N 135 Temp. Sensitive ?

[WILLIAM PIPPEN]

Sensitive as in.
Summer is in the 90`s. Fall is mid 70`s. It doesn`t seem to make a difference.
The other day it was mid 40`s. My ammo was cold. My bullets were going all over the place.
It was not a wind problem.
But could have been caused be another ammo issue. I`m thinking that could have caused it.

But I need to cross out cold ammo. If that`s not an issue.
I`m shooting a 6 BR, 68 gr. Bart`s Ultras.

Thanks for the help

 

[urbanrifleman]

Do a temp test.

It only takes 9 rounds, an ice bath, and a hot pack.

 

[Rdlningcltchdmpr]

I had a scope go bad once.

 

[dgeesaman]

I’ve had days when there was no wind and the mirage would periodically boil up and shift the apparent point of aim. It ruins groups.

But I agree to run a temp test. It can be as simple as keeping a few rounds in your shirt pocket under a warm jacket.

 

[Big Mc]

Sensitive as in.
Summer is in the 90`s. Fall is mid 70`s. It doesn`t seem to make a difference.
The other day it was mid 40`s. My ammo was cold. My bullets were going all over the place.
It was not a wind problem.
But could have been caused be another ammo issue. I`m thinking that could have caused it.

But I need to cross out cold ammo. If that`s not an issue.
I`m shooting a 6 BR, 68 gr. Bart`s Ultras.

Thanks for the help

Do you think it might have been a cleaning problem ? My 6br does the same thing wen it needs to be cleaned. Summer and winter.I live in South TEXAS and we really don't have winter. Just my two cents Tommy Mc

 

[urbanrifleman]

Take a big gulp mug and full it with ice and salt. Submerge 3 rounds in a ziplock bag.

Grab a small cooler and add several hot packs after heating in a microwave. Add 3 rounds in a baggie. Cover with a blanket.

Take these and 3 rounds from your pocket to the range.

Fire all over a chronograph. Note velocities.

That will get you about 14 degrees F.
About 75-90 degrees
And about 140 degrees

This will give you the whole range typically tested.

I plan on doing these tests and posting some results soon.

 

[johara1]

Take a big gulp mug and full it with ice and salt. Submerge 3 rounds in a ziplock bag.

Grab a small cooler and add several hot packs after heating in a microwave. Add 3 rounds in a baggie. Cover with a blanket.

Take these and 3 rounds from your pocket to the range.

Fire all over a chronograph. Note velocities.

That will get you about 14 degrees F.
About 75-90 degrees
And about 140 degrees

This will give you the whole range typically tested.

I plan on doing these tests and posting some results soon.

I'm glad you believe that, I saw test with artificial testing like that and isn't even close to real world conditions. You have the gun and shells at 40 degrees and the same at 60 and finally 80 and you will get an eye opener. I sure can back it up also, all powders are temperature sensitive..... jim

 

[urbanrifleman]

I'm glad you believe that, I saw test with artificial testing like that and isn't even close to real world conditions. You have the gun and shells at 40 degrees and the same at 60 and finally 80 and you will get an eye opener. I sure can back it up also, all powders are temperature sensitive..... jim

Yah you keep saying that. I explained your test.

Your test only shows the effect of air density on velocity which changes with temperature. You describe the effect of ambient temperature on velocity, which I agree that 1 deg f per fps is pretty much a fact. And the temp range you tested is so narrow your powder sensitivity is a tiny percentage of the overall change.

TWO DIFFERENT THINGS

 

[johara1]

Yah you keep saying that, but clearly you have no interest in understanding your own test. Or don't understand your own conclusions.

Your test only shows the effect of density on velocity. You describe the effect of ambient temperature on velocity, which I agree that 1 deg f per fps is pretty much a fact. And the temp range you tested is so narrow your powder sensitivity is a tiny percentage of the overall change.

TWO DIFFERENT THINGS

The only thing I'm interested in is the velocity and group size at that temperature and what I have to do to obtain the end result is to win. Your dribble means nothing to accomplish this. It is useless for long range shooting because the gun and ammo are at the same temperatures and I test at that temperature to get true results...jim

 

[JimPag]

I have found that all the VV powders that I use in my bench rifles, (120, 130, 133 & 135) to be temp sensitive when shooting up here in Maine in the winter. When it's warm up here I have to back off on the loads.

 

[urbanrifleman]

The only thing I'm interested in is the velocity and group size at that temperature and what I have to do to obtain the end result is to win. Your dribble means nothing to accomplish this. It is useless for long range shooting because the gun and ammo are at the same temperatures and I test at that temperature to get true results...jim

Haha.

Ok man. You win. Apparently, ALL "long range shooting" happens between 40 and 80 degrees on your range or wherever you happen to be shooting at the time.

My goodness....

 

[urbanrifleman]

I dribble pretty good for a white guy.

 

[jimmymac]

I dribble pretty good for a white guy.

But can you dunk?

 

[urbanrifleman]

But can you dunk?

Only a donut

 

[jimmymac]

LMAO... Me too.

 

[johara1]

Haha.

Ok man. You win. Apparently, ALL "long range shooting" happens between 40 and 80 degrees on your range or wherever you happen to be shooting at the time.

My goodness....

No, not hardly but what i saw from those numbers was a 1fps loss per degree. So from 60 degrees to 40 degrees it dropped 20 feet a second. The test on an other thread with artificial cooling and heating they were getting less than that over 80 degree span and that is not even close to the truth... You have to shoot groups to get to the tune. Then you know what takes for that powder to work at that temperature. You will find that from 60 to 80 range they are better but when you extremes at each end it gets worse and the cold is the big one..... jim

 

[urbanrifleman]

No, not hardly but what i saw from those numbers was a 1fps loss per degree. So from 60 degrees to 40 degrees it dropped 20 feet a second. The test on an other thread with artificial cooling and heating they were getting less than that over 80 degree span and that is not even close to the truth... You have to shoot groups to get to the tune. Then you know what takes for that powder to work at that temperature. You will find that from 60 to 80 range they are better but when you extremes at each end it gets worse and the cold is the big one..... jim

Last time I will say this. And I mean this in the most genuine way. I will not belabor the point after this. And you can choose to believe whatever you want.

You are talking about two different things and calling them both "powder temp sensitivity".

What you are describing is AMBIENT air temperature velocity effect. This is the effect of the density of the air slowing the bullet down as density increases as the temperature drops.

This is about 1 fps per degree F of ambient temperature. Within the range you defined the effect is nearly 100 percent the air density effect and not the powder.

This velocity change will be very linear within the very mild conditions you describe. However, once you go above 80 into 100 degrees plus the effect will become non linear and velocity and pressure will begin to spike if using a temperature sensitive powder because the effect of the powder becomes coupled to the ambient air density effect.

If you shoot between 40 and 80 degrees all powders will appear the same as nearly all of them are pretty flat in that temperature range.

 

[johara1]

This the last, those were the latest, As I said at the at the extreme ends cold or hot and I have shot at 99 with the humidity the same also shot at 40 so what ever you want to call it doesn't mean anything to me, the only thing that does is group size and how many tenths I have to add or take out to get in tune. The end result is all powder is temperature sensitive...... jim