I always found this to be a strange decision. Most of our Nato allies are using the .338 Lapua in their long range rifles, and it seemed that with the upgrade of the Remington to the PSR, that it was a logical time to move to the larger cartridge. SEALS and other Special Forces operatives had used it, and everyone seemed to love the ballistics.
Then the stories started to circulate that the .300 WinMag approved by SOCOM had performance bordering on the .338. That made no sense, but I decided that there might be more than one way to skin a cat and maybe they had found some magic.
This past weekend I got the chance to spend hours with some of the most knowledgeable weapons system guys out there. Guys who had spent literally years shooting, coaching, and building high performance systems when the subject came up. One of them offered that the .300 WinMag that was being used wasn't really a SAAMI WinMag, and that the cartridge being used wouldn't fit any factory chamber out there. He told me it was loaded much longer than SAAMI. That made sense, the first reasonable thing I had heard.
Then I picked up Sniper mag today, and a lot more of the story came out. The military wanted 2850 FPS from a 220 grain bullet. The way to do that was load out to 3.50 inches, well longer than the 3.34 SAAMI allowed. They also bumped acceptable pressure from a max of 65,000 to 68,000 PSI at 70 degrees. I'm not sure what that translates to at 125 degrees in the Sandbox, but I'm guessing its a LOT higher. They also had to use a smaller firing pin than normal in a tighter than normal channel. They almost created a .300 WinMag Mag!
All of those make sense, and I guess there really is no free lunch. You want more velocity from a given barrel, you have to have more pressure. I just found it interesting that the military made those compromises to get what they wanted vs. just using the .338 Lapua.
When the decision was made, there was much ballyhoo about the fact that .300 WinMag was already in the supply chain, but that was all BS. The .300 WinMag in the supply chain isn't the .300 WinMag that was decided on for the system! This system creates a cartridge that requires doublestruck brass, since its so hot that primers may blow otherwise, especially in the heat! Interesting stuff, that!
Then the stories started to circulate that the .300 WinMag approved by SOCOM had performance bordering on the .338. That made no sense, but I decided that there might be more than one way to skin a cat and maybe they had found some magic.
This past weekend I got the chance to spend hours with some of the most knowledgeable weapons system guys out there. Guys who had spent literally years shooting, coaching, and building high performance systems when the subject came up. One of them offered that the .300 WinMag that was being used wasn't really a SAAMI WinMag, and that the cartridge being used wouldn't fit any factory chamber out there. He told me it was loaded much longer than SAAMI. That made sense, the first reasonable thing I had heard.
Then I picked up Sniper mag today, and a lot more of the story came out. The military wanted 2850 FPS from a 220 grain bullet. The way to do that was load out to 3.50 inches, well longer than the 3.34 SAAMI allowed. They also bumped acceptable pressure from a max of 65,000 to 68,000 PSI at 70 degrees. I'm not sure what that translates to at 125 degrees in the Sandbox, but I'm guessing its a LOT higher. They also had to use a smaller firing pin than normal in a tighter than normal channel. They almost created a .300 WinMag Mag!
All of those make sense, and I guess there really is no free lunch. You want more velocity from a given barrel, you have to have more pressure. I just found it interesting that the military made those compromises to get what they wanted vs. just using the .338 Lapua.
When the decision was made, there was much ballyhoo about the fact that .300 WinMag was already in the supply chain, but that was all BS. The .300 WinMag in the supply chain isn't the .300 WinMag that was decided on for the system! This system creates a cartridge that requires doublestruck brass, since its so hot that primers may blow otherwise, especially in the heat! Interesting stuff, that!
Comment