Interesting. 300blk and SPP

[jkor]

One of the powders I use for 300 blk is, 2400 which tended to flatten primers quite a bit. For murom's they would pierce regularly.
The ambient temperature is quite low right now but, I ran federal and murom Spp To near max charge and everything looked fine. I forgot my tripod though, so I couldn't check velocity.

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[jkor]

I figured 300blk is kind of like 357 magnum.

 

[edzz]

Your using what primer?

 

[jkor]

Your using what primer?

Federal spp, and murom/fort Smith spp. Standard, non magnum

 

[jkor]

Murom kvb-9, federal 100

 

[Cerberus Group]

Should be using small rifle primers, not pistol primers.

Also, Murom primers are known for being on the soft side.

 

[jkor]

And I usually do. Just doing a experiment. I used standard spp's for 357 mag, with 2400. The data for 300blk and 357 mag are very close (a little less for 300blk because of a slightly smaller case capacity)

 

[jkor]

And all the off label muroms are the softer kvb-223 not magnum or 5.56

 

[orygun]

Should be using small rifle primers, not pistol primers.

Yeah, at 300BLK pressures, I'd be using SRP, also. The 357 Maximum operated at fairly high pressures and SRPs were the norm.

 

[solv3nt]

It depends on what you're making. If you're making rounds with H110, you should be using a magnum primer. Likewise, if you're making bunny fart pistol loads, I don't see why a pistol primer would be a problem.

 

[edzz]

As has been mentioned, WRONG primer for cartridge.
.300 BLK is a very different cartridge from .357 Mag.
Assuming you are using an AR15 also introduces its own primer issues with soft primers.

A good read on primers.
Primer primer

It depends on what you're making. If you're making rounds with H110, you should be using a magnum primer. Likewise, if you're making bunny fart pistol loads, I don't see why a pistol primer would be a problem.

Potential slam fires in an AR15. After all AR platform is most common for 300 BLK.

 

[solv3nt]

Potential slam fires in an AR15. After all AR platform is most common for 300 BLK.

Forgot about slams, carry on.

 

[jkor]

As has been mentioned, WRONG primer for cartridge.
.300 BLK is a very different cartridge from .357 Mag.
Assuming you are using an AR15 also introduces its own primer issues with soft primers.

A good read on primers.
Primer primer


Potential slam fires in an AR15. After all AR platform is most common for 300

Im well aware spp are not recommended for 300blk. they did work though. This was a bolt gun.

 

[jkor]

But, yeah. Don't use spp in rifle cartridges. The higher end of the load range did start piercing the cup a little.

 

[ferret427]

It depends on what you're making. If you're making rounds with H110, you should be using a magnum primer. Likewise, if you're making bunny fart pistol loads, I don't see why a pistol primer would be a problem.

I've been using regular small rifle primers and H110 in my SBR, but lately it seems that magnums are more widely available in bulk. Been thinking of trying them. Have had no issues with ignition or reliability with the regulars. I might need to go back to the manual to make sure I should be using magnums. I do use only LC brass that I convert, which I think has dimished case capacity over dedicated brass? Maybe that is why the regulars work for me...Would magnum primers be optimal given my brass choice? Always looking to improve my reloading.

 

[solv3nt]

I've been using regular small rifle primers and H110 in my SBR, but lately it seems that magnums are more widely available in bulk. Been thinking of trying them. Have had no issues with ignition or reliability with the regulars. I might need to go back to the manual to make sure I should be using magnums. I do use only LC brass that I convert, which I think has dimished case capacity over dedicated brass? Maybe that is why the regulars work for me...Would magnum primers be optimal given my brass choice? Always looking to improve my reloading.

You should be using the harder primers if you're shooting with an AR. H110 is a slow burn powder, so magnum will ensure better ignition.

If you're going to use pistol primers, only do it with low pressure, bunny fart loads where the primer meets the minimum requirements.

 

[saxon]

357 mag

Maximum pressure (SAAMI)

35,000 psi

300 AAC

Maximum pressure (SAAMI)

55,000

ERGO
The single reason that I would not do this is cup hardness.
Different primers are designed to handle different pressures.
With a low pressures load, you will not likely see any issues with this, but in full power supersonic loads, it may be a problem.
Remember, that tiny piece of nickel plated brass separates your face from 55,000 psi of burning gas.

 

[Ben B.]

Subsonic in a bolt gun, use SPP. subsonic from an AR, probably fine with SPMag. But I only use SRP in an AR to avoid possible slam fire from that floating firing pin.

SuperSonics use SRP.