Robarms XCR FAQ post

Hey all,

A while back there was some discussion pertaining to removal of the 6.8 muzzle device on the XCR L. I have just purchased a Battlecomp BABC to go on mine, and I am about to undertake the task of removing my muzzle device, so I am once again looking for advice and/or tips on the process to make it as painless as possible.

If you have taken off your 6.8 stock muzzle device and you have any tips or tricks, please let me know! As for now, I am going to go with the "clamp barrel in vise between wood, drill out rivet and twist" approach. Cheers in advance for any help.
 
Got the xcr-m back on friday. Fired about 100 rds saturday and a few more sunday. One FTF, nothing serious. I surprised at how nice the groups are at 100 yds, dialed in with a Trijicon Acog 4x scope.
 
On my xcr In 7.62 my spring looks all kinked up and everyone's pics I see theirs looks like its brand new is this a issue and should I replace it fires and cycles fine ATM
 
To my knowledge they are all pinned and spot welded. The purpose of this technique of pinning and welding is to avoid fusing or damaging the actual threads which would damage or destroy them. The pin is the only thing keeping he muzzle device in place not the weld , the weld only holds the pin in place. All I did to remove mine is , with a 1\8" grinding disc grind away at the surface of the weld ( about 3 millimeters down , such a small spot does not have much penetration ) , then once I could see a small discoloured ring around the pin I new I was past where the two had fused. Then all I did was take a 3\4" wrench and with the barrel in a vice just rock the muzzle device back and forth to loosen out the pin till it just fell out. Be sure not to overturn the flash hider when wiggling the pin out so that you dont damage the threads.
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Excellent post.

And exactly correct.


I followed the process on my XCR-L chambered in 7.62x39mm. It took me a couple deep breaths to commit to the process and about an hour of cautious grinding, but following your guide I managed to do this with a POS dremel and a cutoff blade.

The tense moments were the 3-4 mm mark. Right around that point where you start wondering if there even IS a pin in your flash hider because all you have managed to expose is a blend of indistinguishable shiny metal. I'd be lying if I said that the metal and pin were anything less than smooth and indistinguishable from each other.

But you gut check and keep going. And sooner or later, those small occasional movements side to side with a crescent wrench cause the factory break started to reveal the outline of the steel pin.

You saved me a pile in fees to have this simple process done. Because of your work I am installed my AAC 51T break; and came out cash ahead.

cheers
 
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Excellent post.

And exactly correct.


I followed the process on my XCR-L chambered in 7.62x39mm. It took me a couple deep breaths to commit to the process and about an hour of cautious grinding, but following your guide I managed to do this with a POS dremel and a cutoff blade.

The tense moments were the 3-4 mm mark. Right around that point where you start wondering if there even IS a pin in your flash hider because all you have managed to expose is a blend of indistinguishable shiny metal. I'd be lying if I said that the metal and pin were anything less than smooth and indistinguishable from each other.

But you gut check and keep going. And sooner or later, those small occasional movements side to side with a crescent wrench cause the factory break started to reveal the outline of the steel pin.

You saved me a pile in fees to have this simple process done. Because of your work I am installed my AAC 51T break; and came out cash ahead.

cheers

I missed this post; thank you very much for re-posting!
 
Removing material should be done like any other metal working operation. Slowly and carefully.

Using either a dremel, grinder or hand file, you should remove approximately 3mm of material from the spot weld. At the start, you will only see shiny bare metal as the weld has blended the pin together with the factory muzzle brake's steel.

As you progress, you will start to see a black ring develop around the pin.

The first picture here should show you how deep in this pin goes.
P1010538_zpsc0febcf2.jpg


I was worried about how much metal was being removed. But reasoned that the bare minimum I could rapidly remove was a depth equal to the machined 'flats' that a wrench is intended to lock against. Hopefully this picture shows the relief in sufficient detail.

Removal of any further material was done around the steel pin. Not on the pin itself.

P1010536_zps21471742.jpg


At this point, I used a crescent wrench to rock the brake back and forth. Not hard clockwise to try and remove. Rather, gently back and forth as if trying to break a coat hanger wire with pliers. The point was to assist in breaking any remaining metal bond on the weld.

Once I had worked it back and forth sufficiently, the pin actually popped out completely. From there it was a simple matter of unscrewing the brake (counter clockwise) until it was completely off the firearm.

Here is a shot of the pin as it came out of the brake.
P1010535_zps3b29c0a5.jpg

You get another really good idea of the depth of material removed here. You should pay VERY close attention to this picture with the steel pin. See how much deeper the pin goes into the muzzle brake? That shows the broad safety margin you have in terms of material you can remove without damaging the barrel threads.

Despite my worries to the contrary, I wasn't even close to the threads. No more than half way through the brake and the job was done. ;)


One final angle for those considering similar home surgery
P1010539_zps35dd3668.jpg


Was it worth the effort?

I certainly think so. Installing the 5/8X24 AAC 51T brake was not difficult. The threads were not damaged or marred in any way. So a couple of tries seating the new brake and the addition of two shims had the task completed in entirety. Torqued to 55 ft-lbs as per spec and called it a day.

Here's the completed assembly.
P1010541_zps47f769d1.jpg


I hope the pictures are satisfactory and help you overcome any reservations about doing this easy job yourself.
 
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Removing material should be done like any other metal working operation. Slowly and carefully.

Using either a dremel, grinder or hand file, you should remove approximately 3mm of material from the spot weld. At the start, you will only see shiny bare metal as the weld has blended the pin together with the factory muzzle brake's steel.

As you progress, you will start to see a black ring develop around the pin.

The first picture here should show you how deep in this pin goes.
P1010538_zpsc0febcf2.jpg


I was worried about how much metal was being removed. But reasoned that the bare minimum I could rapidly remove was a depth equal to the machined 'flats' that a wrench is intended to lock against. Hopefully this picture shows the relief in sufficient detail.

Removal of any further material was done around the steel pin. Not on the pin itself.

P1010536_zps21471742.jpg


At this point, I used a crescent wrench to rock the brake back and forth. Not hard clockwise to try and remove. Rather, gently back and forth as if trying to break a coat hanger wire with pliers. The point was to assist in breaking any remaining metal bond on the weld.

Once I had worked it back and forth sufficiently, the pin actually popped out completely. From there it was a simple matter of unscrewing the brake (counter clockwise) until it was completely off the firearm.

Here is a shot of the pin as it came out of the brake.
P1010535_zps3b29c0a5.jpg

You get another really good idea of the depth of material removed here. You should pay VERY close attention to this picture with the steel pin. See how much deeper the pin goes into the muzzle brake? That shows the broad safety margin you have in terms of material you can remove without damaging the barrel threads.

Despite my worries to the contrary, I wasn't even close to the threads. No more than half way through the brake and the job was done. ;)


One final angle for those considering similar home surgery
P1010539_zps35dd3668.jpg


Was it worth the effort?

I certainly think so. Installing the AAC 51T brake was not difficult. The threads were not damaged or marred in any way. So a couple of tries seating the new brake and the addition of two shims had the task completed in entirety.

Here's the completed assembly.
P1010541_zps47f769d1.jpg


I hope the pictures are satisfactory and help you overcome any reservations about doing this easy job yourself.

Looks great!

My Battlecomp BABC should be here Monday, so I'll be venturing into this project probably tomorrow. Your post is exactly what I needed to see in order to begin the task, thank you.
 
Looks great!

My Battlecomp BABC should be here Monday, so I'll be venturing into this project probably tomorrow. Your post is exactly what I needed to see in order to begin the task, thank you.

Good stuff.

Nice to have a community to share this stuff with. Someone here helped me and the least I could do was to give a little back.


Here is are a couple older 'before' pics, for reference. (Yes. I am enjoying my XCR and love to share pics of it)

945412_10151412095606949_1786460212_n_zps6d775612.jpg


P1010505_zpsbb66232d.jpg


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This was actually the maiden shoot with this rifle, taken at Alberta's Wildwood range. 'Break in' consisted of 250 rounds of 7.62x39mm russian milsurp through the rifle on gas setting 2. No stoppages. Only issue was a single failure to lock open on last round.

Accuracy to 300 meters was precisely exactly as expected with a 4 moa red dot. (Barrel is torqued to 250 inch lbs with a proper wrench)

Not a heavy run through. But for a recreational shoot I was very satisfied nonetheless.
 
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Well my BABC arrived today so I set about the task of factory muzzle brake removal..... Things did not go well.

In fact I have walked away from the job as of 10 mins ago. I am near certain I have gone way to deep and the f*****g pin still will not come out. I believe my mistake was grinding everything too low and then trying to isolate the pin. I can clearly see the pin at this time, but do you think that little prick will free up; no. Very, very angry at the moment, so I am going to leave it for now and price a new 6.8spc barrel.... F**k me....
 
Slug870,
Try taking a scribe or something pointy and sharp. Run it around the outline of the pin to clean up a bit of a groove, you don't need much. Then with the barrel properly supported in a vise with the pin facing down. Use a wrench to alternately tighten and loosen the muzzle brake. I'm talked more of a pressure than actual movement of the muzzle brake. For me the pin dropped right out at this point and I have removed 3 of them.
Good luck.
 
I do have a small press and I think that is my next course of action. I only hope I have better luck drilling! LOL!

Have you tried torquing the muzzle brake back and forth with a wrench as per the writeup? Best of luck, hope it all goes well.
 
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