So, a 7.62mm x51, which in civilian clothes is the .308 (read part one here). It has impeccable credentials, is still on active duty in sniper rifles, designated marksman rifles, and machine guns, and is carried by legions of hunters. Back in the 1960s and ’70s, poachers used FN-FALs in 7.62 to slaughter elephants. There is tons and tons of ammunition of all kinds readily available.
Next choice: Direct impingement or gas-piston operation. According to AR purists, no gas-piston gun is a true MSR, or PAR, or whatever you want to call it. Direct impingement was the brainchild of Eugene Stoner, whose AR-15 directed powder gas directly against the bolt carrier, forcing it backward and cycling the gun. The advantage is fewer parts and lighter weight. The disadvantage is that serious amounts of dirt and heat are blasted back into the bolt, and that a direct-impingement AR has to be kept clean and lubricated or it will not function.
A gas-piston gun, or a gas gun, your choice, bleeds gas from the barrel to push against a short-stroke piston which pushes the bolt carrier. It adds weight and machinery, and if your piston system ever needs replacing, you better hope the manufacturer is still in business, but on the other hand it keeps the heat and the dirt away from the breech.
I’ve heard that gas guns are not accurate. However, the only super-accurate AR I’ve ever shot was a gas gun.
In the end, I can only meditate on the fact that Sergeant Mikhail Kalashnikov’s masterpiece is a gas gun, and that it is the most reliable auto/semi-auto rifle ever made, and very possibly the most reliable rifle ever made.
So, gas gun.
This led me to SIG-Sauer, which makes an extensive line of gas guns, and the one that drew my eye was the Model 716 DMR, which leads us to a digression on military tactics.
Both the Marines and the Army have created the job of Designated Marksman to bridge the gap between Infantryman with M-4 carbine and Sniper with heavy, bolt-action scoped rifle. Tactically, the guy with the M-4 is expected to engage targets up to 300 meters. The sniper goes to work at 800 to 1,200. The Designated Marksman has everything in between 300 and 800. Designated Marksmen are always issued semi-autos, not bolt guns, because they sometimes must do a volume business. DM rifles are either massively rebuilt M-14s, or modified M-16s, and always scoped.
(The Russians first issued the Dragunov, which is a terrific DMR, in 1963, roughly 45 years ahead of us. How come godless atheist communists are so much better at weapons procurement than we are, huh?)
So, SIG-Sauer. I own several of their handguns, and I like the way they build handguns and do things generally. They never scrimp anywhere, or run in cheap parts to make a few dollars profit. Everything is put together like they give a s**t. I noticed that the feed ramps on the DMRs that I looked at were polished like glass. The detachable iron sights that come with the SIG 716 are detachable, and excellent. No one said, “Since we’ve got to put iron sights on this gun, where can we get cheap ones?”
The trigger is by Geissele. It’s a double-stage, breaks at 6.5 pounds, and is much nicer than the standard SIG trigger, although not in a league with a well-set-up Jewell. The medium-weight barrel is 18 inches long, has a standard thread at the muzzle for a can, or a flash hider, or a muzzle brake and, if I understand correctly, is chrome-lined for its entire length, which means that you will never be able to wear it out.
SIG lists the weight of the 716 DMR at 12.3 pounds without the magazine. My scale says 10.5. In any event, this rifle is a load. Put a scope on it and slap in a 20-round magazine, and it damn well does weigh 12 pounds plus. This may be an issue for you. It’s a rifle designed for careful, precise shooting, not run and gun, and if you’re looking for something for 3-gun competition or to take with you when Hillary gets into the White House and decent folk have to take to the hills, you may want to consider something a lot more portable.
However, I’m too old to go much of anywhere, and everything else I’ve bought in the last couple of years has been heavy and accurate, so why not?