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9/5/2014 7:15:45 PM EDT
I just finished up my .308 build. I took it out to the range today to break it in and ran into some issues. The build is an Aero M5 set, Ranier Match barrel, DPMS bcg and I was using 20 round pmags. I dropped the bolt and this happened (recreated at home with a snap cap):


It seems like the bolt couldn't grab the case correctly and it was slightly off center and wouldn't feed into the chamber. Thus happened numerous times with 20 and 10 round PMags.  Here is a pic of the feed ramps/chamber:


Here is what it ended up doing to my snap cap after a few tries:



I could load single rounds in and the gun shoots like a dream, unfortunately as a single shot! Any ideas on what is causing this? Any help would be greatly appreciated!
9/6/2014 10:35:09 AM EDT
[#1]
Does it have any lube on the bolt? Appeared a bit dry in the pictures.
Does it have the right buffer spring?
Was this happening from a fired rifle or loading from dropping the bolt release?
Did it cycle ok after being fired?

Maybe short stroking and/or not having enough forward pressure to strip the cartridge?
In a new rifle I always lube the hell out of it then cycle it about 200 times before even loading it with a magazine to "mate" in all the new parts.

Thats all of my guesswork good luck. Its a good list of quality parts youve got so I bet its a simple fix.

AL
9/6/2014 12:23:36 PM EDT
[#2]
Could it be that the case head is not being allowed to slide under the extractor by an anomaly with the ejector (or the likes) resulting in pinching of the casing sides as it tries to chamber?
Just a thought..
9/6/2014 12:30:20 PM EDT
[#3]
My first thought is that looks pretty damn dry for a new build...
9/6/2014 4:51:42 PM EDT
[#4]
Are you sure it's .308? The damage to the snap cap body and how far out-of-battery the bolt is looks as if it's a .260 or .243, but I don't see any damage to the snap cap "bullet" which would be probable. Have you tried to load any ammo? It should slip into the chamber completely without having to close the bolt. Inspect the barrel to make sure it's clear of foreign objects (like cleaning patches).

Sorry - I re-read and discovered your rifle fires fine, but won't cycle. I think the snap cap is irrelevant. Check your trigger with the action open, being careful not to let the hammer slam against the receiver when you pull it. See how much effort is needed to re-set the trigger after it's been fired. How easy does the charging handle cycle the bolt?

What ammo are you using?
9/6/2014 7:19:09 PM EDT
[#5]
Quote History
Quoted:
My first thought is that looks pretty damn dry for a new build...
View Quote


Same thing happened to me when I finished my 308 AR last month.  Was having issues with extraction and it wouldn't close the bolt all the way when loading a new round, I though it just might be built to really tight tolerances.  I felt dumb when I realized I had forgot to oil it, even though it's a NiB BCG, after I oiled it, it ran like a raped ape.  No more cycling issues.
9/6/2014 7:45:59 PM EDT
[#6]
Thanks for all the suggestions. It was indeed a bit dry so I lubed it up good and cycled it by hand a bunch. It will now feed correctly if I charge it via the charging handle as I'm now having issues with the bolt catch hardly contacting the carrier and it goes into battery with the slightest bump. BUT the feeding issue is (hopefully) taken care of. I'll take it to the range to see if it was something as easy as lubing it. Thanks again!
9/6/2014 7:56:41 PM EDT
[#7]
Where did the bolt catch come from? An issue I've been hearing is *some people having to use an armalite ar10 bolt catch on the m5 receiver
 
Edit- *some people, not all
9/6/2014 8:16:33 PM EDT
[#8]
Quote History
Quoted:
Where did the bolt catch come from? An issue I've been hearing is *some people having to use an armalite ar10 bolt catch on the m5 receiver   Edit- *some people, not all
View Quote



It is from the DPMS LR308 LPK I got from Brownells.
9/7/2014 7:41:47 AM EDT
[#9]
The alignment of your feedramps is certainly less than desirable. Looks like a fair amount of lip to impede the case rim into and out of round chambering.
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