Alliant Blue Dot temperature sensitivity...maybe not???

[Kenk]

I have read a great deal in regards to Blue Dot's temperature sensitivity in colder parts of the country; Minnesota for example. From my readings, I have been hesitant to shoot BD in say, 15 degree temps or lower.

This is from Duane with Alliant Technical Services

Kenneth,
As long as you are using piezoelectric tested, reliable load data and following proper reloading technics, your loads will be fine. All bets are off if the data comes from Billy Job-Bob from the internet.
Thanks,
Duane

Technical Services Rep
Alliant/Blazer/CCI/Speer
?2299 Snake River Ave?
?Lewiston, ID 83501?
?1-800-379-1732?


Hi Duane, I have been told / read that shooting Blue Dot in sub zero temps increases the normal pressure to possibly dangerous levels
Thanks

Ken

[sqlbullet]

This is why there appears to be so much headroom in the load data.  Blue Dot can be temperature sensitive.  The published load data takes that into account.  So if you are testing your loads in a temp range that results in lower pressures, they it will appear the book loads are very conservative.

[The_Shadow]

It is why I never put much stock in the reports and warnings...I've run many canisters of Blue Dot in many calibers and gauges of shot shells over the years...when I started with 10mm there wasn't any printed data for 10mm, but that didn't stop me from working up my loads at the beginning of 1990, using 10.4 grains under my 200 grain XTP's and also under my 175 grain cast for target play out to 130 yards...

It doesn't get much below 18 degrees very often down here but it does get to 100 degrees at times...

[Kenk]

Thanks, my concern is that if I wanted to do some target shooting after coyote hunting at my buddies farm, and it was, say  -10, am I going to blow something up
Thanks

[fltbed]

Most powders are temperature sensitive.  That is, as the temperatures get warmer they generate more pressure.  Some more so than others, especially some of the older powders.  Can be an issue if you develop your loads in say 50 degrees and are heading somewhere where it's 100 degrees or warmer.

A few powders are what is know as "reverse temperature sensitive".  That is, as the temperature rises, they develop less pressure and accordingly, they develop more pressure as it gets colder.  (VV 3N37, 3N38 and WST come to mind)

A few of the newer powders are claimed "temperature insensitive".  The few I've tested so far live up to that claim.  Weather it's -10 or 100 above, the velocity and apparent pressure remains unfazed.

Blue Dot, (being one of the older powders) is definitely in the first category in all of my testing.  example:  My 10mm 180 grain load of 10.4 gr of Blue Dot generates aprox 1180 f.p.s. at 80 degrees, only does 1070-1100 when the temps were in the mid 20's.  However, accuracy (my main concern) and point of impact, remained unchanged, so I don't really worry about it.  YMMV

Hope this helps.
Jeff

[Kenk]

Thanks Jeff, it's looking like my concerns are unfounded???

[Kenk]

Hey Jeff, so from your findings, I take it running my standard load of 10.4gr BD under a 180gr XTP should not be an issue, regardless of temperature, correct?
Thanks man!

Ken

[tommac919]

10.4 and a 180xtp make a great load... in stock G20, very accurate

[Kenk]

Yea they are!!!

[fltbed]

Hey Jeff, so from your findings, I take it running my standard load of 10.4gr BD under a 180gr XTP should not be an issue, regardless of temperature, correct?
Thanks man!

Ken

The only issue my testing has uncovered is lower velocity and pressure in colder temps.  That may affect accuracy and point of impact in your gun so I'd advise testing for yourself. 
Some report their guns failure to cycle and they blame the ammo but I suspect it's probably the lube they were using not being suitable for cold temps.

If you don't mind my asking, where did you read Blue Dot was reverse temperature sensitive?