Question about the temperature sensitivity of Varget

thump_rrr

thump_rrr

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I have a Savage 10BA which I bought last fall.
Up to now I've been shooting my handloads using range pickup brass with great success.

All my brass was once fired and separated by headstamp.
The brass was full length sized and had the primer pockets uniformed, flash holes deburred, trimmed to length, chamfered then weighed in .0.5gr lots by weight.

I then fire formed the brass in my rifle and started load development.

In both Winchester and Federal cases using 180gr SMK's I was able to achieve 0.5 moa accuracy using 40.9gr of Varget which I chronographed at 2550fps give or take.
This was in 40F weather.

Last week I bought a box of Lapua brass and did a ladder test along with 30 rounds of 40.9gr and 41.2gr which worked well for me in Win and FC brass.
The ambient temperature was 80F and at the max load in the Sierra manual which is 41.7gr I was only able to achieve 2390 fps.
The ladder test seemed inconclusive. The first 4 rounds began stringing vertically then for some reason the next 3 rounds not only leveled off but had nearly identical velocity out of the chronograph which I can't explain why.

Is this due to the ambient temperature or more to do with case volume?
The weight of the Lapua brass is nearly identical to the FC brass and heavier than the Winchester brass by nearly 30gr.
Should I keep pushing the load till I see pressure signs and do another ladder test?
 
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Thats a big difference. I have always been under the impression from everything I have read that Varget was not temp sensitive???
 
Probably has more to do with lighting conditions. Were they the same on both days? Was the chrony at the same distance, height and orientation as the last time you were out?

These factors can play on your chrony readings as well.

Having the chrony tilted toward or away from you even slightly can skew the readings, along with different light on different days.
 
Sorry for the typo. I corrected it
The actual velocity is 2390 fps with 41.7gr of Varget over a 180gr SMK using Lapua cases in 80F weather.
This is compared to 2550 fps with 40.9gr of Varget over a 180gr SMK using
FC cases in 40F weather.

To answer a few of the questions:

Varget and SMK's were all from the same lot.
8# jug of Varget and 500 round box of SMK's.

The chrony was setup 18' from the muzzle exactly where it was on both days.
It was setup in the shade behind our great wall of restricted range wood (thanks Sureté du Quebec)
 
I would suspect the primer, BR-2 and Varget are like peas and carrots, it is a very insensitive combo to temperature variations, BR-2 is closer to a magnum primer and is very equal from one to another, try them if you dont, it may make a difference... JP.
 
caramel said:
I would suspect the primer, BR-2 and Varget are like peas and carrots, it is a very insensitive combo to temperature variations, BR-2 is closer to a magnum primer and is very equal from one to another, try them if you dont, it may make a difference... JP.
Click to expand...
Sorry I forgot to mention that I am using BR-2 primers.

I'm going to do 2 ladder tests with both types of brass side to side to see how they perform once my Lapua brass is fire formed.

I will also start with a fouled barrel to be sure.
 
I have shot Varget extensively for my .308win. In a large temp variation, I have experienced very little velocity variance. May 30-40 fps or less (-15 to +30 celcius).

I have heard of some Varget lot discrepancies though.

Good luck and good shootin!
 
They may be more temperature sensitive but uniformity between batch seem a lot more regular R-17 for 190-220 gr bullets and R-15 for 155-180 gr bullets, for a fact my top load in 308 with 208 Match with R-17 did not show nothing different from minus 10c to plus 25c, no accuracy lost, no pressure signs, these powders are tossing away my Varget use... JP.
 
dthunter said:
I have shot Varget extensively for my .308win. In a large temp variation, I have experienced very little velocity variance. May 30-40 fps or less (-15 to +30 celcius).

I have heard of some Varget lot discrepancies though.

Good luck and good shootin!
Click to expand...

I too have used Varget in many temperature extremes. Chrony results vary just a bit in cooler weather. Very stable powder in my experience.
 
I've tested Varget on several occasions by actually heating and cooling the rounds and firing them in a barrel equipped with a pressure sensor. It was extremely temperature stable:

190SMK_Varget_Temp.jpg

Velocity vs. temperature (deg. F)

My money is on the chrony...
 
Dogleg:
What Was your load density like?
Varget in my .308 Winchesters is normally 95% plus. This may aid the Varget to be stable/consistant.

In a 3006 case, I would hazard a guess that the load density is closer to "80%-ish" ?

Its amazing how different load combinations can be between shooters, and still get good performance.

It is a good time to be a shooter/reloader! All kinds of bullets,primers, powders, rifles, scopes....on and on!


CARAMEL:
I will probably give the heavies a try from my .308 this summer. What kind of velocities,S.D and E.S, are you getting with the RL17 and the 208A-Max?
 
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