Reversing Rifle Bullets to Increase Penetration?

[Piorun]

When did opposing sides start using armour plate? It certainly was not used on early tanks.

Alan

Do you mean as other than sniper plates? A.

[TonyE]

I don't think reversed bullets striking a steel plate, at any range where penetration could be realistically hoped for, could end up looking like this. Whether or not the penetration occurred, the jacket would likely be destroyed in any recognisable form because of the thousands of ft.lb. involved in the collision.

I'd suspect that what these may be are remains of rounds fired from aircraft or into the air, arriving at the ground tail-first at some 300 ft/sec in the behaviour typical of projectiles at that end of their trajectory.

Regards,

MikB

I don't think that is the case Mik. Bullets landing on the ground at maximum range at the end of their trajectory are usually undamaged. When hitting the gound at shorter ranges the Mark VII bullet tends to bend or break at the point where the light tip joins the lead core. Have a look at the butts of any old military range.

The bullets in the picture seem to have hit something base first, and without re-igniting the whole argument I would expect the lead core to melt /penetrate and the envelope to peel back around the impact point. This also would allow the tip to be lost or thrown out.

Regards

TonyE

[MikB]

I don't think that is the case Mik. Bullets landing on the ground at maximum range at the end of their trajectory are usually undamaged. When hitting the gound at shorter ranges the Mark VII bullet tends to bend or break at the point where the light tip joins the lead core. Have a look at the butts of any old military range.

The bullets in the picture seem to have hit something base first, and without re-igniting the whole argument I would expect the lead core to melt /penetrate and the envelope to peel back around the impact point. This also would allow the tip to be lost or thrown out.

Regards

TonyE

Well, yes, it does depend to some extent on bullet construction, and the scenario you propose could be more credible for 303 because of the 2-part core.

(Incidentally, recovered 303 bullets that have folded or snapped due to turnover/deceleration forces in sandtraps tend in my experience to fold rather further back than the core boundary, perhaps around the cg.)

I hadn't really thought these might be 303 because of the difficulty reversing them in their case discussed earlier, but if a clean-surfaced nose core still adheres within them, that would be strong evidence for it - although I guess absence of it wouldn't disprove it - any comment, rumjar?.

Against your main argument I'd say that at ranges of a few hundred yards, the bullet jacket itself has considerable energy, even if some event separates it from the core(s). It it were to strike a hard surface base-first at velocities in the 2000 fps range, even the jacket alone would have energy in the 100 - 200 ft.lb. range, and it's hard to see that it wouldn't peel open right to the point and split into dispersing shards. So I'd think these must've struck base-first at velocities considerably less than those in the early part of the trajectory.

I take your point about max range 'spent' bullets often being recovered intact - this is quite true, but only of the ones that don't strike hard surfaces! Those that do still have 30 to 60 ft.lb. and might well end up looking like rumjar's samples.

Regards,

MikB

[TonyE]

I appreciate your point about the envelope carrying a reasonable amount of energy, and in fact you underestimated what it is likely to be. The envelope of a .303 Mark VII weighs about 40 grns, which gives an energy at 2000 fps of 355 ft.lbs., about twice that of a .22 LR 40 grn bullet moving at 1000 fps.

However, all sorts of things could interfere with this, as the envelope would never separate as a complete piece.

I don't think we will ever know for sure.

Regards

TonyE

[MikB]

I don't think we will ever know for sure.

Regards

TonyE

Of course not. But forensics are fun!

I was also basing my argument on probability. For every bullet arriving tail-first through painstaking reversal by a soldier of whichever side, for whatever purpose, there must've been many, many thousands arriving tail-first from overextended trajectories; for example fired at or from aircraft, or in suppressive long-range MG barrages after passing over the reverse slopes they were sweeping.

I was reckoning on the jacket comprising about 10% of bullet weight - I didn't realise the Mk.VII's weighed as much as 40 grains. Your energy calcs were slightly adrift, though - at twice the velocity of the 40 grain .22LR it would have 4 times the energy. Velocity squared.

Regards,

MikB

[TonyE]

100% correct Mik - I was day dreaming!

Cheers

TonyE