Marvin Pitts from Nefarious Arms did an amazing job on the barrel treatment
The heart of building my “Do it all” carbine is the barrel. In order to get what I was looking for in a very lightweight and handy carbine that carries and shoots like a light M4, but offers better penetration and performance than 5.56mm and hits like a light .308. I also wanted to avoid the many issues of a short-barreled 5.56mm or for that matter, a short .308 (excessive blast, recoil and accelerated wear). I was fortunate to locate the perfect person to get my new little carbine to where it has a near perfect level of length, weight, and balance.
Marvin Pitts of Nefarious Arms has a fantastic reputation on all the reviews I found on-line of work he has performed. I wanted to find a way to lighten the factory 12.5” LMT MRP 6.8 SPC barrel. Marvin does a golf ball style dimple treatment to the barrel to relieve weight, but keeps the same contour of the barrel. Marvin has prior experience working at both Knight’s Armament and currently works at the Wilson shop as his day job. This is someone who has the experience and skills to do a high quality job on a project like mine. I contacted Marvin via e-mail and we came up with a plan for my project.
My barrel was sent to Marvin along with a Surefire Muzzlebrake/Suppressor adaptor for the 6.8 SPC. This is a fairly unique device as it is shorter and smaller than most of the Surefire brakes, and has a treatment on the front that looks like a meat tenderizer. Marvin met the agreed on timeline for the work and when I opened the box that I got back, my jaw literally dropped at the sight of my barrel. I do not take pictures to a level that does this thing justice. I am planning on a more in depth review for the print media in the future, and hopefully Ichiro Nagata can better capture the quality. The barrel was fully dimpled, Cerakoated black and the Surefire brake expertly mounted.
I was luckily able to put the whole package together while at a demo at an agency with an agency owned M4 lower. It is amazing how much better it feels than with the factory 16 inch barrel that is currently in the upper while waiting to get it SBR’d. I have plans for this gun to be able to shoot a much wider variety of ammunition than the 6.8 SPC 110 grain Hornady that I run almost exclusively in my other 6.8 SPC MRP’s. This barrel will be sent out to have the chamber cut for a SPC II chamber to handle some of the higher-pressure loads as well as hoping that it works well with some of the “military loads” that are coming down the pipe.
I have also made some minor changes to the rifle. I am now running the Tango Down front sight with a Surefire 200 Lumen 300C Scout light behind it and am moving the Fusion Unity set up to a new 5.56mm Centurion build that will be a better platform for it. I have had this carbine at several shows with Aimpoint and everyone who picks it up really loves the feel of the LM8 upper. When fully assembled down the road, the Nefarious Arms modified barrel is a perfect fit for the upper.
Marvin Pitts can be reached at: Nefariousarms@live.com.
Absolutely fantastic!
A 12″ 6.8 mm is my preferred SBR and my favorite lightweight, quick handling AR15 that offers more capability than a 5.56 mm. If more than that is needed, I’d step up to a 16″ .308 KAC or LaRue.
Very nice, DB. Paul Ertsgaard built a nearly-identical upper for me that is surprising accurate. It’s my favorite gun for hog hunting.
What about the new 140 berger loads Will you be avble to use those?
I honestly had not even thought about the 140’s. I do not reload, and do not hunt (although it is only a matter of time before I end up doing some hog hunting here in Texas), so I am generally more interested in defensive rifle use against human predators. In this regard I was looking more towards some of the new rounds coming from Federal, and I have had great luck with Hornady’s 110 gr. stuff. I tend to be the guy who likes off the shelf stuff, and easily supported systems like the LMT and factory ammunition. As far as long range shooting where I would be using VLD’s…I have much better systems in .308 for this. I would much rather use my LaRue PredatOBR that shoots .49 MOA and is set up with a 3.5-21 HDMR, or my Colt 901 with its Bushnell 1-8.5 than this 12.5″ LMT LM8MRP with a Micro Aimpoint.
I know that a lot of the 6.8 SPC shooters are very geared towards pushing the system to its max for performance and for hunting use, but I am not that guy. I am simply a guy who looked at a lot of the work by DocGKR and thought about what is the best route to go in a easy to handle carbine in the 10.5-12.5″ barrel length, and this is what I cam up with. I could have easily gone with a full boat custom build from somewhere, but the Nefarious dimpling work gets me the weight and balance I wanted with a factory, user replaceable barrel combined with a proven system from a proven manufacturer that I can easily support myself.
I can’t help but think Barnes 85- or 95-gr TTSX projectiles would be very effective for felon and quadruped control. Barrier blind and very disruptive to tissue; my oldest, who popped a couple of whitetail w 12.5 BFMI M468 in ’05 loaded with the wan 115 OTM from Big Green, zapped a couple this Jan. w 110 TTSX at about 3,300+ from std .270. Very sanguine visuals. Lighter pills from 6.8s should be poison on hogs or armed miscreants…
Darryl I’m telling my wife its your fault when i get my 6.8spc barrel for my MRP. I’ve had the MRP for a while, but with having a SPR and a few 14″ guns the 16″ MRP never found it getting much rotation. Since its a rifle length MRP, getting a 300 blk and probably a 6.8 barrel just makes more sense… well at least thats what i’ll keep telling myself.
If I was doing a rifle length MRP, the 6.8 SPC is a no brainer. In a 16″ gun, 6.8 SPC makes far more sense to me over the .300 Blk. In an 8″ gun, it would be the other way around. I took a 16″ MRP in 6.8 SPC through police sniper school (with the 18″ factory LMT stainless match barrel cut to 16 and a Surefire brake) and took second place against 27 bolt guns. That gun with Hornady 110gr. ammo shot very well, especially in the “practical exercises” as opposed to just shooting bipod prone groups at a 100 yards.