cratered primers in the 223
Posted 21 October 2012 - 05:43 AM
Posted 21 October 2012 - 07:15 AM
Check out this information on Small Rifle primers.
CCI 400 -thin .020" cup, not recommended for AR15 use by CCI/Speer. Good for .22 Hornet, .30 Carbine.
CCI BR4 - match primer with a thicker .025" cup.
Federal 205 - Mil-Spec cup thickness according to Federal - okay for 5.56mm. .0225" cup thickness.
Federal 205M - same as the 205 but the match version.
Magtech PR-SR - .025" cup thickness (not much feedback yet on this new primer as to AR15 suitability but with the same cup thickness as the Rem 7 1/2 it looks good so far)
Remington 6 ½ - thin .020" cup, intended for older, lower pressure rounds Remington says do not use for the .223 Rem or other similar pressure rounds. Good for .22 Hornet, .30 Carbine.
Remington 7 ½ BR - A match or "bench rest" primer. Lyman & Nosler classify this primer as a Standard. Remington says the compound is the same as the 6 1/2 but with a thicker .025" cup.
Winchester WSR - some piercing issues noted when changed from silver to brass cup. Cup thickness is a bit thinner at .021". Most say they are good to go for the AR15 despite that, probably because of the hardness of the cup. Some feel they are less resistant to higher pressures.
Wolf Small Rifle SR - soft, sensitive copper cup, not recommended for AR15/military rifle use or high pressure rounds.
Posted 21 October 2012 - 07:33 AM
I have tested quite a bit of loads with mag primers in several calibers, including the 2 above. I no longer use any mag primers in my standard rifle calibers.
With that in mind, you are correct, Eric, that as a general rule, I found that I had to use 1/2 grain less powder with mag primers. There was also a slight velocity loss, perhaps in the 50 fps range?! And you know how that had to give me the chills. LOL
I personally would re-test or try some CCI BR4 or other primers with your loads. If the problem does not go away, I guess it cannot hurt to have a gunsmith look at it. Could it possible be the spring is too strong??
Posted 21 October 2012 - 12:40 PM
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