Effects of cold during comps?

[broncman]

I set up a reduced f class target to shoot at while chrono'ng some loads. It is in the low 40's. Was trying to simulate exactly how I would do things in a match. My rounds were cold from the outside temps. I was trying to watch the wind, load then shoot.

On three occasions the load set in the chamber for about 30-45 seconds waiting on the wind. These three loads were 20-25 fps faster. I had been shooting pretty fast so chamber was warm.

I chambered one and let it set for the same time. It did warm up a lot from the cold ones in the block on the mat.

Poowder was Varget. Is this normal for cold weather? It may explain some of my velocity differences. I may need to start chambering immediately before shooting?

..

 

[FroggyOne2]

Yes,

When I do my load development, I do it with letting the round sit in the chamber for a lil bit, that way, during match conditions if I have to wait, the cooking of the round will not bother the load.. I kinda shoot slowly most times.
Though I have been known to go fast as well, the main thing though I do in a match is that as soon as I get the empty case out of the chamber, I put the next one in and close the bolt. The round is going to warm up just so much and then table off.

 

[Tozguy]

Cold temperatures will keep your barrel and chamber cooler as well as the ammo. I'm not sure just how well you can translate results from cold temperatures to warm/hotter conditions. I have stopped trying to test or practice when it gets near freezing. It seems to me that if I had to shoot in the cold I would carry my ammo under my jacket to keep it warm, avoid leaving a round too long in the rifle and shoot quickly.

 

[Immike]

Temperature control is a must, I go to great lengths to keep my ammo a consistent temperature. You can throw all your load work out the window if you neglect this. Mike

 

[Cakes]

++ Have to agree with Mike and Donovan. Temp control during a match is critical and I myself won't chamber a round until its time to throw it downrange. I might go 6-7 rounds rapid if the conditions hold and then maybe a lull so that barrel gets quite hot. I also don't let the ammo cook in the sun either during a string. Whatever works and gives you the warm & fuzzy. Eric in DL

 

[Immike]

++ Have to agree with Mike and Donovan. Temp control during a match is critical and I myself won't chamber a round until its time to throw it downrange. I might go 6-7 rounds rapid if the conditions hold and then maybe a lull so that barrel gets quite hot. I also don't let the ammo cook in the sun either during a string. Whatever works and gives you the warm & fuzzy. Eric in DL

I must admit that many things we do is not much more than confidence building. It's seems best to work with medium loads and try to keep the ammo at the temperature your testing was done. I'm sure that Randy's method works by his shooting pace, and any attempts are better than none. We can't control extreme temperature change but can protect ammo from the worst of it. I have witnessed plenty of rifles shoot out of control when the weather went bad ,especially the cold!!! Exposure to the sun will do the trick also. When it's extreme then I put my ammo in a insulated container and try to keep shooting straight. Mike

 

[FroggyOne2]

Yes we do do things differently. I am not saying that it would be the same thing for every load for a particular rifle. But this year, the 223 that I shot, wanted to be hot, wanted the ammo to be hot. Now when it was say 90 and above, I didn't need to cook the round, but if it was 70-75 degrees or lower, yeah, I would shoot slower and cook the round some. Becuase I knew what that rifle and rifle wanted to do. I have done very well with that rifle this year.. won a few and lost a few.. but it sure has been fun doing it. I love shooting that 223, it now has 2200 rounds on it, it still shoots good, but I have no clue for how much longer that would be. So I have retired that barrel.. when the new barrels come in, well then it will be a whole new ballgame and my approach may be intirely different next year.
Mitchell Maxberry once said that powder is a great insillator and in many ways I would have to agree with him. Because of the way I did my shooting through the year, I never once saw elevation issues due to cooking the ammo when the temps were cooler.. when the temps were from 80 - 95 degrees, there were no changes in the performace of the load and the elevation zeros did not shift. This tells me, that at a point, there was a plateu as the effects of the heat and temps on that particular load. In the past I have had used Varget and when it cooked because of a change in the conditions, or having to wait on target repair or what ever, I would have to take 3/4 elevation off to compensate for the cooked round. Now as for the 223, I was using Beger 90VLD's, jammed into the lands. I knew that if I tried to pull that round out, I would get powder all over the place. So I started the season using Varget, once the temps reached 80 degrees I switched to RL15, which is the powder that I really wanted to use. I ended up for the rest of the season using 25 grains of RL15 till the very end when I shot one Fullbore match using 2000MR. I am going to revisit that powder, for that load that I used, pushed the bullet a 150 fps faster over the RL15 load. Some think that I am a speed deamon for loads, no, I am a accuracy deamon, but if the accuracy node just happens to be fast, well then so be it. By the way, that 25 grain load of RL15, velocity was ave 2785 out of a 30 inch barrel.

 

[broncman]

What really brought this to my attention saturday, was I held one if the rounds I was ready to load in my palm while making a scope adjustment and it had condensation on the outside from my warm hand. Really made me wonder if that happens inside a case?

Looks like I need to take the cold days off and process brass!

 

[flatlander]

This thread reminded me of issues I've had with 6 & 6.5x47 in cold (34-40F)temps. I've chrono'd both cartridges in colder temps, and found that ES/SD go up as temps go down, probably more so than with any other cartridge I've worked with. Not much doubt in my mind that this is due to the small primer pocket in a case of medium capacity that's nearly alway loaded with relatively slow powders.

I shot a LR steel match Sat morning using a DTA SRS with a custom 6x47 Lapua barrel, using RL17 with a 105 Hybrid & CCI 450s. Temp started out at 20F, and had risen to at least 40F by the time we'd finished. My elevation come-ups were lower than what Applied Ballistics predicted by at least 1/2 MOA out to 600yds, but I'd used 48F when I printed out my data sheets. As I progressed out past 900yds, it became harder to predict elevation, and I kept missing high or low even when I managed to dope the wind correctly. Not that the rifle wasn't shooting consistently, but my data for that ammo just didn't match the conditions. Looks to me as though investing in a Kestral weather station is going to be manditory if I intend to keep using RL17....the area where this match is held has no cell service, so having the Applied Ballistics app on my droid didn't help much when it comes to adjusting solutions to the conditions.