Hi vipa,if MV isn't important why did vince bottomly use 540 and ran his rifle at 3100fps when he became champ,I value your advice vipa,600 ain't a prob,
Vince Bottomly is a really nice bloke... he also shoots bench rest with barrels he makes himself out of very soft stainless... and using equipment you and I do not have (if you did you wouldn't be discussing it here on a hunting forum as you would have sunk your heart, soul and and bank account into it!) bench rest is a law unto itself and doesn't translate into real world shooting. When he gained the british record.. the conditions were perfect and the string of shots was all loosed in under 10 seconds... this is not the same type of shooting you or I do at 1,000 at Bisley where the wind has chance to change completely in between shots... If it is Vince you are trying to mimic, then you are in the wrong place, using the wrong equipment with the wrong method...
I think Roger Federer is a fantastic tennis player but I can absolutely guarantee that me going out and buying the same raquets and balls he uses WILL NOT turn me into a world class player. or any kind of player for that matter.... it is never, ever about the equipment... it can't be or we could all just go out, buy the same kit, use the same loads and be in the record books over night... and whilst I applaud you wanting to emulate Vince, unless you are going down the bench rest route, he is the wrong bloke to be copying!
Last time I sat down and discussed 1,000 yard loads with Vince we were talking about the exact same things you are talking about now... he recons 540 is great but using it won't get more than a few hundred rounds out of a barrel before it is scrapped.. he also loads with zero neck tension and uses the bolt closing to push the bullet into the lands and therefore seat the bullet consistently, that means if you open the bolt you pull the round and end up with an action full of powder and a projectile stuck in the barrel... none of this is very practical for day to day shooting! he also doesn't shoot .308 and hasn't for a long while!
Vince is a very talented benchrest shooter but whilst he is good, there are better out there in disciplines more akin to your shooting... you need to look towards the States and start looking at what the f and f/tr class shooters use and have success with... look at the US Palma team and see what they use... I think you will be very surprised at the MVs they end up working with and it is not always hot! You may also want to look at bullet stability rather than just BCs... Scenars are no where near as stable as SMKs but get glowing press because they have a better BC... you need to take a step back and ask yourself what's better... pushing and pushing to get as much speed as possible just so you can keep away from the transonic range with a scenar when you can go slower with an SMK and not really bother too much with transonics because the extra stability means it is less of an issue.. and pushing MVs to the kinds of levels you are would, to my mind sort of make the gains from the better BC rather pointless!
Look at -
http://www.snipershide.com/forum/ubbthreads.php?ubb=cfrm/ for probably the largest collection of current and past REAL operators and world class competitive shooters or
http://www.6mmbr.com/index.html which is dedicated to accurate long range target shooting...
Your questions will be better answered there by people who are passionate about that aspect of the sport.. Buy Bryan Litz's book and start learning about the theoretical side of exterior ballistics instead of going on what people think is the best option and trial and error, both of which will cost you a fortune and confuse you and ultimately get you nowhere!