Last month, I asked a question about how to get into CMP rifle matches using equipment that I have or could purchase. I already own an M1 Garand and an M1A (M14 clone) as well as a SIG SAUER 516 piston gun. I wanted to know if any of those would work or if I should instead be look at picking up an AR-15 platform gun. The general consensus was that the 516 would not be legal for Service Rifle CMP matches, so that’s out. Either the M1 or the M1A would be the way to get started without laying out any additional coin. I hate to admit it, but that was not the answer I was looking for . . .
See, I suffer from the terrible condition of holophilia: I regularly get the unnatural desire to go out and buy guns simply because I haven’t bought one in a while. Fortunately, I’m also able to sell guns that I no longer use to fund this disease. I’ve even sold several guns that I never even got around to shooting. The AWB scare of a couple of months ago was rather helpful in this regard as I was able to actually make some money on a few of my sales as opposed to losing cash on my flips.
With that as background, I was really looking for some folks to say, “Jim, go ahead and get that SIG SAUER M400 Hunter you were looking at and trick it out into a CMP match gun.” Guys, you let me down. Fortunately, my aforementioned affliction overrode the common sense that was so prevalent in the comments and I went out and got myself the M400 after all.
Now, what I could have done would have been to go out and pick up an Armalite AR-15 in the National Match Configuration such as the one that Foghorn reviewed a couple of years ago. Then again, maybe not.
Foghorn reported some interesting problems with his gun that he traced to some manufacturing issues a few months later and ultimately fixed with a new bolt carrier (at least $200). Either way, the chances of picking up a National Match Armalite at this time of the year with the high power season shifting into high gear and the backlog from the Great AWB Panic of 2013 still impacting the market was pretty slim.
So I decided that if I’m going to do this, I’ll need to build it myself. And I’m starting with the SIG SAUER M400 Hunter as my base platform.
I chose this gun for several reasons. First of all, it has a 20” match grade barrel, rifle length gas system and a fixed stock – all requirements for the Service Rifle category. It also has an unthreaded barrel and no bayonet lug which is nice because I can take it across the border into Massachusetts if I want to compete there.
Unfortunately, SIG aimed this rifle at the hunting market and assumed that users would just slap a scope or other optic on the flat top and be done with it. That means no front sight was integrated into the gas block. Furthermore, since the rifle shipped with a Magpul MOE hand guard with an integrated front sling mount, there’s no place to mount a sling once I changed out the stock for a CMP-legal classic hand guard. And the final reason I chose the rifle was that it was in stock at the local SIG dealer.
The first step was to change out the sights. I bought a Colt detachable carry handle from my local gun shop which had just gotten in a batch of surplus units so I got a good deal on a new piece of kit.
For the gas block, I decided to go with a JP Enterprises JPGS-2FS front sight with gas block.
I went this route for two reasons. First, it mounts to the barrel with screws rather than pins, so nothing special had to be done to the barrel to swap out the included low profile gas block for this one. Second, it has an adjustable gas system so the gun had just enough gas to cycle the bolt and no more. When I explained this advantage to one of my colleagues, he sneered at me and pointed out the gas ports built into the Ar-15 bolt. These, he told me, already regulate any excess gas so you don’t need an adjustable gas block.
While that’s technically correct, he overlooked one thing. The JP block isn’t designed to vent excess high pressure gas from an overloaded cartridge. Rather, it’s designed to tune the gas system so that the bolt doesn’t come flying back with any more force than it actually needs to cycle. This reduces the shock of the bolt hitting the rear of the gun and should help to improve accuracy on those 600 yard shots. The only downside to the block is that it doesn’t feature the standard sling mount one usually finds attached to the A2 front sight.
This is actually less of a problem than you’d think because for highly accurate shots, you don’t want a sling pulling directly on the barrel, as it will cause deflection and a change in point of impact. What was needed was an attachment that doesn’t actually pull on the barrel – afree floating solution. For this, I turned to the folks at White Oak Armament and their Service Rifle Float Tube.
This little gem attaches to the receiver of the upper and allows attachment of a sling and the hand guards so they don’t touch the barrel. This is certainly something that an experienced person could install, but I’m not that sort of person. Plus, I suspected that I’d have some clearance problems where the sling attachment point met the gas block, so this was something that I referred to the professionals at Wicked Weaponry in Hooksett, New Hampshire. Just as I thought, some milling was indeed required to get the float tube to properly mate with the gas block.
In addition to the float tube fitting, the Service Rifle hand guard needed to have its heat shield removed and the end milled to properly fit into the hand guard cap. By the way, the SIG M400 came configured with a round cap, but the hand guards I bought needed a triangular one. Fortunately Wicked Weaponry had one in stock.
Since this had to fit the Service Rifle as-issued specs, I needed to replace the Magpul hand guard and pistol grip with a stock rifle-length hand guard and A2 pistol grip. These were bought from Fulton Armory.
The trigger that came with the SIG wasn’t bad, but it was also not competition grade. I’ve had a lot of success with Geissele triggers, so that was the next thing that was swapped out. I went with their two stage SSA trigger. The rules of Service Rifle competition state that 4.5 lbs of pull is the minimum and since their SSA-E model has a slightly lighter trigger pull, it didn’t make the cut.
The final pieces of the puzzle were replacing the front sight post with an Armalite National Match post and the rear sight with an Armalite National Match Rear sight. One minor problem that I noted is that the Armalite rear sight screw extends further down than the sight screw that came with the Colt carry handle. What this means is that when the carry handle is attached to the rifle, the rear sight cannot be brought all the way down.
I suspect this may be a problem for long distance shots. I’m in the process of investigating my options. I may attempt to grind off a bit of the bottom of the sight screw so that it is flush with the bottom of the detachable carry handle. Alternatively, I could drill a small hole into the rail mounted on the receiver of the rifle, but I am loathe to make that sort of modification to a gun. I’m in the process of figuring this out with Armalite now.
Total cost for the build: about $1,700. For comparison purposes, an Armalite National Match rifle with a nearly identical part list would have cost around $1,200 before Newton. I know because I owned one. I sold it during the height of the AR-15 panic for $2,000, so depending on how you look at it, I either paid a bit more or saved a bunch. I’d estimate that today, if you were able to find one, you would probably be looking in the neighborhood of $1,700, so overall the cost was not too bad.
The JP adjustable gas block and Geissele trigger are nicer than what Armalite ships on their NM gun, but if you chose to forego the trigger upgrade, you’d have a price around $1,500. Geissele also offers the Geissele 2-stage trigger which they claim is the same as the SSA. That would save you $45 over the SSA. Since I already had an SSA in my SIG 516 and liked it, I decided not to roll the dice with the cheaper model.
I’m pretty pleased with the way everything turned out. I have an accurate rifle that qualifies for the Service Rifle category on the CMP competition circuit for a reasonable price. If you’re looking to build one yourself, this would be a decent place to start.
Bill of Materials
- SIG SAUER M400 $940
- Colt Detachable Handle $50
- JP GS-2FS $130
- White Oak Float Tube $105
- Handguard & A2 Grip $30
- Gunsmithing & Cap $130
- Armalite NM Sights $95
- Geissele SSA Trigger $219
Total build cost $1,690