Number 34 Primer with .303 British

[AD-4NA]

Just curious, has anyone tried a CCI No. 34 primer in a .303 British loading?
Was thinking of experimenting with trying that combination as part of a new load even if it might be considered a waste of money.

How "hard" was the primer in MkVII/MkVIIz or MkVIII/MkVIIIz ball? Did any other countries use a "hardened" sort of magnum-ish primers in the WWII period?

Information

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[oldfoneguy]

The nato spec primer is more geared towards autoloaders and is somewhat pricer. However the thought has crossed my mind for all my milsurp loadings especially M2 Ball and I will be watching this thread with interest.

[bob q]

If your rifle will set them off then it would be no problem . That would depend on a few factors , how strong is your spring , firing pin condition , how tight is your headspace and chamber ? Many countries used hard primers in their military ammo . Pick your primer for your application , I have a few old odd military rifles that have weak springs . But a pistol primer used with a light load solved those ignition problems .

[Parashooter]

Beware of internet assertions that the CCI #34 is a "hard" primer. There is credible evidence that the cup is the same as other CCI primers but that the anvil is in fact shorter.

[Low & Slow]

Interesting. Still, might be a viable alternative to a firing spring kit in the MAS 49/56.

[Parashooter]

The shorter anvil means it's likely to need a deeper impression (stronger strike) to ignite. That's probably how the #34 gets its reduced sensitivity.

[Low & Slow]

Your pic makes your point well. I'll bet this would pretty well absorb the forward inertia of a free floating firing pin, preventing a slam fire. Thanks for illustrating how this primer actually performs this function.

[Bruce_in_Oz]

Remember that ALL of the Cordite-loaded .303 (at least that I have encountered) uses the .250" COPPER cupped BERDAN-style primer.

Collectors of vintage ammo in general will have noted the popularity of copper primer cups before WW1.

The priming mixture contained a "primary" compound, Mercuric Fulminate, an impact sensitive brew that was ideal as a primer component. The Mercuric Fulminate did not react with the Copper cup.

The stuff would, however, react positively to being whacked by a striker in any environmental condition on the planet. This made it ideal for military use.

For the reloader, there is a problem; Mercuric fulminate, when it "reacts", releases metallic Mercury vapour. In a cartridge, this means that the interior of the brass case is subjected to a super-heated shower of Mercury vapour. Mercury breaks down the alloy bond between the Zinc and Copper in the brass. The "good" news is that the mercury vapour has NO negative affect on the bore, contrary to urban legend.

That role is carried out by the "supplementary compound" in the primer mix; Potassium Chlorate. (and helped along by the minuscule amounts of finely-milled black powder and glass.)

The Chlorate is there to enhance "Brissance" ("flash" duration and intensity), needed to ignite the bundle of Cordite "sticks" in the case.

All very good, except that the "Chlorate" reaction results in a "Chloride" product. Like Sodium Chloride, this stuff is VERY good at causing RUST, especially if there is even a hint of atmospheric humidity..

So, a "double whammy" if you are a reloader who is a bit cavalier about barrel cleaning. In military service all of this was understood and procedures for barrel preservation "enforced". On the two-way rifle range, NOBODY cared about the spent brass. (Apart from the gnomes in field workshops who used some of it to cast "souvenirs" for the troops to send home to their loved-ones).

[Bruce_in_Oz]

A MODEST, IF DISORGANIZED LIBRARY COME IN HANDY. Old blokes' memories are subject to "fluctuations".

Primer update / corrections.

Per the “Textbook of Small Arms”, 1929 edition, the composition of the brew in a primer for the .303 service cartridge.

This starts on Page 233.

Per primer:

Total “weight” of compound: 0.6 grains.
Composed of, by weight proportions:

Eight parts Fulminate of Mercury
Fourteen parts of Chlorate of Potash (Potassium Chlorate)
Eighteen parts of Sulphate of Antimony
One part of Sulphur
One part of Mealed Powder (Finely milled Black Powder).

DO NOT try playing with this stuff at home unless your affairs are in order and nobody else is home.

[Bruce McAskill]

Well its a good thing cordite is a thing of the past with the .303. There are much better powders around for the .303. Is the type 34 primer needed with the .303? I doubt it is, as there are plenty of well made primers available for use in it.