Originally Posted by Taterhead
Blue Dot does cleanup with more pressure. With a full-house charge, spent cases are sparkly clean with virtually no residue. I would look to other adjustments before going with a mag primers.
I like to seat 155s at 1.25". Do you have good neck tension? That helps with the slower-burning powders. Reducing the COL will reduce case volume and might contribute a bit to additional neck tension by putting more bearing surface in the case.
I have not shot the 155 MG, but 155 XTPs at 12.8 grains are pretty clean-burning and running at about 1400 fps. CCI 300 primer, Starline brass, and 1.25" COL.
My guess is that even with some unburned flecks, you are still getting pretty good groups. I have found Blue Dot to group well even when not pushed. If it is otherwise functioning well, I would not be too concerned with unburned flakes. Your gun will get pretty sooty after a while though. For a few years, my IDPA load was a modest pressure 180 gr Blue Dot load. It grouped very well. My gun would get pretty sooty, but it would still run 100% even with a few hundred rounds between cleanings.
Regarding velocities, you are running a shorter barrel than most books, so Hornady Blue Dot data is running a bit slower for me than what Hornady publishes. Other loads like Accurate no. 9 track a bit closer for some reason.
Great points. The G20 shoots GREAT! It's a keeper and I LOVE it! I just got it so I'm getting the feel of it shooting ~45'/15yds and getting about 3" grps standing shooting supported. For now, I'm OK with that. Coming from Precision Rifle background, that was HARD to accept when I started pistol...I digress.
I think going to mag primers might be too drastic at this point. Thinking of reducing the COAL to 1.250" first, with following 12.0g BF load.
My load is not far from yours, Taterhead, and I'm getting significantly lower vel.'s... for ex. in my G20 stock bbl:
155g JHP MG w/ 12.5g of BD CCI #300 @ 1.26" - avg 1210 fps in 15 rd string. (ES-60, SD-19) According to avg data, I'm about 100-150 slower with this load.
Another load with 12.0g of BD and exact same components, day, string ct., ect. avg 1178 fps.
Whattya guys think about running the sub-max loads (12.0g BD above) back through my resizer to reduce COAL to 1.250" then re-crimp w/ usual Lee FCD ? I'd think it'd be more 'apples/apples' but not sure of any gotya's.
Bottom line is that I'd like to see less unburned powder via improved powder combustion efficiency in reasonably charged loads in a reasonable bbl length. I'd care less if I was shooting a 2" bbl ...but 4.6"... it shouldn't be snowing BD flakes everywhere.