Headspace 300 Savage in auto loader

[Barlow]

I was loading some ammo for my old Rem, 81, 300 Savage, and I was trying to determine fired case dimensions for headspace set up. Fired cases were all over the place from 1.588 - 1.594 using the D400 gauge on the Hornady set up. I set the sizing die to end up at 1.588, put the empty case in the chamber and let the bolt slam shut. Case then measured 1.583. I did this three times and they all came out within .0005 of that number. Is this the right way to go about this, or is there a better way? Remington brass once fired. Thanks, Barlow

 

[searcher]

Taking the measurements off the fired brass is normally the best way - as you are doing. That the measurements are "all over the place" is due to either ammo that was loaded with the shoulder pushed too far back or just generous chamber dimensions. Either way, I'd take the measurement of a few of your longest case measurements and deduct about .003" to .004" for your new shoulder setback as the semi's need a bit more than bolt guns. Your shoulder is getting pushed back when the shoulder stops the round from forward momentum when loading. The amount and variance of the shoulder pushback on the unfired round can be influenced by heavy carbon buildup or other foreign matter in the forward portion of the chamber, varying levels of brass softness, etc.. I have a Browning BAR 7 Mag that did that - but not quite as bad. if your gun is clean and consistently pushed the shoulders back a minimum of (for example) .003", I'd be inclined to leave that much extra when setting back the shoulders.

 

[Barlow]

It's old but clean. Thanks for the info. Barlow