Hopefully this will be the ultimate bolt life discussion thread...

[constructor]

If we are thinking about the same MG-42, changing from the locking rollers to a multi-lug, rotating bolt would have been a major alteration to the design.





Compared to the rotating bolt design of the MG-34:

Not even close. He was designing a lighter weight GPMG to replace the 240 and said he was converting a MG42.
I know he had already built an AR10 in 7mmUIAC to test the performance of the cartridge and was wanting to build a FA mg to show what it would do as a belt fed.
https://www.thefirearmblog.com/blog/...ult-cartridge/
https://www.m4carbine.net/showthread...rray-cartridge
I've looked around and don't see any bolts that look like the ones I made. They say he was working on a PKM and he was in the sand box so it could be something found on the ground over there or something they had in inventory. It wasn't an AR10 bolt bolt, was longer than an AR10, 5 lug but closest to an AR bolt than anything else I have seen. Was not a MK48, Mk46, m249, M60, SCAR17.

[lysander]

That would have been interesting. Did a prototype ever get made?

Although, one thing I can say is designing links is one of those things that looks simple from the outside, but becomes a nasty can of worms when you try to do it. There was a lot of effort into what would be the M27 link, despite it looking like "just" an M13 scaled down.

[M995]

10 to 12 rpm = one round every 5 to 6 seconds, which is the maximum sustained rate of fire.

120 to 150 rpm is a 3 to 5 round burst every three to four seconds.

It's enough to get the barrel up to about 500 to 600 degrees F after 120 rounds.

I'm just wondering whether the above mentioned firing schedule was for a different test than the US Army's 2007 baseline assessment for reliability for the M4? IIRC, you said that the 2007 baseline assessment used the following firing schedule:

120 round cycles with two 30-round magazines shot in bursts and two 30-round mags shot in semi-auto.

semi-auto mags: 1 round every second

burst mags: 3 to 5 rounds every 5 seconds for full automatic weapons and 3 rounds every 5 seconds for 3-round burst weapons.

[lysander]

I'm just wondering whether the above mentioned firing schedule was for a different test than the US Army's 2007 baseline assessment for reliability for the M4? IIRC, you said that the 2007 baseline assessment used the following firing schedule:

120 round cycles with two 30-round magazines shot in bursts and two 30-round mags shot in semi-auto.

semi-auto mags: 1 round every second

burst mags: 3 to 5 rounds every 5 seconds for full automatic weapons and 3 rounds every 5 seconds for 3-round burst weapons.

1 round every second is way too fast, I must have mistyped, According to the TOP, you should not exceed the maximum sustained rate of fire.

[M995]

1 round every second is way too fast, I must have mistyped, According to the TOP, you should not exceed the maximum sustained rate of fire.

Thanks for the clarification and no worries. May I ask which TOP you are referring to? The version of TOP 3-2-045 that's available online says to fire the two semi-auto mags at a rate of 1 shot per second and the remaining mags in 3-5 round bursts at approximately 85 rpm.

[lysander]

Maybe an older version.