Large Rifle Primer Loads for 300 PRC

[calinb]

My large rifle magnum primer supply is getting very low. I tried Win large rifle primers with the published Hodgdon 175 gr. Superformance 300 PRC load and got erratic chrony results and accuracy (Win LR magnum primers worked fine). Superformance is a weird powder though. I have other brands of LR non-magnum primers too and a wide variety of other powders in my inventory.

Does anyone have any load or powder selection advice for me? I don't need to shoot full-house loads. I just need an accurate load to shoot this rifle at targets. I attended an Appleseed KD (known distance) shoot last weekend and burned up 400 LR magnum primers. I can't keep going through them like that (400 per weekend)!

I figured I'd ask here rather than waste more reloading supplies experimenting unnecessarily.

Hopefully we'll see LR magnum primers soon, but I've been hoping for them for about three years now!

 

[lancetkenyon]

First off...you shot 400 rounds of .300PRC last weekend??? Holy CRAP! I see a new barrel every month or two in your future at that rate.

.300PRC is a pretty big case to try and light off. My personal rule is:
Under 50gr powder, LRP/SRP.
50-60gr, more than like LR, but could use LRM.
Over 60gr capacity, LRM.

CCI200 are almost as hot as Fed GM215M/Fed 215. If you are using a Fed LRM, try the CCI200. It might be really close.
CCI250 are the hottest primers I have found to date. If you are using those, I don't know of a replacement.

Superformance is a ball type powder I think, and they are known to need mags to touch them off properly. You might need to swap powders if you are getting poor ES/SD from the combo.

 

[Tac-O]

CCI200 are almost as hot as Fed GM215M/Fed 215. If you are using a Fed LRM, try the CCI200. It might be really close.
CCI250 are the hottest primers I have found to date. If you are using those, I don't know of a replacement.

For non-mag primers, I thought the brisance from low to high was something like:

Cci
Federal and Remington
Winchester

I'd that not correct?

 

[Weaver93]

Not sure it means anything, but a neat setup none the less.

Primer Testing Reference

 

[calinb]

For non-mag primers, I thought the brisance from low to high was something like:

Cci
Federal and Remington
Winchester

I'd that not correct?

Thanks! I tried the standard Winchester LR primers. Maybe they'll work if I use a faster stick powder instead of Superformance (which would not be my first pick, but I have a lot of it and it did shoot well with the Win LRM primers). I read a post here on a 6.5 PRC thread here claiming that extruded powders on the faster side work better than spherical when substituting LR for LRM primers.

 

[calinb]

Not sure it means anything, but a neat setup none the less.

Primer Testing Reference

Yes--interesting. Thanks for your reply and post!

 

[lancetkenyon]

For non-mag primers, I thought the brisance from low to high was something like:

Cci
Federal and Remington
Winchester

I'd that not correct?

Just from my personal findings.

Every time I have had to do a primer test (when I wasn't satified with charge weight and seating depth) the CCI250 has produced higher velocities than Feds. By 10-15fps.

 

[calinb]

First off...you shot 400 rounds of .300PRC last weekend??? Holy CRAP! I see a new barrel every month or two in your future at that rate.

.300PRC is a pretty big case to try and light off. My personal rule is:
Under 50gr powder, LRP/SRP.
50-60gr, more than like LR, but could use LRM.
Over 60gr capacity, LRM.

CCI200 are almost as hot as Fed GM215M/Fed 215. If you are using a Fed LRM, try the CCI200. It might be really close.
CCI250 are the hottest primers I have found to date. If you are using those, I don't know of a replacement.

Superformance is a ball type powder I think, and they are known to need mags to touch them off properly. You might need to swap powders if you are getting poor ES/SD from the combo.

Thanks for your reply, lancetkenyon. Yeah--Appleseed shoots are mostly about "expeditious" shooting. They will really wear you out--especially a KD shoot with walking out to the 400 yard line over and over (or running / jogging with the shoot boss yelling "quickly, quickly, quickly..). Carpooling from the line to the targets in vehicles becomes essential for ol' farts like me!

Thanks for the tip. I thought that might be the case with Superformance. I just wanted to use it because it proved to be an accurate load and I had about 10 lbs of it, but it also turned out that it was only accurate with the WLR-mangum primers and I have plenty of chrony data that tells why (high ES and SD)!

I'll try some other powders, rather than burn all my remaining magnum primers. At least Bergara B14 barrels are cheap, compared to ammo! I think I'll be doing this KD shoot about 2x per year and I'll have to emphasize a lot of dry fire at my range on our homestead so maybe I can get a few years out of this barrel.

 

[ajvinyard]

I hope you guys get this ironed out and post the results. I am about done with my 300prc and one of my holdups is the lack of mag primers. Those in my circle have always had amazing results with 4831 power in most large rifles so that was going to be the first powder I try.