Not sure about the 375. But there is a few guys on the cast bullet forum that make gas checks very reasonable. I have used the 357 and 30 cal ones with good results. Much cheaper since they are aluminum. But the 2000 that you have will last awhile!!!

Dave, don't scrimp on a scope. You can't shoot any better than you can see. Minimum purchase should be MK 3, Preferably MK 4, Nite force if you can wait. ATB, Lee

Just a thought. For your gas check useage. I have found that annealing them will make them work very well. Will lock on to the bullet better and no springback from the cooper checks. Just heat them up to red heat and air cool. This will also burn off the laquer coating and make them a bit odd looking. Give them a chance, I like them so treated. ATB