The Smallest Minority on earth is the individual. Those who deny individual rights cannot claim to be defenders of minorities. - Ayn Rand
Impressive groups. Glad the scope's doin' it's part.
I concur with the Citizen. I'd be proud to have shot the groups.
As to the question, pressure, maybe.
According to the real numbers that have become more common in recent years, primer cratering may or may not be an indicator of excessive pressure. I note that the primers don't seem to be flattened to any great degree.
Are your loads showing any other symptoms such as sticky extraction, etc.?
You might want to load a few softer loads to see how the primers compare with these.
There's a little bit of primer flattening that you really can't see in this shot. I think I'm going to drop down to 42.0 grains of Varget. This guy is getting good results with that load in his 5R: Tobystatical
Then may work my way up in 1/10th grain increments to 43.0 checking accuracy at each step.
I'm really interested in how the 155 grain Scenars shoot, though.
I know with all the crap I haul around I'm about ready for one of these: http://www.kaddykarts.com/
Sweet group BTW!!
Those primers look a mite hot to me. Do you have a Wolff heavy mainspring behind the firing pin?
No, other than the Gunkote finish, that rifle is stock-out-of-the-box.
As you probably know, a weak main spring will exaggerate primer cratering. Many years ago (1977 or thereabouts), I replaced the stock spring on my Model 70 with a Wolff heavy duty spring. Signs of primer cratering disappeared. I replaced that same spring last fall. The Wolff spring I replaced was still stronger than the original, which I still have, even after 31 years of use.
It's just food for thought.
Well, the next load I'm going to try for this rifle is 42.0 grains of Varget. If I'm still seeing cratering, I might look at replacing the firing pin spring. Thanks for the suggestion.
I make target stands from 2" PVC, glued into a 2' square with 2 "T"s opposite each other. 2X2 posts trimmed down to fit into the uprights provide stapling space. They cost nothing to make, transport easy, are light enough to carry to the shooting distance you want and work remarkably well.
Hmm, I've been shooting the same 175 SMKs, but using 44.2 grains of Varget. My bone-stock Rem 700 PSS prefers that load.
Mike, every gun is different. What works perfectly in yours might be unsafe in mine. I found some load data last night that suggests that 43.5 grains of Varget will produce about 59000psi, and is "near maximum". Apparently that's correct for my rifle, but not yours.
Nate, I've seen people with frames similar to what you recommend. I think that's the way I'm going to go, since I don't own a welder and I no longer work at a place with a fab shop.
Looks like you are getting ready for Boomershoot 2009. Will I be seeing you there?
I'm not promising anything, but I'll give you a definite "maybe" right now.
I'll send you an email when registration opens up (probably within a month). Sign up then you can cancel with a full refund later on if things don't work out.
Few years back took the son to the range and found it was just us and some guy sighting in for deer season. VERY loud rifle, and during a break I asked what he was shooting. "7mm Magnum. They're a little hot, but they don't flatten the primers TOO much, so I'll use them." At which I thought seriously about moving as far away from his bench as we could get.
What made that even more damn silly was where he was planning to hunt: southern OK, where a LOOONG shot is 200 yards.
Realistically, Firehand, "slightly flattened" primers aren't necessarily indicators of dangerous pressures. They can even be a sign of low pressure (though I doubt it was the case in your example.)
Of course, when I see slightly flattened primers, I BACK THE LOAD OFF.
I like long case life, and I don't like beating my rifles up.
Cratering, on the other hand, is a new one on me - at least as much cratering as I saw here.
There's another trick to pressure management that I've found useful. I police the brass at the range to find spent factory loads in the cartridges that I shoot. The pressure signs of my handloads don't look any hotter than they do, so if they are hotter, it ain't by much.