Using .284 check on a .277 bullet

[7br]

A lot of my casting is for the 7TCU and the 7Br. I am going to start playing with the 6.8 spc. Can I use .284 checks on a .277 boolit?

Of course, no matter the answer, I will probably do it once on general principals.

[GabbyM]

270 checks are supposed to be .255" while 7mm checks are .253".
Yes 7mm gas checks are actually smaller than 270 checks. Which further points out how determined Winchester was to throw a wrench into the prospect of shooters importing any 7mm ammo.

If you have a 270 mould made at mountainmolds dot com you can specify your choice of 270 or 7mm check shank diameter.

If you have a 7mm mould with slightly oversized check shank you can use 270 checks for an easier fit.

6.8 SPC looks to me like it has potential as a boolit shooter. especially with the 1-11" twist barrels.
I sent off a bag of Lyman 122 grain Loverin last year to a fellow with a AR but we never heard back from him on how they worked. Bullet is .813 L with check .500 under the crimp grove. With the .272"L neck of the 6.8 about half the gas check would below the neck if crimped on the top lube grove.

Blamer had 270 checks last year.

[ktw]

I've gone the other way, putting 270 Hornady checks on a lyman 287405 that I'm sizing back to .280. I have to open them slightly, lightly tapping them with a round headed bolt, to get them on. Other than that they seem to work fine.

-ktw