Re: New long range rifle
If you read the posts concerning many of the large caliber 30 cals, such as the 300 Tomahawk and 30/416 and a few others bullet length will play a big part in whether or not your action is going to be a repeater or a signle shot due to OAL and magazine well length.
You must take into consideration what weight bullet you are going to use and what style it is I.E. VLD, Match King's, LRBT.
All of these bullets work well at 1k, and the optimun setup is when only the boatail of the bullet protrudes past the shoulder/neck intersection leaving you the most case capacity. However this presents a problem because OAL will be longer than magazine well length and thus you will have a single shot rifle.
Another problem arises with throat length and using lighter weigh bullets, seating depth may only leave a small amount of the bullet sitting in the neck and would not be the best condition.
Many of the guys on here that shoot long range use the heavier bullets 200,220,240. You will need to match your case capacity with weight of bullet and required twist versus velocity to get maximun stability results.
This may present a problem when heavier bullets are used and may require you to use lighter weight bullets that will not perform as well as the heavier bullets with all things being considered.
Its a give and take issue, what weight bullets are you wanting to shoot and will they stablize with the correct velocity without reaching over pressure signs before maximun accuracy has been acheived.
Two things come to my mind, short cases with no belts, and short powder columns.
300 WSM for the short caliber, and 300 Ultra for heavier bullets and maximum velocity for extended ranges with respect to accuracy.
Hope my thoughts can help you make an educated guess.