Gunsmithing Cycling problems with LR 308 build

[sirKandal]

Hi I have a DPMS build that I testfired today and it did not work with Norwegian Nato 7,62x51 ammo, but the I tried with some handloads that had 168gr bullet and 42gr of N140 behind it at this made the gun cycle.

The gun Is buildt up with:
DPMS lower and upper
DPMS BCG
DPMS bull barrel, a 24" that is cut down to 22"
Brownell std buffer and bufferspring

Have checked gasblock posision and it's ok
You see the emty casing in the second picture

Need help here

 

[bptactical]

It not occurring with the other ammo makes me lean towards the Norwegian being a bit under powered. Did it happen with every Norse round or just one?

What you are showing is a classic short stroke, typically gas related.
Check the standard items such as gas ring condition, stagger, gas key secure to bolt carrier etc.
Keep in mind this is a new build so things are tight, especially if you selected premium bolt and carrier components.(NVM, you used stock DPMS)
Keep it well lubed and shoot known, good factory ammo. Let the machine wear in a bit.

 

[sirKandal]

Thanks, will check gasblock alignment ones more just to be sure. And will put on the suppressor next time on the range to get a little more gas pressure See if it's coming along then

 

[bptactical]

I would hold off on the can.
Get the rifle dialed in first before you add another variable.

 

[Turd in the Pool]

Every one I've seen that short cycled had the wrong bolt buffer/spring/tube combo. You should be able to pull the bolt back well beyond the catch without feeling like you're charging a ma deuce. ;-)

 

[sirKandal]

Cleaned the BCG and lubed it good before I went to the range today, and now the rifle works. Just a pair of FTF, but it's coming around
Thanks for Help