7x300?

If I were looking for a 7MM wildcat I think I would look at the 7MM Mashburn. But then you didn't say what you plan on doing with it Hunting or long range target shooting.
 
Agree w TD. Scottys doing cool stuff w the Mashburn.
But, of the two you mention, I'd do the 7-300 wby. 7-300 win is going to be real close to a 7 RM. And just because. :grin:
 
I really like the 7mm Mashburn. Does the exact same thing as a 7-300. I believe the trick with the MSM and 7-300 is to coordinated the bullet of choice is able to be seated near the rifling and having enough mag space. Mines set up so the 160 AB sits in the rifling at 3.605". My accuracy loads are around 3.550 or so. None of the bullet is below the neck shoulder junction. Either of them should get about 3150-3250 with 160's.

The 7-300 WBY is nothing more than a STW. Great cartridge but unless you have the ability to really seat your bullets out you won't gain much off the Win Mag based cartridges.
 
Elk and long range muleys is what I want it for. Long range shooting would be done with it also.
 
The question is, how much do you want to spend on brass? Weatherby is high, 28 Nosler are really high, and then you have 300 Win mag. Any will do what you ask. Hell a 260 Rem will take a elk at a lot farther than most hunters should shoot with less kick and blast.
Personally I like the Mashburn enough that I bought my own reamer. But out of your choices I'd take the 7-300 because I like to shoot and brass is easier to get.
 
muzz":2ehfh6ec said:
Elk and long range muleys is what I want it for. Long range shooting would be done with it also.

I don't think you'd dislike the 7-300 at all for those purposes. 160's at 3200 or 175's at 3050 in a 8.5lb scoped and loaded rifle are why I made mine.
 
6mm Remington":3eqnomsi said:
Or you could go with the new 28 Nosler if you want a hot-rod 7mm and it comes without a belt!

+1 for the 28 Nosler.

JD338
 
I'd go 7mm-300wm... That round has been around for years, many, many years. There is a lot of load data out there for the heavy bullets if you look for it and it has done extremely well for a friend of mine. Personally I wouldn't go 28 Nosler because I haven't seen much data on it and if I'm spending the money on a build, I want something proven to work, 7 RUM is probably close to the 28 Nosler as well. I wouldn't shy away from the good ol' 7mm Rem. Mag. . . It's a good round too. But I understand the appeal Of something 'different' looking forward to see what comes about! :mrgreen:
 
Here is the 7mm Mashburn Super Mag compared to the 7mm Rem Mag.

The Mashburn pictured is not fireformed yet, but it's a very slight case blowout.

 
These were 160 ABs and PTs in fireformed cases.



Here is the speeds I got from H1000





77 grains was too warm. No major drama but 3200-3250 is about all you should expect with a 160 and a Mashburn with a 24" tube. I ended up at 75.5 with the 160 AB. Haven't gone back to the PTs yet. The 160 ABs do shoot nice groups though.



 
Here is what I'm getting with 175's so far.





Didn't have a lot of Retumbo left so I've been working with H1000

They are slowly coming together.



Anyhow, a 7-300 would do the same things, so it's a relatively decent comparison. Scotty
 
...or you could go "full overbore" w/ a 7-300 Norma Magnum, based off the .338 Norma Magnum, a shortened, 'improved' .338 Lapua. Be like a 7mm WSM on steroids...
 
Nice shooting Scotty. So are those 7mm Rem cases you use to fireform, or what exactly is the 7mm Mashburn? Scotty how about a 7mm-308 Norma mag on the old Norma round, or the 7mm-338 Win which is about the same as the great 308 Norma? I always thought the 308 Norma is what the 300 Winchester should have looked like. Not sure why Winchester just didn't neck down the 338 Winchester case or up the 264 a bit.
 
6mm Remington":4hu0noob said:
Nice shooting Scotty. So are those 7mm Rem cases you use to fireform, or what exactly is the 7mm Mashburn? Scotty how about a 7mm-308 Norma mag on the old Norma round, or the 7mm-338 Win which is about the same as the great 308 Norma? I always thought the 308 Norma is what the 300 Winchester should have looked like. Not sure why Winchester just didn't neck down the 338 Winchester case or up the 264 a bit.

David, the 7mm Mashburn is a 300 Win Mag case necked down to 7mm with a longer neck and then the little bit of taper is blown out of the Win Mag case during fireforming. There is no real benefit to the Mashburn over the 7-300 Win Mag other than the longer neck. Most folks don't care about a longer neck nowadays, but I think it is a nice feature if you like to use the shorty 140's and the longer 175/180 bullets. With the Mashburn, I have the ability to seat a 140 PT at the same spot in regards to the rifling as a 175 PT. Most folks don't care a whole lot about it, but I like the ability.

It's funny you mention the old 308 Norma. I am pretty sure I have a set of 30-338 Win Mag dies sitting at my house. Thinking it might be the .308 caliber rifle I wanna build up next. :grin:
 
A 7-338 Win Mag. is a 7mm RM and a 308 Norma is basically a 30-338 Win. as far as ballistics are concerned. The 300wm holds a good deal more powder in comparison and is good for 100+fps. Usually a 7-300wm/Mashburn will easily beat a 7RM by 100fps and most times its closer to 150fps. A Mashburn is a 7-300wm with the shoulder pushed back and made steeper to lengthen the neck.
 
IdahoCTD":1jof1l07 said:
A 7-338 Win Mag. is a 7mm RM and a 308 Norma is basically a 30-338 Win. as far as ballistics are concerned. The 300wm holds a good deal more powder in comparison and is good for 100+fps. Usually a 7-300wm/Mashburn will easily beat a 7RM by 100fps and most times its closer to 150fps. A Mashburn is a 7-300wm with the shoulder pushed back and made steeper to lengthen the neck.

Yeah.... What the rifle ninja said! :grin:

Thanks Nathan, I was hoping you'd see this and come along to sort out what I couldn't say...
 
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