My next project is to rebarrel my Savage 116 Weather Warrior 7RemMag to a 1-8" twist and try to optimize it for shooting the new 7mm 180 ELD-M bullets. I intend to order a reamer that will be throated long, so I got some boxes of the 180 ELD-Ms today and began measuring. I'd like to seat my bullets out as far as possible to maximize powder volume and keep the bullets in the neck of the case. Initial measurements show that doing so would result in a overall base to bullet tip length around 3.65-3.67", but the factory 7RM magazine box has a max length of right about 3.5". The magazine is a factory magnum center-feed magazine.

Pushing the bullet into the case enough to get a COAL under 3.5" puts a significant amount of the 180ELD-M into the case. I realize that I may have to live with that, and probably can, but I wonder if any of you guys have found a work-around. For example, is the factory Savage magazine box of a RUM cartridge longer? If so, will it fit the same action? I realize that Savage RUMs are built on a large shank action but that shouldn't affect the magazine box. The feed lips and follower would probably need to be changed/modified to compensate for the smaller diameter 7RM cases, but it looks to me like the feed cut-out in the standard Savage long action is long enough to for a 3.65" cartridge to pass through it.

Failing that, maybe some aftermarket options? I know you can get Remington 700s fitted with a Wyatts extended magazine. Anything similar to that for Savage?

Thanks in advance for your help! I've been building short action Savages for a while now and this forum has always been a great source for experienced feedback.