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Old 08-20-2012, 16:27   #20
Counting Beans
Join Date: Dec 2008
Location: Boise, Idaho
Posts: 2,895
Originally Posted by pasky2112 View Post
If I may butt in here...
I'm researching an issue I have just seen in my new 10mm loads. I have actual unburned powder ( Blue Dot discs ) forward of my muzzle with only mod loads... for ex.:
155g JHP (montana golds)
12.5g BD
CCI- 300 (LPP)
1.260" COAL
I'm shooting these out of a factory new G20FS...not SF... w/ stock bbl and a 22# SS RSA. I know BD is slow but the max load for this in Hornady guide is 12.9g. But I was also getting less than advertised vel.'s per book speeds. Usually, I get higher than adv. vel. in .40 loads out of this book. Not sure that even matters. But something is afoot at the Circle-K.

So, why the inefficient powder burn?
Maybe shorten my COAL gradually but hold the charge?
Use mag primers ( CCI- #350 )?
Is this characteristic of BD w/ lighter projectiles?

I have other powders that are faster but I bought the 5# keg of BD specifically for loading hot 10mm. It seems like I'm just wasting powder. I'd' like to resolve this issue. (duh) I'm open to sound advice from anyone else who's seen and resolved this 'problem' and would like to share some remedies. TIA!!
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.
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