SK Match BIG temperature effects?

[jlow]

I was out shooting recently in the cold with some SK Match I had brought back in 2014. This is out of Volquartsen Fusion 10/22 and had some problems.

Back in 2014 during summer, I have checked MV using a Oehler 35p with a 4’ rail and confirmed that MV was around 1065 fps. Back then, using this number and a ballistic calculator, I was able to get rounds on target at 200 yards with a DOPE of 7.5 Mil (50 yard zero).

This week, I tried the same thing at temperature closer to 30degree. No rounds on paper using the 7.5 Mil DOPE….. I keep dialing up and managed to get center hits with a DOPE of 9.5 Mil. Checked MV with a LabRadar set on doppler and got an average MV of 970 fps.

With the Ballistic calculator the significant increase in DOPE is about correct with the drop in MV. Has anybody seen anything like this?

 

[moondog]

Every time I shoot 22!
Cool temps in the morning, get everything trued up out to 220. By early afternoon you better take 3 10ths out or your going over.
I see a different Chrony used since last time out too. 22s are super sensitive to temp difference especially at distance. 970 fps does seem a bit low though.

 

[jlow]

Yes, there was a chrony change. The Ohler 35P was the gold standard back in 2014, I've since upgraded to the new gold standard which is the Labradar. Both are very accurate and is the best you can buy and will not be responsible for giving you bad information.

It was cold, temps in the high 20s...

 

[Delfuego]

Of course! It's not just the temp and velocity, it's also environmental. (Baro/DA/Etc). Shoot the same ammo at sunrise and 4pm on the same day and you will be over the target.

Keep your ammo in the car with you on cold mornings

 

[Lesloan]

I can't quantify it, but my accuracy seems to drop off somewhere around 40 deg. F. So now I keep my ammo in my "hot box" when shooting in the cold. This is an empty Lapua box that once held 500 6mm bullets, with a folded microfiber cloth in the bottom and 2 "Hot Hands" handwarmers for heat. Seems to help.

 

[topclass2017]

22LR is notorious for being cold weather finicky. Polar or Biathlon rounds are typically closer to 340m/s vs standard velocity of 320m/s. when I was shooting silhouette in cold weather (under 35*) I kept my ammo in a plastic tupperware type box that I sat on top of one of those disposable hand warmers in my range bag. If I didn't I could expect an additional 2-3" of drop at 100m dues to diminished velocity.

 

[Dusty Stevens]

Is it the wax causing the irregularities?

 

[Sieg]

Is it the wax causing the irregularities?

Good question.

Our monthly year round matches the temps range from high 20* temps to 90*. Wintertime vertical strings will drive you nuts and your flags don't come close to explaining/justifying 2-4" high or low of POI variances at 200yds.

Oddly, I've found CCI SV will hold it's own or better against Lapua/SK during the winter.... target scores don't lie.

I have a Magneto Speed V3 with MK Machining stand alone mount coming to hopefully help explain some of the rimfire lunacy. Taking it a step further, I'm signed up to upgrade to Vudoo's newest generation of fire control to possibly eliminate another rimfire unknown variable.