7 stw vs 7 ultra mag

[Trickymissfit]

So how many rounds do you think you can get from the 3- STW,ULTRA MAG AND THE WEATHERBY all 7mm without overheating them. 2 shots then cool before firing another one
Thanks Guys

Tony got less than 400 rounds thru his STW before the barrel went south. His second barrel was a Krieger, and it did last a few rounds longer (maybe 600). Last time I talked with him he was using a Hart made of 17PH4 stainless steel. The only reason I know this is that he came to me with questions on how to machine the steel. Now I have not talked to Tony in a few years, so I can't say for sure he's still using that barrel. The other guys and I were not all that close. One thing on the plus side about the STW was that it seemed to group very well at very long rage consistently (750+ yd.). The Ultra mag neck is too short and the vortex of the flame path is right into the throat. This means barrels suffer greatly. The Weatherby neck is slightly under .40" in length with a 47 degree shoulder angle (data is in the AA manual). This puts the flame pathe in the first two thirds area of the neck. In otherwords a great design. The longer neck also helps to guide big long bullets into the throat better. My guess is that if Tony got 600 rounds out of the Krieger barrel, then he should see at least 1200 or maybe even 1500 rounds out of the Weatherby mag. Now for the disclaimer! If you ream a chamber without free bore (all rounds have some free bore by the way), you'll have to back your loads off to something like a 7mm mag for starters. Then work your way back up. (you may use even less powder to get there by the way). There are other 7mm mags out there that also are very good. I kinda like the Mashburn series (either one). There's also the 7mm Ackley mag.
gary

 

[Trickymissfit]

Call me prejudice, or call me, been there, done that. But that is a hands down 7MM STW answer. The law of deminishing returns comes into play here also. The velocity difference between the two, versus the powder to get that is quite high. That being said, the more powder you burn, so does the barrel. I have been a STW fan since it's conception, and have experienced extremely long barrel life in my own rifles . ( plural)
I have heard of 1200-1500 rounds before burn out. In the case of the 7 RUM, I have heard of them " biting the dust" at way less then a thousand. Actually heard of one that didn't see 600.
As another part of your equation, I would like to throw in the accuracy and shoot ability issues. I had a 7 RUM a while ago, that at best was very finicky. By the time that I got the thing to shoot, I had about 200 rounds through it. Hear comes the good part. When I finally did get it to shoot, the velocity was no better then my STW's. And to be totally honest, it wasn't as accurate as all the hype made it out to be. I believe that you can have TOO much of a hood thing. What I mean by that is, the 7 stw is about as overbore that 7mm can be and still be SHOOTABLE.
This may give you a little to think about. But my vote goes to the STW, imagine that !!

Looking at the case drawings of the 7STW and a couple others, and also the amount of powder they go thru (powder's not getting cheaper by the way). I think a guy would be smart to make the same basic case with a 35 degree shoulder and and push the shoulder back about .100". I doubt you'd ever see the difference in velocity, but I also think you;d see a honest 1500 round barrel life out of a medium weight barrel. This is kind of what Mashburn did with his long 7mm mag.

Now I know that the word "overbore" is a touchey subject around here, but suggest you read what Ackley had to say about his own 7mm mag. Basicly he said it was an overbore case, and also said why bother when you have the 7mm Remington mag on the shelf! Ackley was a fan of the Mashburn super short magnum, and felt the Weatherby was the best of the bigger capacity mags. Had the STW used a 35 degree shoulder with a "real" .35" neck length the barrels would have lasted much longer.
gary

 

[7stw]

Looking at the case drawings of the 7STW and a couple others, and also the amount of powder they go thru (powder's not getting cheaper by the way). I think a guy would be smart to make the same basic case with a 35 degree shoulder and and push the shoulder back about .100". I doubt you'd ever see the difference in velocity, but I also think you;d see a honest 1500 round barrel life out of a medium weight barrel. This is kind of what Mashburn did with his long 7mm mag.

Now I know that the word "overbore" is a touchey subject around here, but suggest you read what Ackley had to say about his own 7mm mag. Basicly he said it was an overbore case, and also said why bother when you have the 7mm Remington mag on the shelf! Ackley was a fan of the Mashburn super short magnum, and felt the Weatherby was the best of the bigger capacity mags. Had the STW used a 35 degree shoulder with a "real" .35" neck length the barrels would have lasted much longer.
gary

Tricky, that is all interesting info, and it's good to hear from you on this thread. I read quite a bit of your " contributions" on other threads, and always take something away from them.
I have heard of the Mashburn round, but can not recollect how it compares to the seven mag, as far as capacity wise goes.
Yeah, and that word " overbore" definitely is a touchy word for sure, but it lights a lot of fires on this forum, that's for sure.
I suppose if someone was to " improve " on the STW with the changes you mentioned, it would add to the barrel life. Comparatively speaking, at least in my guns, I haven't really experienced premature throat or bore wear, in my STW's, but then again, for one, I never shoot them til they are hot, and I don't shoot " HOT" loads. Then again, I don't shoot them a thousand times either.
I don't think that we have heard the last of the STW as a factory cartridge. In some ways, I think it is sort of resurging, because interest in the cartridge never really faded. It disappeared when the RUM came out, and I believe that was the only reason. In my opinion, I think the RUM is dead, and really did not catch on as it was intended to, but it is a shame that Remington dropped it when they introduced the 7 RUM.
Take care, and as always, thanks for your input, very informative.

 

[Lefty7mmstw]

I don't know how to kill a 7stw in under 1000 rounds without beating the rifle like a red-headed stepchild. It only uses a half dozen grains more powder then the 7rem or roy and runs right between the two pressure wise.

As to the o.p.'s question about barrel life, it is terribly subjective as to conditions and user error(letting them heat and letting fouling accumulate), but I'd guess 1/2 of the barrel life from the 7rum as a 7 remington with the stw at 80% of the 7 rem's barrel life. If I were put on the spot I'd go 600-800(rounds) for the 7rum, 1200-1500 for the 7stw, and 1500-1800 for the 7rem/roy. All full throttle of course; back off a few percent and the numbers will go up.

 

[Trickymissfit]

Tricky, that is all interesting info, and it's good to hear from you on this thread. I read quite a bit of your " contributions" on other threads, and always take something away from them.
I have heard of the Mashburn round, but can not recollect how it compares to the seven mag, as far as capacity wise goes.
Yeah, and that word " overbore" definitely is a touchy word for sure, but it lights a lot of fires on this forum, that's for sure.
I suppose if someone was to " improve " on the STW with the changes you mentioned, it would add to the barrel life. Comparatively speaking, at least in my guns, I haven't really experienced premature throat or bore wear, in my STW's, but then again, for one, I never shoot them til they are hot, and I don't shoot " HOT" loads. Then again, I don't shoot them a thousand times either.
I don't think that we have heard the last of the STW as a factory cartridge. In some ways, I think it is sort of resurging, because interest in the cartridge never really faded. It disappeared when the RUM came out, and I believe that was the only reason. In my opinion, I think the RUM is dead, and really did not catch on as it was intended to, but it is a shame that Remington dropped it when they introduced the 7 RUM.
Take care, and as always, thanks for your input, very informative.

I just have a vivid memory of all the barrels that Tony and the other guys went thru. Tony pretty much did his own chambers with his own custom ground reamer. The other guys bought one off a grinder out of Michigan and used it to chamber the other rifles. I was greatly impressed with the extreme long range accuracey that Tony saw which kinda violates the overbore concept, but also know that Tony is a very dedicated reloader. I saw similar results with several gys that did the 6/284 round, and kinda sat back and watch their chambers and throats evolve into a round that worked well. Both got better by pushing the shoulders back a little bit while not loosing much in velocity and gaining a much longer barrel life.

The gist of my post is that you can only burn so much powder in a 26" or 28" barrel, and apparently Mr. Mashburn was way out in front of the rest of us newbies. You start out with something like the 7-08 (very efficient and pretty good accuracey) and start gettting bigger and bigger in capacity with deminishing returns. This tells me we are simply blowing a lot of unburnt powder out the end of the barrel (hard on the barrel as well). This is why I said the 7mm WBY was about it for powder burn in a 26" or even a 28" barrel.
I do think that by simply pushing the shoulder back .100" and leaving the case alone you will see a much greater barrel life with similar velocities. Plus it will help guide those 160 thru 180 grainbullets a little better into the throat. Perhaps I'm wrong, but it sure looks good to me.
gary