I read the FAQs first, but haven't been able to find anything about my particular issue.  I'm hoping one of you folks can help me.

I have an RRA upper and bolt carrier group on an Eagle Arms lower w/ RRA lower parts kit.  I took my rifle out to the range for the first time Saturday, and it functioned perfectly.  My strange "problem" is as follows:  I will dry fire the rifle with an empty magazine (both 30 round GI and 30 round British steel Royal Ordinance) and, when I pull back the charging handle, I can only pull it back 3/4" or so until the bolt carrier seems to "jam up".  I then need to close the bolt with the forward assist.  If I leave the empty magazine in, it will continue to jam when I pull back on the charging handle.  However, if after closing the bolt with the forward assist I then remove the empty mag, the bolt carrier will pull back smoothly (the bolt carrier will not pull back if I remove the empty mag without first closing the bolt with the forward assit).  The odd thing is that this happens intermittently; it does not happen all of the time.  It seems that the empty mag is causing the bolt carrier to jam up somehow, but I can't figure out how.  

Any insight is appreciated.

I don't think this is in the FAQ but it outta be as frequently as it comes up. The bolt catch in your lower is being forced up by the follower in your magazine. The right upper corner of the bolt catch is catching on the bolt carrier. The Right upper corner (as you hold the rifle) needs to be radiused slightly.

The bolt catch or the bolt catch pin hole are out of spec.

As a check, with the bolt forward and the magazine out, press in on the bolt catch (the bottom half) and retract the bolt, in your case the bolt should hang up. Insert a mag and press in on the bolt release (the upper half) and retract the bolt, the bolt should come back smoothly.

ETA, it's in the FAQ now.



[clarity]

Sounds to me like the bolt catch is binding in the "cut/ramp" in the unshrouded carrier (I'm guessing you have an unshrouded carrier). Does the gun still bind up if you manually hold the bolt catch down?

Wow... thanks for the diagnosis.  I tried your check, and you are correct!  Now that I look at my bolt catch, I can even see more wear marks on the right edge (especially around the upper right corner (as I hold the rifle).

How much should be filed down?  Should I file on that corner alone, or also along the right edge?  I want to fix this (although it isn't a HUGE issue), but I don't want to take off too much metal and ruin the bolt catch.

Thanks!

Just slightly radius the corner, or you can replace the catch. Reinstall and check for binding. It often does not take removing much material. G-Code has a point, and I almost included it in my original edit above. I, too, have seen the squared corners of the slotted carriers snag on the bolt catch. Sometimes the snag is a combinations of errors. Depends on how you want to fix it.

 

Not to disagree with Tweak, but it may be that your carrier that is the problem. If possible, try manually manipulating your bolt/carrier in a couple other AR’s and see if the same thing happens. If it does, it’s more than likely the carrier.  If not, as Tweak said , it’s probably the lower.

I just had this same problem. I tried my carrier in a Colt, Bushy, Mega, and Oly lower and the carrier bound up in all of them.  What I found after cussing the lower and every other thing I could think of, was that the 2 “fins?” at the middle bottom of the carrier, right by the firing pin head,  were the problem.  It seems that during the deburring/finishing process, the top edge of the fins (on the bottom of the carrier) were radiused too much and just  allowed the bolt catch to enter the ramp in the carrier causing the severe binding and much headache.    


Edited to add: Weather it's the lower or the carrier, Tweak is right, filing the bolt catch is the easiest fix.

Don't worry about disagreeing with me G-CODE, the more correct info the better.

I've modified carriers before, I'm not opposed to it. That's why I ended that last post with "depends on how you want to fix it."

Cutting a radius on the bolt catch is an exception to my personal "fix what's broke" rule.

I have the same problem as Martoski, and a quick way to diagnose wether it is the carrier or bolt catch would be to switch uppers or even carriers (of different makes would be better.)

I had the problem with a Bushmaster upper and Mega lower. I tried it with a Fulton Armory upper and had the same problem.

Bolt catch issue.

Thanks for all the info guys.