Lube grooves and bbl length

[helg]

How big should be lube grooves on a cast projectile?

Bore leading on a muzzle side means that there is not enough lube. OK, the longer the barrel, the more lube is needed.

4" pistol and 20" rifle barrels - it is 5 times difference. Does this mean that rifle bullet should have 5 times more lube on the grooves? I do not see this when comparing my rifle and pistol molds.

One of my pistol mold has big lube groves, bullets from it take a lot of lube, and smoke much more than bullets from Lee tumble lube mold, which have less lube on. I suspect that the first mold lube grooves are just too big for a short pistol barrel.

Is there a rule of thumb, something like "cast bullet should carry X grains of lube per square inch of the bore that it travels through"?

[44man]

How big should be lube grooves on a cast projectile?

Bore leading on a muzzle side means that there is not enough lube. OK, the longer the barrel, the more lube is needed.

4" pistol and 20" rifle barrels - it is 5 times difference. Does this mean that rifle bullet should have 5 times more lube on the grooves? I do not see this when comparing my rifle and pistol molds.

One of my pistol mold has big lube groves, bullets from it take a lot of lube, and smoke much more than bullets from Lee tumble lube mold, which have less lube on. I suspect that the first mold lube grooves are just too big for a short pistol barrel.

Is there a rule of thumb, something like "cast bullet should carry X grains of lube per square inch of the bore that it travels through"?
No, most pistol lube grooves carry enough lube for longer barrels and even the TL designs work but I apply regular lube like Felix to the little grooves.
Proper lube does one of two things, It is soft and spins out evenly past the muzzle or stays in evenly to the target, keeping boolit balance. What you don't want is a brittle lube that breaks out on one side of a boolit in flight.
A lube coating can run out in a longer barrel so use a better lube.

[runfiverun]

i have found it is the powder not burning efficiently in the revolvers that produce the majority of the smoke.
i use the exact same loads and boolits in my 44 revolver as i do in my lever action the revolvers smoke the rifle don't.
neither one leads anywhere.
my rule of thumb for lube grooves has been the faster i go the more lube i need not the further in most cases.

[StarMetal]

[quote=runfiverun;633048]i have found it is the powder not burning efficiently in the revolvers that produce the majority of the smoke.
i use the exact same loads and boolits in my 44 revolver as i do in my lever action the revolvers smoke the rifle don't.
neither one leads anywhere.
my rule of thumb for lube grooves has been the faster i go the more lube i need not the further in most cases.[/quot

I don't think that's it. I think with the handgun's shorter barrel the powder is still burning, and carrying along the lube and burning it too, outside the muzzle. You can shoot one or two bullets without any lube at all and not see all the smoke you're talking about.

Joe

[Wayne Smith]

I have always wondered this. Most of my rifle boolits have less of a lube capacity than my pistol boolits - never really made sense to me. Casting BPCR the rule is to have a good lube star on your muzzle - easy to see on those big octagonal muzzles. That tells you that your lube is lasting to the muzzle.

[243winxb]

Seems the handgun bullets have plenty of lube to spare. Using 50/50 bees wax/alox. The gas check on the back of the rifle bullets would seem to protect the lube somewhat if all this is true at this link.
lube is injected forward during the firing process, as the result of high-pressure gas leakage into the lube groove. This injection process forms a floating fluid gasket around the bullet, and serves to limit gas cutting and is a kind of ballistic stop-leak. Hard lubes must first melt before they can be pumped or injected by any of these mechanisms.http://www.lasc.us/FryxellLubeCastBullets.htm

[Bret4207]

There's no formula that I know of. In truth I don't think that lube is that simple. The hows and whys of how it works is open to speculation.

[geargnasher]

Don't ask Guy Loverin this question!!!!!
(or Waksupi, for that matter, he hoards loob grooves, so his boolits are probably missing a few!) :kidding:

My 452664 with one big lube groove shoots about as well as the 454190 sized and lubed the same, I was curious so I recovered some using JimInPhx's method and found they both had a little lube (stick Alox) left on them and a very faint lube star on both pistol and rifle. The .45 Colt revolver accumulates an annoying amount of lube on the frame, front of cylinder, and even blows residue into adjacent chambers causing goo buildup on unfired rounds. I get no leading in either the rifle or revolver with either boolit.

If there is enough lube in the grooves to do all that coating and still make it to the target with some, I think the lube grooves are plenty big, and I probably need a harder lube.

My limited experience with revolver/rifle combos seems to show that just about any groove size will work if you use the proper lube, alloy, and velocity for your application.

Gear

[cajun shooter]

It's almost say 85% lube and then groove. If you have a good working lube it will solve many problems. Like too small of lube groove or not enough lube groove. That is why this question has and will be asked until the end of time. You have some shooters that will refuse to try a new lube because of the results they have with a certain lube. They are correct, why fool with something that works. Go to any type of match and ask the shooters what they are using, both smokeless and BP. Now remember that some of them are sponsored by these people so sort them out. If someone is taken care of by a lube company, you know what his answer will be. If you find that you have guys who are not given anything and they use it then it is a good lube.

[mroliver77]

I believe if your using a good modern lube that most boolits over lube. I have the Lee (Ed Harris designed) boolit for the SKS with TL grooves. With FWFL it works well in my M14 types and 03 etc. There is not much lube capacity there! Other Lee designs I have offer little lube capacity and work just dandy with the Felix lube.
Jay

[Leftoverdj]

I agree with Jay and several others. Lubes have greatly improved over the years. It no longer takes nearly as much as it did when the bullets of the '20s and '30s were designed. Several of our posters report improved accuracy when only one or two grooves are filled in multi band designs.