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Military Guns and Ammunition

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NGSW Phase 2 Consolidation and info   Small Arms <20mm

Started 30/8/19 by gatnerd; 137474 views.
smg762

From: smg762

28-May

the BRG 15 had driving bands to reduce wear, could this be scaled down allowing you to use a 22-250 or hot-rod 556 without wear?

also i heard that the steel core in 556 is a tiny 7 grains. that seems really light. assuming an all-steel saboted bullet, could one realistically make it 62 grains of pure hard steel....is steel heavy enough?

lastly it seems the armour most referenced here, is armour which takes plate inserts. if someone wore that, (and you had yoru choice of any scratch-design AP round), what would the ideal round be, if tungsten was not an option. i'd have thought a 6.5, for the energy advantage at range

QuintusO

From: QuintusO

28-May

smg762 said:

also i heard that the steel core in 556 is a tiny 7 grains.

that's because it's tiny, not because it's 5.56.

the penetrator in M855A1 is only half length and weighs circa 19 grains. the penetrator in RS101 is even heavier (roughly twice as heavy), for just a 55gr bullet.

ZailC

From: ZailC

28-May

In the early 1990s I worked on a 25mm Frangible Discarding Sabot round. It was very similar to Oerlikon's 25mm APDS, except for the penetrator composition and manufacture. Intended as an anti-materiel round it was superb against armored and unarmored aircraft targets; often producing spectacular aluminum/air secondary explosions. Penetration against homogeneous armor was only slightly inferior to its anti-armor cousin. Mud-brick and reinforced concrete penetration was superb and very much better than 25mm HE rounds. It was similarly effective against unexploded ordnance and demolition charges. I believe the Canadians bought some. 

smg762

From: smg762

29-May

yes, i was reading the old 'body armour' thread, and the general emphasis on level 4 plates.

it seems like tungsten will never be economical so surely an entirely steel projectile (saboted), 70grains, with extremely dense steel, would come closest to a tungsten round.  my original question was whether its viable - is steel dense enough to total 70 grains in 556

smg762

From: smg762

29-May

what were the dimentions of the penetrator...was it apds or apfsds

smg762

From: smg762

29-May

have u seen the forgotten weapons vid of the south african 20mm grenade launcher. it seems like a better option than the short range 40mm M203.  allocate one guy with the 20mm (possibly with an MP7 bolted underneath)

 and you can make short work of cover

ZailC

From: ZailC

29-May

The frangible round is FAPDS. Frangible penetrator composition is unsuitable for fin-stabilized projectiles: extreme initial compressive strength and near-negligible tensile strength. I don't know the dimensions adopted for production, but diameters of 12-18 mm and masses from 120 to 170 grams were all effective. Mach 4 Zirconium/Aluminum tips on truncated-cone fore ends and two second tracer cavities were common. 

smg762

From: smg762

31-May

do the autocannon sabots generally separate in 2 pieces or 3...is there anything in particular that makes them so accurate, where small arms sabots often struggle?

ZailC

From: ZailC

31-May

20 to 30mm sabots generally have three or four petals . Their accuracy above that of small calibers come from three sources: 1) Concentricity (with a capital C), usually 0.0001 inch or better, 2) they open from the rear, centripetal forces open the petals on muzzle exit and reverse flow helps move the petals away from the shot line, and then 3) base drag pulls the pusher plug or base away on the shot line once clear of the reverse flow. The penetrator is usually in clear air about 20 calibers beyond muzzle exit. 

RovingPedant

From: RovingPedant

1-Jun

smg762 said...

do the autocannon sabots generally separate in 2 pieces or 3...is there anything in particular that makes them so accurate, where small arms sabots often struggle?

Size.

Machining tolerances are a smaller proportion of a larger projectile.

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