450Bushmaster.net

I am trying to minimize chambering creep for 250 grain All Copper BARNES #30996 TTSX bullets used in AR-15 reloading. Could you measure the major length shank diameter of YOUR expander plug if you use it to reload for a 450BM AR? I would expect that Expander shank to be between .446" to .450". If you have anecdotal info on your creep, feel free to expound. drayks+

drayks+ wrote:I am trying to minimize chambering creep for 250 grain All Copper BARNES #30996 TTSX bullets used in AR-15 reloading. Could you measure the major length shank diameter of YOUR expander plug if you use it to reload for a 450BM AR? I would expect that Expander shank to be between .446" to .450". If you have anecdotal info on your creep, feel free to expound. drayks+

Very few if any reloaders use the expander mandrel that comes with the die set, for precisely the reason you are asking about. I have over 2k 450b reloads under my belt and I used the expander the very first time I reloaded some 450b cartridges and that was it. The adverse effect it had upon neck tension garnered a permanent trip back into the die set box.

Hooy

shouldn't need to use a expander with those boattailed bullets, just lightly chamfer the inside of the case to minimize scraping on the bullet.