I saw cases just like that for years shooting competition where the use of light loads was permitted. It doesn't hurt anything. If I bump my charge up just a little to Major power level the blowby goes away. I wouldn't spend much time sweating cases showing blowby like yours. Blowby stains on cases do not mean the gun's timing is off. It simply means the case is not expanding fully and sealing the breech off. There's either not enough pressure or the cases are resistant to swelling up or the chamber is oversize. It's just a little more dirt in the gun. You're going to clean that thing anyway. What you're seeing is normal for some ammo. Now if factory loaded ball rounds loaded to full power (230 @ 850) show that much blowby then something is out of spec - either the chamber or the brass. And as far as Springfield calling their barrel "match grade" it's meaningless. They don't make match grade barrels. They do make very good barrels though. I have seen plenty of their standard barrels (two piece) fitted to guns that would shoot a one hole group out of a Ransom Rest. My wife has one.
Last edited by drail; May 13, 2012 at 06:09 PM.