Hello all, hope everyone had a great Christmas and had some quality time with family !
Finally managed to get a few hours and conduct a test I have been itching to do and as promised earlier, report my results here .
This water case capacity test involves the 375 Mjolnir cartridge only
The test consisted of 20 Jamison 500 Jeffery cases fireformed (once fired) in the chamber ..
I full length sized the cases and trimmed them all to minimum length, primed each case with Federal 215 mag primers.... I wanted the water reading to show the capacity of a case ready for loading and not a fired case fully expanded in chamber !
I placed a case on my Dillon scale, zeroed it out then filled the case with water flush to the top of the neck, wrote down the reading and dumped the water out and refilled with water and weighed again, repeated that process 5 times to get a consistent reading .
I zeroed the scale out on each dry case before filling with water , this process was done with all 20 cases with the utmost care to get a consistent and accurate reading .
Out of the 20 cases weighed 5x's each, the scale showed 140.8 gr of water almost every time with several readings of 140.6 gr and a few at 141.0 gr..
I am calling case water capacity at 140.8 gr !!
Now my earlier case capacity report of 147.8 gr was an estimate by Quick Design !
The Ammo Guide estimate shows capacity at 132.9 gr .
My test shows the water capacity right in the middle of those estimates, not knocking or dismissing those estimates but reporting my findings ..
If someone has a more accurate way of determining case water capacity , Please inform me and I can try again !
My new wildcat projects have become reality as I have completed crunching numbers and reamers have been ordered !
I have named the cartridge the ".375 EXECUTIONER"
and yes a .338 is in the works at the same time !
338 Lapua and 378 WBY sized boltface actions are the target for this cartridge
Case capacity is 14.2 gr more than my .375 Mjolnir, ( Quick design estimate shows 162 gr, I subtracted 7 gr due to results with the 375 Mjolnir)
making it a 155 gr capacity case in a 338 Lapua sized casehead cartridge
I believe this cartridge has the max capacity in a 338 Lapua boltface case .
more info soon !
here is a Quick Design image with my dimensions plugged in ..
I believe the 338 version will be the best of the bunch. Custom action makers usually use 1.125" threads for the 338 Lapua size cartridges & 1.187" for Cheytac cartridges, I see no problem opening up the 338 Lapua chamber to your 338 Wolverine in a 1.125" tenon. The Cheytac action boltface won`t work of course but would be stronger since tenon size is even bigger. With the popularity of the 375 Cheytac with heavy per caliber projectiles, it will probably be a better choice since powder capacity is a bit more. It looks like the 500 Jeffery Jamison brass has a thicker head than the Bertram 500 Jeffery or the 500 AHR. I talked to Marc Jamison and he said all of his rifle brass is made to handle 70,000psi.