Back on August 1 I ordered a .375 Weatherby reamer (with a few changes), from Pacific Tool & Gage. A nice lady called yesterday to confirm my CC number and it is on the way up. Only took nine weeks, much longer than I thought, but am happy PT&G takes the time to watch the details.
As-soon-as it arrives I will pack it (the reamer), in with the rifle and ship the whole to Jim Brockman along with a list of things I'd like him to do. Not many things, just those that will complement the potential benefits the tight reamer will bring. I did ask him about CZ barrel quality and he told me he is quite pleased with the results of many previous rechamberings. I saw Krieger has a 1:12 .375 barrel on their inventory list, but that would have made a $500 re-chambering into a > $1k rifle build, don't need to do that. I like the express sights built into the barrel of the CZ, I know Brockman can do those, but they cost as it takes time to mill down the excess metal and we all know time = $$$ in the gunsmith trade.
Since my original thread is waaay back a few pages, and this software doesn't allow editing on old stuff, here are the changes I made:
This reamer will be a "match grade" reamer for a very tight chamber.
The following changes:
Neck diameter: 0.405" to 0.401", which is 0.001" over the neck diameter of two full boxes of original 1958 .375 Weatherby cartridges I have.
Cartridge case mouth to free-bore: 0.0145" to 0.010".
Free-bore diameter: 0.376" to 0.3754".
Free-bore length: 0.735" to 0.125".
Throat (length of entry into the rifling): 0.261" to 0.100"
Angle of rifling entry: 1*-19-0 to 1*-30.
I have posted before I have PressureTrace pressure testing equipment. I have a couple of gages I can use, one of which will go onto the rifle barrel when it comes back. I will ask Mr. Brockman if he will make a chamber cast so we can verify the dimensions, not that I think PT&G will mess up, but I just want to be sure.
I want to fire a couple of my precious original 1958 Weatherby rounds to compare against new manufactured rounds. BUT, there is a reason Old Man Weatherby put those long throats in there: to keep down peak chamber pressures, so maybe I won't. I'll have plenty of time to think about it. Don't want to make a mess of my rifle before I have a chance to really play with it.
All of my cases I have prepared have 0.398" necks when loaded with .375" bullets, the 0.003" neck clearance isn't benchrest tight, but it will be tight by factory standards. I might take the time to locate some new .375 H&H Winchester cases to turn with different clearances to see how much difference it makes pressure-wise the tighter the neck.
So much to think about and get ready for!!