Barrel steel ?

[.30carbnut]

Hello all, hope everyone is in good health today. I have built several Muzzle loaders for myself, rifles and pistols from scratch using 4130 or 4140 stock for barrels. My father brought me a 5 ft long x 1 1/2" wide piece of 6 sided 306 stainless steel stock and said here make a rifle with this.Not wanting to disappoint him I thought I would ask the collective here. I know BP has a low chamber pressure but what do you guys think, would the 306 SS be ok for a 45 or 50 cal. muzzle loader barrel? Thanks in advance for any recommendations.

[M-Tecs]

SS rifle barrels are normally 416R. For high pressure barrels hoop strength and lack of sulfur inclusions are very important.

http://obermeyerbarrels.com/steel.html

http://firearmshistory.blogspot.com/2010/06/barrel-making-making-modern-steel.html

http://www.outokumpu.com/SiteCollectionDocuments/Firearms.pdf

http://www.m4carbine.net/showthread.php?141291-Stainless-Steel-Barrels-410-vs-416-vs-416R

http://yarchive.net/gun/barrel/barrel_steel.html

That is for smokeless. With black and black subs the pressures are much lower. In the mid 1800's most barrels were iron. While it's not a definitive answer the 306 will be stronger than the mid 1800'a iron barrels. The 306 might be softer???????? 306 is not common http://www.bssa.org.uk/topics.php?article=606&featured=1 . This is the only data sheet I could find http://www.beststeels.com/html/2016/StainlessSteel_0304/AISI-306.html

Springfield Armory used wrought iron for barrels up until the 1873 Trapdoors. Remington used both wrought iron and cast steel for barrels but they did start using steel as early as 1831. More details below.

http://www.muzzleblasts.com/archives/vol4no3/articles/mbo43-3.shtml

http://flintriflesmith.com/ToolsandTechniques/barrel_making.htm

http://flintriflesmith.com/WritingandResearch/WebArticles/ironandsteel.htm

http://americanlongrifles.org/forum/index.php?topic=27026.15

[waarp8nt]

From Sam Fadala's Muzzleloading Notebook chapter 1 pages 3 and 4. "Nobel and Abel, In England's 1880's showed a psi rating of 96,000 using black powder in tests". He also quotes the United States Navy reached pressures in excess of 90,000 psi.

[MarkP]

416 R has Sulphur in it (R is for re-sulphurized) allows for free machining chips break into small pieces.

Sure it is not 304 or 316 SS? It will not have the strength as compared to 4140 or 416 SS (it is not heat treatable)

I would be more concerned with impact properties of the steel at lower temperatures(charpy) material toughness is the ability to absorb energy.

[M-Tecs]

From Sam Fadala's Muzzleloading Notebook chapter 1 pages 3 and 4. "Nobel and Abel, In England's 1880's showed a psi rating of 96,000 using black powder in tests". He also quotes the United States Navy reached pressures in excess of 90,000 psi.

Seen the 100K pressure quoted before. Problem is I can't find any first hand tests data that comes close. Over the years I have research this a fair amount. 36,000 PSI is the normal accepted absolute max for BP. I did see one British test they claimed 52,000 PSI. The point is BP has a very long history of being used in low strength irons and steel barels.

[Geezer in NH]

For the amount of work needed to make a barrel I would get a blank of known barrel steel and forgo the unknown one. To me that would be the way

[jjarrell]

Seen the 100K pressure quoted before. Problem is I can't find any first hand tests data that comes close. Over the years I have research this a fair amount. 36,000 PSI is the normal accepted absolute max for BP. I did see one British test they claimed 52,000 PSI. The point is BP has a very long history of being used in low strength irons and steel barels.

I think the 100,000psi result was from a closed chamber test. Meaning there was no outlet for the expanding gasses when the charge of black powder was ignited. I think I remember reading that somewhere a year or so ago.

I would do more research to make sure the steel will hold up to pressure. Think about this......you know to be cautious with it because you are the builder and you're not sure about the durability of the material. But what about 2 or 3 owners down the road when some knothead gets his fingers on it. Stuffs it full of powder, a heavy conical, and thinks its a Howitzer? I'm just playing the devils advocate here.

You can always build it as a chunk gun for target use. You will inherently have precise powder charges and extreme barrel wall thickness, which translates to a measure of safety.

You could build a fowler too. The larger bores and moderate powder charges also equate to lower bore pressure. A stainless barreled fowler with brass furniture and a nicely figured stock would be quite a looker. Maybe a hex to round barrel.

Many, many things can affect chamber pressure in a muzzleloader. I'm at work so the book is not in front of me right now. But, if I'm not mistaken my Lyman blackpowder manual says that a .54 cal round ball, over 120gr charge of Goex FFFg, 32" barrel with a 1:60 twist produces 8300psi of chamber pressure. Round ball pressures are much lower than other projectiles. They are lighter, and have less bearing surface in contact with the barrel. Smaller bores, conicals, and sabots are where the real pressure comes into play barring a bore obstruction. Check my info here though, because as I said, I don't have the book in front of me at the moment.

[Omnivore]

If I were doing it, I wouldn't think twice. Make the barrel and run with it. It'll be stronger than most anything used in the black powder era.

50,000 to 100,000 psi is a preposterous range. That's starting in the modern smokeless high power rifle range and getting vastly far above it. The 50 BMG (Browning Machine-gun) chamber pressure is around 54,800 psi. Who cares? You're not building a 50 BMG are you? Forget that silliness and get on with life. And by the way, the commercial BP rifle barrels, such as from Green Mountain, when they were still making them, qualify as mild steel, and that stainless of yours, whatever it really is, will be at least that strong and probably stronger. Any BP gun I've actually had hardness tested ran in the range of mild steal, far below any modern high pressure barrel steel such as 4140 or 416. And I know; hardness ain't tensile strength, ain't ductility, but don't overthink it unless you're planning on some super-duper magnum, heavy conical shooter.

Do a proper proof test, as always. I proofed my 15/16" straight octagon, 30" fifty cal Green Mtn. barrel, which is designed for round ball, using 150 grains of Goex 2F and a 320 grain REAL bullet. It passed that test just fine. It'll actually be used with patched round ball and probably between 70 and 90 grains 2F. Use good, proven design and fab techniques, allow good thread depth on the breech, fit the breech precisely, don't make it super thin anywhere, and you'll be just fine.

[Texantothecore]

94,000 psi was the Navy number. Pretty stiff load.

[smokeywolf]

If I were going to go with stainless, I'm not sure I'd feel good about anything other than 440C.

[Ballistics in Scotland]

Just about everybody who makes commercial barrels feels fine with steels other than 440C. I don't see strength as any issue here. Very few original black powder barrels were made with anything other than mild steel, and shotguns would hold pressure in the last half or so of the barrel with thinner mild steel than anybody actually used.

"Stainless" barrels aren't actually quite as stainless as we would like, and there has to be a reason for that. Being sufficiently free-cutting is the main issue here, in two ways. Deep drilling is a tricky enough operation with anything, and stainless steels of the most corrosion-resisting grades are notoriously liable to resist drilling, work-harden and overheat the drill. The wrong stainless would also be hard to rifle really smoothly. Uf you go ahead I would advise sticking to either smoothbore or cloth-patched ball.

You also don't see many heavy hexagonal barrels, and there would be quite a bit of work in reducing it to octagonal or round. As you surely don't need a five-foot barrel, you could always use a little of it as a pistol barrel to find out its properties, and if necessary convince him it isn't practical.

[M-Tecs]

I am not aware of anyone making barrels out of 440C. 416R is what the majority of barrel makers use.

[smokeywolf]

440C would be expensive, but also does not suffer from temper embrittlement that the sulphur in 416R sometimes causes. Possibly a good compromise between economy, machinability, strength, wear and corrosion resistance would be 17-4PH