Troy
Well-Known Member
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.
Cauterucio Bullet Diameter
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.285
Given my lack of an accurate micrometer calibration gauge, a better answer would be that my mic says .2849
This is .0006 greater than my mic says for Matchkings, JLK's and A-max's.
[ 04-14-2004: Message edited by: Len Backus ]
Given my lack of an accurate micrometer calibration gauge, a better answer would be that my mic says .2849
This is .0006 greater than my mic says for Matchkings, JLK's and A-max's.
[ 04-14-2004: Message edited by: Len Backus ]
Brent
Well-Known Member
Len
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.
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.
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Brent
Very timely question.
I have the diagrams from 2 different reamers I have used for rifles that seem to fit the Cauterucio bullets. The freebore varies from .2850 to .2855
The reamer for my upcoming 7/338 Lapua Improved is speced at .2849.
Guess I better question Dave Kiff about that close of a tolerance.
Very timely question.
I have the diagrams from 2 different reamers I have used for rifles that seem to fit the Cauterucio bullets. The freebore varies from .2850 to .2855
The reamer for my upcoming 7/338 Lapua Improved is speced at .2849.
Guess I better question Dave Kiff about that close of a tolerance.
Brent
Well-Known Member
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.
Troy
Well-Known Member
Brent not a tangent at all that was where I was going with this thread anyway. I wanted to know what people were using for reamer specs when using this bullet.
chris matthews
Well-Known Member
Len,
Kiff's blueprint for your 7mm Dakota has 0.2845" for the leade diameter.
Troy,
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.
[ 04-14-2004: Message edited by: chris matthews ]
Kiff's blueprint for your 7mm Dakota has 0.2845" for the leade diameter.
Troy,
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.
[ 04-14-2004: Message edited by: chris matthews ]
Troy
Well-Known Member
I could not agree with you more Chris. Dave is one knowledgable guy and has never refused to talk with me about setting up my reamers. What I plan to do is acquire all the bullets I plan to shoot in the heavy range and then make some dummy rounds and send them to Dave and tell him what my goals are. From this point he can spec my reamer and then we can review it.
As Brent knows, I am having trouble acquiring the heavy 7mm VLDs. I have Berger 180s. Jimmy Knox said nothing in the 180 range until maybe June. Who knows how long Bob is going to be out of the picture? Finally there is the elusive 175gr Sierra MatchKing with the green tip. I am not in a big panic just yet. My components for the project are going to be awhile yet.
I would however like to get a reamer going so that when the components are ready so is the reamer.
As Brent knows, I am having trouble acquiring the heavy 7mm VLDs. I have Berger 180s. Jimmy Knox said nothing in the 180 range until maybe June. Who knows how long Bob is going to be out of the picture? Finally there is the elusive 175gr Sierra MatchKing with the green tip. I am not in a big panic just yet. My components for the project are going to be awhile yet.
I would however like to get a reamer going so that when the components are ready so is the reamer.
