H335 and Standard small rifle primers?

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FoghornLeghorn

New member
I'm working up a load for 5.56 cal bullets and have never used H335 powder before.

I'm using CCI 400 small rifle primers and figure to start at 24.5 grains.

My Speer manual says starting load is 25 grains. Speer also uses/recommends magnum small rifle primers.

According to my googlefoo, many shooters use standard primers with no ill effect. Is that accurate?
 
Hodgdon manual says use a standard primer. You can use either one, but as you’re already doing start low and work your way up. FWIW, I got excellent results with that powder. Suggestion: get a Lyman manual and visit Hodgdon’s web site for all their loading data for free. You need several sources sometimes to get more information. Good luck.
 
CCI 400's can pierce with hotter loads or heavier bullets. 450's have thicker cups. I will look for 450's when I run out of Tula 556m.
 
My standard load is 24 gr of H335 with a CCI 400 primer under a 55 gr SPBT for 3000 FPS in a Ruger American. You results may vary.
 
Cup thickness is the same on regular and magnum. The difference in cup thickness is between rifle and pistol primers. I have a chart around here somewhere, I’ll see if I can find it. If I can, I’ll post it. If anyone pierced a rifle primer it’s a firing pin problem, not a primer problem.
 
Ive had a couple of slam fires out of 2000 in floating pin rifle using 400's. (technically a double fire) . never happened with 450's yet. h335 is a ball powder iirc, magnum primers deserve consideration.
 
MilSpec Primers prevent Slam-fires and ignite Mil-Spec Ball Powders

450's have thicker cups and are more resistent to slam-fires and piercing. US / NATO mil-spec is #41's; 450's are very similar. So are Tula 556M.
I do not purchase CCI 400's any more, after piercing issues with hotter loads.
 
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I don’t know about the thickness or hardness of the 400’s vs 450’s . I will say Marco is not wrong as far as piercing of the 400 . I use the 400 exclusively and have had a total of 2 primer piercings out of thousands of loads . There is one thing that was the same though . Both piercings were in a very hot 69gr smk load which I don’t load anymore . I have never had a piercing shooting my 25gr and 25.5gr H-335 loads pushing 55gr bullets and the CCI 400 primers .
 
The table in this old article shows the 400 cup as 0.020" and the 450 cup as 0.025" thick. This article explains why magnum primers are commonly used with the old spherical powder formulations. Failure to use them does not mean failure to fire, but rather that the ignition time can be more consistent with the magnum primer which helps accuracy issues. The 450 and the military sensitivity spec #41 primer are not the same. The cup and the priming mix are the same, but the #41 has an anvil with a shorter, wider leg angle to reduce normal #450 sensitivity to the military h-test sensitivity level.
 
Thanks for all the responses. The Hogdon online reloading data says for a 55 grain bullet, the starting load is 21.5 grains of the above powder.

Based upon the responses, I don't think standard primers will make a difference. Plus, these are plinking rounds.
 
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