WW 2 Winchester .303 ammo

[Hardcast416taylor]

A friend gave me a tan cardboard box of Winchester 1943 MK VIIz .303 inch fmj ammo that he got at a yard sale this month. There are 48 rounds in the box as the intact label says it contains, in rows seperated by paper. My question, is this ammo meant for machine gun use only- or is it rifle ammo? Simply put, should I just tear it down for the brass and bullets? I should know this, but must plead ignorance.Robert

[Bloodman14]

MkVIIz indicates nitrocellulose propellant. The MkVIIIz was the round for the Vickers machine gun. What you have is rifle ammo; shoot it up!

[JeffinNZ]

Probably getting a bit rare. It might be worth keeping for collecting. Still, shooting is a good idea also.

[303Guy]

Collectors piece. Keep it! It's a bit old to fire anyway. Old brass might just split on first firing too. No, too valuable as collectors pieces in the original box.

[Multigunner]

MkVIIz was also used by MGs, so was the standard MkVII.
I've run across test firing articles where Winchester WW2 era ammo was used the ammo being first removed from Vickers Gun belts.

Not sure but I think Winchester may have used Olin Ball powder instead of IMR type single base powder for at least some of its milspec .303 ammo.
Britain had bought rights to manufacture Olin Ball powders and a factory was built in the UK to produce it.

PS
Some Winchester .303 ammo did not meet specifications and was marked not for combat use or not for synchronized guns.

[Gtek]

I would not tear down. There is an Enfield fan some where that would trade out for his collection. Win-Win! Gtek

[sail32]

The regular Mk VII .303 used cordite, and I believe the Mk VIIz used a ball powder.

[Multigunner]

The regular Mk VII .303 used cordite, and I believe the Mk VIIz used a ball powder.

Apparently several non cordite propellents were used at one time or another, but IMR 3031 was the approved powder first adopted.

Modern MkVIIz and MkVIIIz equivalent ammunition may contain just about any powder, from square flake powders or the type used for some mauser ammo to silvery looking extruded double base powders or conventional olin ball powders.

I haven't found any two piece core bullets among the equivalent loads as of yet, and the Indian Ordnance factory lists their Mk7z as having a lead core with no mention of a nose filler.
They list the Mk7z as being for use in rifles or machineguns.
That load uses a single base powder though ball powders are used for some other calibers manufactured there.
POF now uses only single base powders, but last time I looked they had deleted listings for any .303 ammo. Possibly to prevent fresh ammo from being diverted to the Taleban for use in remaining .303 weapons.

[Four Fingers of Death]

They would shoot ok, no doubt they would even be single flash hole brass as well, so you could reload them (well, the ones that didn't split at the mouth anyway).

Sold to a collector (especially in America, being made there) they would be a nice little earner for you. No doubt being Winchester (nearly all of it would have been loaded onto a liberty ship soon afetr being made) it would have all left the country pronto and should be rarer than the rest.

I reckon you should be able to sell them individually for $5-10 each.

[Hardcast416taylor]

Thanks for all the info on these rounds guys. My friend said he paid a terrible price of $2.00 for the box! He claims that now I owe him the $2! The primers are crimped in place with 3 stake like crimps around the primer. Wonder if they were using corrosive priming in these 1943 dated rounds?Robert

[wiljen]

Yes most ammo made before 1953 by US arsenals for military use was corrosive and I would treat your stuff as if it were.

[Multigunner]

Winchester .303 ammo made for Britian would have been a commercial product rather than an arsenal product , not subject to U S milspecs unless manufactured for use by the U S army.
They might still have been subject to a British purchasing agents specifications calling for a corrosive primer, but might also have have used non corrosive primers since U S powders did not require the extra hot primers necessary to ignite Cordite reliably.

Corrosive primers were still considered to be more reliable in adverse conditions, and only .30 Carbine ammo was regularly loaded using non corrosive primers, probably due to the gas tappet operating system.

Like as not corrosive, and certainly not worth finding out the hard way, so best to clean as you would with any suspect military ammunition.

PS
If corrosive, probably not mercuric corrosive, so the cases should be reloadable if neck annealed after first firing.

[303Guy]

I still say hang on to them and pay the $2. They look good in a display cabinet, lying around where someone will notice them or where you can rediscover them from time to time knowing their value is going up with time (over and above the conversational value they have).