Magnum Primers in 6.5 Creedmoor

nobody

WKR
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Sep 15, 2020
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Before the comments start flying, yes I'm aware it's possible. Yes I know handloading practices should be followed, start low and work up slow, etc.

At the start of the Pandemic, when I had a 7 mag, I picked up about 5k large rifle magnum primers, CCI's. Now the 7 mag is gone, but I've still got all these primers. I don't have any standard large rifle primers, and have been unable to find any locally for some time. Rather than just not loading, I'm getting ready to work up some loads with the magnum primers.

That being said, I know it's possible. I'm just asking to see if anybody is doing this with any sort of success. Loading H4350, Hornady 1x fired brass (fired in my own chamber), and 140 SST's and 140 ELDM's. Anybody having luck with the magnum primers in your creed?
 
I am using Lapua small rifle primer brass for my 6.5CM and using CCI #450s. (small rifle mag primer)

I have anecdotally seen two effects while using magnum primers. First, ES/SD has potential to be more consistent due to a better powder burn. Second, you may experience pressure signs sooner especially with a faster burning powder compared to standard primers.

My load that I developed using H4350 and CCi450s has an SD of 3.. so I'm not motivated to change anything about it.
 
If you are interested, i would trade you about 250 standard for 250 Mag primers.
 
I load my 6.5creed with 41.5gr of H4350, Hornady brass, 143 ELDx and CC250 LRM primers.
No issues at all and very accurate with good ES and SD numbers.
 
I am using Lapua small rifle primer brass for my 6.5CM and using CCI #450s. (small rifle mag primer)

I have anecdotally seen two effects while using magnum primers. First, ES/SD has potential to be more consistent due to a better powder burn. Second, you may experience pressure signs sooner especially with a faster burning powder compared to standard primers.

My load that I developed using H4350 and CCi450s has an SD of 3.. so I'm not motivated to change anything about it.
This is great, thank you so much for the feedback. This helps!
 
If you are interested, i would trade you about 250 standard for 250 Mag primers.
No thanks, I would trade a full 1k for a full 1k if you were local to Utah, but looks like you're across the country...
 
I load my 6.5creed with 41.5gr of H4350, Hornady brass, 143 ELDx and CC250 LRM primers.
No issues at all and very accurate with good ES and SD numbers.
Hmmm... Looks like somebody got their hands on Hornady's factory load data for the AMAX/ELDM! I've got direct from Hornady that this is the recipe to duplicate their factory ELD Match load, with the exception being the magnum vs standard primer. Nice to see somebody running this, as it's my goal.

Just out of curiosity, what rifle are you running?
 
You should be good to go. As mentioned you may see signs of pressure early but you may not. I've seen ES/SD changes in both directions when switching back and forth from standard to mag. As above it's anecdotal and very much just a 1 off kind of test.

If you were much closer I'd consider a trade if it made you feel better but a trip to UT from MT is expensive these days.
 
You should be good to go. As mentioned you may see signs of pressure early but you may not. I've seen ES/SD changes in both directions when switching back and forth from standard to mag. As above it's anecdotal and very much just a 1 off kind of test.

If you were much closer I'd consider a trade if it made you feel better but a trip to UT from MT is expensive these days.
Sounds great, thanks for the response. If we ever make it up to visit the in-laws in Three Forks maybe I'll take you up on that haha.
 
I have seen it do better, worse and about the same in terms of pressure and sd.

Some combos will shoot better and some worse, depending on powder, neck tension and bullet choice.

You should be able to find a load that shoots very similar with a bit of tinkering.

Cci being about the hottest, I'd certainly back up a bit and they run the thickest cup, so DO NOT rely on cup flow to validate pressure. It can take north of 70k to flow that primer.
 
I have seen it do better, worse and about the same in terms of pressure and sd.

Some combos will shoot better and some worse, depending on powder, neck tension and bullet choice.

You should be able to find a load that shoots very similar with a bit of tinkering.

Cci being about the hottest, I'd certainly back up a bit and they run the thickest cup, so DO NOT rely on cup flow to validate pressure. It can take north of 70k to flow that primer.
This is good advice, and good to be aware of. I appreciate it!
 
Mostly use mag primers but I use 748 powder For .308 win. 30.06 I use standard primers with 4350.
revolvers I use mag primers 100% cuz I want them to work if I need in them outside in Minnesota winters.
 
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