M&P 15 Volunteer XV Pro M-Lok & The 6mm ARC Parte Terza - Conclusione

03/07/2023 – In Maine, it is never good to say that winter is coming to an end and sunshine will soon follow… for a couple of reasons. The first, it will jinx this happy ending and it will snow until June. Second, men should never phrase the weather with such poetic flourish. It was, however, a terrific day and a nice opportunity to get outside with the S&W M&P 15 Volunteer, the place I find best to conduct live fire assessment. But first, let’s not get off topic. I need a welder.

In the olden days, first came fire, then followed shortly with two tanks, one filled with oxygen and one filled with acetylene, with lines feeding either a cutting or welding torch. My Uncle Eddie, a crusty ex-Marine, was a masterful welder and machinist. I remember him as a mustached wearing guy,  wearing a crumpled fatigue cap, brim curled up, and dark goggles over a suet covered, but smiling face.

Unfortunately, oxyacetylene welding is not a casual endeavor, and another recollection is from the pits at Island Dragway where a guy set up shop, welding on long ladder bars and modifying or making custom headers. Unfortunately, he did not understand the need for pivots on anything that connects differential to frame. Consequently, his ladder bars would often separate from their weld points, mostly at the front, at speed, giving way to the little known, non Olympic sport “Auto Pole Vaulting”.

After a short while, his headers became known as Leakies… which they did… profusely, and racing was often halted to give the starting line crew time to pick up, and/or sweep up, a shed primary tube or the occasional collector. It was all very exciting. Mr. Leakies career terminated, following a discussion with my cousin Gerry, a guy who could have made Jake LaMotta cry.

The current welding applications are vehicle patch panels, welding thin wall mild steel tubing, and fabricating 1/4″ steel brackets. The aims are vehicle repair/restoration and a powered custom cart, fashioned out of the same, to haul trash cans out to the street… and maybe haul them back. I may try welding aluminum.

MIG, gas and not, seems about right. Although the more I research, the more paid reviews I read, the more lost I become. Is double pulse MIG a way to avoid TIG? Do I want to avoid TIG? Do I need AC/DC or would Led Zeppelin get the job done? Should I say yes to Yes or turn over what is left of my battered IRA to Miller? No, the latter is not a real consideration.

I am open to suggestions. Portability is not an issue, cost is important… $600… $1,000 if I can swear for several days after purchase, both 120v and 240v services are in the work area… aka garage. The 240 is 50 amp service with 6-50 receptacles.

I am writing as fast as I can…

Back to the real reason we are all gathered here today.

The S&W M&P 15 Volunteer XV Pro M-Lok performed without skipping a beat. Magazines full of mixed ammo, light loaded to heavy, maximum cartridge overall length to short, below SAAMI minimum length spec. Shooting condition ran from 22°F to 40°F, cross winds were 10 knots to 30 knots gusting. Suppressed or not, other than a little soot back pressure blow back, the Voluteer just kept chugging along.

I was able to collect some accuracy data, but not all. Waiting form winds to calm down and working in snow and cold slowed progress severely. I was able to knock out a few more bullet selections, non boat tail, non VLD, non cannelured. All of the originals were left in place.

The 6mm ARC is a nifty cartridge, successful in bumping the AR 15’s lethality. The cartridge is relatively inexpensive to reload to respectable performance levels. There is further potential in bolt action firearms with a higher than 51,000 psi loading. At gas gun levels, it is deer hunting worthy. It is a solid addition to the S&W M&P 15 line up.

Personally, I would prefer the 20″ barrel Volunteer XV Pro DMR M-Lok. From a hunting perspective, I think there is something to gain ballistically from 4″ more of barrel. For folks with security applications, the short barrel benefits might be a beneficial compromise.

Load Data

Warning: Bullet selections are specific, and loads are not valid with substitutions of different bullets of the same weight. Variations in bullet length will alter net case capacity,  pressure and velocity. Primer selection is specific and primer types are not interchangeable. These are maximum loads in my firearms and may be excessive in others. All loads should be reduced by 5% as a starting point for development where cartridges have greater than 40 grains in capacity and 10% for cartridges with less than 40 grain capacity following safe handloading practices as represented in established mainstream reloading manuals. Presentation of these loads does not constitute a solicitation for their use, nor a recommendation.