What-if SMG for late 1930s and on

[stephen the barbarian]

tbh, mine would likely end up as the bastard lovechild of the M50 Reising and the Ingram Model 6,
i like the tilting block delayed blowback action of the m50, but the rest of the gun needs to be redesigned and simplified

 

[marathag]

British used one ammo type on Enfield revolver, another on Browning HP, and the classic .303; add the 7.92mm for Besa

And .455 still, plus 45 Auto for LL Tommy guns
30-06 too
.50 Vickers
.50 Browning
.55 Boys

 

[tomo pauk]

And .455 still, plus 45 Auto for LL Tommy guns
30-06 too
.50 Vickers
.50 Browning
.55 Boys

Roger that, although the last 3 rounds are not really for small arms.

 

[marathag]

Roger that, although the last 3 rounds are not really for small arms.

..as complaining squaddies said about having to hump the Boys AT around

 

[jsb]

So - let's 'make' as good SMG as possible. ......... Size, weight, RoF are important, so is reliability and suitability for mass production.

For who and when? The best might simply be a Sten/PPSh41 knock off depending on your industry and urgency?

 

[tomo pauk]

For who and when?

For countries that historically were making and using SMGs from late 1930s on.

 

[jsb]

For countries that historically were making and using SMGs from late 1930s on.

But that's virtually everybody, the issue is that the best advice for a SMG would be very different for the USA in 37 and Poland in early 39?

 

[Driftless]

For countries that historically were making and using SMGs from late 1930s on.

There's an element of changing ideas too. Think of the US use. The heavy and heavily machined Thompson from the 20's, through several iffy less costly, less sophisticated different makes in the late 30's. Still in small quantities in both ideas. It wasn't till seeing the Sten's and PPsh's used in great quantity that US shifted its planned use, and we got the development and improvement of the M3

 

[Vabasion]

SMGs should focus on rate of fire and stopping power for urban or close quarters combat. 100 meters is an acceptable range in such circumstances, most of the squad is composed of either bolt or semi auto rifles capable of reaching out much further and the machine gun which can do the same at a faster rate. What is lacking is the ability to clear buildings, bunkers, trenches and otherwise close quarters, around the corner fighting that often happened when taking or defending an objective. No SMG is going to be the war winner or turn the war around but well designed one can increase enemy cassualties suitably.

 

[tomo pauk]

There's an element of changing ideas too. Think of the US use. The heavy and heavily machined Thompson from the 20's, through several iffy less costly, less sophisticated different makes in the late 30's. Still in small quantities in both ideas. It wasn't till seeing the Sten's and PPsh's used in great quantity that US shifted its planned use, and we got the development and improvement of the M3

US Army was surely aware of Thopmson's drawbacks already in the 1920s, indeed it's high price and weight will be very visible, the former shortcoming will be especially be visible by late 1920s/early 30s due to the economic crisis and lower budget for Army needs. They also know that in many instances a SMG-outfitted infantry is very useful.
Does not require a genius for Army to conclude: okay, we need and want SMGs, but lighter and cheaper than Thompson. If it can reach another 50 yards - great; in not - not a deal-breaker.

 

[sonofpegasus]

Does anyone know what barrel length gives the highest velocity possible from 9 x 19 ammunition with a delayed or locked bolt?

 

[tomo pauk]

Does anyone know what barrel length gives the highest velocity possible from 9 x 19 ammunition with a delayed or locked bolt?

A quick search yields the very interesting CMMG MkG 9mm with 16in barrel, as well as this British straight-pull take on AR-15 with same 16in barrel length. Seems like longer barrels are very rare, unless custom made (makes sense).

 

[sonofpegasus]

16inch barrel length is i think a legal requirement in the USA rather than a ballistic performance choice.

 

[Blue cat]

Does anyone know what barrel length gives the highest velocity possible from 9 x 19 ammunition with a delayed or locked bolt?

This might be of interest ?

BBTI - Ballistics by the Inch :: 9mm Luger Results

(statement of intent)

www.ballisticsbytheinch.com

 

[tomo pauk]

16inch barrel length is i think a legal requirement in the USA rather than a ballistic performance choice.

CMMG offers it's carbines (5.7, 9 and 10mm; 45 ACP) with delay-blowback bolts in barrels as short as 5 inch long.

 

[marathag]

16inch barrel length is i think a legal requirement in the USA rather than a ballistic performance choice.

If it's a Carbine.
Under that, has to be legally classed as a Pistol. Which can have a 'brace' that is absolutely not a shoulder stock, despite looking and kind of acting like one
A Short Barrel Rifle takes ATF approval and a $200 extra tax stamp to be legal

 

[sonofpegasus]

looking at the table from Ballistics by the Inch for a 9mm Luger round firing SMG depending on the actual cartridge load chosen a barrel length of around 9 to 12 inches would appear to be an appropriate compromise between the three factors of, bullet velocity, weapon weight and length. YMMV. with different calibres a longer barrel might be advantageous, Rounds like the 7.2 Tokarev being a bottle neck cartridge og similar case capacity to a 9mm might benefit from a longer barrel to achieve the same expansion volume as a 9mm calibre gun.

 

[NotBigBrother]

Box magazines have vastly improved from the very early days and the Sterling is an exemplary example. More rounds is more weight and the box magazine has to be carried and extracted/reinserted into the soldier’s webbing pouch or similar and this limits length.

Soviet and German soldiers also carried magazines in their bootlegs.

 

[Rickshaw]

The Owen Gun

 

[tomo pauk]

Looking at some videos at y-tube, the 9mm and .45 can pierce a 3/4 in thick wooden board at 200 yds when fired from pistol, and from 44o yds when fired from carbine.
9mm video
.45 video
Granted, making hits at these ranges with these weapons is a challenge for 99% of infantrymen, especially under combat.