I have a couple factory Remington Senderos in 300 RUM that I am building some loads for. The fired necks on both of the senderos measure .344, likewise the loaded round neck measures .337.
What I am finding that happens is this;
2X fired, Remington brass, decapped, tumbled and annealed.
The neck on the fired brass starts with less that a half of thou runout. After running it thru the Redding T7 with Redding Competition dies, and using a .335 neck bushing, my runout on the neck is .007-.009!
I have the die set so there is a bit of play in the neck bushing, avoiding it being clamped down, free floating the neck bushing if you will. The depth of the neck bushing leaves an area above the junction of the shoulder/neck of about 1/16-3/32 that is not neck sized.
I have went thru and cleaned the die, sleeve and neck bushing. No help. At this point Im convinced it is not the press as I load for several other customs and no such problem, though no big spread between fired and loaded rounds.
Here is question because I have never loaded for a factory chamber with such a wide variation between the fired neck compared to the loaded neck. Any thoughts that I am taking to big of jump/difference in bushing size and causing some abnormal "shock" to the brass?
Currently I dont have the bushings on hand to try stepping the neck down, but they are just now ordered.
I have also turned the brass 1/3 turn increments and sent the brass thru the press on each turn, and that has made a bit of improvement, .005ish on runout.
Thoughts/Help on cause? I am sure hoping some of the wildcat reloaders can tell me their thoughts, especially since I have a 7/300 finishing up at the smith soon, and Id like input on what size steps are most effective when such big tolerances are encountered. Thanks, Dave
What I am finding that happens is this;
2X fired, Remington brass, decapped, tumbled and annealed.
The neck on the fired brass starts with less that a half of thou runout. After running it thru the Redding T7 with Redding Competition dies, and using a .335 neck bushing, my runout on the neck is .007-.009!
I have the die set so there is a bit of play in the neck bushing, avoiding it being clamped down, free floating the neck bushing if you will. The depth of the neck bushing leaves an area above the junction of the shoulder/neck of about 1/16-3/32 that is not neck sized.
I have went thru and cleaned the die, sleeve and neck bushing. No help. At this point Im convinced it is not the press as I load for several other customs and no such problem, though no big spread between fired and loaded rounds.
Here is question because I have never loaded for a factory chamber with such a wide variation between the fired neck compared to the loaded neck. Any thoughts that I am taking to big of jump/difference in bushing size and causing some abnormal "shock" to the brass?
Currently I dont have the bushings on hand to try stepping the neck down, but they are just now ordered.
I have also turned the brass 1/3 turn increments and sent the brass thru the press on each turn, and that has made a bit of improvement, .005ish on runout.
Thoughts/Help on cause? I am sure hoping some of the wildcat reloaders can tell me their thoughts, especially since I have a 7/300 finishing up at the smith soon, and Id like input on what size steps are most effective when such big tolerances are encountered. Thanks, Dave