Coyboy,
For the 300 RUM I recommend at least 26" and 27 or 28 is even better. 30" is great but your getting into the area where you need more weight in the barrel. With an 11 lb finish weight goal I would personally go with a standard length Lilja at 27" finish length.
Contour, the #7 contours are very hard to beat for good barrel mass and relatively light weight. Similiar to the Rem Sendero contour but with a longer full diameter barrel shank. If weight is a concern have Dan flute it with his heavy flutes, nearly 3/4 lb drop right there.
As far as the brake is concerned, they are all loud, The so called "Quiet" brakes are the ones us hiring impared shooters are using /ubbthreads/images/graemlins/grin.gif!!.
Seriously though, in most cases, the amount of perceived noise is a direct funtion of how efficent the brake used is performing. The brakes that reduce the most recoil will generally be the loudest. These are the partition style brakes such as the Holland and JP and all others of this design.
The radial port brakes such as the Vias and KDF and all those, BOSS included are not as efficent at reducing recoil as the partition style but are said to be a bit quieter to the shooter????
Basically I use the Holland for a couple very simple reasons.
1. It is extremely efficent at reducing felt recoil. Your 11 lb 300 RUM would recoil less then a 25-06 in the same weight rifle.
2. They are compact, adding only 1 1/4" to the length of the barrel and only marginally larger in diameter.
3. They have a solid bottom and which makes then perfectly designed for shooting from prone positions which may occur often in the field. They do not blow ground debris around like the radial port brakes do.
4. They virtually eliminate muzzle jump in any rifle weight or chambering.
I have tested most out there and will only use Hollands on my personal rifles so take that for what you will. I have yet to have a customer use a Holland and not be happy with them.
Me personally, I never notice the muzzle blast from my braked rifles. Course most of them have 30" pipes as well which makes a dramatic difference as well.
For minimum contour for a 300 RUM, I would say that will depend on barrel length. Again, I think anything less then 26" in barrel length and your better off with a 300 Win Mag, 300 Wby or something in that class.
I would not go lighter then a #5 contour at 26" finish length and personally would prefer a #6 contour. at 27 to 28" finish length I would say min should be a #6 and recommend a #7.
Please keep in mind I have consistancy in mine much more then extreme low weight so take this for what it is, simply my opinion on what I recommend for getting the most accuracy and consistancy from this big 30 cal magnum.
Good Shooting!!
Kirby Allen(50)