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Old 08-20-2012, 18:30   #21
fredj338
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BlueDot is really quite slow burning & runs best closer to max. So if you want midrange loads, I would switch to something like PowerPistol.
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Old 08-20-2012, 19:21   #22
dla
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They're not "unburned". They are powder zombies.
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Old 08-21-2012, 09:44   #23
pasky2112
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Quote:
Originally Posted by Taterhead View Post
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.

THX!
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Old 08-21-2012, 10:01   #24
pasky2112
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Quote:
Originally Posted by fredj338 View Post
BlueDot is really quite slow burning & runs best closer to max. So if you want midrange loads, I would switch to something like PowerPistol.
Power Pistol is my fav .40 load. I WILL eventually dev a load in 10mm w/ it for IDPA.
I'd really like to get the BD combustion issue solved in 155's. If not, I may use it for heavier 180's. I just want a fast mid-range round to try silhouette shooting @ 50 yds. Besides, I can't back down to an obstacle and challenge of figuring this BD out. There's something new to learn, here.

Thanks for sharing!

Last edited by pasky2112; 08-31-2012 at 14:48..
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Old 08-21-2012, 10:16   #25
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I checked Alliant's website and their max is below what you are running so the Hornady data might be a true max. Some powders will leave unburnt flakes and you might just have to live with it with the 155's. The range floor used to have so much left over 296 from when I ran it with 125's in 357mag that the floor would be slippery and it was truly at a max load.
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Old 08-21-2012, 10:21   #26
pasky2112
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Quote:
Originally Posted by dla View Post
They're not "unburned". They are powder zombies.
Yet ANOTHER Zombie problem. I can't imagine what they'll do on 12/21!
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Old 08-21-2012, 13:20   #27
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Quote:
Originally Posted by F106 Fan View Post
I mentioned in another thread about JUST getting a copy of Richard Lee's "Modern Reloading - Second Edition". I haven't even begun to read it!

In it, he discusses case capacity and how much it is reduced as rounds are loaded shorter in terms of both reduced case capacity and increased pressure (starting on page 96).

His example of a 1/16" (0.060") change in OAL makes a 14% change in case volume for a .45 ACP (it would be more in a 9mm, I think). There is a table that enumerates %change in pressure for 1% change in volume. For a powder like Titegroup, the %change is 2% for every 1% change in volume. That number is HUGE even with light loads
.

Bottom line, be careful when you make large changes in OAL, especially on small cartridges.

I have mentioned elsewhere that I use 700-X for .45 ACP and I will admit that I get a LOT of soot and the cases have a black smudge on the outside. It's been that way for many years and I don't expect it to change. I just don't get too excited, one way or another. They go 'bang' and the bullet usually goes right where I was aiming (whether I was aiming correctly is another story) so I just keep making them.

Richard
That is kind of voodoo though, you can't track pressure increase w/ volume decrease in a linear fashion, it varies w/ each powder. Then when you reach a certain volume, pressure go up dramatically.
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