LMR primers in 30-30?

[Captain Skip]

I've done all my homework. I've read all the threads I could find here about casting for my Marlin 336 .30-.30. I just placed my order with Arsenal Molds for their .311, 170gr Ranch Dog clone. I ordered the mold for gas checks but plan on powder coating all the bullets. These are going to be used for plinking/target shooting and not competition so I don't need MOA accuracy. Just a heck of a lot cheaper to roll my own.

My son gave me an 8lb jug of Hodgdon H380 and I've found published loads for the .30-.30 170 bullets so I can check that off. My only issue is the lack of primers on the market....at least the lack for a reasonable price. I refuse to pay $140 for a brick of primers. My LGS had magnum large rifle primers (CCI #250) in stock with a one brick limit so I bought a brick. I measured them compared to a single sleeve of standard large rifle primers that I managed to scrounge up. Depth and diameter are identical so I know they'll fit. I also know magnum primers burn hotter than standard primers so I have absolutely no intention of loading up to maximum load range.

That being said, I've never used magnum primers before so I'm not sure what to expect. I'm going to err on the side of caution and take the minimum load and reduce it by 5%. I'm making an educated guess that with the hotter primer this will bring me up above the minimum load pressures and velocity. The 336 has never been fired so it hasn't been abused with high powered loads in the past. The Hodgden manual (the older one) shows H380 with a starting recipe of 34 grains of powder for a 170gr bullet and lists the velocity as 2,016fps and a CUP of 31,800.

Before I do something stupid, someone want to spot me on this? Do I need to reduce the minimum load by the 5%? Do I need to reduce it more? Or, am I letting my OCD get the best of me and using the minimum load with the magnum primers won't even be noticeable?

[Winger Ed.]

The cup wall is a little thicker to handle magnum pressures, and they're supposed to be a little hotter.
I'd use them, starting at the minimum loads..... not below it.

The differences are small enough that Winchester lists their large rifle primers as being recommended
for both standard or magnum loads.

I've never done a side by side comparison in a medium-ish case like .30-30 with the only variable
being the brand of primer-- but I doubt the differences would be enough to worry about shooting your eye out.

[Shuz]

Since H-380 is a ball powder, and ball powders are known to work best with magnum type primers, your CCI 250 mags should be appropriate for your use. To be sure, call Hodgdon and ask them.

[Texas by God]

It won't hurt a thing just use starting loads and work up if wanted. I've been using Remington 9-1/2 M for everything that takes large rifle size. Cast and jackets.
Only because I have more of them than standard ones.
I do consider them necessary for ball powders in big cases, though. Hang fires freak me out just a bit.

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[BLAHUT]

Just start with listed starting load and work up and find what you gun likes for accuracy?? I use LRM in all my loads, all my guns.

[M-Tecs]

Some good info here https://www.accurateshooter.com/technical-articles/primers-and-pressure-analysis/

[Hick]

Everyone pretty much said it already. I've used them and H380 in my 30-30 (also CCI #34 military primers). Just start low and all should be fine.

[Captain Skip]

Thanks all, I appreciate your input. I’ll start at the minimum load and see how it goes.

[Maineboy]

I recently chronographed some loads using the Lee 150fp cast boolit and 28.3 grains of surplus CMR100 in Remington cases with both Winchester LR and Winchester LR magnum primers.
The results:
WLRmag primers velocity was 2030fps, ES 67fps, and SD was 22.
WLR primers, velocity was 2040fps, ES was 66fps, and SD was 23.
The rifle used is a Savage 340 in 30-30 with an 18 inch barrel.

[Winger Ed.]

I recently chronographed some loads using the Lee 150fp cast boolit and 28.3 grains of surplus CMR100 in Remington cases with both Winchester LR and Winchester LR magnum primers.



Thanks for posting that.

Just curious-
Was the flat spot on the primer any different to indicate a harder/thicker cup?

[Maineboy]

Thanks for posting that.

Just curious-
Was the flat spot on the primer any different to indicate a harder/thicker cup?

Sorry Ed, I do not recall. The only thing I can say is that I always check fired primers for pressure indicators and neither load showed anything unusual.

[Soundguy]

Important tip.. if you substitute a magnum primer for a regular.. when you pull the trigger.... they go bang. that's all. Yeah.. start your load development as you normally do.. start low.. work up.

As you found out.. large rifle and large magnum rifle are same size.

small pistol.. small pistol magnum small rifle and small rifle magnum are all same size

large pistol is same diameter as the large rifle.. but shorter.... why did they do this? large should be large.. small should be small.

PS.. I load for my 336 30-30 often.. if i'm going to be in cold weather.. it always gets a magnum primer.. in fact.. anything I load for freezing temp weather gets a magnum primer.