Vargets response to temp changes

[azhank]

Does anyone have any confirms data regarding the powder performance when the temp increases?

My current data for varget is at 75 and I will be shooting at 105 this week.

 

[azhank]

Re: Vargets response to temp changes

safe to assume that they will shoot hotter?

 

[Paladin2147]

Re: Vargets response to temp changes

Its hard to make generalizations on things like this. What works in your rifle is not mine. Also, primers play a big role in this. Different primers different results. Varget is said to be temp insensitive by the manufacture. What were their parameters for their test? Best bet - work up your own loads. If you can't, I'd stay away from max or near max loads on the chart, and keep your ammo out of the sun.

 

[azhank]

Re: Vargets response to temp changes

My loads are at 45.2 and I will be using the same fed match primers. I was trying to get an idea of what these will be doing. The "safe" range for the powder is 44-47. When I did my ladder the temp was 75 degrees and the final 47gr round showed no signs of over-pressure. Was looking for someone who has fired varget with a 25-30 degree positive change.

 

[kurt]

Re: Vargets response to temp changes

shot it from -10 to 90 with no big change notices in presure but did not run it over a chrony to see if there were and velocity change

 

[Paladin2147]

Re: Vargets response to temp changes

What bullet - or did I miss it? What case?

 

[azhank]

Re: Vargets response to temp changes

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Kurt</div><div class="ubbcode-body">shot it from -10 to 90 with no big change notices in presure but did not run it over a chrony to see if there were and velocity change </div></div>

Thanks kurt.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kolkio</div><div class="ubbcode-body">What bullet - or did I miss it? What case? </div></div>

155gr amax
laupa

 

[Paladin2147]

Re: Vargets response to temp changes

With a 155 you are likely ok. Know that Lapua brass has much less volume than say Winchester. Dump 45 grains of Varget into both cases and you will see a real difference. All said - keep it out of the sun. You should do that anyway. Consider that even without excessive pressure signs, velocity changes will make doping targets a hit or miss affair.

 

[leid]

Re: Vargets response to temp changes

OP,
Hodgdons did propellant temperature stability testing 4 or so years back. They tested MV difference between 0 & 125 degrees F. The 168gr SMK over Varget in a 308 Win measured 8 FPS difference which is extraordinary. Hodgdons data was reformatted and published here but I have not verified this in my rifle: http://www.hodgdon.com/smokeless/extreme/page2.php#top

 

[azhank]

Re: Vargets response to temp changes

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: leid</div><div class="ubbcode-body">OP,
Hodgdons did propellant temperature stability testing 4 or so years back. They tested MV difference between 0 & 125 degrees F. The 168gr SMK over Varget in a 308 Win measured 8 FPS difference which is extraordinary. Hodgdons data was reformatted and published here but I have not verified this in my rifle: http://www.hodgdon.com/smokeless/extreme/page2.php#top </div></div>

wow thank you for the answer. Looks like its a non issue.

 

[kwak]

Re: Vargets response to temp changes

I do not think that you will notice any difference in impact with only a 30 yard difference in distance.

 

[vinsonr]

Re: Vargets response to temp changes

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kwak</div><div class="ubbcode-body">I do not think that you will notice any difference in impact with only a 30 yard difference in distance. </div></div>

Actually it would be about a .2" difference using a Hornady 178 gr BTHP at 2600 fps.

But since your comment was a joke, I'll just chuckle quietly =).

 

[jaycoux]

Re: Vargets response to temp changes

I can verify that, at least from 40 degrees to 100 degrees. Pretty much the same velocity out of my AIAW 308 with lapua brass, ccibr2 primers, 175 grain smk and 43.5 grains varget. No pressure signs noted. I chrono'd loads over an Oehler 35.

Hope that helps.

 

[Deadshot2]

Re: Vargets response to temp changes

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jaycoux</div><div class="ubbcode-body">I can verify that, at least from 40 degrees to 100 degrees. Pretty much the same velocity out of my AIAW 308 with lapua brass, ccibr2 primers, 175 grain smk and 43.5 grains varget. No pressure signs noted. I chrono'd loads over an Oehler 35.

Hope that helps. </div></div>

Ditto here only my "low temp" was in the teens. Only differences I noted were attributable to my heavier clothing or the sweat dripping in my eyes

Also, my chrono was a Pact XP Professional with IR sensors.

I've found Varget to be the most temperature insensitive powder for my use. Even better than Hodgdon's highly touted IMR 8208 XBR.

 

[mkollman74]

Re: Vargets response to temp changes

look up posts by member kombayotch here on the 'hide