New ammo dac help

[gsimmons]

MkVIIz is nitrocellulose. MkVII is cordite. That's marked as cordite and corrosive.

[Bruce_in_Oz]

A lot of folk get all excited about the "corrosiveness" or otherwise of the ammo.

The only way any corrosion can occur is if the "nut behind the butt" is slack with maintenance. The old, "boiling water down the bore 'til it runs clear" is a good start.

A lot of people also seem to confuse "mercuric" with "corrosive" Probably the last folk loading mercuric primers would be India and Pakistan. That is for a number of reasons:

1. That is the way the plants were built many decades ago.

2. If the "brewers" do their chemistry correctly, mercuric primers last for decades AND work at both ends of "infantry" temperature scale(minus 45C to plus 45C).

The German military was the first to investigate non-mercuric compounds for primers, way back nearly a century ago. Somebody twigged that the "interesting" chemistry of Mercuric Fulminate could be applied to Lead, a vaguely related metal. Lead is a LOT cheaper and more common than Mercury.

Military grade "non-corrosive" primers came a lot later. The problem was that the early "non-corrosive" mixtures had a short shelf life and were adversely affected by extreme heat and cold.

Primers contain two "elements" in that tiny cup. The first is the crush / impact sensitive compound, for example, Mercuric fulminate. Then there is another compound / mixture to add "Brissance". Brissance" is the extended stream of "flash" that races through the flash hole(s) and ignites the propellant.

When Black Powder was the propellant du jour, you didn't need much of a "flash" to ignite it; ask anyone who has had a "mishap" with the stuff.

"Smokeless" propellant is a whole different thing. You need a "flash" of greater magnitude and duration to get it going. However, once it gets cooking in a confined space, it releases a LOT more energy than Black Powder ever could, weight for weight. However, the burn rate is, oddly enough, pressure dependent. That is why there are so many different smokeless propellants, a opposed to about three basic granulations of Black Powder for small arms.

That is also why there are such things as "magnum" primers. Some of the special, slow-burning propellants like the classic H-4831 and even "slower" modern ones, need a heavy-cupped primer that contains a brew that provides a longer and hotter brissance to ignite them reliably.

That is part of the trick to loading .303 ammo. The cartridge was historically loaded with a relatively fast-burning propellant; Cordite. If you happen to have a stash of the correct Mk7 bullets.......anyone.....anywhere....???, loading a slow propellant like 4831 or N205 may give disappointing results because the bullet acceleration will be quite different from that when driven by Cordite. Therefore, even if you are lucky enough to match muzzle velocity, barrel vibration will probably be quite different due to that different acceleration. Winchester 760 or Du Pont 4350 (or equivalent), may be better bets, if you can get them in your neighbourhood.

[Beerhunter]

I believe all Canadian WWII small arms ammo production was non-corrosive Boxer primed. Pull one and check for the number/style of flash holes.

Not the stuff that I have come across. (also DAC): Berdan primed and "corrosive" primers.

---------- Post added at 07:37 AM ---------- Previous post was at 07:35 AM ----------

MkVIIz is nitrocellulose. MkVII is cordite. That's marked as cordite and corrosive.

Just to be clear, it's not the propellant that tends to promote corrosion but rather the primer. Nitro loaded rounds may also have "corrosive" primers.

[TonyE]

First, as Bruce says, it is the salts in the primer that are corrosive, not the propellant itself. Both cordite and nitrocellulose are erosive over time, but in different ways.

All Canadian WW2 .303 inch ammunition made at the government Dominion Arsenal (DAC Headstamp) was Berdan primed and corrosive. Only the .303 inch made at the privately owned government contractor Defence Industries (DI headstamp) was Boxer primed and non corrosive. Most of this ammo has the "universal" headstamp of "D I Z" and date whether ball, tracer or whatever, relying on tip colour for identification.

Secondly, the ammo is not original to that box. Label H3282 is a British label from the 1950s and the ammo is 1944. Also note the label says "Mk.7" not "Mk.VII". Roman numerals were not replaced for Mark numbers until January 1945. "ISAA" is "Inspectorate Small Arms Ammunition".

Regards
TonyE

[mgarrno4]

Thank you all for the responses they were a great help. I know where I stand with this ammo I will enjoy and clean accordingly. All of the boxes were wrapped in in a thin plastic wrap seemed like factory wrapping, since they didn't use that box until 1945 wouldn't they put left over 1944 ammo in the boxes ?
And thanks for the reloading info on the primers I mostly use mag primers when reloading I have some Win 760 that I am using now. Sure hate to see all that good brass going to waste.
Thanks again for all the help it was outstanding in my opinion

[browningautorifle]

The thin plastic wrap is used by people to preserve the markings on the box. For collectors. It's just commercial stretch wrap. The boxes were issued as you now have it from a case. As for the mixed numbers between box and ammo, they didn't leave ammo lying around waiting for a box. They were boxed at the end of the assembly line. I'd suspect it was re-packaged by a salesman after military possession.

[mgarrno4]

Thanks Jim that's very good to know when looking for military surplus ammo. at a gun show or website. I will look inside the box from now on if I can. These were a gift from my sister.
Have a good day Mike

[browningautorifle]

They'll work fine. Wish my sis would give me something like that...even a brick of .22 would do...

[MKV111Z]

The 32 round box looks like its from ROF Hirwaun (Wales) where much of the Canadian .303 was repacked loads of them turned up in the UK about 20 years ago from somewhere as surplus.

Cheers

H

[mgarrno4]

Thanks again all of you, went out yesterday shot several rounds no click bang all rounds went off as they should. very accurate ammo.