10mm & #107 initial range test.

[Black Snowman]

CAUTION: The following post includes loading data without published pressure tested comparisons. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

#107 is advertised by Bartlett Reloaders as being able to use the same load data as AA #7. For my particular lot #69545, this was not the case. Fortunately I have a chronograph and was able to determine this before doing any permanent damage to anything.

Conditions weren't ideal for the Chrony so I wasn't able to get velocity data on every shot. I'll skip right to the velocity test loads that I made on a single stage with the following components and specifications.


Test firearm: Colt pre-Enhanced Delta Elite with 5" barrel.
Lee dies including a Lee factory Crimp die were used.
135 gr Nosler JHP bullet
Starline new brass, resized.
Winchester WLP primer
COL: 1.252"
13.0 gr of powder, hand weighted on a Cabela's digital scale.

I shot 5 rounds of these loads for each powder.
AA #7:
1) Error
2) 942
3) 995
4) 861
5) 1071

#107
1) Err
2) Err
3) 2007
4) 2042
5) Err

I didn't continue testing as a velocity of 2000+ FPS is most likely NOT safe. I did try some 165 Gr Star FMJ TC rounds I loaded on the progressive with slightly lighter loads and they also produced velocities hovering around 2000 FPS.

There were no consistant or obvious pressure signs. Primers tended to be flatter on the #107 loads but there were occasional AA #7 rounds that looked the same. Not all brass was recovered however.

The #107 loads didn't seem to have an appreaciable increase in muzzle flash or recoil and there wasn't a large enough sample taken for meanful accuracy comparisons. They did however eject brass with signifigantly more force.

For a comparison of the powders themselves I also compiled data during the loading process. First, here's a photo of the two side by side.

I found the average volumetric density (as used by Lee) in this lot of #107 to be 0.0962 CC per grain. The lot of AA #7 I'm using I found the average VMD to be 0.0668 CC per grain. I think this has more to do with the fact that #107 is a flattened ball rather than a plain ball powder than the actual desnity of the powder itself.

My powder throwing samples were done using a Lee Pro Auto Disk power thrower operated by hand with a home-made baffle. This was a worst case scenario for throw consistancy as I had to set the thrower down to write down the amounts. Through the actually loading process on the progressive the throws were more consistant. I threw and weighted 10 charges for each powder.

AA #7
0.88 CC disk for a typical charge of 13.2 gr.
Maximum spread was 0.3 gr.

#107
1.26 CC disk for a typical charge of 13.1 gr.
Maximum spread was 0.7 gr.

With this info I'm going to pull appart all the #107 loads I created and load up a batch with a gradient of powder weights to try and find a load that falls into the velocity range that should indicate a safe pressure level and try to identify any trending in the powder and see if I can find a powder with more comperable load data or see if there is a corrolation between it and AA #7 by volume or relative weight.

 

[stans]

WHOA!!!! Ball and flake powders tend to be very different animals. Those flakes look (and looks alone can be dangerously deceiving) more like Unique, which is a faster powder than AA#7. Maybe it is just me, but using ball powder data for a flake powder just seems dangerously wrong.

 

[FireInTheHole]

Nice report BlackSnowman. Are you going to make any workups for other calibers?

 

[Black Snowman]

I emailed Jeff at GIbrass.com pointing him to this thread and here's what he had to say about the origins of the powder:

"This particular lot was manufactured for Accurate Arms in the early 1990s by Hercules Powder Co. During this time frame, Accurate was buying powders from many different manufacturers.
Sometime around 1994, Accurate quit buying from everybody except Lovex (Czechoslovakia). Since all the powders made by Lovex were of ball type, they wholesaled off all their bulk stock of powders other than Lovex.

If you had bought some AA#7 in say,1990, this flake powder, made by Hercules, is exactly what you would have gotten."

Once I find a safe level to reduce to with the more forgiving 10mm I might try it in the .40 S&W as well although Jeff warns of bridging in some powder throwers so I'll have to keep a good eye on it, which I normally do anyway. It's nearly as large as the Univeral I'm using now and it seems to throw much more consistantly on the press than in my test. I'll measure the loads as I pull them appart to verify this.

For my magnum pistol loads I got a bunch of WC820 pull down powder which is esentially H-110. That will be feeding my magnum pistol thirst for .357 Mag, .44 Mag, and .50 AE so I'm not likely to make a load for those.

 

[FireInTheHole]

FWIW my Father has been using an 8# jug of wc820 he bought from bartlett a couple years ago in his .357mags... the advice to use h110 data seems sound. I have not had the opportunity to chrono any of his loads but the starting loads appear safe.(no sticking cylinders on his wheel guns)

Our lot# is 50283.
Cheers.

 

[Black Snowman]

OK, pulled the 200 or so 165 grain loads I made last night and weighted the first 13 before I got lazy I don't have the numbers in front of me but the high was 11.6, the low was 11.2 and most were 11.5 so it did throw a little better than my previous test.

I then loaded up 10 rounds with 8.1 gr and 10 with 8.8 gr in the progressive using the thrower. As Jeff warned it bridged once on each batch. I cought the first one when I looked in and saw only a little powder which turned out to be 1.7 gr. The 2nd time I saw it in the disk and just tapped the thrower and it dropped. I'll chrono those next chance I get, maybe even tonight if my CZ-40B has arrived.

 

[Black Snowman]

Update: I re-chronoed my "base line" 13.0 gr of #7 loads under better conditions and found them to be running in the 1500 FPS range they should have been chronoing in so there's a good chance that all my chrono data from that day was complete garbage. 8.8 grains of #107 was pushing the 165 gr Stars to only about 850 FPS. I'm going to work back up but I believe I'll be looking at loads only slightly reduced from the #7 loads.

In other news, don't get lazy and just start with a "light" load instead of a "starting load". I blew up my FAL a "little" I'm OK and it's repairable but the shrapnel in my thumb and lip are a nice remider of how close I was to going blind.

 

[FireInTheHole]

What were the components/conditions??????

 

[Black Snowman]

44 grains (basicly the light end of a full power load) WC846 pull-down with 147 grain collet pulled bullets in IMI military once shot brass and CCI Large Rifle primer. Gun was cool and the barrel was clear. I'll post a seperate thread when I'm feeling good enough to get some more pictures of the carnage Right now I've been avoiding messing with the gun because it's a bit depressing

Case head seperation, case in chamber, blew off the scope mount, bent the charging handle and turned the magazine into a nice exaust tip.

Fortunately I didn't have any other rounds in the magazine and the scope mount was a nice heavy duty DSA and did a great job of deflecting the blast away from me. I think it helped that it was only clamped down on the side facing me. The other side hit the bolt carrier so I couldn't put the clamps on that side. When it blew it was able to vent out the right side more easily than just through the ejection port.

 

[Grump]

I've had .357 loads clock at 2100 fps using 125-gr bullets out of a 6-inch gun, then discovered that the shadow of the powder gases was being chrono'd instead of the projectiles.

Don't chrono in the late afternoon with your back to the sun. Turned 90 degrees (direction was still safe there) and got repeats of the prior readings for that load. Glad to hear your pistol loads weren't that stressfull. I would have expected expanded primer pockets at those speeds. Sorry to hear about your FAL. My loads used more powder than that, but would not fully press the primers back after they took up the headspace. This was with both moly and bare bullets. Strange things happen.

 

[Black Snowman]

Ya, lighting conditions weren't the best and I had to have the chrono closer than I'd like. I'm guessing I was running into the same situation Grump. So the #7 data should be fairly safe to work up loads with the #107 powder, just like it says at Bartlett's site.