Gunsmithing cut VS. button rifled barrels..........the truth!

[Frank Green]

Cutting is similar to broaching. A broach has mulitple cutters on it. We do single point cut rifling. So we are only cutting one groove at a time at an approx. depth of .0001" per pass. Maybe .0002" per pass.

Button rifling can be done a couple of different ways but basically it is a cold swagging process. Some button makers pull/push a button for the bore and a separate one for the rifling/grooves. Some do it all with one button. Let's say your making a .308 groove barrel. Depending on the lot of steel you might need a .3115" size button. The button is oversize and the material will expand and spring back for a lack of a better description. The button displaces the material. It does not cut and remove the material like we do with cut rifling.

Later, Frank

 

[pawprint2]

No I don't have anymore information on what FN does or how the testing was done with the FBI guns etc...I'm going off of experience with barrel life, test barrels that we've made gun companies and ammunition makers, bullet makers etc.... I know GA Precision has built rifles for the HRT guys and have used our barrels etc....

I'll give you another example. I have a pre64 Winchester target rifle in .30-06. The barrel judging from the wear etc....is in excess of 5k rounds. With a clean barrel and cold bore the first 10 rounds that gun will shoot right around 1/2moa but after that it won't hold 1/2 moa. If you clean the barrel it will go right back to pounding them but again it won't hold it.

So the questions need to be asked are. How many rounds in between cleaning, number of rounds in the group etc....

If your accuracy requirement is 10 round groups and 1/2 moa I would go on a limb and say barrel life is around 4k rounds. If the accuracy req. is 1/2 moa with 3 or 5 round groups yea the barrel life could be 10k rounds.

What is the accuracy req. and the number of rounds fired for accuracy?

Later, Frank
Bartlein Barrels

I am assuming (we all know what that does) the FBI tested more than one brand of rifle, in fact I would guess every maker wanted to get that contract and submitted a rifle or two for testing. I would also guess all the rifles submitted to the FBI for testing were subjected to the same, established and recorded testing procedure. FN got the contract-the others did not, I again am assuming they "won" the test in a fair and honest way. If on the other hand, they tested the other brands with other ammo/cleaning times/cool down periods etc. then something stinks. I am trying to get ahold of the test procedure and results if possible, I'll post here if I am able. Regarding GAP building rifles for HRT, I have no doubt that is true, why would anyone doubt that? I believe HRT shoots a lot, and even at 10,000 rds/1/2MOA, they will need new tubes-once in a while. FN boasts about their chrome lining technique, their ability to chrome bores without any distortion (any that matters), they must be on to something, or the FBI testers should have a lot to answer for, rigging U.S.Govt contracts carries some time off in a Fed Penn, unless those laws have been changed when I wasn't looking. That's a lot of people to keep quiet and pay off, I don't think the contract was actually that big, again assuming everyone involved was a low life scum and stood back and allowed cheating, or were part of it. I sure hope that isn't the truth.

 

[Nortex]

I am assuming (we all know what that does) the FBI tested more than one brand of rifle, in fact I would guess every maker wanted to get that contract and submitted a rifle or two for testing. I would also guess all the rifles submitted to the FBI for testing were subjected to the same, established and recorded testing procedure. FN got the contract-the others did not, I again am assuming they "won" the test in a fair and honest way. If on the other hand, they tested the other brands with other ammo/cleaning times/cool down periods etc. then something stinks. I am trying to get ahold of the test procedure and results if possible, I'll post here if I am able. Regarding GAP building rifles for HRT, I have no doubt that is true, why would anyone doubt that? I believe HRT shoots a lot, and even at 10,000 rds/1/2MOA, they will need new tubes-once in a while. FN boasts about their chrome lining technique, their ability to chrome bores without any distortion (any that matters), they must be on to something, or the FBI testers should have a lot to answer for, rigging U.S.Govt contracts carries some time off in a Fed Penn, unless those laws have been changed when I wasn't looking. That's a lot of people to keep quiet and pay off, I don't think the contract was actually that big, again assuming everyone involved was a low life scum and stood back and allowed cheating, or were part of it. I sure hope that isn't the truth.

Not sure where I read it but it has been mentioned that the FN rifles aren't the primary rifles the GAP built ones are. Again I believe it was mentioned on here but it has been a while. That being said there are plenty of people on here running the FN A3G rifles and even winning their share of matches so they obviously perform as advertised as do GAP rifles.

 

[swampbuck]

I've always heard that cut last longer and is better for fluting becuase it is done before final rifling.i have been told that button has no tooling marks and a superior internal finish and easier to break in. I guess it should be the same if they are lapped to the same mirror finish. I currently have 3 harts, 1 Krieger, 1 Broughton and 1 rock. From strictly a consumers standpoint and not a smiths I have seen no difference. They are all A+. For me it comes back to price, wait, options and CS.

Tim is right. Broughton and Krieger have been the prevailing barrels at Williamsport recently. Harts used to win all the marbles and still hold their own. Options and availability are usually what leads me to one maker or another.

Krieger doesn't do SS sporters and is tied up with military contracts.
Broughton doesn't like to flute. 175.00
Hart doesn't do 5 R or 5 c

I encourage friends to spec it out to narrow down the choices.

 

[Greg Langelius *]

I'm a little curious as to why so little mention is made about Lothar-Walther barrels. They are, after all the 800lb Gorilla in the room, being simply the largest single barrel producer on the planet, and the first to employ Button Rifling.

http://www.lothar-walther.com/359.php

Can anyone please give a factual basis for where their products fit in all this discussion?

Greg

 

[nhm16]

I'm a little curious as to why so little mention is made about Lothar-Walther barrels. They are, after all the 800lb Gorilla in the room, being simply the largest single barrel producer on the planet, and the first to employ Button Rifling.

http://www.lothar-walther.com/359.php

Can anyone please give a factual basis for where their products fit in all this discussion?

Greg

I have an 18" LW barrel in an Mk12 Mod 0 clone, and it is about a half-MOA capable barrel with my handloads and is easy to clean. No complaints there. I believe LW uses a different (and harder) steel than most other barrel makers -- they call it LW50. Consequently LW50 is supposed to last longer than regular 416 stainless. I only have about 700 rounds on mine so no idea how true it is.

I have read here and there that some smiths don't like to work on LW blanks because its harder (again no idea how true that is). Also, I don't get the impression that they focus on end users and smiths all that much and seem to mostly be in the business of making barrels in quantity for larger scale manufacturers. Finally, LaRue has stated that they use LW blanks in their uppers and rifles.

 

[Jrb572]

Has anybody done like a blind barrel test? One smith 1 barrel from each manufacture and say have it setup for an AW or whatever switch barrel action and see which barrel wins? I guess you would have to have a smith and a guy who do not know each other so there would be no idea what barrel brand of buttoned or cut riffled.

 

[Greg Langelius *]

Chambering LW-50 barrels requires attention to unique machining requirements. But it can be done with relative simplicity once those parameters are learned. Individuals who are interested should contact L-W directly, they are very forthcoming about the process.

When I ordered my 28" 1:8" Savage Varmint profile barrels, I preferred to have L-W perform the entire process from start to finish. I figure nobody else knows how to do it better. I certainly don't and all I can say about it is that I am still trying to learn how shoot well enough to be able to find any flaws in its performance.

I gifted my second barrel from the same order with the same specs to my shooting partner. It made ammunition processing and load development simpler, and yet, the two 'identical' barrels have developed very subtle differences in ammo preferences. I think that this points to an issue related to 'nature vs nurture' where barrels are concerned. How you shoot a barrel apparently has a real bearing on how it shoots.

Greg

 

[RTO]

As for the chrome lined FN barrels I can bring a little info here. I own a FN and shot out a 300WSM FN SPR barrel. The 300 WSM chrome lined barrel performed very well at 1/4 MOA for the life of the barrel. Barrel was shot primarily with a can, shooting a lot of really hot strings, pretty much abusing the barrel in every way possible to shorten barrel life I pretty much did it. I dont look at barrels as what I can get them to last to but how hard can I push them and get every once of speed and accuracy out of them and then throw them away. These loads were extremely hot and many 30 and 40 round strings run with a can in which barrel was to hot to touch for over 20 minutes after shooting. Barrel lasted over 3500 documented rounds before going south. At this point it went from a sub half MOA to 1 MOA pretty much over night. It would shoot 3-4 rounds sub half then throw a flier pretty much consistant. FN asked for the barrel back and they now have the barrel. I will say I was very pleased with the FN performance of 3500 rounds out of a 300WSM, especially how I abused that barrel.
I am a huge fan of cut barrels. I have spun a lot of different barrels over the years and have found my favorites to be Bartlein and Rock. No others will do in my shop. Others may work but I have found what works every time and that is what I stick with. With that said the barrel I spun up for the FN was a Bartlein. One thing I have found with Bartlein is every one of their barrels I have used all seem to cut exactly the same. All of them seem to have the least runout of any I have used. And most importantly the FN replacement bartlein barrel and the the 4 other Bartleins I have cut for myself in the past year have all shot 1/4" groups at 300 yards. I am not saying others wont do this and I dont really shoot paper but I do all my load development at 300 yards. I have talked with Frank several times over the past few years and I can say without a doubt I will never search for another barrel because from machining to target Bartlein is not just about accuracy but consistancy from barrel to barrel, top notch material which shows in machining, least runout that I have seen in any maker, to exceptional accuracy.

With all that said, the biggest detriment to accuracy is the space between the ears. Use what gives you confidence. With confidence comes accuracy.
just my .015 cents