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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; 40682 views.
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?

taschoene

From: taschoene

8/3/21

graylion said:

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

Adjust the shoulder angles on the locking piece for one.  Shallower angles mean more delay which should mean lower cyclic rate.

PRM2

From: PRM2

8/3/21

Thank you, that is a very pragmatic approach without being distracted by emergency cases.  

Farmplinker

From: Farmplinker

8/3/21

(Insert Favorite "This Is My Safety" meme here)

In reply toRe: msg 292
graylion

From: graylion

9/3/21

Also it strikes me that one way of making the ammunition more compact is CTA. What do ye think? Chances will be better if NGSW ends up CTA of course

stancrist

From: stancrist

9/3/21

CT cartridges are shorter, but also fatter.  This will reduce magazine capacity.

graylion

From: graylion

9/3/21

been wondering that - how much liberty is there in the proportions?

roguetechie

From: roguetechie

9/3/21

Not as much as you'd likely want/need.

There's potential workarounds but they definitely aren't risk free and would require some level of development.

The much better option is something like shellshock nas3 cases which can be ran up to pretty hefty pressures safely and reliably. I think you might get a slight bit of extra case capacity over brass even.

Being able to run 70k psi Though should do you well.

Oh, did I mention that they're also cheaper than brass cases? 

Since it's a pdw you're probably gonna go through a bunch of rounds so that's not a bad thing.

stancrist

From: stancrist

9/3/21

graylion said:

been wondering that - how much liberty is there in the proportions?

Case proportions vary with projectile length and diameter, and propellant charge.

Presumably what you actually mean is, how small can the case diameter be made?

With the Textron design, case diameter is ~0.195" greater than the bullet diameter.

Caliber ---- Bullet --- Case

5.56mm --- 0.224" --- 0.419"

7.62mm --- 0.308" --- 0.504"

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