lazyengineer Wrote:Picture? I'm not sure what 2/3 closed means, but if that means the BCG is only 2/3 the way forward in the ejection port, that sounds like a bullet nose hitting the breach face or something- which I haven't really seen before.

oyster Wrote:This week when it happened after I dropped the mag and did a few function test with the charging handle the bolt would slam to a stop before going into battery. From what I could tell it almost looked like the bolt was out of synch and not camming over to miss the lugs on the extension. Not sure if that's possible.
Thanks for any help.
Jay

LRRPF52 Wrote:I’m going to try to graph out the configuration of your rifle using text, but I just want to understand the order of components.

JP SCS with H2 weight buffer installed on the captured guide rod assembly (What spring weight did you use?)

BCA Bolt Carrier

Sanders Armory Bolt

18” Stainless Barrel with Mid Length Gas (What barrel brand is it and what’s your gas port diameter?)

Superlative Arms Adjustable Gas Block

Suppressor (Whose can is this? Bore diameter, high-efficiency vs flow-through?)

LRRPF52 Wrote:How much lubrication do you use and what kind?

What were the temperatures during the hunt?

A dry gun, especially running suppressed can cause FTFeed.

Do you have a Crane O-ring around your extractor spring?

For more detailed troubleshooting, you can inspect:

1. The JP SCS to ensure the retaining pin hasn’t come loose

2. Your bolt carrier gas key has not come loose ( I wouldn’t personally trust parts from that vendor. I have become more jaded on who I order parts from.)

3. Your gas rings for any wear, pitting, shearing, flaking

4. Your carrier bore, looking for any rough texturing of the inner surface

5. Your fire control group pocket, looking for signs of soot deposit

6. You mentioned a RRA lower. Do you by-chance have a Rock River Arms 2-stage trigger in it? (I have had them hang up the bolt carrier group in the DPMS LR-308, but not AR-15s.)

7. Did you change to a different magazine? Have you disassembled and cleaned your magazines lately? Is the spring inside your magazine broken? (This has happened before with either ASC or CProducts on one occasion if I recall. It’s been a while.)

8. Anything funky going on with your magazine catch, Cerakoted lower, magazine not seated fully?

9. Take your stripped bolt carrier with no other parts in it. Slide it back and forth inside the upper receiver to feel for any binding or grinding, stops in the raceway.

10. Does your bolt bind up with the barrel extension when articulating through the action and into battery? (We’ve seen more and more of this in the after-market AR-15 and AR-10 world lately.)

11. Is your gas tube flange worn down or clipping the carrier key? If you look at the gas tube inside the upper receiver, a worn tube flange will look like this:

chatterbox Wrote:I had the same problem and found that it was two problems: 1. Broken extractor 2. Undergassed. New extractor, and a good cleaning, fixed the first and an adjustable gas block fixed the second.

chatterbox Wrote:Sorry, but it did increase the prot pressure. It is possible that the old gas block was not properly positioned, thus blocking the port. And when I properly installed the adjustable gas port there was more pressure available. However, this can only be true if the Superlative Arms gas block's instructions are backward, that at 4.5 full turns the port is barely opened and as the adjuster is backed off the port opens more fully. Beats me, but whereas I was undergassed before the adjustable gas block, the rifle was functioning perfectly at nearly fully opened.

chatterbox Wrote:True, but installing the adjustable gas block did solve the problem, in this instance. Another plus is that, after installing the gas block, my group size dropped from 1.25" down to .75" at 100 yards.