Barrel weight per inch?

J

jmwcj8

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How much does a barrel weigh per inch if it is a 1.25 in a 6mm?The reason I was asking is I got a bench setup that weighs somewhere in the 19.0lb and I am thinking about cutting it back to try and get to 17.0lb so I can shoot light gun.The barrel is 30in long now.
 
From the Lilja website:

In his article Otteson used the weight value of .28 pounds per cubic inch. In checking with our supplier of stainless steel it was found that the value of .276 pounds per cubic inch is a little more accurate for the 416 stainless steel we use in barrels. This corresponds to a specific gravity of 7.64. In a five pound barrel this difference in the multiplier would change the calculated weight by about an ounce. For 4142 chrome-moly steel the weight for a cubic inch is .283 pounds.
Click to expand...
 
(.625 X .625 X 3.14 =1.227) - (.1215 X .1215 X 3.14 = .046) = 1.181 X .29 = .3425 Lbs per inch of 1.25 straight 6mm barrel. 2 / .3425 = 5.84 inches to remove 2 lbs. I'm going out to the shop to weigh some scrap barrel stubs and see if this is correct.

Scott Roeder
 
Hmmm... My real world weight of a 1.25 Krieger 6mm stub comes in at approximately .3254 Lbs per inch. I'll have to recheck my math. (I'm not really dyslexic.)
That would equate to about 6.147 inches of barrel. This estimate is not guaranteed, so I would re check everything before taking the barrel to the saw.

Scott Roeder
 
The barrels are tapered at the front, so the front of the barrel is lighter per inch then the back... but with a quick calculation on my barrels, 22 inches, 82 ounces comes to an average of 3.7 ounces per inch. over the whole barrel. If you take weight off the muzzle it will be less weight per inch than the breach.

Paul
 
I attached a simple spreadsheet where you can enter the barrel weight density, as a guide I included the densities given from Lilja posted above, you are free to enter your own. You are enter the OD of your barrel and the caliber in inches and how much you want to lose and it calculates the weight per inch and the amount to cut off.

As an estimate for tapered sections try entering the diameter of the barrel about 1/3 of the way from the larger diameter and this estimate should be close. I have left out some math here and this is my off the cuff estimate so do not take it as the gospel, when in doubt cut off less than is calculated as you can always cut off more, but gluing a section of the barrel back on is a much harder operation.

You can open the spreadsheet in Excel and enter what you have and want and it should calculate a reasonably close estimate of how much you need to cut off. As I said it is simple and no instructions, but if people want I can clean it up so it easier to use.

Disclaimer: There are many things that are not taken into account such as rifling information and other things that will affect the final accuracy of the final result but the affect should be minimal.

Hope this is helpful and have a good day,

wade


View attachment BarrelWeight.xls
 
3.009in weighed 15.6oz.So I actually put some weight back in it.But all is good thanks.
 
In my message I forgot to state that you need to enter the density of the steel you are using, as an aid I included the densities from Lilja as stated in an earlier post.

Using the density of stainless steel my estimate for the weight of the 3.009 inch piece of your barrel is 15.69 ounces which is pretty close to your actual weight of 15.6 ounces.

I apologize if I misled anyone by not telling you to input the density of your steel.

Hope this helps,

wade
 
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