Weight of a barrel before and after machining ? How much is weight is lost.

[Munkey1973]

I am not a machinist … but merely a simple accountant/economist planning his next F T/R build over the upcoming off season.. If you want to get to the crux of my query, scroll to the bottom !

Currently choosing between Krieger 2 barrels to purchase:

(1) Krieger Contour # 17..... 31 5/16 inch (raw) ..... 30 5/16 inch (finished) ..... it weighs in at 7.82 pounds (raw.....obviously)
(2) Krieger Straight Cylinder (contour # 11)..... 33 inch (raw)..... 32 inch (finished )..... it weighs in at 10.8 pounds (raw)

So, here are the constraints to this optimisation problem.

(1) Based on the weigh-in of all other rifle components I have approx. 7.63 pounds in which to allocate to the barrel (based on F T/R rules) (finished... after chambering, threading, and crowning).
(2) Ideally I would like to have the barrel come in at 30 inches finished.

Other information:
(1) Chamber is a 308 Winchester
(2) I really want to come in at 7.63 pounds finished weight
(3) This is my first full custom build that I want to do right

Decisions:

Do I go with contour # 17 and hope that the machining (chambering, threading, crowning) creates less than (or equal to) 0.19 pounds ( = 7.82 - 7.63) of stainless steel shavings ?
Or, do I cut 3 inches off of the straight tapper barrel (then proceed to have the smith put in widdle down a custom contour that would bring me to 7.63 pounds finished) and pay additional $175 for machining which I'm fine with.... but if I can safely avoid paying then awesome.

The ultimate question comes down to does finishing a barrel as 308 Winchester create approximately less than or egual to 0.19 pounds of stainless steel shavings (for short action Remington 700) ?
Has any smiths out there weighed a barrel before and after all the machining... if so what is the differential ?

 

[AikiNut]

Why is the weight of 7.63 pounds for the barrel so important? Harmonics? Ergonomics? I may be way off base here but it seem an odd thing to worry about.

 

[tiriaq]

The total weight of all the other parts of the rifle leaves 7.63 pounds for the barrel before the rifle exceeds the maximum allowable weight.
I would start with the Kreiger #17, breech it up, cut and crown at your desired 30", then weigh it.
Set it up on the lathe so that the tool will follow the factory contour. Take light cuts until you reach your desired weight.

 

[Mystic Precision]

I use a #17HV at 30"... I would take weight out of the stock and non essential 'fat'... scope rings, bipods, buttpads, trigger guards are great places to loose a few ounces.

Worst case, contour or light flutes.

Easy.... just remember that you have to plan for rain. The odds of anyone at a local match caring is slim but if you are going to National or International level matches and do really well, you have to make weight as the rifle is fired. Some rain coverings can add a bunch of weight so keep an eye on that.

Good luck...fyi, got a sale on some Krieger 30cal #17HV barrels.

Jerry

 

[Munkey1973]

The total weight of all the other parts of the rifle leaves 7.63 pounds for the barrel before the rifle exceeds the maximum allowable weight.
I would start with the Kreiger #17, breech it up, cut and crown at your desired 30", then weigh it.
Set it up on the lathe so that the tool will follow the factory contour. Take light cuts until you reach your desired weight.

You said it much better and much to the point than I did LOL.
So you are of the thinking that the contour #17 might weigh in around the 7.63 pound mark after the machine work ? ….. good to know and thanks for your input !

 

[Munkey1973]

I use a #17HV at 30"... I would take weight out of the stock and non essential 'fat'... scope rings, bipods, buttpads, trigger guards are great places to loose a few ounces.

Worst case, contour or light flutes.

Easy.... just remember that you have to plan for rain. The odds of anyone at a local match caring is slim but if you are going to National or International level matches and do really well, you have to make weight as the rifle is fired. Some rain coverings can add a bunch of weight so keep an eye on that.

Good luck...fyi, got a sale on some Krieger 30cal #17HV barrels.

Jerry

Thanks for your advice Jerry.

Flutes !! … why didn't I think of that .. retain some rigidity (benefit from additional heat dispersion)… brilliant idea

The fat has already been trimmed to the fullest.
My components are already lean (except for the Defiance Elite action that I have on order... its expected to be a hefty single-shot action at 2.5 lbs).

Other than the action, the rest is pretty light (at least I think they are)...

Dolphin Chassis (& Jewel trigger)… 4.8 lbs
Nightforce scope with aluminum rings … 2.17 lbs
SEB Joypod … 1.09

I have about 20 grams worth of cheek rest locking screw that I could possibly do without... but that kind of gain is a fart in a wind storm

Curious, do you know of any stocks/chassis in a (Rem 700 footprint) that offer the same or better rigidity as the older model Dolphin FRT but weigh in as less ?


BTW... I shot in the rain (massive thunderstorm in fact) for the Provincials at Nokomis this past July.
And even though my little 223 shot the best it ever had (after 2 years in this sport placed in top 3 for a day)…. I'll NEVER shoot in the rain again. LOL

 

[Mystic Precision]

Yeah, getting soaked while trying to keep up precision shooting, is a pain but rain is certainly part of the sport. Chat with anyone that has gone to Connaught... that can get miserable in a hurry.

Good luck with your build and just remember that metal is easy to modify... things like adjustment bolts and rods can be hard mounted or switched to CF tubes. A few more holes here and there.

If you decide to flute, you are just running shallow cuts parallel to the bore line... remove enough to get those few ounces you need an enjoy.

Jerry

 

[AikiNut]

The total weight of all the other parts of the rifle leaves 7.63 pounds for the barrel before the rifle exceeds the maximum allowable weight.
(snip)

Ah. Thanks for the concise explanation. Haven't been shooting much lately and all my toys are under weight limits. Will join Genesee and APRA when the new year rolls around.

 

[tiriaq]

If you wanted, you could sit down with a calculator and determine how much steel would have to be removed. For example, a 3/16" flute might be half a 3/16" rod. How much does 3/16" diameter steel weigh? Etc. There are weight tables available.