Just after I thought I had my load all worked out for my .30-06, I thought I better check it in cooler weather, it was 26 deg this morning!

Going from 60 deg. F to 29 deg I went from 2900 fps to 2770 using RL17! That's too much for a powder I thought was supposed to be good in various temps. Is anyone else seeing the same thing - or did I just have a bad day? JB had similar or worse results with I4350, so I am not inclined to go that route, I didn't get the velocity I was looking for with H4350, and the accuracy wasn't great with Big Game (and I don't think BG is that temp stable either - anyone tested it?)

By contrast my .338 Fed went from 2775 to 2735 in the same temps using I8208 not great but I can live with that.

Thoughts from anyone else that has actually done some cold weather testing?

I have not noticed RL17 being temp sensitive the most I seen it loose was 50fps. I tested it in the 257bob, 270win, 6.5x284, 280AI, 7-08AI, 7saum, and 243win. velocity loss was between 30-50fps in all cartridges tested. Seeing 130fps is really surprising to me.

I've shot R17, H4350 and H4831sc in temps ranging from below zero up to about 90F.
Didn't use a Chrony everytime but shot out to 400 or more yards as I'm more interested in POI shift rather than actual velocity loss.

For hunting purposes out to 400 yards in temps ranging from 10-90F I wouldn't worry as I didn't see much if any difference in POI. When temps did get colder than 10F accuracy went to hell in a couple rifles.

Thats because colder than 10F, you are friggin cold and shaking like a dog schitting a rusty razor blade!

RL 17 is supposed to be temp resistant, but it's apparently not working out for you, but try your test again to confirm.

2900 is a somewhat standard loading with H-4350, so I would take a second look at that powder as well.

Fed 215s might not be a bad idea in cold weather either.

TC

According to Hodgdon, Reloder and IMR are very temperature sensitive. H4350 would likely be your best bet. See this link:

Temperature Sensitivity

Temperature sensitivity also depends on the cartridge, bullet and pressure--just like burning rate.

In other words, some combos will show more temp-sensitivity than others, yet another reason to test YOUR load to make sure what's happening.

I am loading tonight - I am wondering if my chronograph was off, the sun was low in the morning and it seemed a bit jumpy. If the cold weather holds I am trying some cci br2, and fed GM mag primers to see if that helps. I have been running fed GM standard primers. I'll report back.

Just got back - appears it was an earlier chronograph problem. Here is the data from today - certainly not enough to draw conclusions, but interesting none the less. 35 deg F, 6-12 mph gusty wind, 5 shot groups, 110 yds. I believe the gun is 1" with stuff it likes, the shooter never has proven to be in the 1/2" class. All data is RL 17, Nosler brass, 3.27" OAL.

59.3 g
Fed GM
AVG 2910 fps
SD 16
Group 1.3"

59.0 g
Fed GM
AVG 2909
SD 6
Group 1.4"

59.0 g
CCI BR 2
AVG 2871
SD 31
Group 1.6"

59.0 g
Fed GM Mag
AVG 2900
SD 3
Group .9

Those Gold Medal Mag primers might have some promise!

I was going to suggest chrono and sun angle. I had the same thing happen to me two days ago. I set up at dawn. Range faces north. At first no readings then around 7:30 I got some...the pet load for my 30" barreled 7 rem mag with moly'ed 140 accubond is 3400 fps @ 80 degrees. I got readings of 3300 FPS!!!! Another hour later it was up to 3375 which would be right for 55 degrees.