PDA

View Full Version : Reversed MG Projectiles?



Rising Sun*
11-19-2007, 05:03 AM
I've read in several places (can't think of references - just one of those oddities that sticks in the mind) that in Papua New Guinea Australian troops found Japanese MG rounds (don't know what calibre(s)) with the projectiles reversed in the casing, apparently to create a more damaging round.

Leaving aside the work involved, I would have thought it would cause problems in chambering the rounds in auto weapons.

Would it be likely to cause stoppages?

Anyone aware of similar reports / actions?

Man of Stoat
11-19-2007, 08:45 AM
Depends entirely on how the feed operates.

It is reputed that the Brits or the Germans did the same thing to punch through armoured loophole plates in the First World War with sniper rifles. supposedly the flat base of the round punches the plate rather than tries to spear its way through. Reversing the bullet increases the pressure in the chamber severely, so don't try it.

Japanese troops were also found in battle in possession of bulleted blank ammunition (essentially ammunition with wooden bullets and a small charge of fast powder which would normally be used with a constrictor device over the muzzle to cause them to shred) which the troops they were facing believed they used to cause worse wounds, but the truth was that they were running out of live and were resorting to bulleted blank training ammunition.

Rising Sun*
11-19-2007, 04:04 PM
MOS

Thanks.

Would the projectile be less or equally stable in flight as one pointing the usual way? Common sense seems to suggest less stable, but if it's spinning and the weight's at the front does it actually work a bit better?

I'm assuming you'd lose a fair bit of range with a blunt nose?

Why does chamber pressure increase? Harder to force a non-tapered shape into the rifling?

tankgeezer
11-19-2007, 04:56 PM
That is one way to deliver a soft point bullet without actually using one,and in the case of a flat bottom bullet,If it can be made to feed, there will be a spike in pressure as it swages into the rifling, and bore erosion will increase as well with the long ogive of the point forcing propellant gas to compress along the narrowing space between bullet and bore.

Man of Stoat
11-20-2007, 04:53 AM
Stability is probably not hugely affected, although accuracy will be (the most accurate bullets have their centre of mass as far back as possible). The loss of range will not be significant because we are not shooting at extreme range here, only a few hundred yards.

Chamber pressure increases because the point of the bullet protruding into the interior of the cartridge case reduces the powder space. Less space plus same amount of gas equals more pressure.

The swaging into the rifling will not be significantly different, particularly in the case of a boattailed bullet, likewise "gas cutting" of the edges of the bullet will not be significantly different.

Essentially, when a normal bullet hits steal at a decent velocity, the back-end of the bullet does not decelerate as fast as the tip, and so the jacket peels forwards and shreds itself. If it is travelling backwards, this shredding cannot happen, and the front of the jacket acts like a metal punch.

Rising Sun*
11-21-2007, 04:43 AM
tankgeezer & MOS

Thanks.

I've never understood how they could crimp the projectile into the casing satisfactorily in the field, particularly after damaging the crimp by removing the projectile.

It would seem that they'd have to crimp the projectile on a taper. What's to stop it falling out, or wobbling around on a feed?

It seems to be beyond something that could be done with pliers. Would they have suitable crimping tools in the field, bearing in mind we're talking about Special Naval Landing Forces and IJA infantry on hard foot slogs in Papua New Guinea where they didn't carry anything they didn't absolutely need? I have no idea what those units might have had attached in the way of armourers.

Man of Stoat
11-21-2007, 05:35 AM
You don't actually need to crimp, particularly if you are only single feeding. The tension in the neck is quite enough. I don't crimp the ammunition for the wife's sniper rifle, for instance.

The bigger issue is removing the bullet without damaging the neck of the case. The easiest way would be to jury rig some kind of kinetic bullet puller, also known as a "bullet hammer". It's then a matter of gently tapping the reversed bullet back into the case

Panzerknacker
11-23-2007, 08:36 PM
It is reputed that the Brits or the Germans did the same thing to punch through armoured loophole plates in the First World War with sniper rifles. supposedly the flat base of the round punches the plate rather than tries to spear its way through


That is weird, teorically the reversed bullet is more or less like a soft nosed flat point, and the wider impact area should cause less penetration/damage to the armor plate.

tankgeezer
11-24-2007, 10:53 AM
It would be interesting indeed to try the idea out with a rifle, and some military A.P. ammo, although its pretty hard to find anyone willing to let any go these days, try a few as issued, against a 1/2 "(12-13 mm) plate, and then again with reversed projos.
But in the case of use against troops, its just going to be a flat nosed soft point, which is a violation of the convention, but more difficult to prove as intentional, being its a fmj to begin with.

Man of Stoat
11-27-2007, 04:16 AM
Try it with a normal military FMJ.

PK, for the same reason that a metal punch is flat faced and not a spike.

tankgeezer
11-28-2007, 12:56 PM
Try it with a normal military FMJ.

PK, for the same reason that a metal punch is flat faced and not a spike.
Do you know the thickness of the target plate? and was it armor, or just steel. any ideas?

Man of Stoat
11-29-2007, 04:19 AM
The loophole plates I have seen appear to be something of the order of 3/8 or 1/2" mild steel, more or less the same stuff used as steel targets in practical rifle shooting

Panzerknacker
11-29-2007, 06:10 PM
PK, for the same reason that a metal punch is flat faced and not a spike.

Well, definately I need some field test to see it with own eyes.


The loophole plates I have seen appear to be something of the order of 3/8 or 1/2" mild steel, more or less the same stuff used as steel targets in practical rifle shooting

Interesting, 9,5 or 12,7mm seems a bit much to be penetrated but I if is mild steel and no hard one probably works.

tankgeezer
11-30-2007, 12:01 AM
I can see it as possible on 5-7 mm of mild steel, though I doubt if it would perf anything thicker. I dont own any small bore rifles, but if I can find a willing participant, and a place to try it, (probably in spring) I'll set up some test shots to see. If someone else out there has the resources to do it, that would be cool too.

Panzerknacker
11-30-2007, 01:23 PM
I can see it as possible on 5-7 mm of mild steel, though I doubt if it would perf anything thicker.

I am inclined to believe that also. As you said some field test is needed.

Go fo it mythbuster !! ;)

tankgeezer
11-30-2007, 05:19 PM
I am inclined to believe that also. As you said some field test is needed.

Go fo it mythbuster !! ;)

I'll submit it to their website,, they like to do those sorts of things,, we used to have a quarry to shoot in, $5 for all day, shoot anything you like, cannon, full auto, whatever, but that has long since closed, because of the yuppies buying up the land, and complaining to the city about those "dangerous people" ( so what if a few stray tracers would go flying into the sky,, its pretty....)