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No, the question isn't about the process, but how often were service rifles furnished with ball burnished barrels?
I have a No4 Mk1/2 that was acquired direct from the military and it has a ball burnished barrel. The rifle was originally issued to my regiment for cadet use; that being the case would it have come from Ordonance Stores, or were cadet rifles sometimes purchased from the trade? (It was brand new when I got it)
That's an interesting one Harry, my gut feeling (or assumption) would be that the hand of Parker Hale or AJ Parker lies somewhere in the supply chain.
An old customer of mine regaled me once with stories of an SMLE at AJ Parkers whose furniture was made of lignum vitae, (it wasn't a success!) but went on to say that the RAF's shooting team always went to AJ Parker's for their rifles. I'm guessing this would have been mid or late 1950's.
I would say that this would have gone from the Cadet Foprce to the outside contractor to be accurised and not done as part of any military contract. Quite how ball burnishing worked - or didn't work, depending on your point of view and/or naivety - has mystified engineers and musicians* since it was dreamed up by '.....someone'. We say that it's based on fuzzy logic. Anyway............. you'd often see a Cadet No4 with the 'Regulated by Fulton' mark on the nocks form and it was accepted that they'd been sent there for accurising.
*The people who know best about vibrating tubular instruments are those with a degree in music - for obvious reasons
Can someone explain what ball burnishing is? I suspect it involves lapping the barrel.
As I understand, or DON'T understand it - and once again, it really depends on who you talk to or ask about it......... It involves drawing a series of gradually increasing sizes of ball bearings through the barrel until one size will draw through cleanly with the exact loading all the way along its path. This indicates that the bore is exactly parallel (ho, ho, ho.....) throughout its length. Yep....., that's it....., and it can ONLY increase the diameter don't forget - because someone clearly DID forget that simple fact. Alas, whoever invented this load of, er........., balls if you'll excuse the pun....., wasn't a metallurgist.
You might have established from this that while the......, yes........., mmmmm, I'm not totally in agreement with some part, say 99% of the notion. But each to his own as they say. Or as my great old and much respected Physics tutor, the late, great Prof Percy used to say to us as students '.....it wouldn't stand up to a great deal of close stupidity'
Huh, no that doesn't make sense.
I assume that if the ball burnishing squeezed out small irregularities in the diameter of the rifling; it would actually change the width of the lands at the areas that were tight. After all the metal has to go somewhere! That does not seem like a good thing for the projectile.
Or is there a second part to the process that I'm not aware of?
Interesting thread with more info here Todays Interesting Facts - Barrel Ball Burnishing
https://www.milsurps.com/images/impo...burnish2-1.jpgQuote:
Originally Posted by WarPig1976
I have visions of mushroomed lands.Quote:
Originally Posted by 30Three
Ball burnishing simply smooth's the radial grooves from the top of the lands from the boring process creating a surface that is less likely to strip lead or jacket material creating metal fouling. The amount of metal displaced is so minute that the lands will not mushroom. I have seen boroscope pictures that comparing a regular bore to a ball burnished bore and the difference is night and day. On a regular run of the mill barrel the lands look almost like files, while a ball burnished barrel I suspect displaces metal from the high spot into the low and was done from the breech to the muzzle.
Pictures would be good. Ta
Mmmmmmm, interesting theory Mr Moose but, pray tell, exactly how does this 'transfer' or 'displacement' of metal take place in a squeezed-down area? During which time, while taking into account............ Nope. I'll leave the second part for when the answer to the first part comes in!
Please don't think that I don't enjoy and respect reasoned argument but so far........... Nope, its what used to be called sheer quackery.
I have a question! How is the ball forced through the barrel?
It will be drawn through a barrel I should imagine, liberally sprinkled with fairy dust and ju-ju paste during a full harvest moon for good measure
IIRC compressed air was used.Quote:
Originally Posted by 30Three
Compressed air...................!!!!!!!!! Impossible I'd say because the air would be venting forwards all the time via the 5 rifling grooves. Unless the volume/pressure of the air was soooooooooo great that it would.......... Nope, I'd say drawn through as button rifling might be today
Barrel makers who use the button-rifling process use something vaguely related, but NOT after the barrel is "finished"
After the blank is drilled and reamed, (a whisker "undersized"), they run a "button" that is essentially a polished, tungsten-carbide "rugby ball", through the barrel. This is intended to "iron out" any fuzzy bits before the rifling button passes through. The more precise the blank is before rifling, the better, and that applies to all rifling methods.
Probably more useful with stainless-steel barrels, as that stuff is weird.
Folks making hammer-forged barrels don't do it, but prefer to concentrate their efforts on producing a blank that, after a basic drill and ream,is machine-lapped to a mirror sheen internally, before it goes anywhere near the big, noisy, rotary-hammer gizmo.
And as for "ball burnishing a standard, "mil-spec" SMLE barrel. They seem to have ALL been hand lapped, as per manufacturing instructions.
Early ones were also "taper-lapped, but in a weird way. The rifling lands were deliberately lapped to form a slight taper that belled slightly outwards towards the muzzle.
Apparently the goal was to reduce the "resistance" of the lands on the bullet, in order to try to increase muzzle velocity closer to the "proper" Lee-Enfield rifles.
Probably kept a lot of skilled tradesmen "off the streets" for a while, until the Mk7 bullet came along and all bets were off. HOWEVER, I have TWO MINT Lithgow "Heavy' barrels here that display slight but measurable "belling" towards the muzzle. Did Lithgow maintain the practice across the board til the bitter end, or was this another bit of "target-rifle Voodoo"?