Primers. Which primer would work best for an extruded powder? Specifically Reloder 15. Trying to work up an accuracy load for .223 and will be using SMK 69 gr. Probably around 23 grains of powder. I know for ball powders a magnum is best or extreme cold. I have both. Just not sure which might be best. Any experience? Or ideas if this sounds like a decent powder/ bullet combo?
What primer does your load books recomend?
There's the rub. One recommend magnums and another standards.
I'm a magnum primer guy personally, maybe because "Magnum" sounds cool & I feel more confident in mag. primers though I doubt standard primers would fail to ignite in my shooting conditions but like these other guys have suggested I'd try both & see if there's a discernible difference accuracy wise, if not use whatever you can get your hands on because primers are like Bigfoot around my area, you hear about them but never actually see any for yourself
I do a lot of testing and did a lot when making loads for my 5.56 and .223
I found my groups stayed much tighter with CCI 450 magnum primers than the CCI 400 when the temps changed outside.
I was using CCI 400's and I would have a good load at 17 F temps but when that temp got to 55 the groups went to crap.
I then had to find a load that shot at 55 degrees and when I did it went to crap when it hit 95 f outside.
Varget was the powder and then I went to H4895 and it was better and I did some research and tried CCI 450's and I only use those now for all my 5.56 and .223 loads.
If you are not looking for sub moa accuracy it does not matter.
I found my groups stayed much tighter with CCI 450 magnum primers than the CCI 400 when the temps changed outside.
I was using CCI 400's and I would have a good load at 17 F temps but when that temp got to 55 the groups went to crap.
I then had to find a load that shot at 55 degrees and when I did it went to crap when it hit 95 f outside.
Varget was the powder and then I went to H4895 and it was better and I did some research and tried CCI 450's and I only use those now for all my 5.56 and .223 loads.
If you are not looking for sub moa accuracy it does not matter.
I have a rather hot load for my .223 SPS Tactical that uses exactly what you have. It will crater primers pretty badly in temps above 80 degrees F:
LC '08 brass
69gr SMK
25.5gr (work up...may not be safe in your rifle)
CCI 400 (standard primer)
2.280 COL
This load is a laser in my rifle. For (5), five shot groups it averaged .502 MOA, and that is with one of the groups opening up to 3/4".
At no point will you need a magnum primer to efficiently burn ball powder in a .223/5.56. You can save those for slightly larger cartridges (6.5 Grendel, 6.8 SPC etc...).
* However, for an AR you may want a primer with a slightly harder cup to potentially reduce the chance of an accidental discharge...Ive not personally seen it happen, but I've heard the internet rumors. But the firing pin will bump the primer as the round is chambered. That small dent is enough to have me save my Federal primers for bolt gun loads.
I use a standard CCI 200 with Ramshot TAC and H4895 with lighter bullets in my .308. Never had an issue, and I hunt hogs in sub freezing temps (limited to about 25 degrees F though...nothing too extreme).
You can also use a #41 primer in place of a magnum SRP if you have those on hand as they are just about perfectly interchangeable. I'd drop the charge weight though and work back up if you are flirting with max weights.
I load for two .223 bolt guns, and over a half dozen 5.56 ARs.
Best of luck to you.
