Primer question

[Mint]

Here's something I have wondered for awhile.

I know to use RNFP or TC in lever guns to prevent magazine tube detonation from either recoil or pushing rounds in.

One time... I got a box of 45-70 ammo that said safe for lever guns, and it had a RNFP.

When I opened it, the flat part (meplat?) of the bullet was about 1% smaller in diameter than the diameter of the primer.

Wouldn't the flat part need to be slightly larger than the primer so it catches on the brass to prevent detonation?

I was considering maybe it's because a primer will only ignite if its impacted with a "needle shape" (firing pin) and even if the bullet were to very heavily impact the primer, it wouldn't go off because its the entire surface area of the primer being struck instead of only a tiny part of it.

I wanted to be 100% sure though.

[Winger Ed.]

Look inside a primer and see the triangle looking thing with the high point in the center.

The primer compound has to be crushed between the cup and that high spot.
That's why firing pins are shaped like they are, and placed where they are.

Lay a primer on the bench, cover it with a rag and start tapping it harder and harder with a hammer.
You'll have to whack it hard enough to crush the cup before it will go off. (the rag will catch the effects of its detonation)

All things considered, this is why RNs won't detonate a primer in a tube magazine and shoot your eye out.
I wouldn't test the theory, but it might even take a FMJ along with a pretty heavy recoil to detonate one.

[Mint]

Look inside a primer and see the triangle looking thing with the high point in the center.

The primer compound has to be crushed between the cup and that high spot.
That's why firing pins are shaped like they are, and placed where they are.

Lay a primer on the bench, cover it with a rag and start tapping it harder and harder with a hammer.
You'll have to whack it hard enough to crush the cup before it will go off. (the rag will catch the effects of its detonation)

All things considered, this is why RNs won't detonate a primer in a tube magazine and shoot your eye out.
I wouldn't test the theory, but it might even take a FMJ along with a pretty heavy recoil to detonate one.

Ah ok, thanks. This is kind of what I was thinking would be the answer.

[Winger Ed.]

Ah ok, thanks. This is kind of what I was thinking would be the answer.

It's wise to be careful and don't be shy about asking questions.

We wouldn't want you to shoot your eye out kid.

[indian joe]

Here's something I have wondered for awhile.

I know to use RNFP or TC in lever guns to prevent magazine tube detonation from either recoil or pushing rounds in.

One time... I got a box of 45-70 ammo that said safe for lever guns, and it had a RNFP.

When I opened it, the flat part (meplat?) of the bullet was about 1% smaller in diameter than the diameter of the primer.

Wouldn't the flat part need to be slightly larger than the primer so it catches on the brass to prevent detonation?

I was considering maybe it's because a primer will only ignite if its impacted with a "needle shape" (firing pin) and even if the bullet were to very heavily impact the primer, it wouldn't go off because its the entire surface area of the primer being struck instead of only a tiny part of it.

I wanted to be 100% sure though.

You will find that with 30/30 -- 348 etc tapered rounds - its difficult to get them to stack in the magazine with boolit nose in primer pocket proly why (in part) they dont blow -

straight body cases a different story I think in particular the 45 colt with its skinny rim you want the flat meplat on that one properly bigger than the primer pocket ahead of it .

I dont want to be the bunny that proves the point on this - my left hand is wrapped round where its gonna blow if it do.

[Mint]

You will find that with 30/30 -- 348 etc tapered rounds - its difficult to get them to stack in the magazine with boolit nose in primer pocket proly why (in part) they dont blow -

straight body cases a different story I think in particular the 45 colt with its skinny rim you want the flat meplat on that one properly bigger than the primer pocket ahead of it .

I dont want to be the bunny that proves the point on this - my left hand is wrapped round where its gonna blow if it do.

Yeah the cartridges in question would be 45-70, .357 mag, .44 mag, 45 Colt

[indian joe]

Yeah the cartridges in question would be 45-70, .357 mag, .44 mag, 45 Colt

you proly get a bunch of fellers say a soft roundnose is safe - they may be right - quite likely are - my take is a wide flatpoint boolit performs fine in these straight case calibers anyway.

[FergusonTO35]

If it was factory ammo, then they must have been certain that the boolit was safe to use in a tube magazine. Otherwise, they are asking to go out of business really fast.

[indian joe]

If it was factory ammo, then they must have been certain that the boolit was safe to use in a tube magazine. Otherwise, they are asking to go out of business really fast.

To counter that we hear of several magazine blowups in the cowboy sport (1860 henry repros ) ? .....I dunno - I wasnt there
I use flatpoint boolits in em and still got all me fingers

I was in a suing one time (we won it) got me enough of a look at the crooked and twisted legal system I do not ever intend to go there again.

[FergusonTO35]

Some CAS people go to questionable extremes in modifying guns. I have heard of rifles modified to not lock up quite all the way in order to shave a few tenths of a second, which I guess they presume is safe with mouse fart loads typically used.

[GONRA]

Picky Picky GONRA reminds ya'll - primers DEFLAGRATE.
They hopefully do NOT detonate!
BLASTING CAPS detonate.....