Hacker News Reader

Comment by jandrewrogers | Hacker News Reader

The manual bolt closure is far from useless in a military context and has two common real-world use cases today that I am aware of.

The increase in twist was because the rifle failed to stabilize bullets in some environments during testing, which is a pretty gross defect. And higher twist rates don't decrease lethality, it is actually the opposite for well-understood reasons. Current barrels are 1-in-9 IIRC.

The switch to ball powder happened after the initial usage of the M-16, which is correctly characterized as a logistical screwup, and they ended up redesigning the rifle so that it would perform correctly with the ball powder.

View on HN

It wouldn't stabilize tracer rounds, it was perfectly fine with standard issue rounds. The manual bold close wasn't in Stoners original design, it was requested by the military. In my opinion the internal piston design is the true genius of this rifle. Recoil is almost straight back so follow up shots are much easier.

As the Russians seem to be moving to 5.56 the American military is looking to move to the 6mm class.

M4 barrels are 1:7. Civ rifles seem to be 1:7 to 1:9. (civ are more likely to use 55gr still; military is 62gr, and there are people using 77gr...)

I hate the forward assist, but not enough to delete it. I mostly use an X95 SBR (13") now, though.

"The manual bolt closure is far from useless in a military context and has two common real-world use cases today that I am aware of."

What are they?

It allows you to manually (re)load and arm the rifle very quietly; the normal charging action to chamber the first round in a magazine is quite loud and recognizable. Useful for stealth. And if you accidentally get a ton of dirty in the action when the bolt locks back i.e. when the magazine is empty, you can force the first cartridge on a new magazine to chamber through the dirt (the first shot will usually clear the dirt out of the critical areas).

Failure to stabilize the bullet was a feature, not a defect. At close range that unstable bullet had more killing power (Assuming fmg, not civi rounds). Increasing the twist extended range but sacrificed effectiveness at likely combat distances.

Stability in the air (external ballistics).

Yup. And flying slightly off-axis means greater chance of tumbling as you enter a soft target. It is the one time you dont want to be flying strait.

Reply on news.ycombinator.com