Sporter barrel and heat

[Pdvdh]

Now we're into Voodoo...
Just keep the water out of the bore.

 

[Predator 22]

I also hate waiting for a barrel to cool. I live in S. Az. where it is hot for months at a time.

I use a 20 lb tank of CO2 with a ball valve attached for modulating the flow. A 3/8" diameter rubber hose with tapered tip is pushed into the chamber. Low flow for 20 seconds or so will bring it down to ambient for more testing. I can shorten a load development session from hours down to 1/2 hour or less.

I shoot two and cool. I agree with Rich to only shoot no more than two shots at a time.
A local gunsmith, Dave Miller, will shoot one shot then cool to ambient for testing his hunting loads.

Do you think there could be any side effects of cooling your barrel down that fast with Co2?

 

[Dosh]

Slightly off topic, but related... Anyone ever notice adverse affects on a barrel due to water, air or any other cooling technique other than naturally cooling? My impatience shows at the range waiting for a barrel to cool

Several years ago saw a guy at the range fire about a dozen 30-06 rounds, reach in a ice chest and throw a icy wet towel on the barrel! IMO that was a bit extreme. We're not quenching horse shoes here, just getting a barrel back to ambient. The air mattress pump does this in a few minutes.

 

[AZShooter]

I have been using the CO2 for over ten years with no ill effects. While I try for ambient I did do some over cooling to see how it affected POI or accuracy and it didn't affect anything with the bull barreled 30 BR I used. Never tried cooling the ammo with the system for a winter conditions type test.

I have three other friends that also use the CO2 system.

IMO a 20 lb tank is minimum as anything smaller will not have the amount of liquid CO2 for sufficient expansion and resultant cooling. I know because one friend used a 5 lb tank and it didn't work. Perhaps someone can buy a 10 lb tank and let us know?

While it does cost to own the tank which gets rotated at the welding supply store there is no need for a regulator. A ball valve works just fine. It costs around $22 to fill at tank. If used for load development or occasional cooling it will last for many range sessions.

 

[Rich Coyle]

How do you know when it is cooled enough? Do you use an infrared thermometer?

 

[AZShooter]

Hi Rich,

I did use an infra red gun and a thermocouple device that was on my multimeter. Now I just feel the scope body temp vs the barrel's. When the barrel starts to cool I stop. It will continue to cool for a bit then stabilize. I feel it is best to try and sight in and test loads close to ambient but I don't believe it has to be perfect.

As a side note, some guys have come over to ask what I was doing. One guy asked if I was using oxygen. Said sure! I hate this barrel and am trying to accelerate the throat erosion by introducing oxygen.

 

[Kimber7man]

I've owned rifles from both GA Precision (GAP) and Beanland, built with medium sporter contour barrels - Rock Creek 3 contour and Bartlein 3 contour and also 2b contour.
All of them would hold 10 shots within 1 MOA without flyers or walking due to hot barrel.
A great gunsmith makes a world of difference sometimes...

 

[Rich Coyle]

May I take us on a side track. AZShooter statement about oxygen reminded me of a time when I was helping a "mill wright". He was trying to get a failed bearing off a shaft and had heated it with a cutting torch. He still couldn't get it to move. I foolishly suggested he go get the propane tank off the forklift. We could spray the shaft and it would shrink away from the bearing. He started to get up to go get it. I couldn't stop him fast enough. I informed him, "If you did that we and this whole block would be gone in a flash!"

Some folks just don't understand jokes or real life.

 

[Barrelnut]

I've owned rifles from both GA Precision (GAP) and Beanland, built with medium sporter contour barrels - Rock Creek 3 contour and Bartlein 3 contour and also 2b contour.
All of them would hold 10 shots within 1 MOA without flyers or walking due to hot barrel.
A great gunsmith makes a world of difference sometimes...

In the above case, I believe, the accuracy is due to vastly superior barrels. The Rock Creeks and Bartlein are cut rifled, the Bergaras are button rifled.

 

[Joefrazell]

Well I think it's actually a different issue. Went back out sunday and the poi was all over the board. Took the gun home took the action out of the stock sprayed the stock down with some cooking spray and cleaned the action. Then I carefully installed the action and it's getting very little contact in the recoil lug and front pad area. I'm pretty sure it's causing shifts.

 

[AZShooter]

Dang Joe!

All this talk of barrel heat and it wasn't the issue!

Hope you get the issue resolved.

 

[WildRose]

Took my wife's rifle out to see how some factory ammo would shoot. It's a bergara b14 hunter in 30-06. Shot the barnes vor-tx 168 gr. 1st 3 shot group .777 moa. Let barrel cool for over an hour while shooting other guns. Brought it back out and dialed the scope to zero. Leopold vx3i 4.5-14 30mm cds. 2nd group .931 moa again 3 shots. Barrel was very hot after 3 shots as its 100 degrees outside. I needed to come over just about .5" so I did and decided to take another shot to make sure it was on for hunting and the shot was 1" high and so I shot 1 more and it was right there with the last one .7" to the right. My question is is it normal to shoot high with a hot barrel? I didn't shoot another just because it was too hot. Anyways these bullets shoot well. Way better then my handloads so far lol. I was tired of trying and we're to close to season.

Joe a hot barrel can be off in any direction or leave you even chasing rounds in circles as they get hotter.

Best advise would be to check it again when it's cooler and even better under the same temp conditions you expect to be hunting in.

I will always at least attempt to verify my zero again before taking one to the field.

 

[WildRose]

How do you know when it is cooled enough? Do you use an infrared thermometer?

Touch.

 

[WildRose]

Well I think it's actually a different issue. Went back out sunday and the poi was all over the board. Took the gun home took the action out of the stock sprayed the stock down with some cooking spray and cleaned the action. Then I carefully installed the action and it's getting very little contact in the recoil lug and front pad area. I'm pretty sure it's causing shifts.

Time for a little bedding then.