Varget: Actual temp sensitivity?

[codemancode]

Does anyone know approximately how much muzzle velocity i can expect to gain/lose shooting varget across a wide temperature spectrum? Say 90 degrees to 10 degrees?

I chronoed my load in 90 degree temps this summer. I validated the trajectory out to 800 yards at a muzzle velocity of 2615. Well, i shot this week in single digit temps and was hitting way low. At 617 yards i was hitting about 2 moa low. It would take more than 100 fps velocity reduction to get this kind of result. Is this normal for varget?

Notes:
Zero was confirmed at 100 that day.
Same lot# of varget and all other components for that matter.

 

[high right]

Did you adjust the D.A.?

 

[Sonic Crack]

0*-125* 8 fps http://www.hodgdon.com/smokeless/extreme/page2.php#top

 

[gigamortis]

Varget is supposedly only about .2fps/degree F temp sensitive. I suspect your lot of Varget may have lost some energy over time.

I recently experienced a drop in velocity from a 8lb jug of IMR-4064. I was having to dial 2 more MOA elevation for 800 yards than what I used to dial a year prior. After thorough investigation, I found my 8lb lot had lost energy to the tune of a 80fps loss for my loading. Supposedly, IMR-4064 is only about .45fps/degree F sensitive. This 80fps loss far exceeded the little difference in temperature I was shooting this same charge weight in a year prior. I sourced some fresh IMR-4064 from a newer lot and loaded to my old specs, and my velocity was back where it was before. Now, I only buy powder in 1lb containers from the same lot so that I only expose 1lb of powder at a time to the air. I only owned the 8lb jug of 4064 for 2 years, and it had always been kept indoors. I do not know how old it was before I originally bought it, though.

 

[J-ROD]

Gig, this would be a good candidate for putting decedents in to see if it comes back

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[Greg Langelius *]

I think that air temps resulted in a denser air column, and provided the main bulk of the drop.

When Varget was first announced, Hodgdon published a little pamphlet handout that reported temp/velocity variances.

Velocities were essentially constant from the high end on down to the lowest, except that at the very lowest (below 0 degrees F.), there was a small UPtick in velocity.

(J-R, do you mean "desiccants" instead of "decedents"? "Decedents" are dead folks.)

Greg

 

[flashhole]

You don't store dead folks with your powder? I thought everyone stored dead folks with their powder. I'm sure he meant desiccants.

To the OP, I haven't seen that kind of change with Varget but I don't get to shoot past 300 yards. I've had good stability with all the Hodgdon extreme powders.

 

[J-ROD]

Lol, oops, no not dead people although the China made versions may contain dead people. Typing on my cell phone, I blame autocorrect and initial bad spelling

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[Service_Shooter]

In response to the OP's original question.... field experience here shows that Varget (2208) is indeed very stable over a broad range of temps, 'as advertised'. We shoot F-class throughout the year in temps ranging from 0 Celsius in the winter to 45 Celsius (120F) in the summer with no discernible variances. Storage conditions and age of the powder can have an effect, especially if the bottle has been left un-capped for a period of time.

 

[codemancode]

THanks for all the input. I guess i'll have to trouble shoot what else could be the issue. My DA was updated for the conditions at hand.