Small Rifle Primers - Magnum vs Standard Hardness

[indyjoe]

Are magnum small rifle primers harder than regular small rifle primers?

The reason I ask is that I am developing loads for .357 Maximum for the Handi-Rifle I just reamed out. Due to the higher pressure of this round, small rifle primers are required. With my last outing, I fired 40 rounds of .357 Max, working powder weight up. I had about 1 in 8 light primer hits. They would fire on second hit each time.

Not sure if regular small rifle primers will help with this, or if I need to take it to a smith to either:
Make the firing pin "pointier", strengthen the hammer spring, or remove some from the top of the hammer where it stops against the frame.

 

[CountryBoy19]

Are magnum small rifle primers harder than regular small rifle primers?

The reason I ask is that I am developing loads for .357 Maximum for the Handi-Rifle I just reamed out. Due to the higher pressure of this round, small rifle primers are required. With my last outing, I fired 40 rounds of .357 Max, working powder weight up. I had about 1 in 8 light primer hits. They would fire on second hit each time.

Not sure if regular small rifle primers will help with this, or if I need to take it to a smith to either:
Make the firing pin "pointier", strengthen the hammer spring, or remove some from the top of the hammer where it stops against the frame.

This questions is very dependent on exactly what primers you're comparing. But generally, yes, magnum primers do have a harder cup than standard primers do so that they can withstand higher pressures. There may certainly be exceptions to this rule and it is definitely not meant to cover all the bases. But as a whole, magnum vs. standard are harder.

 

[rimfire_crazed]

Are you sure they're seating properly?

I've had issues with light primer strikes on LP primers in .44 mag. I inspected each light strike cartridge and saw that the primer wasn't seated as deeply as the others. each time a second strike set it off. Now i seat the primers with AUTHORITY on the press and I haven't had a problem since.

 

[billybob44]

Std srp vs mrp??

Some primers are harder than others. Federal primers are known to be the softest. Wolf known to be one of the hardest/difficult to seat/slightly oversize.
I do not believe that a primer cup is harder if it is titled Magnum. I believe my Standard CCI Small Rifle Primers have as hard of cup as my Magnum CCI Small Rifle Primers. Same with my Win. Standard/Magnum primers.
I believe the MIXTURE of the primer compound IS the difference between Std.+Mag. primers. If you will= the Mag. will have a bigger flash/duration of burn then the Std. primer.
I use Win.-CCI-Rem.-Wolf primers--in that order. The first three listed will shoot in any of my weapons/or others that I have loaded for. The Wolf IS harder, and will be harder to seat, and on light springed actions, may not fire on the first stroke.
Wolf primers are usually cheaper. I use them on my non-tuned firearms, with strong/factory springs.
Did you have any primer problem with your rifle BEFORE you reamed it out to .357 MAX.?? If you did NOT, I would be looking at a head space problem that may have occured during the machine process??
The .357Max. also head spaces on the rim (as does .38/.357Mag.), so that should have not have changed, but you never know??
Hope this helps??....Bill..

 

[indyjoe]

These were CCIs. That is what I have used in the past and been pretty happy with them.

I was hand seating them with an RCBS primer tool. It is possible that I didn't get them all the way in on a few. I will be extra careful with that and see if the problem goes away. That is the simplest explanation, but I thought I was pretty careful. Having not reloaded for a few years, you always have that "don't want to set of the primer" press when you start.

I didn't have problem before reaming, but I only fired .357 Magnum cases with pistol primers. I was very careful in the reaming and stopped before I took off any real metal in the head space area. 99.9% of the head spacing area of the barrel is still properly blued. I think the chances of that being the problem is very slim. I will measure the rim thickness of the rounds I fired and the Rem .357 Max case rims I have. It fired off 50 more .357 Mag and 30 .38 rounds with no issue, so I think I'm good with the actual barrel.

If seating isn't the problem, them I think it is the hardness difference, causing it.

It is good to hear that Magnum and Regular should be the same hardness. (I would discover this after placing my order for 1k of them, wouldn't I?

)

Thanks for all the ideas everyone.

 

[backporch plinker]

IF in a ar type rifle and many others Ive not seen it matter, depends on firing pin and how far it protrudes, there is a tool to measure this and you can adjust for safety reasons ,if a rifle slam fires something is wrong. Always make sure you use a primer that can be seated deep never flush with the base.

 

[CountryBoy19]

I do not believe that a primer cup is harder if it is titled Magnum. I believe my Standard CCI Small Rifle Primers have as hard of cup as my Magnum CCI Small Rifle Primers. Same with my Win. Standard/Magnum primers.
I believe the MIXTURE of the primer compound IS the difference between Std.+Mag. primers. If you will= the Mag. will have a bigger flash/duration of burn then the Std. primer.

That's exactly where primer type falls into the mix. The exact opposite of that can be said for other primers. Wolf Standard vs. Magnum are the exact same compound/flash/etc, but the cups are harder on the magnums.

 

[indyjoe]

That is part of why I want to be able to fire a good hard primer. So I can share my .357 Maximum primers with .223/5.56 that I will eventually load for the AR. That will depend on how the primer dimples look when I chamber some rounds though. I would rather just stock one type, but if I need the mil-spec 5.56 primers to be safe, I'll do that.

I currently have enough 5.56 on hand, that I'm not planning on loading for it for a while.

 

[backporch plinker]

The CCI # 41 is the 'hard' primer meant for auto's . I see you can get them again finally.

 

[indyjoe]

The CCI # 41 is the 'hard' primer meant for auto's . I see you can get them again finally.

Yep. The price is a good bit more than the standard. However, if my ARs do much more than a tiny mark on the primers I'm using, that is the route I'll go.

Hard to put a price on not ADing when you drop that bolt.