Question -Temperature AFFECT on ammo

R

RegisG

Guest
How much temperature change does it take to seriously affect ammo accuracy?
Do you have lots for different tmes of the year?
At the 1st PSL, I tested a number of lots in the barn and temp was 20's-30's and found an Eley 1058 that was perfect. Then, the afternoon before the match and day of match the temp was in the 60's and the 1058 opened up. I scrambled and found a little better one but really not enough time to find the equal or best.

So, my real question is do I need to find different lots that shoot at different temps (e.g. 50, or 70 or 90 degrees)? Or, is it just that near freezing shoots different than warm? Or is it more realistic to find a lot that shoots through all temps (ideal I would think)? I do discount a few shots to get barrel up to temp.


Thanks for helping us new folk,,,,,even if we'r epretty old (ha ha)
Regis
 
I would say sometimes you need to find different ammos. I have an Eley Match lot #1324 that pretty much shoots the same no matter what. I have a Tenex lot that's the same way. But I have one Eley Match lot that shoots great down to about 52 degrees and then it's like turning off a switch and it's that specific too. I had a 1081 fps that was great in hot weather but only shot to about 70 degress then it was gone. To some degree I think it's the DA effect, but that doesn't explain why some ammo will shoot through any temp.
 
Regis, it might be an ammo issue, it might be a gun issue. Some guns just want something different at 85deg than what works at 60deg. Outside is likely to be different than inside, all you can do is test and practice with a couple variables.
 
Well, I was hoping for something more difinitive but, sound like I better hang on to that 1058 for another day rather than use it for warm-up. Just another reason to keep a log every time I shoot.

Thanks,
regis
 
I don't know George. Some people seem to claim that, but I never click the tuner. Mine is locked down.
 
What I have found

Is what most are saying. I try to have about 2 to 3 different lots when I shoot in matches now. I started one comp last year with 1059 in the morning ( temp around 60) then as the day started to heat up ( to around 84) the groups opened so I changed up to 1065 with only a slight change to the tuner. It was strange cause I tried changing the tuner with the 1059 but could not get it to shoot as well as it did in the morning. By the late noon the temps dropped and the 1065 opened up so I changed back to 1059 and put the tuner back to it's ( the 1059's) setting. I managed 3rd place overall. To say the least I was blown away from what happened during the day. It was the first time that I had some different Vel lots with me.
Cheers
 
Guys, I'm probably stepping in it with this, but I just could not resist responding to this thread. For over twenty years, I have been a centerfire group shooter. Only in the past four years have I been dabbling in rimfire accuracy. I can tell you exactly what causes your rimfire to go out of tune and why one lot of ammo shoots lights out one day and will not shoot the next. It's changes in air density due to variations in outside air temp!

Yes, I know, many experts dissagree but it's true; just as sure as night follows day. Rather than chase the tune with different lots and brands of ammo, install a GOOD barrel tuner and learn how to use it to compensate for changes in air density/temp. It's as simple as it can be.

The subject of barrel tuners is a big mystery to most; many do not realize that the tuner must be adjusted to compensate for changes in temperature. Let's say your rifle shoots lights out in the morning when temp is 60 degrees F. If you do not adjust the tuner to compensate for increases in temp, your rifle will be completely out of tune when the temp reaches 80 degrees. If you are unwilling to adjust your tuner, you might as well not have one.

I don't have time to explain it all on this forum; I have work to do, but if you will come out to Odessa, Texas and take some training at the tunnel facility, I can show you how to use a tuner in a short period of time with no interference from wind. You can shoot one of my rifles built on the Turbo action using Shilen barrels with a Beggs tuner and Ultralite stock. If you're not happy with what you learn, you owe me nothing. That's about the best, I can do.

Later

Gene Beggs
 
Gene, I followed your tuner odyssey closley on the centerfire board, did you come up with a different style tuner for rimfire, or do you use your centerfire tuner and method? Thanks, Douglas
 
I believe rifles like Lots, not Speeds. They may prefer a certain speed range, but they are going to either like or dislike Lots, regardless of the speed.

I think it's the miniscule differences in components, production environment, or whatever it is, that vary from Lot to Lot either peacefully coexist with a rifle, or they don't.

Once a Lot has been found that is at peace with the rifle, I believe tuning is all that is necessary to adapt to changes in the environment.

I can't provide any scientific evidence, but common sense tells me that atmoshperic changes are going to influence the priming compound and powder of any bullet. It just seems logical to me that as the temperature goes up or down, those combustionable parts are going to react differently.

As the reaction changes, the barrel vibration caused from that reaction would logically seem to have to change as well. While there may still be a peaceful coexistence with the Lot, the weight and tuner setting used to control the previous vibration would now seem to be mismatched.

Changing speeds to control vibration is certainly an option for those with the time and resources to evaluate multiple lots across the speed spectrum in multiple conditions to find more than one peaceful match.

Another option is to leverage the advantage a peaceful Lot can offer and use the tuner and weights to manage the vibration.

Either way, it takes time. But for me, sitting at the range, throwing lead at paper, is still fun, so I don't mind the effort.
 
Temp & Tuner

I had Todd Taylor,the SE Ohio Smith make a tuner.
My idea was to be able to "do" that click or two as the temp would
raise. To me that is what a tuner is for.
I have friends that do the ammo change also.
Which,I do too.
To me the "tuner is to be used to keep the rifle in tune.
Todd Taylor stocks Lilja barrels had several profiles.I know one of his rifles
shot about 53 straight 250's last summer.
Todd does good or reallly very good work
toddtaylor1040@yahoo.com SE Ohio Smith
:):)
 
Don't know if ISSF shooting has any relevance, but hereabouts, where temperatures vary quite a bit & our shooting sheds & car trunks can get oven hot, we all carry our ammo in picnic coolers to keep them at a useful temperature. I can't justify it by experimentation, but I'd be inclined to take a bet that ammo won't heat up enough for it to be an issue while you're shooting a string.

On the other hand, we far too regularly read about children & pets perishing when left in a closed vehicle in hot sunny conditions. Our government authorities tell us that a car can get to 60-80 degrees celsius at such a time, which equates to 140-175 in US currency. I'd about guarantee that that heat would bugger up the best load that money could buy.
 
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