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Good news. It's without doubt a 10.75x52r Grundig. Better news, the 7MMx65r cases fit like a glove only about 6 thousandths off at the base. Best news is that the rim fits flush in the chamber/extractor. I'll fireform tomorrow, trim and start casting bullets. I checked Quickload and nominal velocity with a 347 gr bullet is 1880'/sec with 34,000 PSI and 2700'#'s E at the muzzle. 3 inches high at 100 = 3 inches low at 190 yards and carries >1500'#'s E out to 250 yards. As a bonus I will pull the S&B 173gr SPCE bullets and use them in my Sako 7MM Rem Mag. Life is good!
I'm going with Accurate 2495 with a 317gr cast bullet for starters. The quick load numbers show this powder is the fastest/lowest pressure combination of all of them(1920'/sec with 26,000 pressure and a ME of 2500'lbs). My chamber is not exactly the same as the 10.75x52r Grundig so it's been renamed the 10.75x52r Grundig-Scruggs. I fire formed the brass using 11 grains of Bullseye, topped off with cream of wheat to the neck of the 7MMx65r case and topped with a 22 patch. An old Smith gave me this recipe years ago and it works to fireform brass without wasting bullets, expensive powder and makes a perfect case.
You do realize you're shooting your breakfast...... That's a good recipe for fireforming. There isn't any game in the lower 48 that load won't take.
The only caution on using the CoW recipe is that they should be fired upon loading. You wouldn't want to leave them sitting around for any period of time as you would run the low risk of moisture causing the CoW to harden. I should have the bullets made later this week for testing. I'm also going to need one of those magnetic front sight beads as the front sight is just too skinny for my eyes.
Sakorick,
We don't eat CoW in this part of the world, so most people use grits for fireforming. I usually use worn out polishing media (usually walnut hulls), it's handy. You can use most anything with good results, even corn meal.
Mike
Great, looking forward to the range report. Did you ever make a chambercast? At first, you said the head diameter had been measured as .465", then you said you thought it was 10.75x52R Grundig. The Grundig cartridges have a larger head diameter than .465"( about .494").If it is 10.75x52R Grundig, cases still wouldn't be too hard, Graf has 8x58R Aust/Hungarian cases and they would require only a trimming/fireforming and maybe a rim adjustment.Unfortunately, you couldn't use 444 Marlin dies, and would have to use more expensive ones. This is why I am interested in the chambercast.
Mike
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