Need a 7mm cartridge


Work, load, shoot, hunt, repeat
Apr 19, 2022
I think this is your best bet. You have the brass and will fit the 3.5” limit. Just expand and load , no worries of fire-forming. The right powder and barrel length will easily out run a 7mm Rem Mag.
Lol, I was just searching for 7mm Wby brass in stock....nothing.
I have no problems forming them from 270wby. I have to break in the barrel anyway.
I really believe this is the closest thing to what I want. Its about 75gr powder capacity and I won't feel like I'm wasting a long action by running a short cartridge.


Sep 27, 2010
I have a 7mm rem mag on a savage long action. It's throated long for 180ge Eld-Ms at 3.450" and it's a beast...relatively speaking. I get 3000fps with a 26" barrel which is far above any data you would find in a manual. If you're looking for something new, I'd probably look at a long throated 7mm prc or 28 Nosler. I haven't looked into it as I'm happy with my 7 rem mag, but I'm guessing that you could form 28 Nosler brass from 300 prc or 300 ultra mag to get better brass?


Dec 24, 2006
the 7mm mashburn would be pushing the 3.500" coal limit . the Mashburn has about the same water case capacity as the 7mm LRM . the Mashburn will run with the STW . the STW will have trouble with the 3.500" coal limit . I think sammi length is 3.6xx" for the STW . the LRM had a problem with poor brass quality , I'm not sure if that's solved . the Mashburn is formed from 300 win brass . everyone sells 300 win brass .
I run the 175 AccuBond LR bullets at 3.500" . 76.5 grains of H1000 gives 3145 FPS .
I run the 175 sierra SBT bullets at 3.415" . 71.6 grains of H1000 gives me 3000 FPS .
I'm pretty sure Scotty has his throat a little longer than I have mine .

if you're not worried about a wildcat cartridge , have you looked at the Shermans ? Rich Sherman has a few different 7mm's . he has brass with the correct headstamp , no die forming , or fire forming . he has die sets . it would be an easy one to work with . the only down side I can see is , I " THINK " Rich has all the stuff tied up . you would have to buy everything through him .
I went with the 7mm Mashburn a few times. If 3.5 is your max it's really as easy as getting the rifle chambered and having your smith throat the rifle for the bullet you intend to use. I wouldn't sweat a 3.5" magazine on a Mashburn too much. Warren Page used a 7 Mashburn to kill alot of animals with that rifle constrained to about 3.4"..

I went with the Mashburn since I enjoy using great brass like ADG, Lapua, RWS, etc for my rifles and when the Nosler came out all that was available was Nosler and it doesn't do the best for me. The new 7 PRC will be good to, once someone other than Hornady makes brass.

When I had my latest Mashburn built, I specc'ed it to touch a 175 ABLR at 3.6" which is max mag length, knowing it would likely shoot best at least 50 off the lands it works like a champ, and shoots like a dream.

Nosler rounds are excellent but they can be a touchy deal getting feeding to be excellent the little extra speed they make is more than made up with a little more BC in most cases.