Test of Temperature Sensitivity of Blue Dot and Accurate #9

sep · December 19 2015 10:05:41 AM MST

Fltbd's post on powders for accuracy has got me to thinkin. I've read Blue Dot is temperature inverse, meaning it generates higher pressure the colder it gets. I emailed Alliant and asked them about it but didn't get a direct answer. I've also read, ball powders like Accurate #9 can be difficult to ignite in cold weather. So, I'm gonna do a test since I live in a cold weather climate just outside Fairbanks, Alaska.

I have two chronographs and the CED Millenium won't work well up here during the winter as we don't get much daylight here in interior Alaska. So, I'm gonna use my magnetospeed to overcome the light problem. Unfortunately, that means I can't use the 10mm as it is an autoloader and the Magnetospeed won't work with autoloaders. So, I'm gonna load up 20 rounds with Blue Dot and CCI 300 primers and 20 rounds with Accurate #9 with CCI 350 primers for one of my 44 magnums.

I'm gonna cold soak 10 of the Blue Dot loads and 10 of the Accurate #9 loads along with the revolver overnight and shoot em to see what kind of velocities I get. Then I'll take the revolver and the remaining 20 rounds of ammo to our local indoor range to see how they shoot at room temperature. A comparison of these shot strings should give me some idea as to whether Blue Dot is indeed temperature inverse and whether or not Accurate #9 is difficult to ignite in cold weather. The charge weights for these powders in the 44 are obviously higher than the 10mm, so my logic is if they ignite and don't get spikey in the 44 magnum, they'll be fine in the 10mm with the same primers. Conversely, if both powders act squirrely in the 44, then they just might do the same thing in the 10mm.

I'm gonna wait til we get a cold spell well below zero Farenheit to simulate colder weather than I would normally hunt in to test these powders. I might just add Longshot and 800X to the test too as these can both be shot in the 44 magnum as well.

I'll post the results here for those who may be interested. I'll start loading up some rounds this weekend as it is just above zero Farenheit today...man I love global warming. Sure beats 40 below...

My rationale for doing this test is if Blue Dot turns out to be the most accurate powder for my 10mm and it does get spikey as temperature drops, then I will deliberately load with a less than maximum charge to give myself some wiggle room for pressure, so I don't end up Blacktail deer hunting on Montague or Kodiak Island with a magazine full of proof loads!
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I modified this post with the results on 12/25/15. The first five shot strings with each powder are ladder loads and the next five were at the maximum load of the tested ladder series. I hadn't loaded 44 magnum with these powders before so I wanted to give myself some wiggle room.

Ruger Super Redhawk 250 grain plain base Leadheads Keith style bullet
Blue Dot CCI 300 primer

70 degrees F -15 degrees F
12.0 grains 1149 fps 1026 fps
12.5 grains No Reading 1018 fps
13.0 grains 1226 fps dropped round in snow could not find
13.5 grains 1224 fps 1252 fps
14.0 grains 1291 fps 1214 fps

Five Shot Strings with 14.0 grains of Blue Dot
70 degrees F -15 degrees F
1222 fps 1144 fps
1257 fps 1206 fps
1246 fps 1225 fps
1319 fps 1246 fps
1241 fps 1327 fps

Average Velocity 1257 fps Average velocity 1229 fps

Accurate #9 CCI 350 primer
70 degrees F -15 degrees F
16.0 grains 1170 fps 1110 fps
16.5 grains 1310 fps 1189 fps
17.0 grains 1306 fps 1261 fps
17.5 grains 1415 fps 1331 fps
18.0 grains 1439 fps 1353 fps

Five Shot Strings with 18.0 grains of Accurate #9
70 degrees F -15 degrees F
1356 fps 1250 fps
1429 fps 1297 fps
1447 fps 1289 fps
1418 fps 1288 fps
1416 fps 1339 fps

Average Velocity 1413 fps Average velocity 1292 fps

These results aren't really statistically significant but I'm gonna jump to a couple conclusions based on these tests. First, Blue Dot appears to be a lot more temperature stable than I anticipated based on what I had read. It did lose some velocity going from 70 F to -15 F but it definitely didn't appear to universally increase in pressure. At least the velocity didn't seem to indicate an increase in pressure.

Lastly, Accurate #9 lost substantially more velocity than I anticipated. I don't think it is more difficult to ignite this powder as I didn't experience any hangfires or anything out of the ordinary. It just seems to have lost a lot of velocity.

I'll be doing more load development in the spring with the 10mm and at this point I'd be pretty comfortable using Blue Dot. Hope everyone has a Merry Christmas.

Benchrst · December 19 2015 11:40:47 AM MST

I'm curious about your results.

I've worked up about 260 loads for the 10, with most of them tested in the 35 - 50deg range. It won't get much colder here, so my obsession is on hold until it warms up, then I'll retest the ladders (up to 90deg).

By this time next year all the results should be graphed, charted, and plotted, and I'll have to find a new hobby ${$default_grin_smiley}$

sep · December 19 2015 12:14:32 PM MST

Benchrst,

Have you found Blue Dot and/or Accurate #9 to be consistent powders in the temps you have already tested? Sure, wish the MyLabRadar folks were at full production, then I could run these velocity tests with the 10mm vs the 44 magnum.

Benchrst · December 19 2015 01:02:07 PM MST

You can look (http://webcity.net/benchrest/10MMPublished/10mmAllPowders.html), but I really have no identical-loads-at-different-temps to compare (that process will start next spring / summer).

Have you considered an infrared light kit? I just got one, and the batteries should arrive next week - hopefully I'll get a chance to test it soon.

fltbed · December 19 2015 04:06:36 PM MST

This sounds like a great test and I look forward to hearing your results. I've had good luck at the indoor range using desk lamps with the old style light bulbs, over the sky screens. You might be able to rig up a similar set up with old car headlights and a 12v battery. (yep, I'm a redneck) ${$default_tongue_smiley}$

I've run a few temp tests in the past, mostly on hunting and my USPSA match ammo. It's surprising how many powders are inverse sensitive to temps.
My standard procedure is to take ten rounds, (or loaded mag if I'm testing a pistol) put them in a zip lock bag and put them in the freezer overnight. The next morning, I'll take a small cooler full of ice, pour salt over it to get the temp down as far as I can, and dump the bag out of the freezer into it for transport to the range. I'll take another bag (or mag) and put it in a winter glove with a few of those disposable hand warmers. (Temps usually between 100-105)
For example, I run WST in all my USPSA ammo. (9, 40 & 45acp) In my 9 & 40, I usually pick up 60-70 f.p.s. in the cold. In the 45 acp it's only around 25-30 f.p.s.

I tested Blue Dot & #9 in the 45 Colt many years ago and found them to be standard temp sensitive. Meaning as the temp dropped, so did the velocities. Also, the Federal 155 mag primer was the best at lighting up ball powder in the cold. (especially with 296/H110)

Jeff

The_Shadow · December 19 2015 08:03:33 PM MST

Sep, did I miss your bullet weights for the 44 Mag? ${$default_huh_smiley}$

My pet load for my S&W m-29 8 3/8" is 16.2 grains of Blue Dot with the 240 grain bullets @ 1370 fps

sep · December 19 2015 10:02:15 PM MST

Quote from: The_Shadow on December 19 2015 08:03:33 PM MST
Sep, did I miss your bullet weights for the 44 Mag? ${$default_huh_smiley}$

My pet load for my S&W m-29 8 3/8" is 16.2 grains of Blue Dot with the 240 grain bullets @ 1370 fps

Thanks for pointing that out Shadow. I corrected it. Have you found Blue Dot to be stable and consistent in your neck of the woods? I know you've done a lot of load development with it in 10mm. I've seen posts where you reference your 200 XTP load of 10.5 grains Blue Dot.

sep · December 25 2015 04:34:49 PM MST

Updated with results 12/25/15

The_Shadow · December 25 2015 08:44:37 PM MST

Thanks for the update! ${$default_cool_smiley}$

fltbed · January 01 2016 08:02:23 AM MST

WOW! Testing in -15 degrees F! ${$default_shocked_smiley}$ My hats off to you. The coldest I've ever tested in was in the low teens when I was much younger.

I see your also getting wide velocity spreads with #9. I also have this issue in the 44 Special and 45 Colt. Have you ever tried a filler like Puf-Lon? It's messy and a PITA to use but it reduced my ES by 75% and improved the accuracy a bit at 50 yards.

Jeff

sep · January 01 2016 01:16:35 PM MST

fltbed,

Filler is a really good idea. In 44 magnum, I've got some ladders loaded up using Unique and Universal for mid range loads. Don't wanna shoot the max loads anymore. It's just no fun for me. Probably won't test those ladders til spring due to the outside temps and lack of an indoor range with suitable distance for evaluating the accuracy of the loads.

In the 10mm, I think both Blue Dot and A#9 will give better case fill density, so hopefully the ES will be smaller. I'm dyin to hunt blacktails on Montague island next fall with the 10mm. Due to the presence of brown bears on Montague Island, I'll be carrying 200 grain WFNGC bullets...just in case.

sqlbullet · January 01 2016 03:15:36 PM MST

+1 on filler making sense sometimes. I have used it to great effect in large capacity rifle cartridges when loading gallery loads.