Rifling

[warbirdlover]

I've been researching the barrel making processes and as you all probably know they mostly fall into button rifling, hammer forged rifling and cut rifling. Lot's of good articles on the web. Just search button rifling and usually you'll get an explanation of all of them.

Savage, Remington (I believe) and most use the button rifling process since it is the fastest and cheapest way to put it in. It involves (gun) drilling the hole, reaming it to size and forcing a football shaped carbide tool down the barrel to put the lands in. Since it develops high stresses the barrels have to be stress relieved afterwards (and maybe straightened?).

Ruger, Sako, Tikka, Winchester (new) and some others use the hammer forging process where the barrel is drilled, reamed to about .020 over caliber size and a die is put in the barrel. Hammers form the barrel around this die and it also puts in high stresses which require stress relieving and sometimes straightening.

Cut rifling is where a barrel is drilled to the caliber size or slightly smaller (if the broach is also designed to cut that diameter) and leaves the roughest finish of the three processes. Stress relieving is usually not necessary.

Most good barrel makers lap the bore after the cut and button processes.

Stress relieving is done around 1000º F which doesn't lower the hardness.

Please add your comments or disagree if you feel this is not correct and also your experience as to which you prefer and why. It might make rifle buying a little easier for some. Being a former (retired) metallurgist for a large transmission company and familiar with all these processes I prefer the hammer forging method. But I'm a hunter and not a bench rest shooter.

 

[gitarmac]

tag for interest

 

[TXGunNut]

I'll be very interested in the responses. I have a beautiful new .30-06 Super Grade with the highly touted hammer forged barrel. The wood is beautiful, fit and finish are fantastic, trigger is as advertised but the bolt face is not quite square and only one locking lug engages. The barrel is another disappointment. I've tried three tested and true handloads and dozens of variations on them. Have even tried factory loads! I've invested over $200 in components, a new set of dies and made several disappointing range trips since taking delivery last August. I can't accept 1.5-2.5" inch groups from this rifle.
My brother's nearly identical rifle has a serial number just a few hundred away and is just as beautiful but fired a .3 inch three shot group on it's only range trip. I know this could be a fluke but it's an indication of this rifle's potential.
I think Winchester will make it right but they have the option of replacing the entire rifle and I really like the wood. I'm considering a button rifled barrel and action work by Shilen but will watch this thread for a few days before going to Ennis.

 

[rudy270]

barrels

Why do you think savage, remington say theres are the most accrate out of the box

 

[warbirdlover]

I would be interested in what the bench shooters prefer.

TXGunNut, is there a "bedding" problem? Or is the barrel free floated? Winchester is touting their barrel making process. Very strange.

My Ruger Mk II all-weather .300 WM is a tack hammer with the cheapest factory loads. Always under MOA at 100 yards. I always thought the barrel was free floated but checked it yesterday and it's not. I don't know how I could have missed it but probably because it shoots so good never checked before.

I know most in here prefer a free floated barrel but when I built two rifles years ago I used the "old" method of barrel/stock contact 3/4 of the way up the forend and both those guns really would group. I never really got the barrels warm and never noticed any change in point of impact either. Maybe the "old timers" knew something about barrel harmonics or vibration and this was their fix. Now we are seeing BOSS systems and de-resonators to fix this problem with free floated barrels?

I could see a possible change in impact if a barrel makes contact with a wood stock since the wood can expand etc due to moisture but with the composite stocks maybe this is not a problem?

More comments please.

 

[Dingoboyx]

I read a bit a while ago, rather than trying to push/pull the tool thru the barrel with mechanical force, some companies do it hydraulically..... push the tool thru the barrel with oil

I would like to see video of barrels being made, that would be excellent

Very interesting subject, rifling

 

[fisherman66]

I've read that hammer forging leaves the smoothest path and usually results in the highest chronograph readings. I tend to favor these, but really more due to my manufacturer preference.

 

[LukeA]

I read a bit a while ago, rather than trying to push/pull the tool thru the barrel with mechanical force, some companies do it hydraulically..... push the tool thru the barrel with oil

I would like to see video of barrels being made, that would be excellent

Very interesting subject, rifling

That sounds a little like how they make car doors now. They don't make a die set, they just make a male die and have a cavity with the right volume of water to act as the female die. Don't need to lubricate it, don't need to cool it, basically free, excellent resolution. It's pretty neat.

 

[Scorch]

Well, since you mentioned button rifling, cut rifling and hammer-forging, you just about covered the whole spectrum (you just left out broach rifling). A few notes:

* Broach-cut barrels are made with a deep-hole drill and a broach that looks like a drill that cuts the rifling into the barrel in one pass. Since the rifling is cut by a broach, you need a different broach for different rifling twist rates. This was a common method of rifling from the early 20th Century until the 1960s. It produces moderate amounts of stress in the steel, which can be stress-relieved and straightened.

* Cut-rifled barrels are drilled, then reamed to bore diameter and honed, then a cutter is used to cut the grooves into the bore. The cutter can be either single-point or multi-point. The barrel is rotated as the cutter passes back and forth using a sine bar, so the same cutter can be used for barrels of different twists rates. This method produces the least amount of stress of any current rifling method. Barrels can be stress-relieved and straightened after rifling.

* Button-rifled barrels are drilled, then reamed to less than finished bore diameter, sometimes honed, then rifled. Button rifling uses a carbide button pulled through the barrel by a hydraulic ram to form the grooves and finished dimension of the bore. The button has the bore and grooves formed into it, and is pulled through the barrel one time, fully forming the grooves and bore. Each bore size/twist rate combination requires a different button. This produces a moderate amount of stress in the steel, but the barrels can still be stress-relieved and straightened after rifling.

* Hammer forging involves a tube- or doughnut-shaped blank, a hydraulic hammer forge, and a long mandrel with the rifling on the outside of the mandrel. The blank is attached to the hammer forge and the hammers beat the metal into the desired shape, forming the outer barrel profile and impressing the rifling and bore on the inside of the barrel. When finished, the barrel will be much longer than the blank it started with. Hammer-forged barrels cannot be stress-relieved for all practical purposes (you could, but the result would look like a pretzel). Additionally, turning or machining the outer diameter of a hammer-forged barrel often causes the barrel to warp.

Any of the barrel-making methods can deliver barrels of outstanding quality, but broached barrels tend to be rough. Single-point cut-rifled barrels are considered by many to be the acme of barrel-making quality, but due to the many steps required in making them, they tend to be a bit more expensive than other options. Most target shooters and gunsmiths prefer a single-point or button-rifled barrel because of good bore quality, ease of use and installation, and moderate cost. Many hammer-forged barrels deliver excellent accuracy and are used on some of the most accurate factory rifles available, but since you cannot do much machining on them without issues arising, they are not very popular for aftermaket barreling projects.

 

[Jimro]

Well, there is ONE more process I can think of...

Electro chemical rifling. Kimber used to use this process but changed when it didn't produce accuracy superior to cheaper broach cutting.

Jimro

 

[warbirdlover]

I didn't mention the electro chemical method because it's so rare and can etch pits in the metal. Also a chance for hydrogen embrittlement.

And I consider the broaching method as a cut rifling method since the broach is a cutting tool. Didn't know there was another cutting method either.

 

[N00b_Shooter]

Wow, i never really researched the terms before, i had heard them all but didn't know what each of them involved. Very interesting, thanks

 

[warbirdlover]

Here's the link to the best explanation I've found so far.

http://www.firearmsid.com/A_bulletIDrifling.htm

Working for a transmission company we broached internal splines on parts and gun drilled shafts. They don't leave a very nice finish. We also outsourced some parts which were formed using the button method. Very nice finish. There are some cool videos out there on hammer forging but I can't find them anymore.

I started this thread to see if people found one barrel rifling method more consistently better then the others.

 

[impalacustom]

As far as one method producing a better barrel I'd have to lean towards the cut rifling. But every manufacture produces hummers, Shilen are button rifled and they make some excellent barrels, Bartlein are cut and they produce just as many winners as everyone else. I tend to agree with Tony Boyer, buy as many barrels as you can and shoot them to find the best one.

 

[TXGunNut]

Wow, great responses! Good info as well. Winchester/Browning svc center told me their accuracy standard is 1.5" @ 100 yds with factory ammo. Kinda disappointing for a rifle that refers quite often to MOA in their ads. Poo-poo'ed my handloads as well but that's understandable. OTOH he told me to ship it in if I wished, they would replace the barrelled action if it failed to meet their "standards". I guess I have little to lose, can always have Shilen fix it if they fail. Barrel is quite thin but even Featherweights shoot well sometimes.
Bedding is correct and barrel is free-floated, Warbirdlover. I think I'm missing something or maybe I'm just losing my touch.

 

[mete]

By 1970 many makers were hammer forging barrels and the maker of the machines had more orders than they could fill. My visit to Remington in '73 there was a hammer forging machine and it took a 12" blank, drilled a hole through it and hammer forged it out to 24". Most makers machinerd the OD but one , Steyr [IIRC] left the distinctive marks on the outside.Some of the barrels also used a polygonal rifling which lends itself to the process.
It doesn't make a difference in what process is used for the shooter . A well made barrel is a well made barrel.

 

[L Puckett]

Interesting,

One point that you may find interesting. Remington Hot Hammer forged their barrels until 2000, they now Cold Hammer forge their barrels. They actually perfected their process in the U.S. quite early in their history. They produce upwards of 750,000 barrels a year in their Ilion, NY forging plant. If you ever have a chance to visit you'll say one thing "DANG THAT'S LOUD".

My preferences have always have been single point cut, then button. Between the two methods I have found both to be very accurate, believing that a premium barrel is just that and the end result can be had or lost by who chambers and threads the barrel.

A barrel is an expendable, just like ammunition. When they start losing the accuracy Get a new one.

FYI,
LP

 

[warbirdlover]

And alot of what makes a good barrel might not be the process used but the method of finishing them afterwards. Lapping all the burrs, sharp corners and rough surfaces. Straightening them when needed. Things like that.

 

[RedneckFur]

Savage uses cut rifling on all its centerfire rifles. Its where their legendary accuracy comes from. You need to edit your original post.

 

[warbirdlover]

I have to disagree. On their website Savage says they use the button rifling method.

http://www.savagearms.com/accuracy/barrels/