's the buffer and spring maybe it needs to be heavier or lighter if anyone can help me with that and maybe they have some information I know how to fix this problem before I go spending a bunch of money on other parts that I probably don't need. 

Thank you for your help in advance

David

[sketch]

clean new parts and lube them.  dont rush in to a contest format, take your break in as a get to know your rifle period and keep us up to date in the intro section..  David

[edgecrusher]

4 hours ago, sketch said:

clean new parts and lube them.  dont rush in to a contest format, take your break in as a get to know your rifle period and keep us up to date in the intro section..  David

The forum is doing that, something is up there. We need more info. Buffer, spring and receiver extension measurements. Length, coil count, internal depth. Also barrel details too. How much lube? These large frames tend to like lots during break in. Welcome to the forum and feel free to do an intro

[shepp]

13 hours ago, Dr1620 said:

Hi guys my name is David and I'm just checking out there to see if any of you guys can help me. I bought a new 308 Upper from Aero precision and I built a lower also Aero precision and have a bolt carrier group and charging handle Aero precision.

My issue is I bought 147 grain PMC and every single case I put through it gets jammed either from the tail or straight up on the neck. I read someone else's issues with the 308 also doing the same thing and they said 168 grain fix their problem, so I went and bought 168 grain to see how it work. The first two rounds ejected perfectly but then I start again the same jams again. I ended up getting five clean injections out of the 20 rounds I purchased of the 168.

I'm curious if I'm either under gas or over gas which I wouldn't really think so seeing how it's brand new upper built by Aero precision. Maybe it's the buffer and spring maybe it needs to be heavier or lighter if anyone can help me with that and maybe they have some information I know how to fix this problem before I go spending a bunch of money on other parts that I probably don't need. 

Thank you for your help in advance

David

Welcome David, feel free to tell us about yourself in the intro section

[survivalshop]

Photo of the rifle ?

What stock system ?

& as Edgecrusher posted , we need Buffer Spring total length , coil count , & was it designated as a 308 Buffer & Spring , also  Buffer length & weight ? We see a lot of miss matched Buffer components that cause issues & its not always the Builders fault .

[Dr1620]

Thanks guys. I've been in bed with back pain but will get up tomarrow with the information you guys are requesting. Thanks for the help.

David

[Dr1620]

Okay guys here's what I have my buffer is 3.8 Oz and 2 and 1/2 inch the spring is 11 inch with 26 coils. Yes it was designated as 308 spring buffer tube and buffer. The buffer tube itself is 7 inch. Hopefully this will help you guys help me please respond as soon as you get a chance appreciate all the help I can get thank you. 

David

[survivalshop]

 Spring seems short  should be 11.5" , I have a DPMS 308Carbine Spring & its well used & is 11 1/4" & has 29 coils . Buffer is OK for a DPMS based 308  Carbine . Brownells has the Spring you need .

 

https://www.brownells.com/rifle-parts/receiver-parts/recoil-parts/recoil-springs/308-ar-buffer-springs-prod42988.aspx

[Dr1620]

TY. I'll give it a try.

 

David

[98Z5V]

15 hours ago, Dr1620 said:

TY. I'll give it a try.

 

David

Don't skip this thread, David...  It's worth reading through, in your circumstance...