Range Report Optimal barrel temperature?

[Bob 964]

Just read an article on AccurateShooter.com about using a pocket infrared thermometer to monitor barrel heat. The article explains what happens when your barrel gets too hot, but fails to define "too hot."

My question to anyone who uses an infrared thermometer to monitor barrel temperature is: What temperature or range of temperatures do you use to determine whether your barrel is too hot?

Thanks
Bob

PS - my gun is a Savage 110FP with 24" heavy barrel.

 

[kraigWY]

Re: Optimal barrel temperature?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> anyone who uses an infrared thermometer to monitor barrel temperature is</div></div>

I played with one a bit, mainly to see what happens to my Win Model 70 Featherweight.

Started out measuring the temp before I started, it was 86* if I remember right. Shot 10 rounds as fast as I could and got the temp, just a head of the chamber to 146*.

Didn't really affect the groups of the pencil barrel like I thought it would.

Got to playing with ammo, shooting some that had been in the shade of my shooting stool and compared it with the ammo that had been laying in the hot sun. (forgot the temp difference of the too but it was substanual. The ammo affected groups more.

Next I'm going to play around with the time difference a round sets in a hot chamber before you shoot it. I think that will make more difference.

 

[Bob 964]

Re: Optimal barrel temperature?

Thanks Kraig. So... you saw more significant performance differences resulting from ammo temperature than from barrel temperature? Did hotter temperature ammo perform better or worse?

 

[kraigWY]

Re: Optimal barrel temperature?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Did hotter temperature ammo perform better or worse?</div></div>

The hotter temps made for poor consistancy. The next time I play with this I'm gonna do it over a chrony.

I first noticed the in consistancy when I was coaching my NG Rifle Team. Those who let the round set in the chamber a while had vertical groupings. Those who let the bolt slam forward the instant before they fired had less problems.

I also want to compare the difference between my Featherweight barrels with my Mann device. My 5.56 Mann has a 1 1/4 inch barrel. Takes a lot to heat up that puppy.

I have a couple CMP clinics I'm putting on, when I get them out of the way I want to play with heating up rounds with different powders and see what happens.

Those little Laser Temp gages are fun to play with.

As a side note, I found I can tell whats going on better using ISU Small Bore targets shooting one round per bull as oppose to shooting groups.

 

[Mister Ouchie]

Re: Optimal barrel temperature?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">
I first noticed the in consistancy when I was coaching my NG Rifle Team. Those who let the round set in the chamber a while had vertical groupings. Those who let the bolt slam forward the instant before they fired had less problems.
</div></div>

That is a great observation. Makes a lot of sense.

 

[Bob 964]

Re: Optimal barrel temperature?

Neconos.com offers Bar-L Benchrest strips that visually display heat readings. These are adhesive-backed strips that stick to the side of your barrel and indicate the barrel's temperature.

What I found interesting is the "Benchrest" strip, that reads temperatures from 86 degrees to 140 degrees. There is also a “General Purpose” strip that reads to 196 degrees.

This suggests that 86 - 140 degrees may be the acceptable range for load development & target shooting. Neconos provides no empirical data or studies to support the use of 86 - 140 degrees, but it is the only thing I have found that addresses my original question.

I should receive my pocket infrared thermometer in the next few days and I will use it to "test" the 86 - 140 degree range when I go to the range next week.

I think Kraig is right about the significance of cartridge temperature. I have read a couple of articles that show how pressure increases as cartridge temperature increases, which in turn causes your POI to "walk." Thanks everyone for your input.

Bob