Sporter Barrels vs Heavy Barrels

Discussion in 'Long Range Hunting & Shooting' started by MontanaRifleman, May 2, 2010.

  1. MontanaRifleman

    MontanaRifleman Well-Known Member

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    I am specifically asking what the difference is in a sustained rate of fire, for instance varmint hunting. Which barrel can you shoot at a greater rate of fire without it becoming overly hot and causing excessive wear on the bore. By rate of fire, lets say "x" # of rounds per hour for maybe 4 hours of varmint shooting. Let's assume same cartridge and load to make this a comparison between heavy and light barrels.

    I have my opinion on this, but I would like to hear other opinions and experiences, especially experiences.

    Thanks

    -Mark
     
  2. Aldon

    Aldon Well-Known Member

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    I would think the only thing a heavy barrel gives you is a little more thermal mass so you can shoot a few more before you reach the point where you should allow it to rest.

    The flutes in the barrels should give either a tiny bit more rigidity and more surface area to dissapate the heat.

    I peronally think that the loads themselves and the pressues etc,, have more impact than the weight or length of the barrel.

    I would add that if you have more thermal mass, once you get it to same temp, you would have longer to cool it.....

    but I am not an engineer...completely...in this field. I did stay at a holiday inn express recently though:) LOL
     

  3. MontanaRifleman

    MontanaRifleman Well-Known Member

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    That was a funny one Aldon, you'll have to remember putting your Holiday Inn Express stay on your resume :)

    I agree that once the barrels warm up to the same temp it would take longer for the heavy barrel to cool off... but... if you fired them at the same rate, let's say a shot every 2 minutes, wouldn't the lighter barrel heat up quicker? if so, then it would need to rest sooner. So which rifle could handle a higher sustained rate of fire without overheating?

    Could the varmint barrel be shot 15 times per hour (once every 4 min) vs the sporter barrels 10 times per hour (once every 6 min) or vice versa?

    To keep it apples to apples and simple, let's assume both barrels are not flutted.

    Thanks,

    Mark
     
  4. phorwath

    phorwath Well-Known Member

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    My initial thoughts on this are: the heavier profile barrel will require extra shots to heat the larger mass of steel up to the same temperature as the lighter profile barrel. However, after both barrels come up to an identical too-hot temperature, I don't think there will be much difference between a prolonged rate-of-fire and measured barrel temperature. My first thoughts... :) That way if I decide I'm wrong, I can have a second thought... :D

    Let's see what other's think.
     
  5. J E Custom

    J E Custom Well-Known Member

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    I agree that the heaver barrel will take more shots to heat up but also it will have a
    better cooling rate based on more surface area.

    Of course this is with all things being equal (Same load,same amount of rounds fired).

    An old trick to help cooling is to stand the rifle up and open the bolt . It has a chimney
    effect and will let air flow through the bore for faster cooling.

    For varmint hunting one should have 2 or more rifles if the shooting is fast and furious.

    A fluted barrel should also help cooling .

    Just an opinion

    J E CUSTOM
     
  6. MontanaRifleman

    MontanaRifleman Well-Known Member

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    JE, that's exactly what I believe. The heavier barrel will take more shots to heat it up and the greater surface area will give faster cooling. I was hoping to get a few more responses before I came out with my view but there it is.

    To illustrate... my Sendero barrel has about twice the mass as my Finnlight and about 25% more surface area. So if we were to put some math to it, it would cool about 25% faster than the Finnlight. In theory, you should be able to a round every 4 min through the Sendero to the Finnlight's every 5 min (same load). Not a big difference, but the principle is the barrel with the biggest surface area cools faster, like with fluting.

    And I have also found out that it seemed my rifles cooled relatively quickly when I put them muzzle up in a rack at the range with the action open. i didn't think about the chimney effect, but it makes sense.
     
  7. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Well Paul, I've said my thoughts.... more surface area equals faster cooling. And faster cooling will allow a higher rate of fire. Make sense?
     
  8. Boss Hoss

    Boss Hoss Well-Known Member

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    Easy fix---carry small cans of compressed air... Turn upside down and spray---cools in a few seconds..

    Doing this for many years.
     
  9. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Thanks Boss, that's a good idea, and as I recall one of our members from AZ rigged up a CO2 cooling device which doen't result in a any condesation. Does the compressed air cause condesation?

    Good input, but what I'm really after is folks opinions and experience on whether or not heavy barrels cool faster than light barrels? Any thoughts on that?
     
  10. bigbuck

    bigbuck Well-Known Member

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    Just noticed this thread so I thought I would share what happened to me last summer . I was at our hunting club and dad had his sporter actually more of an in between sporter and heavy shiland barrel (22-250) . He had one of his green 100 count shell holders with him I say it was half full or just over anyways he turns to me and says shoot em up I'm going to reload some more for this gun that are more accurate . So I smiled and said okay sure (because I love to burn powder) I ran through all of these within 30 to 35 minutes to the best of my remebrance I never stopped the barrel was smokin hot I mean you could fry an egg on this sucker ! We'll today it wears a new barrel because evidentally I cooked it . I have always shot a heavy barrels on my RUM and what I notice is it takes longer to heat up but also takes longer to cool or (I'm just real impatient ) I always lean my gun up in a corner or on a tree with the bolt taken out so the air will travel up the barrel usually I can see mirage or heat waves comeing from the end of the barrel . It usually cools faster this way .

    Hope I didn't stray to far off topic.

    BigBuck
     
  11. MontanaRifleman

    MontanaRifleman Well-Known Member

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    I agree that if a heavy barrel gets to the same temp as a light barrel, it will take longer to cool because the heavy barrel has more heat energy because it has more mass. But to get the heavy barrel to the same temp requires more shooting (using the same load) Sooo... if we are shooting the SAME amount of rounds through them, the heavy barrel heats slower and cools faster because of greater surface area - same principle as radiators, base board heating and fluting. Am I missing something?
     
  12. bigbuck

    bigbuck Well-Known Member

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    I guess that if we shot the same amount of rounds then your right. I always would check it with my hand until I realized that the fatter barrel would be cool to the touch but that didn't mean that it was cool all the way through(or in my opinion) . so I would rush back to shooting my groups and wouldn't get the outcome that I was looking for so I took longer to let the barrel cool down. I wonder if anyone on this site has a temperature guage to see for sure ?


    Good Thread looks like i'm going to learn some things.


    Bigbuck
     
  13. Boss Hoss

    Boss Hoss Well-Known Member

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    When you turn the can upside down it comes out as a liquid--around 100 below or so. Takes about 5 seconds to cool a tube to warm from hot.

    Metal is metal the mass is the mass--the bigger tubes heat slower and cool slower.
     
    Last edited: May 3, 2010
  14. phorwath

    phorwath Well-Known Member

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    Mark,
    I'll give this a little more thought based on some simplified mathematical analysis. I can state right now that as barrel diameter increases, steel barrel volume/mass increases to the 2nd power of barrel diameter (a squared function). Whereas exterior barrel surface area only increases to the 1st power - in other words a direct 1:1 increase of surface area due to increasing barrel diameter. So increasing barrel diameter will increase the mass of steel in the barrel at a greater rate than it will increase exterior surface area.

    I'll update this post when I have some more time on my hands. But I think the increased cooling rate is minimal. The greatest advantage, with respect to heat up and cool off the larger diameter barrel has over the smaller diameter barrel is the larger barrel will take more shots to reach an equal temperature during the initial shot string, because of the greater thermal mass (heat sink effect) of the extra steel in the heavier barrel. And for the initial repetitive-fire shot string, a barrel that heats up more slowly will be less prone to warp or shift points of impact, compared to the thin-walled tubes.

    There are, of course, other advantages to the heavier barrel, such as the additional mass results in less shifting of POA during the firing process. It takes more force to initiate motion of the larger mass than the smaller mass. But you've focused on rates of heat-up, cool-off, and even more specifically, heavy barrel versus light barrel temperatures under steady, methodical, sustained rate of fire. I believe that is really what you've focused on. For a given, sustained rate of fire over extended periods of time (like 2 hours), will the heavier profile barrel reach a higher or lower temperature than a lighter profile barrel.

    My current perspective is this: the benefit of the heavier barrel under such sustained fire is substantially less than the benefit of the slowed rate of heat-up during the first string of firing.
     
    Last edited: May 3, 2010