AMMO SPEED CHANGES WITH THIS WEATHER

[TRSR8]

A test with Center-X I did 7 years ago showed the X did much better being warm than cold. It was about the same time of year as it is now that left a box of X in my refrigerator over night and kept it cold in a small flexible cooler with some dry ice. The other box of X I let acclimate to the ambient temperature (`85°F). The warm X's had an average MV 1107. The cold X's averaged an MV of 1086. While the cold has some effect of slowing the powder burning, I think the bigger effect was what the cold did the the lube on the bullet (a combination of both, most likely). The difference also showed up on targets where the warmer did better than the cold.

Ran the same test at the same time with CCI Standard Velocity and the results were, surprisingly, just the opposite.

Just thought I'd throw this out there. Take it for what it is.

Cold kills match ammo performance….a well known fact a why sanctioned matches are over about now. Too much heat, also a killer. Much below 50 deg is usually a waste.

 

[TRSR8]

In 22lr, humidity, not temp, is your deciding factor.
Normal 50-90 degree temps ammo varies accuracy wise little to none.
Dry low humidity, high damp humidity make the difference regardless of temp.
A damp humid barrel shoots faster as the moisture helps as a lube in a 22lr and a chronograph will confirm this. Temp change swing at eqaul humidity will show little if and change.

A factoid for you. Makes zero difference what temperature/ humidity you shoot, your barrel develops condensation during shooting.
Don’t believe me, shoot any time you want, immediately run a dry patch down bore, touch it to your lips….,behold how wet it is.

 

[VLNBYR]

And what about the other 15 or 20 shooters there at the same time, isn't their ammo affected the same as yours?

 

[dusterdave173]

And what about the other 15 or 20 shooters there at the same time, isn't their ammo affected the same as yours?

yes
Yesterday everyone groaned on the first card
I decided to swap to another ammo I had and for whatever reason it responded well and I went on to success

I just want to try and label what happens and not guess wrong It is the hardest part—seeing and understanding exactly what is what If I react based on a wrong assumption then I just get more in the weeds

Right now I am working hard to understand how conditions/ weather affects ammo performance. I am observing swings in ammo ability and performance with the recent changes in weather.
Good winning ammo suddenly goes to mediocre and other ammo stands up and shines then two weeks later , weather changed ammo wakes up and drills

 

[searcher]

Interesting thread. I was thinking about this argument on shooting temperature affecting accuracy. It brought back memories of my putting engine cases for motorcycles in my oven, while putting bearings to be installed in them into the fridge or freezer. Often times, the bearings would just drop in with no pressing required. Think of the barrel as being the hot element and the bullet the cooler element - or a cold barrel and hot ammo. It is the minute changes in internal and external dimensions at play here. I think when a barrel gets really hot and the accuracy goes to hell, it is automatically dismissed as internal stresses in the barrel at play. Seems logical that if the inside diameter of the barrel is slightly larger due to heating - things are going to behave differently - including the velocity - which might change enough to knock one out of the node? The condensation issue is one I've not heard of before. Now I'm not going to sleep tonight wondering about that....

Got me to thinking a test is in order to set the same ammo at different controlled temperatures (maybe at 20 degree increments?) and firing it, recording the velocities at each temperature setting - with the barrel at the same temperature (the tricky part). This might be a verifiable test of sorts if the barrel was also at the same temperature differential as the ammo? Hmmm.

 

[TRSR8]

Interesting thread. I was thinking about this argument on shooting temperature affecting accuracy. It brought back memories of my putting engine cases for motorcycles in my oven, while putting bearings to be installed in them into the fridge or freezer. Often times, the bearings would just drop in with no pressing required. Think of the barrel as being the hot element and the bullet the cooler element - or a cold barrel and hot ammo. It is the minute changes in internal and external dimensions at play here. I think when a barrel gets really hot and the accuracy goes to hell, it is automatically dismissed as internal stresses in the barrel at play. Seems logical that if the inside diameter of the barrel is slightly larger due to heating - things are going to behave differently - including the velocity - which might change enough to knock one out of the node? The condensation issue is one I've not heard of before. Now I'm not going to sleep tonight wondering about that....

Got me to thinking a test is in order to set the same ammo at different controlled temperatures (maybe at 20 degree increments?) and firing it, recording the velocities at each temperature setting - with the barrel at the same temperature (the tricky part). This might be a verifiable test of sorts if the barrel was also at the same temperature differential as the ammo? Hmmm.

22 barrels shooting match ammo don’t get hot, let alone really hot.
i’ve shot matches of 25 shots + sighters in under 4 minutes….bbl not even warm to the touch.

 

[searcher]

22 barrels shooting match ammo don’t get hot, let alone really hot.
i’ve shot matches of 25 shots + sighters in under 4 minutes….bbl not even warm to the touch.

Agreed. Was thinking center fire.

 

[gunsandgunsmithing]

Actual bbl heat matters very little unless you let a round cook in that hot bbl. Powders are generally a cellulose product, which is a good insulator. They literally make insulation with cellulose. So, it doesn't heat up quickly. It's more about ambient temp, or ammo stored in ambient temps than bbl heat from shooting.

If it were about bbl heat, a cf rifle would never shoot well for more than a few shots, even with a properly stress relieved bbl.

 

[dusterdave173]

Cold kills match ammo performance….a well known fact a why sanctioned matches are over about now. Too much heat, also a killer. Much below 50 deg is usually a waste.

Low 40's and Center X is not happy so I pulled out some Polar Biathlon and it shot very well--I have a match tomorrow early 8 am and it is supposed to be 39 degrees--I am taking 5 lots to include some Polar Biathlon and some very fast SK Long Range that has tested well--we will see if Anything works tomorrow.

 

[Hi-NV Shooter]

Low 40's and Center X is not happy so I pulled out some Polar Biathlon and it shot very well--I have a match tomorrow early 8 am and it is supposed to be 39 degrees--I am taking 5 lots to include some Polar Biathlon and some very fast SK Long Range that has tested well--we will see if Anything works tomorrow.

If I am not mistaken you are shooting factory class so no tuner because of this your approach will be different from a UL shooter and temperature changes will affect how the rifle shoots.
with no ability to set optimum bullet exit with a tuner changing ammo makes sense.

Lee

 

[foxguy]

If I am not mistaken you are shooting factory class so no tuner because of this your approach will be different from a UL shooter and temperature changes will affect how the rifle shoots.
with no ability to set optimum bullet exit with a tuner changing ammo makes sense.

Lee

Lee.

if you would please share how you adjust your tuner (in vs out) as the temperature 1. warms up like 10-15 degrees and/or 2. when the temperature cools 10-15 degrees. Does it take more of a temperature change to effect the group size? Thinking 1-2 clicks would be sufficient? Thanks in advance.

 

[Hi-NV Shooter]

Lee.

if you would please share how you adjust your tuner (in vs out) as the temperature 1. warms up like 10-15 degrees and/or 2. when the temperature cools 10-15 degrees. Does it take more of a temperature change to effect the group size? Thinking 1-2 clicks would be sufficient? Thanks in advance.

Once I find the setting for the barrel/rifle setup I do not touch the tuner
I have one rifle with the tuner set 12 years ago and my current rifle about a year.
I tune in cooler weather so I can get the maximum exit with a more stable burn rate
and lower velocity when temperatures rise I see only POI changes tune is not affected

Lee

 

[Liggett]

Low 40's and Center X is not happy so I pulled out some Polar Biathlon and it shot very well--I have a match tomorrow early 8 am and it is supposed to be 39 degrees--I am taking 5 lots to include some Polar Biathlon and some very fast SK Long Range that has tested well--we will see if Anything works tomorrow.

Be sure to report your impressions after the match!

 

[dusterdave173]

8AM this morning on the bench for first card of Two card Local outdoor match it was 38 degrees! 76% humidity
Man! It was chilly
I had 4 lots on the bench to start--first lot 28 speed Center X did good enough I just started the match with it--at this club we shoot ARA Factory targets--scoring is easy if you nick it -you get it--laid back. Wound up with 15X -- So for second card I loaded up some Polar Biathlon--it started out fantastic but after all was done I got another 15X The winner got 18 so I made second place. As cold as it was I was surprised to do that good-- so then I used my left over sighters to keep testing and All of my Lapua shot really well and would have worked. A very pleasant surprise--
We then shot a two card Budget match where we buy ammo from the club--it is cheapo like Tac 22, CCI etc
I grabbed a box of CCI std and after a good warm up it did OK--shot a 10x for the win

Weather was a challenge--but the usual top shooters all seemed to do great today--There were a few groans but for the most part-- most folks ammo did well. For sure this is a relaxed atmosphere--low stress match--there may be 6-8 in a class with some less / some more--we average about 18 shooters who all try at least two and sometimes three classes--just a good crisp fall morning--having fun with friends!

Had deer and wild turkey all around today.