Needing to use charging handle to chamber round - small frame ar

[penguinofsleep]

Have a small frame where I have to chamber a round by pulling back on the charging handle. When the bolt is locked back (via the bolt release), it doesn't sit back far enough to chamber a round when after inserting a mag by dropping the bcg using the bolt release. Will catch a round 100% of the time so far when pulling on the charging handle. Everything else has run 100% from day 1 except for this minor issue. No abnormal wear marks, nicks, etc. anywhere in the rifle or parts that would indicate any kind obvious misalignment of parts that could cause this.

I suspect one of the below is sitting in the rifle is causing the problem - anyone have any ideas to help me speed this investigation up?

Standard forged upper and lower with a standard bolt catch - no ambi or extra "non standard" parts.
6.5grendel with duramag 10rd grendel mags. Last round hold open works 100% of the time with all mags.
JP Enhanced bolt + JP lightweight bcg + JP captured spring in a carbine length buffer.

 

[Bantam1]

Is the round crashing into the feed ramps on the barrel extension? Is your extension clocked in the upper receiver? Have you tried different magazines to eliminate the mag from being the culprit?

 

[Redlion]

It seems like it would be a buffer/buffer tube issue if you can not capture a round with the bolt locked back. The BCG seems to be stationed too far forward if I am following? What buffer tube are you running?

 

[db2000]

Post pics

 

[cas6969]

So when you're locking the bolt back, it's locking on the front of the carrier, as opposed to the bolt face where it should be. (I assume)

First simple question, since you say it's feeding okay.... are you just not pulling it back far enough?

(I had some non standard setup that would cause me to do this, as that last little bit was fairly hard)

 

[bfoosh006]

Your bolt catch might "tongue" need to be longer.... the portion that is pushed up by your magazine follower.

And pics would help.

 

[Redlion]

Is it a 5.56/.223 or other?

 

[LRRPF52]

Have a small frame where I have to chamber a round by pulling back on the charging handle. When the bolt is locked back (via the bolt release), it doesn't sit back far enough to chamber a round when after inserting a mag by dropping the bcg using the bolt release.

Unless the bolt isn’t locked back normally, it has plenty of space behind the cartridge in-presentation to strip the cartridge from the magazine. What happens when you hit the bolt release?

I personally de-edge, blend, and polish all my barrel extensions so there is no real ability for the cartridge not to feed into the chamber.

I also chamfer the ejector so right side presentation doesn’t bind against the side of the ejector.

Troubleshoot your BCG and JP SCS to see where your bolt is actually locking up as well.

There are bolt travel specs for the AR-15 to ensure the BCG retracts rearward enough.

 

[penguinofsleep]

It seems like it would be a buffer/buffer tube issue if you can not capture a round with the bolt locked back. The BCG seems to be stationed too far forward if I am following? What buffer tube are you running?

Yes, the BCG is sitting too far forward when locked back by the carrier. Everything else works fine.

Won't be able to post pics for a few days but will do so if it's not solved by then.

 

[supercorndogs]

The carrier doesn't lock the bolt back the bolt catch does. The carrier holds the bolt and is part of the BCG or bolt carrier group.

 

[Hetzer]

Sounds like the bolt catch is catching the carrier and not the bolt. I've had this happen.