270-300 Win Mag Wildcat?

Djones · Dec 4, 2005

Hello,

I was over on Jarret's webb site today and I saw that they have a 7mm wildcat based upon the 300 Win Mag.
I wonder if anyone here has had any experience with wildcating on the 300 Win Mag cartridge?
In particular I am wondering about a 270 - 300 WM.
I saw that Jarret was claiming 3500fps for a 7mm 140gr bullet, makes me wonder what a 130gr be like? 3500fps? I ran the ballistics on a 130gr SPBT and it was most entertaining.

Don

257Tony · Dec 4, 2005

Ive thought of this cartridge many, many times. Just never had the drive to build one, should be a smoker, I think the main reason it hasnt been done is the .270 wby hits about 3400 fps. But it would be a cool, unique gun. How about you build one and tell us about it.

Bob D. · Dec 4, 2005

I don't see how it would be much different than either the 264 Win Mag or the 7mm Rem Mag???

Djones · Dec 4, 2005

Bob,

Those are excellent points.

What got me on this wild goose chase is when I surfed over to www.jarrettrifles.com today and checked out his pet calibers page.

They list a 284 Jarrett based upon the 300 Win Mag Cartridge.

For his 7mm wildcat, he lists a comparison of case water capacity of the popular magnum cartiridges as follows:
7mm Rem Mag = 73.5 grs
7mm Wby Mag = 78.0 grs
284 Jarrett = 85.5 grs
7mm STW Mag = 98.3 grs

Jarret also lists a 7mm 140 gr bullet at 3450 to 3500 fps. He also goes on to list a 7mm 160gr bullet at what I consider a true magnum velocity of 3200 fps.

This made me wonder about a 270 130 gr (or 140) bullet at a similar velocity.

I am going to talk to my riflesmith and have a talk with him about this madness that has smitten me.

Don

Bob D. · Dec 4, 2005

LAST EDITED ON Dec-04-05 AT 11:54PM (MST)[p]Well, it would be different if that's what you want. And I sure can't argue with that. But, how about the 7mm Remington Ultra Mag? Remington shows muzzle velocity of 3,425 fps with a 140 grain bullet.

RLH · Dec 5, 2005

the .300 win mag has a considerably larger case than the 7mm rem mag and the .264, which are essentially identical, other than bullet diameter. another interesting wildcat on the .300 mag case would be a .338/.300. but like mentioned, weatherby already makes these same things based their .300 case and they are all hotrods, and a little hotter than anything on the .300 win mag would be. still interesting to think about. would be quite easy to have a gun chambered in any of these and also be easy to resize some brass to fit.

Djones · Dec 5, 2005

If I built one most likely I would use a Rem M700 Action, mainly because I am a south paw and M700LH actions are more commonly available.

In '84 I had a M700LH rebarreled to 300 Wby Mag. With that rifle I have found that while the factory load ammo will fit into the action and magazine (barely), you could not seat the bullet out very much and you ended up stuck with alot of free bore. While my 300 does shoot accurately, it took alot of tweeking to develope a load that shot well. This is why I would pass on a 270 Wby Mag.

For some reason the Ultra Mags just do not do anything for me. Between having to use special magazine followers and other feeding problems they are known to have, I think I will pass - thank you.

Like someone else has already said, a 270/300 Win Mag is something to ponder.

Don

BigPig · Dec 5, 2005

why not a .270 wsm?

huntindude · Dec 5, 2005

I think the 270-300 would be a fantastic round but I can't find any load data on it. Pac-Nor barrels does chamber it in thier shop so it must work. as far as the .270 WSM goes don't believe all you read , it's a nice round with a little advantage over the old .270 but it won't run with the .270 Weatherby let alone beat it. I've put several guns and factory loads over my pact and it's the WBY every time by a good 100 fps +

fisrtcoueswas80inches · Dec 6, 2005

what is the average velocity with a 140 gr bullet from a 270wby?
Casey

huntindude · Dec 6, 2005

In a factory waetherby we got 3250 fps with the factory 140 gr. barnes and 3280 with a handloaded 140 TSX in my Bansner custom. With the 270 WSM 140 accubond it was 3120 fps.

264Magnum · Dec 6, 2005

LAST EDITED ON Dec-06-05 AT 03:59PM (MST)[p]I've thought real hard about making a 264-300 Mag. To the point where I've already resized a bag of 300 mag cases. I'd probably go ahead and do it if I could find a cheap enough rifle to convert. With some 125 grain partitions, that should be a heck of a deer killer.

Warren · Dec 6, 2005

I'm a lefty, also. I picked up a Weatherby Accumark in .270 Weatherby Magnum when they quit making lefty bolts last year. I can't imagine how you could improve on the performance.

meatmaker · Dec 8, 2005

a 270/300 win mag would be about the same capacity and so the same performance as the 270 Weatherby. Difference would be in the throating (Weatherby uses a long throat of freebore) and of course with no established loading or pressure data performance could be whatever you want it to be until something breaks.

Some data on the weatherby shows 130 grain bullets at approximately 3300 fps so the wildcat should easily reach that.

Always something interesting.

meatmaker

meatmaker · Dec 8, 2005

huntindude

read your comments on the 270 WSM vs Weatherby. Just curious, other than satisfaction of having the fastest, what does another 100 fps buy?

Answer:

A 130 gr Nosler ballistic tip at 3400 fps zeroed at 200 yards drops 30.1 inches at 500 yards. Slow it down to 3300 with the same zero and it drops 2.1 inches more at the same distance.

Can your eyes define 2 inches at that distance under hunting conditions? And is 2 inches the difference between hit and miss?

Also energy difference at 500 yards is 1543 fpe vs 1441. Can your target tell the difference?

Just a question

Meatmaker

Djones · Dec 26, 2005

It is my belief that a wildcat based upon the 300 Win case would have up to 10 grs more powder capacity.

DJ

dl19 · Jan 13, 2006

If you want a wildcat almoswt every caliber has been used starting off from a 300WM or WBY case. Just contact Redding or RCBS custom shop, and they could probably hook you up. A wildcat is ok if you just have to have one, but todays different factory calibers if reloaded will easily equal and actually be able to surpass most wildcats.

Djones · Jan 28, 2006

The more I look into this, the more I have to agree with you. Looks like the trick is finding a gunsmith who has the reamer you want.
I have been refered to a couple that seem very promising.

Don

huntindude · Jan 29, 2006

Meatmaker,
The answer to your question is 100 fps doesn't get you much but the fact is the 270 Weatherby is faster, not slower as the 270 WSM ads says. just the facts. same holds true with the 300 win mag vs. the 300WSM. I think the short mags are good rounds but I wouldn't scrap my rifles to get on the band wagon and give up speed to boot.

Towedjumper2 · Dec 8, 2021

I have a 270/300 built by JK Cloward. I have a new pacnor barrel on it and am starting load development. probably start with 130 GMX over 65gr H4350, .002" off the lands. Input?