Update on .223 primer blow-by, 1/26/13
I tried a few things to decrease the blow-by. I tried a medium load in 3031 powder- 22 grains. Velocity 2417 ft/sec, 2 of 19 cases with primer blow-by. I tried a really light load of 4064 just to make sure it was not an overpressure problem- 20 grains yielding 2223 ft/sec. One of 10 cases with blow by. I even tried lowering the hammer spring tension thinking that the really deep primer hits might be deforming the primers causing the blow-by. No luck. All the cases were new RP cases full length sized. My prior cases were once fired LC, PMC, FC. A few had the crimped primer and the sharp edge was gently knocked off with a few twists of a hand reemer. Still had blow by with uncrimped and crimped cases.
In summary- there is primer blow-by with all four case headstamps. Same with different powders and loadings from light loads up to medium high loads. The only constant is the Wolf Small Rifle primer. With the current hysteria I am unable to buy any different primers. I've only put 197 rounds through this LMT AR and already have significant flame cutting in the bolt face. If anyone has any other suggestions I'm all ears.
best wishes- oldandslow