Most all of the BR shooters I know use the L in the tite bores and it works fine. I've shot both the L and M and could tell little difference in either. It depends on the lot/or particular batch. I had an old Sako 78 HB that slugged .213 and it shoots the L very well. Mostly I shoot Eley ammo, but some of the newer 6000 series and the newest 7000 series in getting some good reviews. I have enough Eley to last a few years, but I'm always looking for something great, so I keep testing. Harry Deneen sent me some Lapua Midas L a while back to test, but it's been so windy I never got a chance to actually shoot it in a calm condition, and now it's all gone, but I hear the latest stuff is a little better too, so that's good! Good luck.