7mm-300 Practical Options / WILDCAT GIANTS

[RustyPin]

I know from experience when Tapering down a size in Caliber @ the same time you alter the Shoulder it's Easy to GAIN Shoulder Width if you dies allow. Hence Why not Gain Shoulder Width when sizing down from 300 Win Mag to 7MM? I found the 308 Ruger but it's shoulder is too wide, something closer to .499 Would work. Any else doing this? It makes perfect sense to me to do both at the same time for this Wildcat. I see the 30 Degree Shoulder dies listed for $180, I'm looking for a Better & less expensive alternative. It would almost be worthwhile to Improve the 7mm - 300 WM Shoulders to the Rugers .515.

 

[ShaunBrady]

The diameter of the 300wm case above the belt is 0.512", so the chamber you describe will have a reverse taper.

 

[FURMAN]

The real question isn't why not it is WHY? The 7-300 is a relatively efficient case that already pushes 180s at blazing speeds. I actually prefer it to the 28 Nosler(I have both). Neck down with 300 WM bushing dies, load, shoot.

 

[RustyPin]

Silly Rookies. So I was wanting a Mashburn all along. I was going to play around with some 300 Win Mag Brass, now there is no need. Drat. I can keep an eye out for some Dies.

 

[RustyPin]

Well you know what they say, "Be careful what you Ask for". So I just took possession of some Ackley Short Dies, now to find out exactly how wide that improved shoulder is and if it will work on shortening the Win Mag for .284.

UPDATE: The dies I purchased were nothing more than a 30 caliber 7mm RM, Shoulders are .484. Dies FS.

 

[smokinghole]

I'm looking at necking down the 33 Nosler to 7mm for use with 180s and maybe 195s. The case is shorter than 28/26 Nosler with a shoulder at 2.131 plus a 195 Berger puts the coal near 3.55. Brass should be easy, either 30 or 33 Nosler, but the 33 has a longer neck already but it it's a decent neck down. Should mag feed from standard AICS and not require any action mods like the longer RUM cartridges need to run the Wyatt's boxes.

 

[RustyPin]

The real question isn't why not it is WHY? The 7-300 is a relatively efficient case that already pushes 180s at blazing speeds. I actually prefer it to the 28 Nosler(I have both). Neck down with 300 WM bushing dies, load, shoot.

The 7-3xx has more Powder Volume, but still has an Inefficient Shoulder. My bet is with less case volume and a better Shoulder We can form something like an "Improved" 7mm Rem Mag from 300 Win Mag Case. I'm sure this already exists, yet I have no Name for it. Something like a 64MM Sharp & Hart?? IMO if I have to mess with a Case, I'm gonna make it better not just make it Fit.

 

[Ringostar]

I'm not being a smart ass, just curious. What exactly are you looking to gain? Im not seeing the improvement. Case life, barrel life, velocity. I've been thinking about a case mod for several years. It wouldn't gain any of these either, but would increase neck length. It would allow more options in bullet length with the same freebore, but is it worth the cost and extra work. I still have decided to try it.

 

[AckleymanII]

Ringo,

consider the 7 Mashburn off of 300 Win, very sexy long neck, 160's at 3200 no pressure

7/300 Win mag, no brainer neck down,

then the 28 Nosler(see Alex Wheeler), will put you in the money real fast with 195's at 3100

If you want to be flat out different, then a 7 Mag Match, 28" with RWS brass, stomp on the gas with Retumbo and 168's or 162's.

My family, cousins, and I have shot the 7 STW's with zero freebore shooting 120's and 140's at warp speed since we first read Lane Simpson's article in 1988(?). Deer die real quick at 600 yards.

Since Win quit making 7 STW brass, things have gone sideways. 28 Nosler = 7 STW in a shorter package, and 7/300 is nipping at it's heels.

7 Mashburn will give you a woody just looking at it, long neck, sleek no taper body, what is not to like?

If you want to go whole hog, then then the 7/338 Lapua is your Big Guy rig with reported to me 180's at 3500...twist rate calculator please?

 

[RustyPin]

I'm looking at necking down the 33 Nosler to 7mm for use with 180s and maybe 195s. The case is shorter than 28/26 Nosler with a shoulder at 2.131 plus a 195 Berger puts the coal near 3.55. Brass should be easy, either 30 or 33 Nosler, but the 33 has a longer neck already but it it's a decent neck down. Should mag feed from standard AICS and not require any action mods like the longer RUM cartridges need to run the Wyatt's boxes.

Me thinks you are building the 7mm Dakota??

Nice Cartridge Design. Just a little pricey for me, cool idea.

*Something like a 7mm-338 Marlin Express in a 35 Degree shoulder would be the Ticket @ 2.5"

 

[smokinghole]

Me thinks you are building the 7mm Dakota??

Nice Cartridge Design. Just a little pricey for me, cool idea.

*Something like a 7mm-338 Marlin Express in a 35 Degree shoulder would be the Ticket @ 2.5"

Yeah basically but it will run on a 0.535 bolt. Plus the brass isn't made by Hornady for $2 a pop.

 

[fredo]

Given that action & boltface to work with, and the availability of 300WSM brass, I'd sooner neck them down to .284,than 300Win Mag. A proper, long throated 7-300WSM on a long action with a 180-195 stuffed in front would makes for grins...

My idea of a"Monster" .284 would be more along the lines of a 7-300Norma Mag.

 

[smokinghole]

My idea of a"Monster" .284 would be more along the lines of a 7-300Norma Mag.

The cost of admission with a properly sized action makes it a good bit more expensive to build than a standard .535 magnum face cartridge. I didn't want to dig that far in for a 7mm. My feeling is once you're past .550 cases in a long action, might as well move into bigger than .30 cal bullets too.