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Bolt Won't Close/Pierced Primers

20475 Views 32 Replies 20 Participants Last post by  Sean K.
If your bolt won't close sometimes, check both your primers and look for little brass slugs in the barrel extension (sometimes smashed flat).


What is happening is that the firing pin hole has a sharp edge and the pressure of the primer against the bolt face cuts a little slug of primer out and leaves the hole. The slug from the primer can get caught in the action.

The fix is very simple. We very slightly break the edge of the firing pin hole. Don't do this yourself unless you know what you're doing. If you break the edge too much, you can ruin you're bolt.


Symptoms are that the bolt closes sometimes but not others. I'll post some pics as soon as I can. We can fix the bolt in 20 seconds.

If you have any questions, email or call our service department. 801-355-0401 or [email protected]


Alex J. Robinson
Robinson Armament Co.
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No problems of any kind yet, Alex. And that's with both my 5.56 & 6.8 SPC caliber(s). It greets & eats everything I have feed it so far, with good results. Thanks for keeping us all in the loop. 8) ;D :2cents:
As I think of weird problems that we've encountered, I'll try to post them here an our website.

The XCR is such a solid platform that there are few problems. When we do have problems, I want it easy for anyone to diagnose and fix the problems.
Here is a picture of what Alex is talking about.

The case on the left has a hole punched through the primer. It rarely happened to me, but there it is. One out of 500 (mostly Radway) cases checked. Perhaps the Federal case has softer primers than Radway.
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I had the same thing happen in my rifle on Tuesday at the range. It was leaving a very high dimple on the primer cup. Knocked a hole right through one. Sending back my bolt in the AM to have them look it over. I also noticed when I turned the gas down to setting 2 or 3 the dimple was less apparent. Primers are CCI 400's.... I also noticed it wasn't doing it as bad when I shot LC factory ammo with a military primer.

P.S. The rifle shot some great groups!!!

Load data
50gr VMAX
CCI 200400 primer
26.5gr TAC powder
Guat 5.56 brass
Seated to max length for PMAG's

This is .2 grains under book because guat is a thicker brass which will increase pressure.

Sending my bolt in to Robarm cured my problems. I love this rifle!!! No more cleaning after every shoot like my AR15.
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:eek: CCI-200 are large rifle primers-will not fit .223 casing. Maybe CCI-400?
Guy's Part of what Alex is saying here comes from my kaboom. One of the first warning signs that should be given serious consideration is if the bolt locks forward and you have to forcibly pull/slam it back. I had this happen twice right before my failure, If this happens I reccomend AT THE LEAST, field stripping it, inspecting brass and checking bolt tightnesses.

my .02
I had the bolt locking issue. Each time I stopped shooting to clean and inspected the rifle. I have to admit that I never took notice of any brass discs but really didnt' know to look for it.

I sent my upper in. Once RA inspected it, Terra asked if I had primers with punched holes. I had never noticed any and only found the one after inspecting all of my spent brass. The only thing is I didn't keep all my brass, so I don't know how often it happened. My guess is it only takes one to cause a bad day.

Inspect your brass. :2cents:

Simple fix. :rapidfire:
I checked some of my Radway brass, and it's got these signs. So how do I do it, Dremel?
Even though it seems simple, I'd let RA do it. Turnaround should be quick if Terra likes you ;)
Is there a serial number range that is affected more than others?

Thanks Alex for being the type of guy to bring this to the forefront of attention.

Another two thumbs up!
This is the only By Serial Number list that I have seen...


If you are worried about the pireced primers just inspect your brass, especially if you have an instance of the bolt not closing.
Here are mine from 03/11/08. I contacted Terra. I can't shoot on any setting less than 4. I guess all the gas is escaping out of the pierced primers :(

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I went out a shot mine with 5.56 this weekend (had been a while, usually shoot 6.8) and I ended up taking it all the way down to setting 1, and it was still throwing the brass a good 10 feet. I still had the 6.8 ejector thingy on there so that may have helped as the brass was going straight to the side.
I contacted Terra and a new bolt is on the way! Hope that solves my problem.
I would be willing to bet that you wont have any problems when all is said and done.
BTW- here's a picture of my bolt after I had just shot some Wolf (hence the red residue).

Now an AR bolt. I can see more of a chamfer there:

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We don't have to be a mechanical engineer to figure out some OF THE COMMON PROBLEMS we encounter with our XCR's and other weapons. I believe EVERYONE who owns any gun should have some basic mechanical insight. To say that "I don't have it" means to me "I won't try" and "I don't care". These are the same folks who will also bring up that same question I always see/hear "Which is the best for the SHTF gun?" Well if indeed the S-H's-T-F I doubt posting our problems on the intraweb, if so accesible still at that time, will bring a quickly needed solution. Much less expecting courrier services to be up and running.

Folks, the XCR really hasn't got anything new that has't been around for at least 60 years as far as a basic design goes. There are no computer chips to mess around with unless of course somehow you managed to shove one in the XCR somehow. Plus I can't see how RA, or any other gun manufacturer, can make the XCR, or any other gun, more anti-armorer/pro-self repair any simpler. So accessing any part in order to remove and replace, repair, or adjust any simpler.




Ya'll will be amazed, if not astonished, that you can find the tools necessary to work on your XCR at Home Depot, Lowe's, ACE, TrueValue, Harbor Freight (eewww) or mom and pop hardware. You should at least have handy a 1/4" allen wrench for the barrel and a 5/8" open end for the old GB handy, like say in whatever case you carry your XCR along with a cleaning rod (not bore smake-that I just use for cleaning) and broken shell extractor for that once in a million chance a case head separates (not the gun's fault). Ya'll will also be amazed that the same hardware store may carry 90% of the bolts, screws, springs, and clips that are on your XCR. But I recommend to get them from RA because we are talking inexpensive parts here.

Most inportantly;


If it needs to be aired on open forum with da problem, at least give them a call 1st, THEN tell us about your experiences but don't be like this "It's a POS because I can't tighten a barrel bolt, but I'm a high speed operator with 8K post count" guy:


Quote from: Saiga-12 Forum

QUOTE (Zebra @ Dec 4 2007, 05:03 AM)
not impressed with the HK 416. it looks like a piston driven AR as someone stated earlier. still got a hard on for the XCR from Robinson Armament.

QUOTE (Saigaczech @ Jan 13 2008, 03:31 AM)
Lose your hard-on for the XCR, had one and got rid of it in less then 6 months. The barrel requires "exact" torquing of the bolt that fixes it in place. That bolt comes loose easily and the whole barrel wiggles then. If you over tighten the bolt it damages the receiver. I had it come loose during a class, was stringing my groups all over the place at 100 meters and had all the instructors saying, "WTF?" as they know I rate master with a rifle(Master rating? Or was it masturbating? The guy leads one to belive he is a Marine or Army grunt. Neither rates "Master" in any FA qual course.). Another thumbs down is that you have to punch out the front pin if you need access into the receiver. Not very user friendly as it will not open as wide as you need for you to work on it. The trigger sucks too and is proprietary so you can't fix it. Just my $0.02 worth.

As to HKs, I am still partial to the P2000 or USP compact system with LEM trigger. Best DAO system on the market I think. I agree that they are way over priced, about as much as SIGs. I blame the media for the pricing, every bozo wants the gun used in "Rainbow Six", "Collateral" or "24" as ti will make them uber tactical. Most of them are trained with weekends playing Counterstrike or Halo and do not know which end the bullets come out of. Grrr. Not to mention, the HK Mk 23 is the only gun I held that made a Glock 21 feel ergonomically correct. The grips are just too big even for my lumberjack hands.

The HK civilian rifle designs suck and the cool ones are not available to civies. The HK AR mags are way over priced as well as their guns. I seem to do just fine with surplus mags for $11 each and a MagPul follower.

Oh well, the government likes them so they are blowing millions of our tax dollars buying their stuff. What can you do?

QUOTE (i303 @ Jan 26 2008, 10:02 PM)

Let me see if I got this staright, the XCR is a total POS that you don't recommend because the barrel retaining bolt came loose during a class? So just tightening it requires any special skill or tool other than a 1/4 inch allen wrench available at any hardware store, WalMart, and probably any other discount and grocery store?

My gas block screw came loose. You know what I did instead of selling it? I tightened it up.

QUOTE (Saigaczech @ Jan 27 2008, 04:08 AM)
Yes, it is a POS because a barrel coming loose during a real engagement is a big NO NO! Last I remembered I do not carry a 1/4" allen wrench in my tactical gear nor is it standard issue to any individual infantryman. If a rifle can have that sort of problem during a class, which is nice and peaceful compared to a SHTF scenario, it will fail you when you need it most. Unacceptable. Also just tightening it without the proper torque settings will mean it will either come loose again or that you damage the receiver ( I discussed this with the tech support at Robinson so it is straight dope from them). Neither is acceptable for a military class weapon (or one that is trying to be one). Something like that can get you killed if you rely on a gun like this. There are better gas piston guns out there.

QUOTE (i303)
So, as an individual infantryman, don't you also carry a cleaning kit and at times, other tools specific to certain weapons? As an 11B/0311 don't you carry a dental pick, a piece of metal hanger flatened at one end, or small screw driver, or a carbon scraper just for a M16/M4 inyour "tactical gear" in order to perform routine maitenance? So a 1/4 inch allen is all too much to carry? And I supposed as the high speed operator/infantryman that you are't you supposed to perform PCI's and PMCS? I also suppose any vehicle that gets a flat instantly becomes a POS because a tire change, or drive it on the rims if necessary, will be on order. Tell me more about what can get you killed in combat please. It's not always the weapons that need some headspace and timing.

First off the XCR hasn't been around 40+ years to work out it quirks yet. The g'vmt hasn't spent a dime to test/R&D this weapon. The XCR has been out less than 2 years. issues will come up just as issues still come up on current TO&E issued equipment. I've had two issues with my XCR and one was resolved in 30 seconds and the other was resolved in about 3 days only because that is how long it took to snail mail be an upgraded part b/c I have one of the first issued XCR's.

If anyone in my platoon, as in "an individual infantryman" would have come to me with that issue, a loose bolt, I'd have given that individual the 'You gotta be kidding me. Right?' look and I would have told that individual "You gotta be kidding me. Right?".

And, yes, I do know what can get you killed in combat. to include doing nothing. Pahleze, don't get all too hung up on my low post count. More shooty, less posty!

No gun is immune to "issues". Even well proven designs will have issues arise from time to time such as in QC at times falter.

#1) Gas block came loose. Noticed it at around 250 round count and still worked. Resolved: I just tightened it. No lock tite. As later posted by RA carbon will self lock tite it as I noticed that on a recent complete disasembly.

hi, i am new to the forum and this platform. i am interested in purchasing an xcr in 7.62 in a couple of months. i have a couple of other m4 type weapons and have had no issues with them, what knid of issues am i going to run into with this platform? with problem #1 listed above, if i clean the carbon after i shoot is the gas block going to come loose again or do i have to leave it dirty? it's nice not to have to clean but if i have the time i do, is this a problem?
i see alot of minor problems but they all add up, at what point (in rds fired) does the xcr become reliable? i have read some of the posts above and agree with some. but to have things go wrong regularly is kind of scary. before i buy i would like to know how reliable this weapon is going to be and if i will be sending parts back regularly. any help would be awesome.
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This isn't a REGULAR problem. It's to point out a problem that few have reported. Many of us, myself included, are approaching 10k rounds with absolutely zero failures OR problems of ANY kind. I went nearly 4000 rounds without cleaning, again, zero problems. And it was still 10x's cleaner than my AR's with 1000 rounds.
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