(https://s20.postimg.cc/n7wok76al/DSC02430.jpg) (https://postimages.org/)
Hello
I picked up a pound of IMR BLUE while visiting in Idaho. Only one pound was left. The store owner said that he could only get a few pounds of IMR BLUE and has not seen any UNEQUAL as yet.
On my way home I thought I should load up some 10mm and compare this IMR BLUE against BLUE DOT.
So I loaded up some rounds with some generic 180gr FMJ bullets I got from Northeast Target and Shooting Supply, new Starline brass and CCI 350 primers. COL was 1.260"
Charge weights were 10.4, 10.7, 11.0, 11.3grs. of IMR BLUE and BLUE DOT, five rounds each. If IMR BLUE is indeed similar to BLUE DOT, then things should be fairly close with respect to velocity and pressure.
The loads were hand weighed individually.
Loads were assembled with new Star-Line brass.
The pistol is a stock Glock 20-SF
Targets circles 5½" at 25 yards. ( same size as the 'black' on a standard 25 yard pistol target )
Shooting was done off of a Caldwell pistol rest.
Velocity data was taken from an Oehler Model 33 chronograph. Sky screens centered 10' from muzzle.
So, after some shooting this is what I came up with;
(https://s20.postimg.cc/tyd5tlyl9/DSC02428.jpg) (https://postimages.org/)
What we immediately see is IMR BLUE does not produce anywhere near the velocity that BLUE DOT does grain per grain. Nor does it produce as much pressure that BLUE DOT does, according to the expansion data, which might lead me to believe that maybe IMR BLUE is slower burning than BLUE DOT.
The 10.4, and 10.7grain IMR BLUE loads were quite pleasant to shoot, however when the 11.3 grain load came up, recoil was, I would have to describe it as severe. And accuracy deteriorated as charges went higher. The recoil at 11.3 grains wasn't matching up with the pressure measurements I got. Case expansion with IMR BLUE was fairly consistent, where BLUE DOT, not so much.
BLUE DOT on the other hand didn't really start shooting well until the 11.3 grain load was shot. BLUE DOT performed pretty much the way I expected it to.
No smileys occurred during this shoot.
The graph shows a very uniform velocity interval for BLUE DOT, but with IMR BLUE a very significant increase at 11.3 grains.
My initial exposure to IMR BLUE is somewhat disappointing. I'm thinking maybe I should re-shoot this with a heavier spring, or maybe try a different primer, although, the way accuracy deteriorated makes me believe increasing charges with IMR BLUE is pointless.
Maybe this fall or winter I'll experiment with 38 Special +P and .357 Mag with IMR BLUE and BLUE DOT and see what happens.
Here are the lot numbers that were used;
(https://s20.postimg.cc/kqkxcx6yl/DSC02431.jpg) (https://postimages.org/)
(https://s20.postimg.cc/a3r47hbnx/DSC02433.jpg) (https://postimages.org/)
Here is some pics of the two powders;
(https://s20.postimg.cc/a3r47i6j1/Blue_Dot.jpg) (https://postimages.org/)
(https://s20.postimg.cc/79nyu1ox9/IMR_Blue.jpg) (https://postimages.org/)
And here is the expansion data;
(https://s20.postimg.cc/s7u4s7h31/Scan0054.jpg) (https://postimages.org/)
And a velocity graph;
(https://s20.postimg.cc/nvn5k9ynh/Scan0055.jpg) (https://postimages.org/)
Tks for the work, nice data.
I use BDot quite a bit in a G20/3 with 22lb spring... very rarely see expansion over .4334 with starline and 10.7 gr./ 180 Xtreme plated
What does the chamber mic out to?
RDub01, thanks for your great comparison testing between the IMR Blue and Alliant Blue Dot powders. Your results are on par with others who tested these in 12 gauge heavy loads where Blue Dot still performed slightly better.
For a little History originally Blue Dot was made by Hercules which was part of the break up of Dupont years ago. Originally Dupont acquired Hercules in1880 but was split off in 1912.
Here is some interesting reading about the Dupont company, you can search each part of the time line of the pages...
http://www.dupont.com/corporate-functions/our-company/dupont-history.html (http://www.dupont.com/corporate-functions/our-company/dupont-history.html)
Look under the time line 1900 - 1926 for these two bits of powder history; 1902 Laflin & Rand Powder Company & 1912 Split Into Three Parts Dupont / Hercules / Atlas
Another great article can be fount here:
http://www.castpics.net/subsite2/GeneralReference/L&R-Smokeless.pdf (http://www.castpics.net/subsite2/GeneralReference/L&R-Smokeless.pdf)
Forgot to include a graph last night.. :-[ It's there now.
Thanks Shadow.. Interesting read.
I still have some 'Hercules' cans of various powders, some unopened, I found at gun shows. Some I've just saved from the late '60's..
RDub,
Thank You so much for this excellent review of both powders! This is how comparisons and load workups should be done!! Very scientific approach and your results are sound. I'm a big proponent of case head measurements along with chronograph data; as it is the best we can do to ascertain pressure in a given barrel without having actual pressure measuring tools. Because you were so thoughtful and thorough in your approach, it leaves little room for questions. I really appreciate work like this.
For myself, I have been pleased with AA9 (for my heavy hunting loads)and BE-86(for midrange loads). I have used BD also but accuracy in my firearms is better with AA9 and BE-86. So I probably won't try IMR Blue, but had I been looking to try it, this work would heavily influence my decision to do so.
What I do find interesting is that the recoil and casehead measurement with the heaviest load don't quite equal each other. This would lead me to think that the Blue is starting to hit a pressure spike at 11.3 gr. Your data suggests Blue could really go up in pressure quite quickly when you approach the maximum load, indicating extreme caution when going any higher than you did.
Again, thank You for your very sound and thorough comparison of the two powders.
Todd
Sent from my iPhone using Tapatalk
I'm wondering how any of this compares to AA9, which some believe is THE powder for 10mm loads. I'm an experienced reloader, but just now getting into 10mm. So far I've made some FBI-lite AA5 loads, and some strong AA9 ones. I'm going to experiment more with AA9, maybe even do some chronographing.
Very nice comparison! Your data is crystal clear, though I have one question because of some testing I have done. Is this mixed brass? I ask because during my testing I noticed once fired PPU brass, I fired it myself from a brand new box. Expands a lot more than starline or sig brass. I have found sig and starline brass to be on par with one another.
I know this is more about the powder than brass and I think even if the expansion data were left out. Anyone could see the glaring difference in performance between the two powders.
Thank you for the work and time you put in, again awesome work.
It may just the the chamber area of the gun's barrel is looser than others too....
I commonly load in the upper 10.4 to 11gr range with blue dot and don't remember seeing a Starline case over .4334
As a point I use the .4334 as a max expansion range ( data from Shadow's old work up (?)) in my gun
Running a G20/3 with 22lb spring
Quote from: mr.revolverguy on September 09 2018 05:49:35 AM MDT
Very nice comparison! Your data is crystal clear, though I have one question because of some testing I have done. Is this mixed brass? I ask because during my testing I noticed once fired PPU brass, I fired it myself from a brand new box. Expands a lot more than starline or sig brass. I have found sig and starline brass to be on par with one another.
I know this is more about the powder than brass and I think even if the expansion data were left out. Anyone could see the glaring difference in performance between the two powders.
Thank you for the work and time you put in, again awesome work.
My experience, with the re-use of PPU brass, has shown it to have a lot of variation with respect to alloy malleable. Some of their brass being stiffer while other pieces OK. However PPU brass has shown case head separations from its re-use... In a batch of re-man stuff Intercooler sent me for pull-downs, there were several bullets that were setback too deep. After I pulled these and documented the info, I went through the process of resizing the PPU brass. These cases would not hold the resized dimensions as they would spring back open and not hold the bullet at all.
http://10mm-firearms.com/factory-10mm-ammo-pull-downs/lax-180gr-fmj-plated-(ic-51714)-pull-down/msg31299/#msg31299 (http://10mm-firearms.com/factory-10mm-ammo-pull-downs/lax-180gr-fmj-plated-(ic-51714)-pull-down/msg31299/#msg31299)
I did a removal of the primers then annealed/heated the case over the gas stove then allowed them to cool. The next resizing did show them to retain the resized dimension better and when reloaded they held the bullet. http://10mm-firearms.com/factory-10mm-ammo-pull-downs/lax-180gr-fmj-plated-(ic-51714)-pull-down/msg31648/#msg31648 (http://10mm-firearms.com/factory-10mm-ammo-pull-downs/lax-180gr-fmj-plated-(ic-51714)-pull-down/msg31648/#msg31648)
So just a word to the wise, be careful, inspect the cases inside and out and check to see if they hold a bullet tight and securely!
Hey guys, thanks for the kind words
New Star-line brass was used here. I didn't want the pressure indications to be influenced by previously expanded brass.
I'll edit the post to reiterate this. Thanks
Univibe, AA#9 is an excellent powder for high end 10mm. Gives maximum velocities with relatively less pressure. It's my go-to for 200gr max loads.
Shadow, great advise on PPU brass!
Don't mean to thread hijack but yes well aware of the PPU brass issue. I have seen issues with other PPU brass (223) which has made me dump any brass from them in my recycle bucket. This is one of the reasons I performed my 10MM brass check with PPU I wanted to see if they were any better.