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So just getting started loading for the 6.5 Creedmoor, and have some lighter bullets left over from my Grendel that still are useable in the CM. Among those is the Speer 90 gr. TNT. But here's the issue. This is a fairly short, flat based bullet, but Speer lists an OAL of 2.7". Doing a little math, that means that the bullet is only seated in the case .122", or less than half the "rule of thumb" one bullet diameter minimum seating depth. I "assumed" (yeah, I know ) that that had to be a typo, and loaded up a ladder at 2.55". My starting load was nearly at the velocity of the max load in the Speer data, and the max was more than 100 FPS faster, and exceeded the max speed recommended for this bullet. No pressure signs, either on the brass or with bolt lift, just blazing fast, and lousy accuracy. No weird velocity excursions, possibly a slight node at about the middle of the charge range, but otherwise pretty linear velocity increase with charge increase.
I was thinking about running some more at the suggested OAL, but I'm not even sure there's enough bullet in the case to hold it. But I guess my question is, could that OAL be right anyway, and if so, isn't that just asking for issues with bullets backing out under recoil? Not really an issue in my case, I run my Savage as a single shot, but it just doesn't feel right. Was wondering if anyone has used really shallow seating depths to good effect. Any thoughts would be much appreciated, thanks.
Dave
I was thinking about running some more at the suggested OAL, but I'm not even sure there's enough bullet in the case to hold it. But I guess my question is, could that OAL be right anyway, and if so, isn't that just asking for issues with bullets backing out under recoil? Not really an issue in my case, I run my Savage as a single shot, but it just doesn't feel right. Was wondering if anyone has used really shallow seating depths to good effect. Any thoughts would be much appreciated, thanks.
Dave