SBR barrel profile

[dpaqu]

I’m wondering if the mass of a barrel more or less critical as the length gets shorter? Daniel Defense has quite the selection of barrels and I was wondering if it mattered much. Is the heat that a barrel absorbs from firing from the friction or combustion? Will a 10.3” LW SBR heat up quicker than a 14.5 or 16” rifle? I guess the real important question is does it matter?

DD 10.3”

https://danieldefense.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/w/i/with_fsp.jpg

DD 10.3 Light Weight.

https://danieldefense.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/d/d/dd-10195_10.3_lw-complete.jpg

If this has been covered before please lock

[Ghost__1]

Heat is disipated through surface area. If your familiar with air cooled combustion engines it is why they have fins. Since the lw 10.3 " barrel has less surface area it will definately heat up faster however because there is less metal mass I'm pretty sure it will cool faster as there is not as much heat retainability over the thicker longer profile barrels. Thats confusing because you won't notice that unless you take them to the same heat. For this arguement we'll say you heat the barrels to 150 degrees. The sbr will get to that temp with less rounds than the 16". It's will also cool faster from the exdct temp. However if you do two thirty round mag dumps with both the sbr will heat up faster and to a higher overall temp. Making cooling time obsolete.

My last statement is that in no way do I have exact figures as there are to many variables I am just explaining the physics. Too much goes into telling you how much but your experience may vary. It's still right but what matters more is what you and others notice physically.

[rjacobs]

IMO unless you are doing full auto mag dumps all the time the LW barrel will be just fine. I know a lot of guys on here, who shoot WAY more than me, are going to LW barrels.

I dont think the DD LW barrel is SO much thinner than the regular profile that you would notice the difference.

I think the LW profile on 16" barrels is a different argument possibly, but realistically with that 10.3 LW vs. regular isnt a drastic difference.

[dpaqu]

A Shorter barrel has the same "surface area" to bore area ratio (actually a little more due to the chamber section) as a longer barrel. If we assume that the heat from the powder burning is the primary cause of heat then the area around the chamber and the first few inches of the barrel absorb most of the heat. If you think that friction causes most of the heat than the area toward the end of the barrel were the bullet is moving quickest is where most of the heat comes from. Obviously it is a culmination of the two but I'm trying to figure out is do shorter barrels of a similar profile to their longer brothers heat up faster and by how much.

I've read on this forum that a 14.5 LW profile barrel won't stand up to a "breaking contact" drill of 7-8 mags fired in quick succession. Too what degree the barrels are damaged I don’t know. I’m guessing nobody wants to test their barrel to find out. If a barrel that’s 5" shorter and is also similar in profile to the 14.5" LW barrel heats up much quicker than it would stand to reason that it can handle even less rapid fire. At which point it becomes a tactical handicap I’m not really interested in as that depends on to many other variables.


Heat is disipated through surface area. If your familiar with air cooled combustion engines it is why they have fins. Since the lw 10.3 " barrel has less surface area it will definately heat up faster however because there is less metal mass I'm pretty sure it will cool faster as there is not as much heat retainability over the thicker longer profile barrels. Thats confusing because you won't notice that unless you take them to the same heat. For this arguement we'll say you heat the barrels to 150 degrees. The sbr will get to that temp with less rounds than the 16". It's will also cool faster from the exdct temp. However if you do two thirty round mag dumps with both the sbr will heat up faster and to a higher overall temp. Making cooling time obsolete.

My last statement is that in no way do I have exact figures as there are to many variables I am just explaining the physics. Too much goes into telling you how much but your experience may vary. It's still right but what matters more is what you and others notice physically.