Anyone ever had luck getting one of the barrel extensions off? I've got a 5.56 barrel I'm willing to sacrifice for a grendel conversion. Am I nuts or is it a viable possibility? Any advice is appreciated.
- Thread starter long range sponge
- Start date
I personally hadn’t thought of doing it myself, because the system simply isn’t designed for it. It’s probably more trouble than it’s worth. I had a link to a guy that did conversions, but it’s no longer a valid address. Possibly an other member has an up to date link. Definitely a weak point in that particular weapons system IMO.
I love my MRP 10.5”, truly does what it’s suppose to and doesn’t complain. I’ve been looking at getting a pair of the new Mloc LMTs but am hesitant to due to the continuing lack of after market barrel offerings.
I think I emailed the same person I believe El XOLO is referring to years ago and never got a reply about adding a MRP extension to a typical AR barrel.
I think I emailed the same person I believe El XOLO is referring to years ago and never got a reply about adding a MRP extension to a typical AR barrel.
Long range sponge,
Now that I think about it. I’m curious as to what would it take to remove the extension. If you’re willing to sacrifice the barrel, and post your experience online? I think it could be a good lesson. All in the ghetto science right?
RampedRaptor,
That’s unfortunate. It’s a good system for sure. I gave mine to my brother. Logistically it looks like stock piling barrels from LMT is the most practical solution. It’s also the reason why I’m building a more tradition style SPR.
Now that I think about it. I’m curious as to what would it take to remove the extension. If you’re willing to sacrifice the barrel, and post your experience online? I think it could be a good lesson. All in the ghetto science right?
RampedRaptor,
That’s unfortunate. It’s a good system for sure. I gave mine to my brother. Logistically it looks like stock piling barrels from LMT is the most practical solution. It’s also the reason why I’m building a more tradition style SPR.
Tuesday is my next day off. I'll pull the 5.56 barrel and look at it. My wife's uncle is a machinist so I may have him check it out next week. Maybe he can fiddle with it and make relief cuts to release the extension. If we come up with a plan or actually make some progress I'll definitely take pics/video and post it.
The mrp extension is the same length and diameter as a standard ar15 extension, minus the locating pin.
I did some 6.5G barrels by dremelling the locating pin off, installing the barrel-getting the feed ramps lined up, marking, and round filing the front bolt slot. Not elegant, but it works.
Of course a smith could do a much better job.
Std. extension measured with calipers. Dia.=.999”, length to flange=.987”.
I did some 6.5G barrels by dremelling the locating pin off, installing the barrel-getting the feed ramps lined up, marking, and round filing the front bolt slot. Not elegant, but it works.
Of course a smith could do a much better job.
Std. extension measured with calipers. Dia.=.999”, length to flange=.987”.
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Laseredge,
That’s actually good to know. It’s probably a good idea for anybody with this weapon system to know these things. That way we can throw something together in a pinch, or God forbid in some kind of emergency.
That’s actually good to know. It’s probably a good idea for anybody with this weapon system to know these things. That way we can throw something together in a pinch, or God forbid in some kind of emergency.
There’s ways to modify existing ar15 barrels to work with mrps ...no need for the mrp extention.
@Skunkworx something like what @Laseredge mentioned? Any other input would be greatly appreciated. Thanks guys. I'm getting a lil project list for next week.
Found the thread apparently this works with mws and sr25 barrels as well,
https://www.ar15.com/forums/ar-15/-/12-509830/?page=1
https://www.ar15.com/forums/ar-15/-/12-509830/?page=1
I've looked into these conversions a few times. I have a 12.5" Noveske barrel on my bench that I'm working on making a fixture to convert to send to someone for T&E. I can post some pictures when I get a little further along in the process.
I had a barrel done by the guy on ar15barrels.com. Randall is his name. It turned out great. All he did was thread the portion in front of the extension and then put a sleeve on. Then the notch is installed for the cross bolt. Only thing it’s missing is the little thing that supports the gas tube. No big deal as long as you’re careful with it. No need to cannibalize anything. I had a stainless Grendel barrel done this way. Shoots great. I love the LMT setup.
I got a hold of Randall. He sent me a quote of approx $250 to thread the outside of the barrel near the extension and make the sleeve. I'll post up if I have it done.
Just got done making a prototype. Plan to offer this in the near future.
Looks great. Let us know. I have a proof barrel I want to get converted.
Please contact me when you get this process up and running, sir.
Regards
Interesting. I figured they'd just turn a sleeve a few thousandths under then heat it, drop it on then cut the groove
Got the typo fixed.
Correct, you’d need to supply those three things. No modification is done to the upper, just to verify fitment.
Heading to the range tomorrow to test this out.
Another barrel conversion 
Looks good!!! Are those threaded on or press fit? Also it looks like the sleeve goes over the chamber area in the front when the barrel tapers down, is there a gap there?
Tag this!
Have you done a 7.62 barrel for the MRP-H MLOK 15.5 LM308BML4A or MRP-H MLOK 12.5 UPPER LM308BML1 monolithic upper? I have confirmed D. Wilson will not do conversions for those uppers.
I do not have an existing barrel and was hoping to use one of these or something similar:
| Barrels with rifle gas length | |||||||||||
| Brand | L | Description | PN/SKU | Twist | Journal | Material | Contour | MSRP | Gas Block | Gas Tube | |
| Ballistic Adv | 18" | .308 HEAVY PROFILE RIFLE LENGTH AR 308 BARREL, MODERN SERIES | BABL308007M | 1:10" | .750 | 4150 CrMoV | Chrome | $240.00 | |||
| Ballistic Adv | 20" | .308 HEAVY PROFILE RIFLE LENGTH AR 308 BARREL, MODERN SERIES | BABL308006M | 1:11" | .750 | 4150 CrMoV | Chrome | $250.00 | |||
| Criterion | 18" | DPMS PATTERN 308 HYBRID BARREL, RIFLE GAS, NITRIDE | 1018S-HYR-N | 1:10" | .750 | SS-416R | Nitride | $359.99 | Badger Ordnance TDX Gas Manifold 0.750″ Stainless Steel | BCM Gas Tube | |
| Criterion | 20" | DPMS PATTERN 308 HYBRID BARREL, RIFLE GAS, NITRIDE | 1020S-HYR-N | 1:11" | .750 | SS-416R | Nitride | $359.99 | |||
| Criterion | 18" | DPMS PATTERN 308 HYBRID BARREL, RIFLE GAS, CHROME | 10180-HYR | 1:10" | .750 | 4150 CrMoV | Chrome | $359.99 | |||
| Criterion | 20" | DPMS PATTERN 308 HYBRID BARREL, RIFLE GAS, CHROME | 10200-HYR | 1:11" | .750 | 4150 CrMoV | Chrome | $359.99 | |||
| Criterion | 18" | DPMS PATTERN 308 HYBRID BARREL, RIFLE GAS, STAINLESS | 1018S-HYR | 1:10" | .750 | SS-416R | Stainless | $339.99 | |||
| Criterion | 20" | DPMS PATTERN 308 HYBRID BARREL, RIFLE GAS, STAINLESS | 1020S-HYR | 1:11" | .750 | SS-416R | Stainless | $339.99 | |||
| Fulton Armory | 18.5" | .308 AR, Medium Weight, 1x10, Stainless, Match Quality, FA by Criterion | FA-TU-003 | 1:10" | .936 | 410 | Stainless | M110 | $374.95 | Gas Block, Adjustable, Low Profile, .936, Clamp On, SLR Sentry | |
| Fulton Armory | 20" | Barrel, 20", .308 AR, M110, 1x10, Stainless, Match Quality, FA by Criterion | FA-TU-005-TM-SS | 1:10" | .875 | 410 | Stainless | M110 | $369.95 | Gas Block, Adjustable, Low Profile, .875, Clamp On, SLR Sentry | |
| Fulton Armory | 20" | .308 AR, M110, 1x10, Stainless, Threaded, Match Quality, Krieger | FA-TU-007-SS | 1:10" | .875 | 410 | Stainless | M110 | $634.95 | Gas Block, Adjustable, Low Profile, .875, Clamp On, SLR Sentry |
