Barrel Cool device

Get or give advice on equipment, reloading and other technical issues.

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Barrel Cool device

#1 Postby DenisA » Sat Dec 24, 2016 12:18 am

Only just found this on the net. What a great gizmo. Would be very handy and save time when load testing if your like me and don't like running your barrel past warm.

It says it's used by the US F-Open team.

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Re: Barrel Cool device

#2 Postby williada » Sat Dec 24, 2016 9:16 am

Great find Dennis. It would help in load development as you have found we wait a minimum of 45 seconds between shots doing this to preserve the barrel but also to find weaknesses in the barrel's heating and cooling process.

I also like the heat strips for determining barrel temperature. In testing we used to point the infra temperature gun at the barrel and take readings. These would be great for future practice when determining a rhythm suited to a range of barrel temperature which produces tightest groups. Remember, heat will reduce vibration. Not so much a problem in stiff barrels, but if you are relying on harmonics for a nodal tune and its associate the compensation tune you will find best groups occur at the operating temperature the barrel likes. :D Have a Merry Xmas. David

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Re: Barrel Cool device

#3 Postby ShaneG » Sat Dec 24, 2016 10:41 am

Hi Denis

I replied to your post on FB but thought worth repeating here.
Bought a couple and used them in the trip we recently did to US in Sept + Oct.

Couple of brief points

1. heavy on batteries - nor sure as i left them there but recall CR123 so expensive. will look to rechargeable next trip?
2. aids cooling but not a great deal [it is a tiny fan] - would extend barrel life a little? but at battery expense?
3. tube can detach itself and be a hassle to remove from chamber.
4. In US empty chamber indicators are used instead of removing the bolt - thus these serve as ECI also.
5. Most useful after a 20 round relay - gut feel they may reduce cool down time by 25%?

Guys over there also use wet towels from ice boxes draped around barrel to bring down high temps.

Merry Xmas everyone

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Re: Barrel Cool device

#4 Postby Razer » Sat Dec 24, 2016 11:28 am

I have two 16 flute barrels made by Denis Tobler.
They look a bit like a elongated cog as the grooves are quite deep.
I have never seen flutes barrels like these before but one has over 9000 rounds of .308 down it, has never heated up as even on hot days when touching an unfired barrel left in the sun would burn your hand, this barrel is still cool after being fired.
Accuracy? It Was last fired competitively at Mudgee OPM about 3 years ago by my son who is a B grade TR shooter(only because he doesn't travel much at all and has now 'retired ' to raise a family).
Took the second place in the first days open aggregate against Oz shooters who are top international shooters, and, after dropping only one shot in the second day came in 6th overall.(nothing fancy used either, just HBC projectiles, Winchester cases on about 40th reload and CCI primers and some 2208!
This barrel still cleans up easily and internally rifling looks like new.
Heavy profile barrels obviously take longer to heat up so are an advantage in maintaining a constant temperature during the stage, but, ambient temperature is going to be more variable depending on where one shoots and affects the starting temperature. What shoots well on a cold day could well be the dead opposite on a hot day?
Allowing for throat erosion and the need to rechamber in many FO calibres, just how much longer would deep fluting extend barrel life?
There is a rather steep cost to flute a barrel such as these two are, but how many extra shots could one expect from an FO barrel as these flutes seem highly efficient at maintaining low even temperatures which are essential for longevity?
Just asking.

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Re: Barrel Cool device

#5 Postby DenisA » Sat Dec 24, 2016 12:11 pm

The benefit that appeals to me mostly is the assistance in barrel cooling in load testing session which can commonly see 40 - 60 rounds and more through a barrel in a short period of time. Seeing as I don't let the barrel get hot, I'll commonly spend half a day at the range doing that alone. If it saved me an hour per session, for the price, I'd be overwhelmed.

The reason I like to keep the barrel only warm isn't for barrel wear but shot consistency. I hate the idea of mis-interpreting a false result when trying to analyse groups/nodes.

Rechargeable batteries sounds like a good idea and glueing the tube on wouldn't be an issue either.

I think a small fan and mild air flow might be a good idea. I imagine some faster methods that try to cool a barrel too quickly might cause some non-uniform contraction of the steel at ill effect.

For the price I'm going to try them.

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Re: Barrel Cool device

#6 Postby williada » Sat Dec 24, 2016 3:26 pm

Ray, Dennis made some excellent gear. Top fluted barrels work well. They are stiffer because they enable a bigger diameter for the same weight and can dissipate heat but can heat and cool quickly which may not be stable. May I digress to enlighten fellow shooters. Unless the fluting is perfect we get shots that walk. I am reminded of a TR team that went to South Africa and it beggars me why some did not test their new gear to get them past the hump to pick up flaws, but suffice it to say a barrel or two walked on the target during the competition as they heated up. The barrels in question were subsequently examined to find there was an uneven flute. To a casual observer, you would miss it.

When subjecting barrels to a bit of a delay we are also looking for barrels that may walk a little bit due to poor heat treatment or where on rare occasions, the blank cut from a long billet came from a section where the forklift or rough handling bent it. Often barrel steel did not match the certification that came with it in my experience. In the old days when barrels were straightened they did walk on heat up at the pressure points in the straightening process. The other problem came from people using the wrong rake (negative v positive) on the cutting tool when profiling the blank which heats things in an uncontrolled manner. Then you add to the mix varying cuts at the ends of the blank when the barrel is being turned between centres which can be misplaced and in the middle where the barrel may flex out on old equipment with poor cooling. This may also lead to bowed barrels or in some cases variable wall thickness at points in its length. Usually by trainees. Not a problem with the CNC stuff modern barrel makers use. It worries me if armourers profile a blank without proper training. Better armourers run with the natural bend and position that in the vertical plane when fitting to the action.

The other important thing is when you are breaking in a green barrel it is softer and needs to work harden, particularly stainless. You don't want hot loads going through this until the barrel is broken in and this is not just the reamer marks in the throat which catch copper. It is fully broken in when velocities stop increasing at the hump point. That is why load development should be done with trend tests initially over a chronograph working up in single incremental loads to find flat spots for further charge and primer testing then doing seating depth testing etc. The wear pattern is more stable when the barrel is past the velocity hump when new and as such, its a good idea to have a time delay or cool it like Denis is suggesting.

With regards to barrel life there are two areas where wear takes place, one is at the throat and the other is a few inches behind the muzzle and up to the muzzle. The hotter the barrel is, the more inclined it is to wear at the throat. The wear at the muzzle end is not just cleaning rod pull back but it is a place where hot gases come out of a plasma state like precipitation of rain and tend to drop residues which are abrasive.

Of greatest importance is how often you nip the chamber up and by how much because you do change the harmonic length doing that which is measurable in FO barrels on the small targets compared to the .308 and bigger targets of a few years ago. Barrels do differ in steel hardness and composition; and some of the over-bore stuff used in FO would make it hard to identify how much wear will take place. That needs to be followed up as you go with a bore-scope and a chamber cast. David.

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Re: Barrel Cool device

#7 Postby dave » Sat Dec 24, 2016 8:46 pm

in the central west of nsw (and I am sure many other areas), during summer especially, it is quite common for direct sunlight and the ambient temperature to make barrels quite warm to touch before a shot is fired.

even with HV varmint taper and parallel barrels it only requires a few rounds to make them too hot to touch, especially in the region 4-6 inches in front of the throat.

we have found that once heated, the use of a 12volt car vacuum or inflatable pool air pump adapted to either suck or blow air through a barrel ( sucking seems to be slighter better), regardless of barrel weight or contour takes excessive time to reduce temperature to any significant extent.

external barrel temp can be monitored with the following dick smith digital temp gauge, or internally with an extension thermometer lance.


usually in the warmer months a strong breeze seems to make the most effective temperature reduction method, due to the much larger surface area of the outside of the barrel when compared to the very small internal surface area of the chamber and bore.

we have found the best compromise in this area for the warmer months is to shoot on the late afternoon, weather and conditions permitting.

dave g

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Re: Barrel Cool device

#8 Postby plumbs7 » Sat Dec 24, 2016 9:53 pm

Slightly off topic and this maybe where a .284 may have an advantage! Is how are the Saums and mags going to handle 20 shots matches in 30 deg heat next year ? We have only 10 - 15 shot matches so far !

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Re: Barrel Cool device

#9 Postby willow » Sun Dec 25, 2016 10:22 am

DenisA wrote:Only just found this on the net. What a great gizmo. Would be very handy and save time when load testing if your like me and don't like running your barrel past warm.

It says it's used by the US F-Open team.

I have one and like it. It's coming in handy at this time of year. Cost me about $110 landed, so not cheap.

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Re: Barrel Cool device

#10 Postby williada » Mon Dec 26, 2016 10:14 am

Good info Dave.

Graham, I think you know the answer. :wink: The charge test will show heat problems. Can be very barrel specific. David.

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Re: Barrel Cool device

#11 Postby plumbs7 » Tue Dec 27, 2016 8:18 pm

williada wrote:Good info Dave.

Graham, I think you know the answer. :wink: The charge test will show heat problems. Can be very barrel specific. David.

Lol! Just getting people thinking of the future! We should know soon who goes ! Regards Graham.

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Re: Barrel Cool device

#12 Postby Chopper » Tue Dec 27, 2016 9:53 pm

What next ? Wind readers ? :roll: :roll: Anyone got one ? Chop :lol: Electronic ?

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Re: Barrel Cool device

#13 Postby jasmay » Wed Dec 28, 2016 7:22 am

Chopper wrote:What next ? Wind readers ? :roll: :roll: Anyone got one ? Chop :lol: Electronic ?

I've got a good wind reader, its electric too, and you could never be DQ'd for having it on the mound....

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Re: Barrel Cool device

#14 Postby RAVEN » Wed Jan 04, 2017 1:06 am

What next ? Wind readers ?

Yep they call them COACHES Chop [-o<

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Re: Barrel Cool device

#15 Postby aaronraad » Mon Jan 09, 2017 4:21 pm

Just a couple of notes regarding measuring temperatures:

  1. IR temperature devices are sensitive to the target surface emissivity - Principles of Non-Contact Temperature Measurement your bead blasted barrel could produce a different result to the polished barrel; and probably the Cerakoted barrel as well. Fluke recommend "3-M Black" (see pp 11.), I've used black PVC electrical tape in the workplace when comparing (relative) temperatures across various items with different surface finishes, where real temperature wasn't super critical.
  2. IR temperature devices will give an average surface temperature measured over the optical IR area generated for that distance to the target.
    ...hold the device too far away from the target object and the device will average out the background temperature measurements in the display result as well.
    A surface temperature result also means that if the object being measured has a relatively large heat sink capacity you need to avoid any local convection heating/cooling taking place during measurement for an accurate result. Once the convection heating/cooling stops (e.g. fan stops blowing across your lump of steel) the surface temperature of the object will return closer to that of total mass.
  3. Contact type thermocouples are sensitive to the method of attachment to the surface, which is why manufacturers recommend a thermocouple contact cement instead of just PVC tape. Consider sourcing the same brand of temperature measurement strips and hope the manufacturer doesn't go changing the adhesive backing with every other batch.
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