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Military Guns and Ammunition

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This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

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PDW again   Small Arms <20mm

Started 20/12/20 by DavidPawley; 41036 views.
autogun

From: autogun

7/3/21

Interesting. In the Shrivenham small-arms museum there is an SA80 modified to have an electronic trigger, which can be set to any desired rate of fire. As I recall (I was told about it, the experiments took place before I had ever visited) the optimum rate of fire for controllability in auto was found to be 300 rpm.

EmericD

From: EmericD

7/3/21

autogun said:

Interesting. In the Shrivenham small-arms museum there is an SA80 modified to have an electronic trigger, which can be set to any desired rate of fire. As I recall (I was told about it, the experiments took place before I had ever visited) the optimum rate of fire for controllability in auto was found to be 300 rpm.

Yep, I think that everyone made more or less the same experiments.

That's why we selected a firing rate above 1100 rpm for the FAMAS, only to discover that from an operational point of view, what you need is semi-auto firing for dealing with medium or long range, and full-auto for short range. 3 shot burst consume 3 times more ammo than semi-auto at medium and long range without any gain, and does not produce the same effect that a longer burst at short range.

So the studies made during the '80s for the "follow on" FAMAS MSD focused on the lower bound of the rpm, and found than depending on the weapon configuration and ammo impulse, the best results were achieved with a rate of fire between 350 and 450 rpm.

Msg 7776.287 deleted
graylion

From: graylion

7/3/21

So the question is: how, in a roller delayed blowback, do you reduce the RoF? 

roguetechie

From: roguetechie

7/3/21

So, In a roller delayed blowback gun you're potentially going to have problems because you're dealing with natively, and NECESSARY, high bcg velocities because of the way it functions.

You could possibly get away with throwing a couple things at it simultaneously though.

Chiappa has a neat patent for their 9mm pdw thing that harvests energy off the fcg that could maybe work though.

How attached are you to roller delayed blowback?

PRM2

From: PRM2

8/3/21

Apologies for going off topic; when the French Armed Forces adopted the HK416, which has a cyclic rate in the 'bad' zone like most AR15 derivatives (disregarding the piston!), was any consideration given to asking for a rate reducer, or was this a secondary consideration which was too costly to diverge from an Off the Shelf procurement and a potential source of unreliability?

EmericD

From: EmericD

8/3/21

Allows for a long bolt travel and use the recoil-absorbing mecanism of the 75 mm Mle1897 field gun?

graylion

From: graylion

8/3/21

roguetechie said:

How attached are you to roller delayed blowback?

Not very

EmericD

From: EmericD

8/3/21

Well, since semi-auto firing is now the "only" firing mode used during training (full-auto is allowed in emergency case), we had no requirements for full-auto dispersion / rate of fire.

It's even more embarrassing when someone accidentally discharge a burst from his  HK416 F in the floor of a truck, claiming that the gun was in the "safe" position, when the selector was actually in "full-auto". During 6 months, this guy was putting his gun on "full auto" thinking it was the "safe" position, then goes to "semi" to fire and bring it back to "full auto" when not firing.

Excellent trigger discipline, but the training was slightly deficient...

graylion

From: graylion

8/3/21

EmericD said:

Allows for a long bolt travel and use the recoil-absorbing mecanism of the 75 mm Mle1897 field gun?

like in the GD LWMMG?

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