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Barrel cooling devices / practices

 
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  #15  
Old 05-11-2012, 08:49 AM
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Re: Barrel cooling devices / practices

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Originally Posted by Bart B View Post
In long range competition shooting from prone, it's common to shoot 25 to 30 shots with each one about 20 to 30 seconds apart. Barrels from such firing heat up very much. If they're properly heat treated and fit to a receiver whose face is square with the bore/chamber axis, hot barrels don't hurt accuracy. They all maintain sub 3/4 MOA accuracy at 1000 yards. This is for the mild 6.5x.284 up through 30 caliber magnums.

I've shot 30 shots at 20 second intervals testing 30 caliber magnum loads at 1000 yards. All 30 went inside 6 inches. Friend of mine shot 40 shots at 600 yards also about 20 seconds apart; group was 1.92 inch. I put 20 rounds from a .308 Win. at 800 yards into 3.2 inches fired at the same rate. Love shooting fast with those super hot barrels made by Kreiger, Obermeyer and the older ones from Hart. And even those skinny Springfield Armory Arsenal match grade barrels made for 7.62 NATO Garands would hold 1 MOA accuracy at 1000 yards for 25 to 30 shots fired just as fast.

If you barrel shoots bullets to different points as it heats up, you might need to fix the receiver face. Or send the barrel back to its maker and ask for a replacement that's properly stress relieved by good heat treatment. Of course if these typical causes ain't the problem, then maybe you should check the shooter's long-term shooting technique for accuracy at the target.
Bart, I agree with your post. But what about damage to the throat? I will be at a match soon and plan to shoot my Defiance action 300 win with a stout load o H1000 and 210 bergers. I will need to shoot a minimum of 15~20 shots in 15 minutes. The ambient temps will be in the 70's. I am concerned as the last thing I want to do is spoil a good barrel just to shoot a match.

My other option is to switch to my 338 LM 1/2 way through the string. But that will waste a minute or two.

What ya think??

Jeff
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Old 05-11-2012, 02:12 PM
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Re: Barrel cooling devices / practices

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Originally Posted by Broz View Post
But what about damage to the throat? I will be at a match soon and plan to shoot my Defiance action 300 win with a stout load o H1000 and 210 bergers. I will need to shoot a minimum of 15~20 shots in 15 minutes. The ambient temps will be in the 70's. I am concerned as the last thing I want to do is spoil a good barrel just to shoot a match.

My other option is to switch to my 338 LM 1/2 way through the string. But that will waste a minute or two.

What ya think??
Pleasant thoughts. Just plain pleasant thoughs are what I think. But only for the .300. Those .338 LM's kick too much for hand-held rifles to shoot accurate. Which is why the .300 Win. Mag. was the most accurate in the hands of top long range shooters testing different rounds for military use some years ago. The .338 LM was pretty bad but the US Army had egos to please and the rest is history. (For everyone, please don't put that claim in this thread that a .338 LM holds the record for the longest range sniper shot in the middle East. We have no idea whatsoever how many other shots that guy took at half that to all of that range that were misses.)

Folks have been shooting 30 caliber magnums in long range NRA prone matches since 1935 when a .300 H&H was used to win the big 1000 yard match at the Nationals. They still shoot them nowadays in both prone and benchrest long range matches. Course of fire for matches agt 1000 yards are typically 30 minutes long to shoot unlimited sighting shots then 20 rounds for record. Folks usually take 3 or 4 sighters then go for record. They usually fininsh in 20 to 25 minutes. The good rifles use will shoot all day long under 6 inches at 1000 yards; same as benchrest versions. Barrel life at that accuracy level is typically 1200 or so rounds with the .300 Win. Mag. You'll need to seat bullets out about 50 to 60 thousandths more as the throat wears from new to when accuracy starts going bad. I've worn out three and a half barrels shooting 30 caliber belted cases and won my share of matches doing so.
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  #17  
Old 05-11-2012, 05:46 PM
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Re: Barrel cooling devices / practices

Bart, we are shooting in hunting form so brakes will be on all my rifles.

So you dont think I will do any damage in a 15 to 20 shot string in 15 minutes with my 300 win? If there is a chance of too much throat heat I will simply have both rifles ready and shoot 7 with the 300 win, then switch to the 338 LM to finish up.

Jeff
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  #18  
Old 05-11-2012, 06:28 PM
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Re: Barrel cooling devices / practices

I shoot a lot of smokeless muzzleloaders and to keep the barrel cool so sabots don't blow I use a copper rod kept in a cooler full of ice. Just pull out the rod wipe it down and slide it down the barrel for a couple mins and it will suck the heat out. Then just put it back in the ice for next time.
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  #19  
Old 05-11-2012, 09:39 PM
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Re: Barrel cooling devices / practices

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Originally Posted by Broz View Post
Bart, we are shooting in hunting form so brakes will be on all my rifles.

So you dont think I will do any damage in a 15 to 20 shot string in 15 minutes with my 300 win? If there is a chance of too much throat heat I will simply have both rifles ready and shoot 7 with the 300 win, then switch to the 338 LM to finish up.
Doesn't matter whether brakes are used or not. The recoil that makes heavy-kickers harder to shoot accurately happens while the bullet's going down the barrel. Us humans don't hold rifles exactly the same way to our shoulder for every shot; that barrel-time recoil moves the rifle before the bullet clears the muzzle. Same reason that large bore double rifles have their bore axes crossing at 10 to 30 yards down range; they jump to the left when the left barrel's fired, right for the right one. Double rifle breech centers are an inch or more apart; if one inch, the bore axes cross at 4 MOA if 25 yards is where they're regulated at.

No, I don't think you'll do any damage to the barrel's throat shooting it that way. There are two exceptions. One is if your loads are over SAAMI spec for pressure; that really shortens barrel life. The other is if ball powders are used; they're horrible to get good accuracy with but they typically give more barrel life for their not so great accuracy. IMR4350's been the favorite for accuracy and barrel life in virtually all 30 caliber magnums with 190 to 220 grain bullets using between 60 to 75 grains of powder.
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  #20  
Old 05-11-2012, 10:07 PM
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Re: Barrel cooling devices / practices

Ok, Thanks Bart
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  #21  
Old 05-19-2012, 04:59 PM
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Re: Barrel cooling devices / practices

I have tried a lot of the things mentioned. Co2, Water trickled down barrel, ice water on towel over barrel, fans, AC vent in car. Here is what works best for me with no cost. I just have four half gallon frozen plastic jugs I lay in the bottom. Slide the rifle in....and it is cool enough to shoot again in a few minutes.
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