Magnum Cartridge TC Encore Barrels
Here at MGM, we are commonly asked to chamber TC Encores in large magnum calibers. For some cases this is possible and for other case designs, the extreme pressures along with large case dimensions cause issues with safety, performance, and longevity of the brass. In our own testing we have compared un-fired factory ammo brass then fired it in a bolt action and TC encore, set to the exact same headspace with the same reamer and same lot of factory match ammo. then compared case growth to the shoulder and found that often large magnum calibers have an unsafe and dangerous amount of stretch especially when compared to a solid locking bolt action. This is caused by the design of the firearm itself, where the frame and barrel lockup. Flexing occurs when firing a cartridge with excessive bolt thrust and the brass stretches more than traditional bolt actions upon firing with the TC Encore. After repeated stretching and resizing this thins the brass in the web significantly reducing brass life and strength.
Encore barrels are limited to a barrel diameter of 1″, and the super magnums with extra large bolt faces like the 338 Lapua magnum thin the chamber walls to a dangerous level. The scope base mounting holes also sit right above the chamber further weakening a thinned out barrel, therefore we can not guarantee safety or longevity of the firearm and we will not put our customers at risk. Our solution is to not offer cartridges we do not find up to our standards to yield the best experience possible for our customers.