Test on bore wear using GMCS/Bimetal Jackets?


#1

I am wondering if anyone has any military, HP White, or other scientific test results comparing GMCS/Bimetal Jacket material to 90/10 gilding metal jackets with regards to bore wear?

I believe frankford arsenal did some testing back in the 50s or 60s, but I cannot find the report online.


#2

This may be of interest to you:

luckygunner.com/labs/brass-v … ased-ammo/


#3

Yes, that is the report that has prompted me to search for a more scientific approach.


#4

anyone?

maybe some info on the bore wear studies done in Germany on their NATO x51 ammo?


#5

Apart from probably the very early years of the 7.9 mm (I would have to look this up) we Germans have always used steel jackets cladded with gilding. (Being not sure, by cladding I mean the process done in a rolling mill.) We continue to do it with the current 7.62 NATO ammunition (DM111), only a thin tin coating is added on the outside to make up for the fouling definiencies of lead-free primer mixes. (Ammunition purchased abroad, like FN DM41, may have gilding jackets.)

I am not aware of any German scientific/technical discussion of the relative merits of gilding versus steel jackets, which I also would be keen to read. Germany was always short of copper, so the military did not have a real choice. It was even necessary to reduce the gilding cladding from 10 to 5 and 3 percent to save copper.

The military experience in peacetime is that barrels are not worn out by shooting, but by cleaning. My personal experience is that I prefer the risk of a little increased wear by steel jackets to the ensured much bigger copper fouling by gilding jackets (or solid brass bullets).


#6

A far greater source of bore wear in high performance military caliber rifle barrels is gas cutting in the throat area just as the bullet moves from the cartridge case at primer ignition. Barrels wear out at the rear end, not the front, so jacket material isn’t the big problem. Jack


#7

There is record of a note between Frankford Arsenal and the Small Arms Ballistics Station in Miami (dated March 10, 1919) mentioning;

a) Erosion test with caliber .30 ammunition with copper clad steel bullet jackets. Part of this ammunition was furnished by the Western Cartridge Company and the balance by the Winchester Repeating Arms Company.

The reply by the Miami Station to this note states that 24,000 rounds with copper clad steel bullet jackets were supplied by the Western Cartridge Company but that nothing had been received from the Winchester Repeating Arms Company.

Peter