Is there such a thing....

[Bran743]

Howdy folks. I was wondering if there is such a think as a 7mm RM AI? I have tried using Google but it doesn't come up with anything useful.

7mm RM is my favorite cartridge and I'm wanting to build one to shoot the 180's but would like a little bit more umph than the standard case can produce. Trying to get to about 3000 fps w/o any negative pressure signs.

Any feedback or criticism would be appreciated. Thanks

Brandon

 

[RT2506]

Sounds to me like you are wanting a 7mm STW or a 7 Remington Ultra Mag. The Ultra Mag does not have a belted case.

 

[CogburnR]

How about the 7mm/300wm?

 

[MudRunner2005]

Howdy folks. I was wondering if there is such a think as a 7mm RM AI? I have tried using Google but it doesn't come up with anything useful.

7mm RM is my favorite cartridge and I'm wanting to build one to shoot the 180's but would like a little bit more umph than the standard case can produce. Trying to get to about 3000 fps w/o any negative pressure signs.

Any feedback or criticism would be appreciated. Thanks

Brandon

There is a such thing as the 7mmRM AI, but nothing standardized...It is a wildcat caliber and you would have to have a custom reamer and dies made (expensive).

What it sounds like you need, is a 7mm STW. I'm pushing 180's at 3,000 out of a 26" barrel, with no pressure signs. I use Nosler brass, Berger 180 Hybrids, Federal 215M primers, and 7828 SSC powder.

 

[Doublezranch]

......or a 7 rum pushing a 190 matrix 3350

 

[MudRunner2005]

......or a 7 rum pushing a 190 matrix 3350

Unless you have a 30+" barrel and using a compressed load of 50BMG powder, I don't see that happening.

 

[AZShooter]

You could use a longer barrel with a 7 Rem mag. I got up to 3050 fps with a 30" barrel and 180s. I got best accuracy at 2950 fps.

 

[Doublezranch]

I was wrong...3260

 

[MudRunner2005]

That's more realistic. I can definitely believe 3,260 fps with a 190 in a 7RUM, as that would be about the right level of velocity above the average velocities I've been reading with the STW and 28 Nosler's with the 180's and 195's.

It was nothing personal DoubleZ, just the numbers didn't add up at 3,350 fps without having some extra help, like 50BMG powder or a really long barrel.

 

[Doublezranch]

Oh I know...I was going off of memory. Not a good decision at my age. Lol!!

 

[Bran743]

Thanks for all the feedback guys. One reason I was wanting to go with the 7RM is because I'm already setup to reload for it and in my persona opinion (which admittedly isn't worth a lot), once you start getting much bigger you start crossing the line of diminishing returns pretty quickly.

After ballistics comparing there is not a lot of difference between a 180gr and 168gr projectile traveling at the same speed. So I might just go that route. I got a PM about a building getting that might be able to help me out so I'll see what he says too.

Thanks again.

Brandon

 

[Bran743]

Hey how do those Matrix bullets do on game?

Brandon

 

[Doublezranch]

Hey...Like this

 

[el matador]

The best way to improve a 7mm Mag is to rebarrel it to 300 WM.