why do lead bullets require grooves?
- Thread starter alinwa
- Start date
why do lead bullets require grooves
The groves are there to hold the lubrication. also to expand out during firing.
Our modern jacketed bullets are at grove diameter or close to it, They upset at the base while being faired, , The jacket is there for lubrication and also to prevent leading.
The lube on the cast or swaged bullet is there to also help prevent leading of the barrel
Yes you could make a smooth lead bullet undersized then wrap it with a paper patch for lubrication.
The groves are there to hold the lubrication. also to expand out during firing.
Our modern jacketed bullets are at grove diameter or close to it, They upset at the base while being faired, , The jacket is there for lubrication and also to prevent leading.
The lube on the cast or swaged bullet is there to also help prevent leading of the barrel
Yes you could make a smooth lead bullet undersized then wrap it with a paper patch for lubrication.
TomD
e publius unum
Never been a cast bullet shooter but my understanding is that the grooves are lubrication related but I have to admit that I don't know why lead bullets need lube. Maybe because lead is soft and otherwise it will lead foul the barrel in short order.
Edit: Oh well, someone with more knowledge beat me to it.
Edit: Oh well, someone with more knowledge beat me to it.
Not all the answers, but an interesting link:
http://www.corbins.com/ppatch.htm
I'm trying to remember what the old two-piece bullets looked like. Believe they had no grooves, were paper-patched, seated with a false muzzle, and shot better than any breechloader of the time (& most of today).
http://www.corbins.com/ppatch.htm
I'm trying to remember what the old two-piece bullets looked like. Believe they had no grooves, were paper-patched, seated with a false muzzle, and shot better than any breechloader of the time (& most of today).
Lead bullets need lube because the simple answer, under most circumstances, is that without it the acceleration in a barrel exceeds its shear strength on the exterior of the slug. This results in what we'd call leading.
The other reason is that a lead bullet in the cylinder of a barrel works best like a piston in a cylinder of a motor. Ideally we avoid metal on metal, better metal on a thin film of oil/ lube.
The other reason is that a lead bullet in the cylinder of a barrel works best like a piston in a cylinder of a motor. Ideally we avoid metal on metal, better metal on a thin film of oil/ lube.
Don't know about two piece, but in a previous life I shot a Sharps 45-100-550 with paper patched slugs. Most of the target, buffalo, etc. guns that shot paper patched required a throated chamber for such.
Several of the 19th century buffalo hunters, if they ran out of paper on the plains, used trimmed antelope skin in a pinch. How that for some useless trivia?
Thank you!
I'm only pushing half that speed....it's an expensive experiment but I think I'm gonna' try it. Pure lead, smooth sides, lube if needed.I kinda' think that all the innovations and upgrades through the years have been in order to push lead FASTER.
I'm going slower.
al
L
LorenC
Guest
The grooves are also a way to lengthen the bearing surface while using less contact per length.
That's pretty interesting, although obviously an alternative solution using materials unavailable when grease grooves began to be implemented.
I suppose the only caution there is that there is a fair body of info. About the longer term issues with Teflon in rifle bores, particularly smaller bore higher pressure calibers.
Al to reduce your costs simply have a mould made minus the lube grooves to fit your barrel and yor need. The problem with swagged bullets is the cost of the dies, one of the fellows in our group just went that route in lieu of casting them and they don't shooter any better and or worse. I am talking in regards to lead and tin bullets for competitive work. The Teflon spray lube was a DuPont product only handled by Lowe's in my area. The swagged bullets mentioned above have no lube grooves, they are knurled and rolled in I believe to be liquid Alox. There is a fellow by the name of David Bennet who is producing for sale at around 55 cents each. He had an add in the for sale section over on the ASSRA web site and a couple of our competitors have bought some from him for comparison purposes. The down fall at that time was they could only be had in 1-30 alloy but I believe that has since changed?
JLouis
JLouis
243winxb
Member
It would seem lead has more drag/friction then copper?? Without the Lube?
Found this - "coefficient of friction of various metals against other metals- "Kinetic" COF Copper to mild steel = .53
Lead to mild steel = .95 " I cast & use lube. Many variables in lead/antimony/tin alloys.
Found this - "coefficient of friction of various metals against other metals- "Kinetic" COF Copper to mild steel = .53
Lead to mild steel = .95 " I cast & use lube. Many variables in lead/antimony/tin alloys.
OK, I had a mould already made, by arguably the best guy in the biz..... I have a bunch of cast bullets in hand.
And BTW I'd love to just buy the bullets from a pro. I DO NOT want to make bullets! It's just that it's my only option as no one makes the big bullets. They WILL, 10yrs from now once the concept's proven,
but they don't at this juncture.Al go for it, I believe in where you are headed and have no doubts it will work. I love it when someone skates on the other side of the ice and quiets the voices of the naysayers. As I have mentioned before a dear friend and cast bullet experimenter has been there as well as other places no one else has dared to venture with lead and tin bullets. Your approach is quite different than his and I am sure it will be a first as well as being ultimately successful and a unique personnel accomplishment.
JLouis
JLouis
There is always a compromise, Al. Staying below Mach 1, you can get wind drift down for target shooters only by using quite heavy bullets. You can punch a big enough hole in game only by using bullets over .400 or larger, and wind is still of some concern. Not entirely sure what to do about penetration, esp, a head shot on dangerous game, where there is a lot of bone to go through....It's just that it's my only option as no one makes the big bullets. They WILL, 10yrs from now once the concept's proven,
In any case, you're talking about big, heavy bullets. Perforce, you're talking about recoil, esp., in the under 20-pound rifle category...
Al, Have you dismissed the polymer painted lead bullets? It looked promising when I checked it out and it's been around for a good while, so you might get some feed back using that approach. It was a little time consuming for what I was wanting to do, but for 50 cals it might be worth taking a look.
Charlie
Charlie
Yes.
I'm hoping the combination of 10"-16" of barrel and 8"-14" of suppressor or muzzle brake will help with the recoil.
I haven't dismissed anything
If there's a tipped lead bullet or ANY lead bullet available in my wt range I'll order them today. As far as I can tell there's nothing out there over 650gr and that's just not big enough. In fact, I'd just buy Barnes and Hornady ready-mades if it wasn't for the problems of expansion and them getting stuck halfway down the barrel.....From what I've found only pure lead offers the correct expansion coefficient for this velocity range. This thing should range a hippo, on paper.
But remember, I'm early in here. I've got three barrels committed, three chamberings to try and a couple action/stock mules of proper size.
You get those Cookie Cutters worked out and I'll give them a whirl!!
al
Al: As far as competition goes, short range is out. The barrel taper rule limits muzzle diameter, and no brakes...Long range, maybe.
Hunting, well IIRC, in the States, you can't take a suppressor across state lines without more paperwork, but un-suppressed, or hunting only in your own state, after the what's it up to now, year-long backlog getting the suppressor tax stamp? But it you bag the suppressor, maybe...
Hunting, well IIRC, in the States, you can't take a suppressor across state lines without more paperwork, but un-suppressed, or hunting only in your own state, after the what's it up to now, year-long backlog getting the suppressor tax stamp? But it you bag the suppressor, maybe...