I had an interesting problem today with the 300 H&H Mag brass cases reformed back to .300 H&H Mag for fire formed .300 Wetherby Magnum. At the end of the day after working at the range I pull out the Remington 721 that I bought and the reloaded 300 H&H rounds I had just built. The first round would not chamber all the way, the second had the same issue but would not extract, I was able to set the round and fire it, then the case would not extract and I had to drive it out using an old cleaning rod (yes I protected the crown)

Well, I check all the others (18 more) and all of them had the same issue. So with my shooting session cut short, I came home. I pulled the SAAMI specs for the 300 H&H and all of the measurements check-out so I sort of got that 'huh' look on my face. So I resized the fired and unfired the case again and both it still had the same issue he chambered. So I coated one of the cases with blue layout fluid (****m) and stuck it back in the chamber to see where it was tight.

Well, when I drove the case back out of the chamber I found that .250" down from the shoulder there was a section about 1.125" long where you could see that was scraping the chamber when it was inserted.

I mark the resized case and a factory-new case in the exact same places the beginning of the rub, the center, and the end. I found that the difference was .008", .015", and .014"; the results on other unfired cases were almost exactly the same only the top measurement varied between -.002" in a sample lot of three.

So I figured that the case was springing back after sizing. I did not think about how far down I need to anneal the case when I annealed them the first time, I only annealed just below the shoulder when it was in the 300 Wetherby Mag form. I see now that because of how much the case would need to be reformed, I should have done a second anneal and reform. What a mistake....

When I annealed two of the cases to just below where the rubbing ended and resized the case, everything measured perfectly and the case chambered and extracted perfectly. I guess it's one of those "live and learn" things; eh?

Guess what I'll be doing tomorrow.... 18 more, Pull bullet, remove the powder, remove the primer, anneal, re-size, reload - Repeat... Arggggg.... I feel like I'm being taught a lesson by my Dad, when I didn't do something right or to his standards he would wait until I told him I was finished and he would make me do it over because I did something wrong. The first Ford 289 I ever rebuilt ending up building and tearing down three times before he said it was right.

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