Machining flutes on Rem .223 bull barrel

F

foffe1

Member
Rating - 100%
10   0   0
Location
NB
Hi,

I would like to add flutes on my Remington .223 bull barrel to lighten its weight by as much as possible. Cost is not an issue as I have access to a friend who is a machinist. I would appreciate any comments anyone can give me.

1) How many flutes should be added

2) How long, wide and deep should they be

3) How close to the muzzle end should they start

4) Does it need a heat treatment before or after the machining operation

5) Other things I should know.


PJM
 
You are adding stress to the barrel by machining it. This could cause an accuracy issue, but it MAY not. Fluting will shave oz's off the weight not lbs. No heat treat before or after is needed.
 
if your machinist friend has not done this before it might be a good idea to get him a piece of barrel to practice on before he goes ahead and messes with your barrel.

6 flutes, 2-3 inches from the muzzle and stay ahead of the chamber or anything not a straight taper. find a factory fluted barrel and measure or copy.
 
I flute mine with 6 flutes about 16" long starting about 2" back from the muzzle. I use a 9/32 ball nose endmill. I program a 2" radius in and a 2" radius out, cut .09" deep in three or four cuts.....I've fluted about a dozen barrels, some before they were ever chambered and shot, some after. The ones fluted after never lost any accuracy by fluting. Don't worry about adding or removing stress affecting the accuracy. It's an old wives tale propagated by guys who's only machining experience is on the internet.
 
Rembo, i don't know much about machining, i just have a card with a little red seal in my wallet.

anyways any milling operation can cause local work hardening and in the case of a barrel which have already been uniformly hardened and tempered will introduce stress into the barrel which can possibly decrease accuracy.

but don't take my word for it, read: the handbook of residual stress and deformation of steel
 
I too have 25 years experience as a tool maker and own my own machine shop. Anytime a cutter (milling or turning) is put to metal you are introducing stress to the material. As stated in my post above, "This could cause an accuracy issue, but it MAY not."
 
Where does this "hardened and tempered" barrels come from? :confused:

Barrels are soft. If they were not, drilling them, rifling them, chambering them, etc. (all machining processes) would be a royal motherf***er.
Not that it cannot be a PITA to machine, depending on the material of the barrel, but the makers do not harden barrels.
There are a couple custom barrel makers that do take pains to normalize their barrels for stress relief, and there are outfits selling cryro treatment to supposedly do wonderful things to barrels (and blades), but none of that is to make hardness happen. Stress relief, yes, but not hardness.

Does Remington normalize or otherwise stress relieve their barrels ? If their ad copy is to be believed, they are hammer forging at least some of their barrels these days. Their other barrels would be button rifled, which would put some different stresses in place, but, enough to make a difference? I do not know how they would react to the fluting. Maybe they wouldn't. React, that is. I was pondering that myself, as there have been a couple heavy barrels on the EE, and I was contemplating their use as a donor blank.

My suggestion, if weight savings is the goal, is to buy a lighter barrel. Or probably even cheaper, sell the heavy barrel gun, and buy the same model with a sporter weight barrel.
The amount of weight that can be saved by fluting wont make a heck of a difference. Looks cool, though, if that matters.

If it's what you want, have at it. Worst case is that you will be needing a new barrel. (Or your friend ends up trying out making a Sporter weight barrel or octagon barrel out of the failed fluting job, two possible fallback scenarios) Best case is that it all works out good. Your call.

Lilja Barrels says this http://www.riflebarrels.com/faq_lilja_rifle_barrels.htm#stress

Their articles are a good read.

Cheers
Trev
 
Jeez Foffe, if you need a lighter barrel, get a different contour. Don't start carving up some silly new fad voodoo on your barrel.

Fluted barrels are great.....great looking that is.
 
Last edited:
trevj, after a barrel is hammer forged, button rifled or cut rifled they are sent for heat treating to ensure a uniform hardness though out the barrel.

even cold roll 4140 only rates 20 on the rockwell scale. thats too soft for a barrel, you want around 26- 32 rockwell.

seeing as you like quoting lilja:
Lilja worked as an industrial engineer for the John Deere Company in Iowa before he started in the barrel business in 1985. Part of his time at Deere was spent in the heat treating department. Lilja used to heat treat his barrels himself in a small oven in his shop. His increased production over the years, though, has made it easier to send out the barrels to Spokane, Washington, for heat treating.

and not to argue with lilja, but its a common fact any milling operation induces work hardening.
 
Last edited:
I watched Al Pedersen drill, cut rifle and contour several hundred barrels from 1.250" Timken steel shaft. Never was there heat treating. I brought him the steel from Ryerson in Minneapolis. His glasses were as thick as a Coke bottle and he drank a bit of rum in the process. Al's rifles were winning a lot of matches in the 60's and 70's. I have not heard of a cut rifle barrel maker that heat treats after rifling but I haven't been an internet machinist for more than a couple of yr. Mark
 
Last edited:
Barrels are routinely heat treated. They are stress relieved. Cut rifled barrels are usually stress relieved early in the production cycle, button rifled barrels after rifling. Some manufacturers stress relieve their barrels twice. Stress relief is a heat treatment.
What barrels are hardened and tempered after rifling?
 
Sorry iconfig,

I'll throw up the brown flag on that.

The heat treating is, as tiriaq says, all about the stress relief, not about hardening it, or even to make it a "uniform hardness throughout".
Heat treatment can be a lot of things, besides a way to make metals hard.

Same as the assertion that it is a common fact that any milling induces work hardening. Not so much.

Heck though, I don't try to convince the JW's at the door that they are in the wrong religion, so feel free to keep on believing.:slap:

:D

Cheers
Trev
 
What does 'early in production cycle' mean?? Cold rolled steel has a hole drilled in it, rifling cut, then turned to contour. Is the heat treating done before cold rolling?? I'm real confused. Where we come from heat treating and stress relieving are not the same thing. Help me out here, Mark
 
I have seen descriptions that said that the steel stock was stress relieved prior to any machining operations, to prevent it going pretzel when it was rough turned to size.

Cold rolling will usually leave the stock with internal stresses that can make life miserable if nothing is done about them.
Cold rolling, is the process that the bar is made to shape and size, as opposed to hot rolled steel, which usually has fewer stresses, but requires more cleanup (usually pickling in acid) and is often of a looser tolerance dimensionally.

On the other hand, I have a pretty good video on the building and using of a heat treating, inert atmosphere furnace, made by a barrel maker in the US, who uses (used) it to stress relieved his barrels after he buttoned them. I should dig it out and watch it again. The furnace shown, was electric heated, and the barrels were hung vertically inside it. Argon gas was fed in while the furnace was in use, from bottles.
It was interesting enough, but was not the type of heat treating furnace info I was looking for at that time.

Heat treating covers a lot of ground. Achieve a desired result with heat, and it is still heat treatment, whether that result is annealing, stress relief, normalizing, hardening (via a quench, or precipitation), drawing the temper, carbeurizing, case hardening for color, etc.

Different heat treatment processes are appropriate for different materials, depending on the results desired. What works for one alloy, will like as not, provide very different results if done to another.

Clear as mud?

Sending something to a heat treat shop to be "heat treated", but without specifics of what is to be done, is a recipe for disaster. Tell the shop that you want your 1095 steel, hardened and the temper drawn to Rockwell 45 C scale, and they won't treat you (or bill you) like you are too dumb for words.

Cheers
Trev
 
Well put Trev
Hears a snip from a barrel company on the subject.
What about "fluting" a barrel?
Fluting is a service we neither offer nor recommend. If you have a **** barrel fluted, the warranty is void. Fluting a barrel can induce unrecoverable stresses that will encourage warping when heated and can also swell the bore dimensions, causing loose spots in the bore. A solid (un-fluted) barrel is more rigid than a fluted barrel of equal diameter. A fluted barrel is more rigid than a solid barrel of equal weight. All rifle barrels flex when fired. Accuracy requires that they simply flex the same and return the same each time they are fired, hence the requirement for a pillar bedded action and free floating barrel. The unrecoverable stresses that fluting can induce will cause the barrel to flex differently or not return from the flexing without cooling down a major amount. This is usually longer than a shooter has to wait for the next shot. The claim of the flutes helping to wick heat away faster is true, but the benefit of the flutes is not recognizable in this regard until the barrel is already too hot.
Stephen
 
sdeering, indeed.

trevj, im just a dumb machinist :) but it seems the engineers and metal metallurgists that wrote "the handbook of residual stress and deformation of steel" seem to agree with me that any milling operation causes localized work hardening. maybe you should go read what they have to say
 
According to the Lilja link posted above, he has no problem with fluting his barrels. The maker quoted by sdeering does. Barrelmakers' opinions are based on their experiences. Rembo has fluted barrels without any problems emerging.
If flutes are important, have them cut into the barrel. The absolute worst outcome would be a spoiled barrel and wasted time and money.
I suspect that if a barrel with significant residual stresses were fluted, things could get interesting. Hammer forging a barrel creates major stresses. It is not unusual for a barrel to be hammer forged to final profile - like Steyr or even Ruger 10/22T barrels. Are these barrels stress relieved after forging?
Another consideration could be the type of steel in a particular barrel - CrMo vs 416R.
 
You must log in or register to reply here.
Back
Top Bottom