Thanks
Big-un

It is a 300 Win case necked down to take a 7mm bullet.

Or one might call it and "improved" 7mm Rem Mag.

It is not quite what a 7 STW is, just a little shorter.

Capacity wise it is basically a 7mmWby.

Could you see any problems with chambering this round? Anyone here ever done it? Got a 7mm STW now and would like something with a little shorter case length with no fire forming.

Thanks
Big-un

It is not the "uncommon" a round. You would need a new barel and chambered the way you want.

Might be cheaper to buy a Rem 700 in 7mm Mag, and have it rechamberd to the 7mm x 300 by a custom gunsmith.

casewise, it's just about a 7SH or 7weatherby

performancewise...

add 2" to a 7rem barrel and you have the same thing

jeffe

Actually, it is the 7mm Mashburn super reborn. Dimensions are slightly different, but case capacity is nearly identical.

As stated, it is less capacity than the STW, and as a result, gives better performance in 24" barrels. It is however, greater than either the 7 REm or Wby, just has the .300 win mag case has more capacity than .30-338 because of the shoulder being significantly foward.

Because the 7 wby freebore situation, it burns more powder than the Rem. For that reason, many used the Wby data (NOT maximums). to start loading for the 7x300 w/ its increased capacity, but standard throating.

quote:

It is however, greater than either the 7 REm or Wby, just has the .300 win mag case has more capacity than .30-338 because of the shoulder being significantly foward.

Curious what others are showing for capacity. Loadtech shows the 7Wby as having 8 grains more than the 7Rem Mag. And only 1.2 grs less than the 300Win mag.

Beartrack pretty much got it, I shoot a 7 Mashburn Super a lot and I use 300 WM cases to form.

Mark D

quote:

Originally posted by big-un:
Could you see any problems with chambering this round? Anyone here ever done it? Got a 7mm STW now and would like something with a little shorter case length with no fire forming.

Thanks
Big-un

When I started loading 7MM STW it was a wildcat. But now you can buy factory cases in STW so I'm wondering what you saying here about fire forming and what would be the real gain with the shorter case?

I would really like to shoot 168 bergers and still have them fit in the magazine. I cant do that with the STW case. My buddy is loading 190 bergers in his 300 win. he is able to touch the lands and load in the magazine. Thought that it would be nice to shoot a little lighter bullet with a better BC.

Thanks
Big-un

rather than rechamber, buy a custom reamer, buy custom dies, and have something that no one but you want....

rebarrel a 7rem at 26" with a "faster" twist than normal... just one step


stw's and such are impressive at the bench, but shoot them over a chrono and wonder why you are burning a pound more powder for 100-200 fps in a NORMAL length barrel

jeffe

quote:

stw's and such are impressive at the bench, but shoot them over a chrono and wonder why you are burning a pound more powder for 100-200 fps in a NORMAL length barrel

I have 3 7mms. One is basically a 280 Gibbs with about 1.5-2grs more capacity. At 63,000 (measured) I move a 140 at 3200 with 63 grs of powder and a 23" barrel.

My 7 rem mag has a 24" barrel. Factory pressure for the 7mag is 61,000 for the 7stw it is 64,700. I load my 7mag to a calculated 63,000(loadtech) giving 3300 for the 140's with 73grs of powder.

Then I got caught up in the new 7STW wildcat. I load my 7stw to a calculated 64700 (loadtech) and I get 3400 from 83 grs of powder and 26" barrel. All velocities are measured over the same Chrony.

For the life of me I can't make myself carry that longer barrel and burn 20 grs more powder for 200FPS. So it gathers dust.

For the record that is 32% more powder to get 6% velocity gain. The old 4 to 1 would say I would get 8% velocity gain. But, I have found the ratio goes down as the case gets more and more overbore.

Of course another way to loo at that extra 20 grains per round is that say you run 500 rounds a year thru it.

Extra cost, is gonna be about $25 per 500 rounds for the powder. In the real world not much to worry about.

Just a thought.

Mark D

quote:

Originally posted by Mark Dobrenski:
Of course another way to loo at that extra 20 grains per round is that say you run 500 rounds a year thru it.

Extra cost, is gonna be about $25 per 500 rounds for the powder. In the real world not much to worry about.

Just a thought.

Mark D

Sure enough Mark, that specific 25 bucks is small stuff..

the customer reamer is ~200
the customer dies are about the same 200
and the barrel, in either event is at 200
the lead time is generally measured in months (which will help you not to spend that first 25 bucks in powder LOL)
so, 600 bucks additional into a rifle that IF you are luck you'll get back 100

other side of the coin
have your 7rem rebarreled to 26" for 200-300 bucks (whatever the cost, it's the same for the above)

and have a gun that some would buy when you are bored with it.


Why am I going on in wildcats about standard rounds when I am a wildcatter myself?

I don't know... When I wildcat something it DOES something or FITS something that is difficult to do otherwise. What I don't like is for ME to spend a zillion bucks on my latest whizbang 7mm, only to find out that the 7rum totally destroys my new kitten in performance, cost, brass, dies, reamers, and off teh shelf guns....

jeffe

Jeff-I har you on the wildcat costs, I am no stranger to that game.

What I was referring to was (and perhaps I read him wrong) was he was saying (as I took it) that to run the STW he was running 20 grain more.

And of course to run a STW you're not cattin anymore, although I do remember the day when we did cat it.

Make it your best day

Mark D

quote:

to run the STW he was running 20 grain more.

Don't know what "he" you were talking about. If it was me. I could care less as to the cost of 20grs more powder per round. I don't use my STW because I prefer the shorter barrel, less recoil, less blast etc. The animals that I shot with it were no more dead than with my 280 or 7Rem Mag. Guess as I've gotten older trying to get that last FPS is no longer important.

But, everyone should do what makes them happy. If that is the new supermagnum go for it.

Yeah the "he" I was referring to was you.

A couple of posts above you say something to the effect that you can't see carrying the STW because of it's longer barrel, and the 20 extra grains you burn to get the extra 200 fps.

Guess from reading it I kind of got the opinion that you did not like burning the extra 20 grains.

My bad if that wasn't the point you were trying to make, just the way I read it.

Mark D

For the life of me I can't make myself carry that longer barrel and burn 20 grs more powder for 200FPS. So it gathers dust.

For the record that is 32% more powder to get 6% velocity gain. The old 4 to 1 would say I would get 8% velocity gain. But, I have found the ratio goes down as the case gets more and more overbore.[/QUOTE]

------------------------------------------

The part above is where I got the idea that you did not like to burn the extra 20.

Like I said my bad if I read it wrong.

Make it your best day

Mark D

Mark,

No offense taken at all. Fact is I can see no reason to burn the extra powder but cost is not the issue. Like the STW I have several of what were the "new wildcats on the street". After playing with them most I found to provide very little gain over existing factory rounds loaded to the same pressure. I took my own stretched 280 case down to 243 and up to 416 and everything inbetween. There were only a couple stops that the improvement was worth anything more than good conversation at the campfire.

To me the maginal gains just aren't worth the effort anymore. But that is a decision each shooter needs to make on his own. Kind of some like Ford some Chevy.