What is the diameter of your 176 gr Cats in 7mm and 6.5mm? I have been told by a couple of people that the 7mm Cats are measuring a robust .285. I need to set-up a reamer and am wondering about some dimensions.
This is a little tangent off Troy's request but, something I think he and I are still interested in... Did you have the freebore diameter in the chamber ground to .0005 over, or .2845? And did you have problems with too tight of fit if you did and Bob's bullets were .0005 over that?
My brother had this problem with the 338-378WBY he did, measured .3385 in the freebore and 300gr SMK's were all .3388, or only .0003 over. They wouldn't chamber without honing out the freebore area more. They noticed it when trying get the throat cut to the correct length after chambering it.
I was telling Troy that this 176 Cauterucio that came setting on the Juenke ICC measured .285, with my trusty caliper. Looks like my caliper's a tenth off though. [img]images/icons/wink.gif[/img]
Derrick's are still a snug fit, but they do chamber fine now. Evidentely .0003 is enough that it's a problem. I don't think I'd be too worried if I speced it at .2852, but the trouble they went through having it too tight didn't sound like much fun. You might float the question to the guys at BRC that might use the 176 of Bob's too and see what they suggest.
Kiff's blueprint for your 7mm Dakota has 0.2845" for the leade diameter.
Two things I would do- Talk to your reamer maker about this and talk to Bob about the bullets being on the large size.
It's a good thing to increase one's knowledge on such things, but pick the brains of guys like Dave Kiff. He's the expert on these things. Sometime's in our quest for supreme accuracy we over complicate things with tight necks, 1 degree or 1 1/2 degree throats, etc.
Definitely an interesting thread, Len emailed me and asked me what my thoughts were on this subject and honestly I don't have a clue. But that's why I have Kiff's phone # on speed dial. [img]images/icons/wink.gif[/img]