General Purpose Rifle

A General Purpose Rifle (GPR) for a General Purpose Cartridge (GPC)

What criteria should a General Purpose Rifle meet, given that it uses a corresponding General Purpose Cartridge, as described elsewhere in this blog? My thoughts on a GPR follow.

1. AR-10 platform — the AR-15 platform simply does not have enough COAL for long-nosed high BC projectiles, not at sufficient velocities anyway. Furthermore, the AR platform has the advantage of being modular, so that improvements can be made, as time passes, in a stepwise fashion.

Bullpups have the advantage of a shorter length. But there is no bullpup equivalent of the modular AR platform. Each bullpup design is different and propriety. Currently, in my opinion at least, the disadvantages of a bullpup outweigh its advantages.

2. Effective functioning with a 14.5-inch barrel — If the cartridge is well-designed, the rifle and ammo should be effective out to 700 or 800 meters even with the relatively short 14.5 inch barrel. Total length of the rifle with that barrel is about 33 inches (~840 mm).

3. Light weight rifle — I would suggest that an AR-10 with a 14.5-inch barrel can weigh as little as 7 lbs. The DPMS GII and the POF Revolution each weigh about 7.25 lbs with a 16″ barrel. They each represent different takes on the concept of a hybrid between the AR-15 and AR-10. They allow for a longer COAL, but in a lighter smaller package. With a few changes, the weight could be dropped to 7.0 lbs or less.

4. Magazines with 25 rounds — possible with the 6.5×50 due to its narrower diameter as compared to the 7.62×51

5. An effective muzzle device — short of using a large and heavy silencer, a GPR muzzle device should address four areas of concern:

* flash – reduced more than a birdcage flash hider

* blast – muzzle blast is redirected away from the shooter

* sound – mitigated as much as possible, without the size and weight of a full-size sound suppressor

* recoil – reduced to the same level as an M4A1 carbine with a birdcage flash hider (5.56 NATO round)

6. Reliability in both full-auto and semi-auto fire modes

7. Accuracy of 2 MOA or better

8. Folding and collapsing stock – I suggest that the Dead Foot Arms MCS could be used (perhaps in an improved design) to allow the rifle to be fired even when the stock is folded. This would make the gun as compact as a bullpup, with none of the disadvantages.

Wow. That’s quite a wish list. The most difficult criteria to meet, I think, will be the accuracy and the muzzle device.

On accuracy, it’s hard to get a very accurate rifle that can also withstand all the abuse that a military gun must endure. Then, too, reliability and accuracy are something of a tradeoff. The most accurate competition target rifles are said to be less reliable.

The muzzle device requires a set of interrelated tradeoffs. Reducing recoil is difficult to do, if you don’t want to direct the muzzle blast back toward the shooter. And most muzzle brakes increase sound. But maybe it can be done.