The "Big bolt"

[StoneTower]

There is a big bolt concept that is used by Olympic Arms. They use it in their WSSM uppers. They run a modified carrier and use an AR-10 bolt and barrel extension. It is super strong and with a setup like that, you could probably use Grendel loads that were designed exclusively for the bolt guns.

http://www.olyarms.com/index.php?page=sh...&Itemid=37

This guy takes the Olympic Arm's parts and builds custom uppers with them.

http://www.dtechsuperstore.com/WSSM%20page.htm

Cheers,

David