Proofing of Naval guns

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paul mercer
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Proofing of Naval guns

Post by paul mercer » Tue Oct 16, 2007 6:40 pm

Here's a question for you technical chaps.
How did the naval powers go about proof testing their guns?
I'm aware that with shotguns a special cartridge that is two or three times the pressure of a normal one is used in the proof house in England, but if that criteria is scaled up to a 16" - wow, I would'nt like to be around when that went off!
Did they also test the guns out on a range, if so it must have been a huge one?

lwd
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Post by lwd » Tue Oct 16, 2007 7:01 pm

In the US naval guns were/are tested at the Naval Surface Weapons Center in Dahlgren, VA. The Gun line points down the Potomac. Errant shells did occasionally land on shore in less than desirable areas.

Gerard Heimann
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Post by Gerard Heimann » Tue Oct 16, 2007 7:36 pm

BTW, Prinz Eugen's barrels from Anton turret were tested at Dahlgren and were still held there as of several years ago.

Gerard

paul mercer
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Post by paul mercer » Tue Oct 23, 2007 8:04 pm

Thanks chaps, but does anyone know HOW they were tested, i.e. were there special proof loads?

lwd
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Post by lwd » Tue Oct 23, 2007 8:22 pm

You might want to ask on the warships1 BB board. I think there are some people that were involved in this sort of thing that post there. Some of the experts that also post here seam to watch those boards closer as well. Another possiblility would be to email the public affairs director at the Naval Surface Weapons Center, Dahlgren. Here is a link where you can start searching:
http://www.nswcdc.navy.mil/

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marcelo_malara
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Post by marcelo_malara » Tue Oct 23, 2007 9:07 pm

I have never heard of supercharges used to test fire a gun. Bear in mind that the chamber volume is designed for a maximum charge, and there would be no way of putting three times the propellant charge in it. Nor would it be possible to introduce the shell further down the barrel to "enlarge" the chamber because the shell woud need to be forced into the rifling and that would requiere tremendous forces. The only way I imagine it be possible, is building a test barrel with the chamber already larger than normal, and if the design could manage the stress, approve it for production.

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Post by Bgile » Tue Oct 23, 2007 10:39 pm

The British tested their 15" AP projectiles against SMS Baden. They arranged test environments to simulate the impact of their shells on various locations meant to duplicate likely battle damage.

The US Navy performed tests against various armor types and thicknesses.

These aren't what I would call "proofs" though.

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Post by mike1880 » Wed Oct 24, 2007 2:11 pm

"I have never heard of supercharges used to test fire a gun."

The correct term is "proof charge", a "supercharge" is simply a charge larger than the standard service charge. Use of both is quite normal and very well documented. Chambers of heavy guns are not designed to be just big enough to hold the expected charge.

In Britain, proofing of shotguns and other small calibre weapons is prescribed by the Gun Barrel Proof Act of 1886. Proofing of larger (i.e. military) weapons is determined by the armed forces, you can find a (presumably obsolete) copy of DEF STAN 13-92 here:

ftp://ftp.iks-jena.de/pub/mitarb/lutz/s ... 000300.pdf

That explains exactly what proofing is, how it's done and in what circumstances. It specifies that a "proof charge" should be designed to produce a pressure within specified limits of the gun's Design Pressure, and that a proof charge counts as 2 full (i.e. top service) charges (it means from the perspective of wearing the gun barrel, i.e. effects on service life. In the past, proof charges have counted for as much as 4 full charges if I remember correctly; but in those days, guns were designed with very conservative safety margins and would have stood a much larger proof charge in comparison to a normal service charge).

While proofing involves pressures higher than would be expected in normal service, it would be impractical to scale the pressure up to two or three times normal in proofing a major calibre gun; that would require that the gun be grossly over engineered (and therefore very, very heavy). Given that a 16-in gun weighs around 100+ tons, and for much of the 20th century the displacement of warships was limited by treaty, there was a strong motivation to work hard to reduce that weight. The motivation is probably even stronger for land artillery where you have to drag every excess pound across muddy ploughed fields.

As far as "where" is concerned, the phrase you're looking for is of course "proving ground", e.g. Gavre (France), Aberdeen (US), Plumstead and Shoeburyness (UK) but the arms manufacturers also had their own ranges.

Mike

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