Weight reduction for a barrel nut setup?

[memilanuk]

Any of you out there have an idea on how to calculate approximately how much difference in weight there would be for a barrel with a barrel nut (Savage) with a large shank or a small shank vs. a more conventional shouldered tenon setup?

Any one actually measured it to see if the calculated values are correct?

 

[GrocMax]

Look up the weight of a steel tube 1.2" diameter .100" wall 3" long. Subtract the weight of the nut.

 

[Ggmac]

Both setups are made of steel . Aside from the nuts flutes for the wrench , I think it would be less then 2 ounces .
I don't have the way to calculate it , I'm going off material I remove to extend the threads versus a shoulder . Mine are usually 1.25 " straight .
I built 2 near identical savages , one shouldered ,one with a nut , everything else was the same . On my scale ( luggage ) they weighed the same 10.2 lbs . No stock . My scale doesn't read in ounces .
Hope this helps . Next time I thread a barrel for a nut , I'll save and weigh the chips ?

 

[DaveTooley]

look at Dan Lija's website. He has a barrel weight calculator. Just change the diameter of the cylinder section to get the difference in weight. The nut won't weigh much.
WWW.riflebarrels.com

 

[memilanuk]

Both setups are made of steel . Aside from the nuts flutes for the wrench , I think it would be less then 2 ounces .
I don't have the way to calculate it , I'm going off material I remove to extend the threads versus a shoulder . Mine are usually 1.25 " straight .
I built 2 near identical savages , one shouldered ,one with a nut , everything else was the same . On my scale ( luggage ) they weighed the same 10.2 lbs . No stock . My scale doesn't read in ounces .
Hope this helps . Next time I thread a barrel for a nut , I'll save and weigh the chips ?

Typically I don't go with full straight cylinder contours... I have to actually make weight for FTR!

Usually I'm looking at something like a Heavy Palma contour, with a straight shank for somewhere between 2.5 and 5 inches (depending on which manufacturer and their interpretation of the contour), then a radiused reduction for a few inches, then a straight taper to the muzzle. With turning it down to fit a barrel nut, you lose that straight section , and on into the radiused region.

I thought there was something out there like what @DaveTooley mentioned, probably used it in the past, but just couldn't remember it

Anyone have experience with how accurate it is in actual practice?

 

[Ggmac]

Ok that makes sense . Yes there is a formula in the book " target actions and triggers " and the book " Machinerys handbook pocket companion "
Get your calculator ready .

 

[memilanuk]

Anything like what is shown here?

Barrel Weight Calculations for Contoured Barrels

I'm going to tinker with Lilja's spreadsheet for a bit... might be a matter of how bad do I really want to know?!?

One part that will simplify things a bit is that I have an old barrel, turned down from a Heavy Palma contour, that I can take some measurements from.

 

[memilanuk]

Well... that's interesting.

I grabbed the old barrel and took some measurements off of it. With the 2.5" straight shank turned down from 1.250" to 1.120", it extends out to ~3.875", not as far as I thought.

Krieger lists the weight for a 30" Heavy Palma contoured barrel as 5.5 lbs. When I enter their listed dimensions in the Lilja contoured barrel weight calculator spreadsheet, it comes up as a little over 5.8 lbs. Entering the modified dimensions for the barrel I have on hand, calculates out to 5.58 lbs, so about 3-4 oz for the reduced shank.

The barrel I have in hand, chambered, threaded, and then turned down a bit at the muzzle for a Cortina tuner (removed) actually weighs 5.45 lbs.

Assuming UPS ever gets their $__t together and delivers the new blank, it'll be entertaining to see what it actually weighs.