ridingfar
05-05-2013, 09:36 AM
Team Cast Boolits,
First - Thanks for all the great info I've gotten here! Most helpful folks!
Second - I'm working up some subsonic 308 loads and have been surprised at how slowly speed has dropped off with increasingly reduced charges. Using a Ruger GSR w/ 16.5" barrel, 193 grn/.310 to .311 hard cast lead molly coated bollits over Trail Boss and maginum rifle primers in R-P unmodified cases.
Started at 11.0 grn hitting just over 1200 fps and have been between 1100 to 1020 fps from 9.5 grn working down to 7.8 grn. I will go from 7.5 down to 7.0 grn of Trail Boss in the next flight but, wow, that's way less a charge than I expected to get into the 950 to 1000 fps range I'm looking for. It's also down to ~half full, or less, in a 308 case even with this "fluffy" powder. Each charge level I've shot so far show pretty good speed consistancy so that's a good sign, but they do not drop much fps with .2 to .3 grn reduction steps.
So now my question: Is this load range (low 7.X grn of Trail Boss) what others have found to get just under 1000 fps in a 308 with ~200 grn boolits?
Just wonderin'...
Thanks in advance for your consideration and assistance!
Courtney
First - Thanks for all the great info I've gotten here! Most helpful folks!
Second - I'm working up some subsonic 308 loads and have been surprised at how slowly speed has dropped off with increasingly reduced charges. Using a Ruger GSR w/ 16.5" barrel, 193 grn/.310 to .311 hard cast lead molly coated bollits over Trail Boss and maginum rifle primers in R-P unmodified cases.
Started at 11.0 grn hitting just over 1200 fps and have been between 1100 to 1020 fps from 9.5 grn working down to 7.8 grn. I will go from 7.5 down to 7.0 grn of Trail Boss in the next flight but, wow, that's way less a charge than I expected to get into the 950 to 1000 fps range I'm looking for. It's also down to ~half full, or less, in a 308 case even with this "fluffy" powder. Each charge level I've shot so far show pretty good speed consistancy so that's a good sign, but they do not drop much fps with .2 to .3 grn reduction steps.
So now my question: Is this load range (low 7.X grn of Trail Boss) what others have found to get just under 1000 fps in a 308 with ~200 grn boolits?
Just wonderin'...
Thanks in advance for your consideration and assistance!
Courtney