General

Project Complete: The Minuteman Rifle

The minuteman rifle

About a year ago, I wrote about an idea for a minimalist rifle. I wanted something great for general marksmanship and light enough for a long hike. I wanted a rugged and reliable companion. Inspired by the “bush rifle,” I wanted it to have an 18″ barrel, fixed rifle stock, and a basic A1 style sight. Essentially, I wanted a modern M16A1. I wrote a few updates on progress over time here, here, as well as my initial impressions of the barrel.

This is my original mock up done on Gunstruction over a year ago:

Mockup

Concerned about the election, I went ahead and picked up two more stripped lowers in August last year. One of those serves as the base for this rifle (the other went to a different project). I also picked up a barrel and other miscellaneous parts required over time. My move across the country and new career put a damper on the plans to finish the rifle. I was weary to have any valuable parts in the hands of a shop while I was moving. I didn’t want anything to return to an old address.

After the move, the primary challenges I faced was the melonite treatment on the Faxon barrel. Melonite is hell on drill bits for pinning a front sight base. Most folks using this barrel go the clamping (or screw in) low-profile gas block path. Another build I saw using a front sight base utilized Fulton’s power wedge system. I wanted to be old school and bomb proof, and wanted it pinned.

Finding someone to do it was the hard part.

After making a few connections, I was directed to Drew at WAR Rifles in Manassas Park. They agreed to do the drilling, pinning, and upper assembly for a very reasonable fee. Drew and his guys are very friendly guys with quality work. I plan on going back to them for other projects with my bolt rifle.

Once I got it back, I took care of a few final touches. I named it the Minuteman Rifle in homage to both my previous career as a Minuteman ICBM officer, and that it also reminds me of a modern minuteman’s rifle. It is no-frills, built for riflecraft, and should be pretty damn reliable. It carries and balances like a dream.

 

Parts List:

Lower Half:

  • Rainier Arms stripped lower
  • Sionics LPK
  • Hogue Overmold grip without hump
  • Magpul MOE rifle stock
  • BCM rifle buffer tube, spring, and A2 buffer
  • ALG ACT trigger
  • Magpul MOE trigger guard
  • V-Seven short throw safety (non ambidextrous)

Upper Half:

  • Rainier Arms Non-FA stripped upper
  • Faxon 18″ Gunner Barrel (1/8 twist)
  • BCM BCG
  • BCM Gunfighter charging handle (Medium latch)
  • BCM .625 front sight post and handguard cap
  • BCM delta ring assembly
  • BCM Sling Swivel
  • Ashley Performance 1/2 MOA front sight post (with white strip)
  • AAC Blackout flash hider
  • Magpul MOE Rifle handguard
  • Daniel Defense A1.5 rear sight

Other Components:

  • Precision Armament Accu-Washer kit for muzzle device
  • TAB Gear Sling

The Reasoning

I wanted this to be an easy to carry, soft-shooting, “Everyman’s Rifle.” I took inspiration from the original M16A1, but wanted to modernize it a bit. There would be no undue weight or complexity.

The Rainier Arms upper and lower receivers have the tightest fit I’ve ever seen. After pulling the pins, it takes a great deal of effort to separate them. Assembled, the rifle feels solid in the hands. There is no rattling, play, or movement of any kind.

I use the 18″ Faxon Gunner barrel mostly because I thought it looked interesting. It has a nice profile, good reviews for accuracy (I haven’t gotten it out there to test yet), and I wanted to see what the melonite treatment is all about.

 

The AAC Blackout was something I already had on hand. It was the first muzzle device I bought way back in my first build, and it has moved around a bit looking for a home. I swapped the rifle it was on back to a classic A2 birdcage. In both cases, I opted to use the Precision Armament washer system to get good alignment without over torquing the device. I realize AAC says that no washers or alignment is needed, but I’m a bit picky with my rifles and wanted the flats of the device to be vertical. I didn’t want to apply too much force on the threads to get there, since it would negatively affects accuracy. I’ve also found that the best shooting teams go a bit past hand tight. With the washer kit, all I have to do is pick the right thickness, torque it just a bit, and add a little bit of Rocksett.

I stuck with Magpul furniture for the fixed stock and rifle handguards. There is no particular reason other than I like them both. They are very comfortable, stable, and I happen to think they look nice. I’m sure a question will arise as to why I didn’t free float it. The answer is that I just flat out liked the Magpul handuards. I already have another rifle (20″ BCM) that I installed a free float rail on, so I thought variety would be nice.

The rear sight took a while to decide. My choices were between a detachable carry handle (which I already had on hand), LMT, Larue, and DD. I eliminated the first two because adjustable rears were outside the set-and-forget nature I was going for. The DD A1.5 ultimately won out over the Larue because it is slightly lighter and I got a pretty good deal on one. They both have great reputations. Scalarworks recently came out with a very lightweight rear, but i honestly don’t care for its appearance.

The Ashley Precision front sight post was an experiment. Since I planned on this being a nearly pure iron sight rifle, I wanted to offer any assistance that I could. The white strip definitely speeds up acquisition, and the 1/2 MOA adjustment is a bonus. I’m a fan of this sight post.

Of all my rifles, this is now the only one with a single stage trigger. The ALG ACT is a product-improved milspec trigger. It does its job fine, but I can definitely tell the break isn’t as clean as my three Geisseles or the Larue MBT. Since it is essentially a dressed up mil-spec trigger, I don’t think it could get any more rugged.

You will not find any QD studs or swivels on this rifle. The goal is ruggedness, and you don’t get much better than avoiding QD all together. I stuck with a more traditional shooter sling from TAB. I already had it on hand, and it is a very good sling. It was replaced by a SAP Positional Sling on my precision rifle, so this seemed like a great way to let the TAB live on. Equally in contention was my RS2, which is on the M1 Garand and is a closer approximation of a traditional GI sling.

I’ve become a huge fan of short throw safety levers. I’ve been utilizing BAD-ASS-ST levers, but I find that I dislike the ambidextrous nature of them. Unless I am careful, the knuckles of my shooting hand are liable to bump the safety back into the “safe” position. For this project, I decided to keep the short throw lever but only on the left side. I may go back and do the same to my other ARs.

For now, I’ve left the remainder of the top rail open. I do love the KISS concept, but I also understand the advantages that an optic brings to the table. If I ever felt the need, I could slap a red dot on here and carry on.

 

Wrap Up

And there you have it. I’ve been creeping along with this project for about a year now, and I’m happy to see it come together. At a final unloaded weight of 6.9 lbs, it is the lightest rifle in my safe. While not an ultralight by any means, it was never intended to be. It is also nearly perfectly balanced, with the center of gravity falling on the front half inch of the magazine well.

I’m not sure when I’m going to get it to the rang for a quick zeroing and accuracy test. I’ve got a bead on a local indoor spot with a 100 yard range and a good reputation. After that, perhaps a jaunt in the woods is in order.

 

Advertisements
General

Just One More Step on the New Rifle

mockup

This project is almost in the bag…or in the safe. Whatever.

I ordered the wrong size triangular hand guard cap by mistake. I didn’t check if the Colt one I purchased was for .750 or .625 barrels. I needed the latter, but ended up with the former. Not a big deal, since it’s a $3 part and already ordered the correct one from BCM.

Once I have that, the upper is off to West Coast Armory for pinning the FSB and final assembly.

I am very happy with the mock up pictured above. I assembled all the parts without final torquing, and it handles beautifully. Balance is right at the rear of the magazine well. The Rainier Arms upper and lower receivers have the tightest fit I’ve ever seen, and the whole thing just feels solid. I expect this may be a new favorite.

Not much longer until it’s off for a trip to the range.

General

The Skinny on Nitride Barrels

After I wrote about the Faxon barrel I’m using in the latest project, a question arose about the benefit of nitrided barrels. I’m not surprised, since the gold standard for so long has been chrome lining. Nitriding is just the “new thing” that all the cool kids on the internet are talking about.

But, what is it? Does it have any benefits over the tried and true methods? I want to dig into that for a bit.

Here is a quick description of the process from an industrial coating company, IBC Coatings, I’ve bolded some key elements.

Salt Bath Nitriding/Nitrocarburizing was originally created as an alternative to gas nitriding that would produce a more uniform case through surface contact between the substrate and liquid salt. When steel parts are placed into a preheated liquid salt, there is sufficient energy localized near the surface due to differences in chemical potential that then allows nitrogen and carbon species to diffuse from the salt into the steel substrate. The process is carried out at 750-1050°F, making it faster than gas nitriding. Lower temperature cycles produce an S-Phase/Expanded Austenite case in stainless steels. Post-oxidation after nitriding combined with polishing produces coatings with exceptional appearance (black color) and high corrosion resistance (greater than electrolytic chrome plating). To ensure part quality, our salt baths are continuously monitored, with chemistry adjustments made when necessary.

Salt Bath Nitriding/Nitrocarburizing is well known under various trade names, including ARCOR®, TENIFER®, TUFFTRIDE®, MELONITE®, and QPQ®.

The idea here is that the barrel is immersed in a sodium-nitrogen solution and heated to a high temperature. The ensuing chemical reaction causes the nitrogen to diffuse into the surface of the barrel (inside and out) and convert a thin layer of the surface into a very salt-bath-nitriding-dhn.gifhard coating. From what I can find, the surface of a nitrided barrel is in the realm of 60 to 65 Rockwell, while the typically gun barrel steel is 28-32 Rockwell. This surface layer becomes a very corrosion resistant “case” around the barrel steel.

Additionally, the surface layer created by the nitriding process has a much lower coefficient of friction compared to bare metal or chrome. Ostensibly, this would mean that nitriding barrels may present a small boost in velocity. I have read some accounts verifying this on Accurate Shooter, but it was only by about 1% or so. Still, a boost is a boost and nobody will ever turn down velocity.

 

The real benefits of this process is that nitriding performs all the same functions as chrome, such as increasing corrosion resistance and prolonging the life of the barrel, and it does it without the associated negative impacts on accuracy. Since the surface of the bore is being converted into a harder material, rather than adding a new layer of material, the uniformity of the bore is maintained. As I’ve mentioned before, consistency is accuracy.

From my reading, this process is not perfect, though. The surface may be harder than chrome, but it is not as heat resistant. Weapons fired on fully automatic for prolonged periods may burn through the nitrided layer quicker than a comparable chrome layer. This should not really be a factor for semiautomatic weapons, though. Also, per the bolded portion in the paragraph above, the barrel must be heated to a temperature of 750 to 1050 degrees fahrenheit. Coincidentally, this is about the same temperature that barrels are heat treated/stress relieved. There is a very real risk that heating to such temperatures (particularly with stainless barrels) can undo heat treatments already performed by the factory that machined the barrel to begin with. While I haven’t seen anyone mentioning decreases in accuracy after nitriding, I have seen many warnings to not perform the process on a barrel that’s already been fired a significant amount. The micro cracks in the surface of the bore and chamber of such barrels may be aggravated by the high temperatures, making them worse and degrading accuracy.

The Faxon barrel I purchased is my first real experience with a nitrided barrel. I’ve handled at shot some rifles with them before, but I’ve never done accuracy evaluations or had to care for one. For the most part, I’m told that care procedures are the same- except that some products (like those from Bullfrog) will tend to discolor the finish.

I will continue reporting back on my results. If you are waffling back and forth on a standard barrel or chrome lined barrel, I don’t think you can really go wrong either way as long as the barrel is well made. Find one that suits your needs in size, profile, and accuracy and let the manufacturer worry about the rest.

General, Reviews

Initial Impression: Faxon 18″ Gunner Barrel

img_0925

I received this in the mail over the weekend. It is a Faxon Firearms 18″ Gunner barrel. Here are the key stats from Faxon’s web page:

  • Barrel Type: Button Rifled
  • Barrel Caliber: 5.56 NATO
  • Barrel Twist: 1:8
  • Barrel Length: 18″
  • Barrel Profile: GUNNER Light Hybrid
  • Barrel Gas System: Rifle Length
  • Inside Finish: QPQ Nitride
  • Outside Finish: QPQ Nitride
  • Muzzle Thread: 1/2-28 TPI (Threads Per Inch)
  • Gas Block Diameter: .625″
  • Gas Port Diameter: .093″
  • Gas Block Journal Length: 1.9″
  • Barrel Extension: M4
  • Magnetic Particle Inspected!
  • 11-degree Target Crown
  • Weight: 1.44 lbs

This is part of my KISS walk-around rifle concept, which I wrote about a while back. The intent is for a lightweight iron-sighted rifle that would make a great companion for walking around in open areas, or handing off to someone as an introduction to marksmanship. This is my original mockup done through Gunstruction.

B+Cfilg06wwtAAAAAElFTkSuQmCC

I already have the lower assembly complete, which leaves the upper receiver, operating parts, and final assembly.

This barrel makes a very positive first impression. The QPQ/Melonite/Nitride coating is a nice even black. While not as flat as a parkerized barrel, it is not really shiny, either. The machine work appears very clean, with no sharp edges or burrs in the threading. I don’t have a bore scope or lathe to check for runout or rifling quality, but the buzz on the internet was that both have proven to be good.

The profile is the most interesting part to me, though. Notice that it continuously tapers from chamber to the gas block journal (which is sized to accept a standard .625 FSB), and then continues the taper down to the end. The muzzle end flares out a bit again to allow for solid contact with a muzzle device. The section in front of the gas block journal might be one of the thinnest profiles I’ve seen on an AR.

I happened to have enough spare parts on hand to get a better mockup and play with weight/balance a bit. I grabbed my old Spikes stripped upper, standard barrel nut, Samson/Rainier Evolution rail, and a birdcage flash hider and slapped it together (nothing fully torqued, of course). I borrowed a BCG and charging handle from another rifle.

IMG_0926.JPG

I’m not going to lie, this feels pretty damn nice. I’m almost tempted to mount a gas block, torque it all down and call it good. The rifle feels very spright in the hands, with a good rearward balance at about the middle of the magazine well. The Samson/Rainier rail weighs 11 oz, not including the standard barrel nut. The Mapul MOE Rifle handguard I will be using weighs just a bit more, at 12.2 oz. I also have to include another .8 oz for the handguard cap and delta ring assembly, which I don’t have mounted here.

In any case, a bit more forward balance by a few ounces would still leave a very nice handling rifle. I still need to order a few more parts, and then send it off to have the FSB drilled and taper pinned. I will probably have final assembly done at the same time.

The more parts that come in, the more excited I am to have this project complete.