Originally Posted by 7stw
A 9 twist will be very adequate for the 180's. Maybe " Dano1" will chime in and verify that, as he is the heavy for caliber " guru". The 180's have really caught on, and now 185-200 grain bullets are being talked of a lot. Those latter ones need a 8.5 or faster twist to stabilize those. I think the STW will do just fine for what you want. Just my 2 cents.
A 1-9 twist is just about perfect for a 180g Berger VLD and it's what my 7stw has. I shoot the Bergers, but they have to be single fed as they don't like to be jumped at all in my rifle and it has a long throat. I have harvested both muleys and elk using Berger VLDs in my .30-06 AI, but haven't had the opportunity to use them in my STW as of yet. I wouldn't hesitate to use the 180s at all on large game. That being said, I don't like the idea of having to shoot my rifle single shot. So I developed a load for 175g Sierra Gamekings and they shoot very well. But the exciting thing is that Nosler is coming out with a 180g Accubond Long Range that has a higher BC than the 180g Berger VLD, and Berger is going to offer a 190g VLD or Hybrid (I can't remember) , but they are saying that a 1-8.5" or 1-8" is necessary to stabilize these heavies. I may just buy a box just to try them out when they become available.
SFR292 is right about Dave Kiff, he will build you a custom reamer for the job, but at $150, it may or may not be worth the extra expense. Most Gunsmiths worth a darn, will have a 7stw reamer as they are still quite popular, so that expense is definately up to you.
Stick with the 7STW its by far a better cartridge. There are some valid concerns and problems associated with the 7 RUM that just don't make it worth the effort and WildRose it completly correct about the barrel life and muzzle blast, the velocity gain just isn't worth it.
I'd love to have a .300 RUM they are flat out amazing with a 230g Sierra Matchking. Someday I'll get one of those too.
Hope this helps,