Winter vs summer velocity

[thorn653]

I was experimenting today trying to get better numbers with Lil Gun, Hornady 110 gr V-Max with OAL of 2.040".
My winter time load was as follows:
Hornady 110 gr V-Max, OAL 2.050, 19 gr Lil Gun, Velocity 12.5" bbl - 2263 FPS, ES 65, SD 26 (Pathetic numbers I know, that why I was working on new loads)
Now the weird part.
Here's the load I was using today. About 85 degrees out today.
Hornady 110 gr V-Max, OAL 2.040, 19.4 gr Lil Gun, Velocity 12.5" bbl - 2109 FPS, ES 98, SD 42 (Holy crap! Way worse numbers in summertime)

Can someone clue me into to why this is happening?
Should I develop and test loads in the middle of summer?

[bangbangping]

You should develop and test loads with a different powder.

IMO, 110 grain bullets call for H110 powder. And magnum primers.

[rebel]

Lil gun has been reported to get weird as it gets cooler. Get it cool enough and it gets primer popping weird reportedly. I stay away from it. H110, W296, 300 MP are all decent powders for supers. The VV offerings I have only used with subs. 2400 is another I haven't tried but the possibilities go on and on.

[dellet]

In short yes, but too many variables.

My winter/summer temps can vary 125+ degrees, more if I travel.

In your case there is no way to tell. Basically a 1/2 grain of powder can make a lot of changes in a load.

Without complete load data and temps, about all anyone can say is, "you need to refine those loads." That will likely be the answer anyway, but something else might jump out.

[thorn653]

Okay, thanks for the replies.
So do any of you have ES and SD numbers with powders other than little gun and 110 gr V-Max?
I'm just trying to get an idea of what to shoot for.
And at what point in the ES and SD numbers is it getting dangerous?
The worst numbers I've gotten so far have been with the Lil Gun and 110 gr V-Max, it has had me a bit worried.
I'd like to use these bullets for HD and a bit of varmint shooting because their relatively cheap for .308 bullets.

[rebel]

A chronograph is a great tool, and it's good to pay attention to velocity swings (ES). However, I let my brass and the signs of excess pressure be the determining factor. No chrony is fool proof.