Re: .243 rebarrel
The best load, that is most accurate out of 243 Remmy using the 90grn Scenar is:
41.5 grns of H4350 ext sparked by a Fed. 210M primer, for a velocity of 2880fps
Cartridge overall length with the bullet engraving into the lands by about .002" is 2.784".
I dont know if it would feed out of the mag box because i single loaded all my rounds.
This load would shoot into 1/2 moa all day with the best being just under 3/8" at 100yrds for 5 shots.
Loads of 42 and 42.5 grns gave higher velocities for a slight drop off in accuracy.
43 grns started to get a bit hot with a heavy bolt lift but gave 1/2" accurcy at 3050fps
Similar charges of Win 760 and H 380 gave excellent accuracy and velocities in the same bracket but burned dirtier and sooted the casses more.
All cases were Lapua, trimmed, neck turned for a approx.3/4 clean up, primer pockets uniformed and flash holes de-burred even though it may not be neccessary, i just like doing it.
In a custom chamber like your 243 ACK. i think the scenar will do very nicely [img]/ubbthreads/images/graemlins/smile.gif[/img]
PS. Just as a matter of interest 34 grns of H322 and a 70 grn SMK traveling at 3115 fps has given me my best accuracy to date with a 5 shot group of .348" but very sooty cases as far down as the case head! indicating incomplete sealing of the chamber by the case. [img]/ubbthreads/images/graemlins/frown.gif[/img]
A 1 grn increase eliminated the sootiness but ruined the accuracy. [img]/ubbthreads/images/graemlins/frown.gif[/img] [img]/ubbthreads/images/graemlins/frown.gif[/img]