Lube Grooves--rifle designs vs. pistol

[AlaskaMike]

The more I get into bullet casting, the more I've noticed something--why do rifle cast bullet designs tend to have tiny little lube grooves and pistol designs tend to have these massive chasms holding bucketfuls of lube? Specifically I'm thinking of rifle designs like Lyman 311332, 311299 and pistol designs like the Keith styles.

Granted there are exceptions of course, but with pistols generally having shorter barrels than rifles, I would expect the opposite. And I realize that some rifle designs have lots of small lube grooves, but most seem to have 1 to 3.

Just curious,
Mike

[felix]

Revolters tend to blast off the lube where and when a shorter boolit goes into the forcing cone and the tail leaves the cylinder at the same time. If the lube were more towards the front of the boolit, the problem would be much less because the lube would be covered by the barrel internals. But, that being the situation, the lube would be out of the case and pick up dirt when carrying. ... felix

[MakeMineA10mm]

I think there may be even more to it than that.

For example, what about the Loverin designs that have up to a dozen lube grooves? Is there any information out there that explains what Loverin's design theory was? I know it apparently works, whether for what his theory was or some other reason, as the Loverin's are very well regarded for their accuracy.

Also, I have been wanting to ask this, but never got around to it, and remembered reading this thread - FELIX (and others feel free to join in), is there some sort of formula regarding the quantity of lube for a bullet? (Presumably, revolving around velocity, bore size, pressure, and bullet design, but how?)

I notice that the fellow who has bullet design software, has a calculation for the volumetric size of the lube groove in cc's. Is there a rule of thumb on cc's based on those factors?

Even though I've casted for 30 years, I've never thought about this until now, and you're the smartest guy I know about lube.

[Bass Ackward]

I think there may be even more to it than that.

For example, what about the Loverin designs that have up to a dozen lube grooves? Is there any information out there that explains what Loverin's design theory was? I know it apparently works, whether for what his theory was or some other reason, as the Loverin's are very well regarded for their accuracy.

Also, I have been wanting to ask this, but never got around to it, and remembered reading this thread - FELIX (and others feel free to join in), is there some sort of formula regarding the quantity of lube for a bullet? (Presumably, revolving around velocity, bore size, pressure, and bullet design, but how?)

I notice that the fellow who has bullet design software, has a calculation for the volumetric size of the lube groove in cc's. Is there a rule of thumb on cc's based on those factors?

Even though I've casted for 30 years, I've never thought about this until now, and you're the smartest guy I know about lube.



Nope. No golden rule on lube grooves. Some designs added them believing in controlling the balance of the bullet.

Some guys liked lube grooves to control the width of drive bands believing that friction played a part. While still other guys believed that fouling sized down your bullet and an empty lube groove gave it someplace to scrape up into. When that band filled up, the band behind it sized down and the next groove started filling.

So there are as many theories out there as there are different designs. But mostly to handle the particular type of lube you are using at a certain velocity. Remember, they used to shoot stuff like water pump grease that needed smaller grooves to remain on the bullet, etc.

[45 2.1]

There has been several articles written on "lube index" in the Wolfe publications, however they don't go into too much detail about what is actually needed. I am teaching another guy how to do this and he has found that the formula isn't a absolute in terms of how much lube is needed. It depends on the firearm/use your going to put it to, pressure range, lube type etc. I won't go into it any furrther as this board doesn't seem to want "benchrest" type of explanations or methods.

[BABore]

Some need mo, some need less. Some need slick, take yo pick on the rest.:-D

All depends if you just want to shoot the bull in the ass, or pick the flys off.

[leftiye]

Aww c'mon guys, can't we do better than that? I've been watching this thread with interest thinking I'd get some knowledge of this subject out of it. Seems to me we're (not just on this thread either) begging the question when we do that little song and dance about "every gun is a law unto itself," and "you'll just have to experiment and find out."

I'm not attacking anybody, and we all know that these concepts do have effect in a lot of different areas. But just as easily we could go into factors that require more and less lube. Just as "accuracy may be where you find it", there ARE standards that are known to promote it (accuracy), and when they are all followed in any given scenario one's chances of success are greatly improved. This subject (lube amount caried by a boolit, to include over lubing) is one that will help greatly in that search for accuracy if standards can be identified.

Is I said I am looking for knowledge in this area, and therefore don't have a lot to contribute. However It seems to me that some of the newer lubes by themselves are altering the scenario vis-a-vis how much lube. Specifically I'm referring to the Carnauba lubes that don't coat the bore, and therefore avoid the lube fouling problems of some other lubes. I suspect that they require less lube simply because they don't coat the bore. This may be one of those benchmarks that I alluded to earlier.

Another would then be obviously a smooth and well lapped bore (some bores are smooth and still lead. I'm supposing that lapping would preclude this scenario), as it would seem to require less lube. I've heard Bass Ackward refer to "lubes without lubricants" (when referring to Lee tumble lube) and I suspect that he has a point. While I know there are lube ingredients that work (reduce leading), and do not lubricate, I suspect that the best softening ingredient in these Carnauba lubes would best be a superior lubricant like Bullplate lube. So, one of these criteria as to how big lube grooves must be must relate to what lube, as less of a real good lube is preferrable from several standpoints.

[Bass Ackward]

Aww c'mon guys, can't we do better than that? I've been watching this thread with interest thinking I'd get some knowledge of this subject out of it. Seems to me we're (not just on this thread either) begging the question when we do that little song and dance about "every gun is a law unto itself," and "you'll just have to experiment and find out."


Well not to be a cop out here. You know how I hate long posts. :grin: But lets look at some of the variables shall we.

Bore condition, bullet hardness, lubrication, and temperature are factors that team up to provide a working option for a certain pressure / velocity combination.

Bore condition X Hardness X Lubrication X Temperature = Velocity / pressure.

Change any one of those 4 factors from it's "perfect" state and it forces you to compensate in one of the other factors. OR .... you must alter your pressure velocity combination. How many possible load combinations do we have in say 357 Magnum alone?

This is a very simple model that pretty much everything else falls under one of these factors. But you can also alter pressure curves by changing powder speed that will change the requirements from those four factors. And you have certain things, like gas checks that throw those factors into different relationships. Want to talk just one caliber? OK, which one? Calibers obviously posses different strengths just from it's diameter. Take two bullets of exactly the same hardness, one a 22 caliber and one a 45 caliber. Whack both equally with a hammer, which one deforms more?

How do you shoot and clean your guns. Do you shoot no more than 20 shots before cleaning or do you like to shoot 500 at a throw? I ask because one scenario allows lube to build up in a bore and thus change how much each bullet requires. And the othermethod requires each bullet carry enough to get the job done straight off.

Did you want to throw bullet design into this discussion for lube groove size too? A bore rider which is a semi wadcutter for rifles has a sharp shoulder to remove fouling ahead of it. Just like handguns. So the semi wadcutter design has to carry all the lube that it requires too where an olgival can use some of the lube already in the bore so it doesn't need as much either. So we would have to agree on a bullet design first too.

And the list goes on. Think about it, if you had a simple equation for lube, you wouldn't need this board. No one would have any problems to solve. We already have a formula buster anyway. It's called the jacketed bullet. Now you know why they caught on. :grin:

[Bass Ackward]

Leftiye,

I couldn't sleep last night wondering if maybe I was any closer to solving this puzzle and providing you with .... knowledge. :grin: I would have to say no I am not.

But I recorded some thoughts.

By far, the single biggest variable in that formula I posted is bore condition. I really should add alignment. With a barrel that is dimensionally correct and properly finished, and ALIGNED to bullet travel, you have almost no limits. You aren't tied to bullet hardness or lube amounts or types. Barrel quality and alignment make you a cast boolit expert. Barrel quality and alignment allows you to shoot PB. And to shoot it at what people here would claim unbelievable levels. You actually have to work to lead. If you don't lead, then your free to work on load development.

Back in lead days, barrel steels were softer. Easier to machine and finish and lead had more of a quick effect on cleaning them up. Not so for today. Veral Smith once wrote that Ruger stainless may take 200 shots or more to clean up with his lapping compound. Think about that. That is a gun that would not correct itself in 3 generations of weekly shooters even using copper. Ever wonder why so many guns get traded?

Bore condition and barrel alignment is the foundation for everything that YOU must do. If conditions exist that require "one size" of bullet to not lead the gun, then sizing is lost to that gun as an accuracy option. Rifles have better alignment by system, so for them chamber alignment is less of an issue but it is still bore condition.

If alignment of a handgun barrel in a frame is not straight inside, then the momentum of the bullet will tend to bring the gun to center and will tend to move the gun in that direction. What you will have is a gun that is harder to shoot as it will be grip sensitive. Impact points will change with load more. You will have to practice with it often. It also means that the bullet is pushing harder on one side of the barrel and more prone to lead there from friction.

Constrictions are over rated, but they will limit your options some as well.

But everything is still related. A fella once told me that the best interior bore finish to shoot lead accurately was 220 grit finish. I said huh? His belief was that lube was a fouling and left in the bore had a way to work around bullets in a rough bore and not cause over lubrication. If true, the really good and smooth barrel could be more prone to over lubrication which may be why some people don't acknowledge it's existence. He was a hard bullet fan and would never consider shooting soft. So maybe in his case, he was correct.

A buddy had a GP100 that we lapped last month. Actually he did it. I am always in search of the "best" methods in everything. I tend to over analyze and then focus believing I am in control. WRONG. This gun was a 4-6 inch performer with everything including jacketed. I was not familiar with the gun. I had no idea what it slugged or any of the little quirks. Normally I do an in depth study so that I end up with this or that. I decided to let the gun speak during the fire lap process.

We started lapping with 220 grit. 24 shots produced no visible results on target and I was getting nervous as he was trusting me. By 36 shots we had dropped to 3". We loaded 6 more. Now the lappers shot into 1 1/2". Loaded 6 more and the group stayed at 1 1/2. Now the gun was ready for finer grits. But we stopped, cleaned well, slugged to see what was now needed and the gun shoots like a rifle instead of a handgun. Rough bore and all. He now does with PB what I can't do (yet) with GCs in mine. (So guess what's next?) What ever was wrong was corrected. His gun seems to shoot everything equally well now and to have no lead limits.

So the problem with fire lapping is that "we think" we should determine when it is finished. In truth, you might have to open a bore a few .000 just to get it nice and straight and aligned inside. If you don't let the gun make the call, you stop too soon and you end up with a grip sensitive and ES dependent piece that you blame on "your" shooting ability or on failed fire lapping.

Bottom line here is that theorizing or guessing only stimulates one's ability to develop options. Options are only needed because something failed. The proof of the taste under every condition is STILL in the pudding. Or shooting a particular gun. There are .... methods or techniques that do tend to work better or solve problems ...." IF ".... you choose or are forced to live with the problem.

But when everything is right or correct with bore condition, very little knowledge of other stuff is necessary and you have no idea what people here are talking about half the time. This is where line boring improves your odds. If it's straight and rifle like, then the rest is easier. Think about this for a minute. Cast independence, just .... like .... jacketed.

So shooting a lube without lubrication is another way of fire lapping only with a slower process and only limited results. If limited results are all that is needed to correct bore condition, then the gun comes round. If it doesn't, we then look for better lubes or "improved" techniques. Sometimes we find them and sometimes we don't. Or can't! Which is why I suppose some can use LLA and some can not.

Bore alignment and then condition is everything to cast. Then it's simple load development. Range time now. :grin:

[felix]

Yep, what BA said should conclude this discussion, but it won't because most folks on this board just cannot justify owning a BR quality gun, pistol or rifle. Reason: money. Simply too much of it is required for a gun that would be difficult to put food on the table unless the deer walked into your back yard and brain-farted himself across the line of sights on a stationary set-up. It is not good for the soul to attempt little groups with guns we typically enjoy having fun with. ... felix

[leftiye]

B.A., Thanks you wery much! (or was that Sanctuary much?) This would exactly be a step or two in the right direction. (Sorry to be keeping you awake, BTW)

I'm starting to believe that (as my previous post said) there may be a possibility of there being such a thing as a BEST lube (or at least good enough to stop worrying about). Your post has outlined a BEST bore condition, and a condition where Best possible boolit alignment exists. And as also alluded to, if we can identify an optimum overall set of conditions, then we can use them for a test platform (or a place to start from).

Slight detour here. Your example of the bore that was not yet smooth, but shot very well makes me want to suggest something. I've got a 6 mm imp. that when it was new coppered like an insane plater had gotten loose inside the bore (oh! what fun- not). As it ages, and gets smoother it coppers less. I'm starting to believe that the barrelmaker didn't do his part right (rough barrel). I'm thinking too that he put the barrel on backwards. It was cut rifled, and the breech end should have been the end where the cuts started, as the microscopic tool cuts left roughness which was oriented toward the opposite end (that should have been the muzzle end). Such roughness also does still exist in button rifled barrels, though not so much. I'm thinking that one huge advantge of lapping is that it removes such imperfections, and/or at least the ones pointed the wrong direction in the bore. This may be the source of the improvement in your barrel, even though it was still somewhat rough.

Any hoo, if these optimum conditions can be as they say, stipulated to, then we can ask what requirements lube grooves must be designed to fulfill for top performance (in a perfect world so to speak).

[felix]

Typically, where the center of gravity and center of pressure meet, both towards the base of the boolit, say 45-48 percent to physical boolit center from base. Cutting lube grooves must make this so. ... felix

[Bass Ackward]

Leftyie,

The world is replete with stories where you can visually see major barrel imperfections that shoot.

There used to be a guy on here named Buck I believe that had a 44 flat top that he said looked like a corn cob after all these years. But shot cast very well.

Years ago we had a Remington 30-06 the guy wanted to build a custom on. It was off centre at the muzzle. Looking through the bore, it appeared to be oval. We got the bright idea to make it a shop demo piece to show to customers along with targets. Thank God we tested before we took it off. The darn thing would shoot an honest inch with two brands of factory ammo after you used windage adjustable mounts to get the scope on target. As a joke I tried 20 grains of 4759 / 311284 cast loaded up that I had loaded for my gun. Held 1 1/2". Needless to say, we gave up on that idea and just trashed the barrel.

What's my point to all the bore stuff? Of all the areas of cast, bore condition has the most dramatic effect on the hoops you must jump through to achieve top success. And you simply have to try it.

Just look at the categories on this board that do well. Almost any Lube Thread gets above average number of responses as we look for:

1. ingredients for that accurate "miracle lube".
2. one that simply doesn't lead.
3. Or something super cheap or fast that goes bang.
4. Some variation of one of the above.

My neighbor twice removed used to cast. The current owners of his house had to replace a rotten floor in the main bathroom. Turns out there was no seal ring for the toilet and it continually leaked under the vinal. Oh yea! Wouldn't put it passed him!!!

Everything will eventually lead if you use it out side of the range for which it's ingredients suffices. Even in a perfect bore. What determines how much and what kind? Your guess is as valid as anyone elses. Think it isn't informed? Welcome to the club.

Moral of the story, always try any advice starting low and come up AND never buy a house previously owned by a caster. :grin:

[9.3X62AL]

GREAT series of posts, BA. Many thanks, sir!

Very astute observation earlier, that most of us don't have the attention span or energy to develop or build rifles and handguns capable of the performance you describe. It denotes my situation perfectly. I have some milsurps and sporters for rifles, some of which shoot very well for my needs--hunting and informal target whacking. My handguns are mostly service-grade semi-autos and sport/general purpose revolvers, and examples of both types can shoot a lot better than I can. I'll admit straight up that I am not a very disciplined shooter--I have worked in venues where mental discipline during firing sequences (or no-fire sequences) was indicated, and now that those days are past I like to shoot things without a whole lot of mental gymnastics going on.

I have the greatest respect for those who can focus their attention to the degree required for benchrest competition, and dedicate the money to the sport to achieve success. There is a lot more than money going on at the top levels of any firearms competition, things like a wealth of natural skill--and a whole lot of hard work. As much as I enjoy the shooting sports and the hobbies associated with them, it's more important to me to be having fun while shooting than to be having precision. Good thing, too--with 36 metallic calibers and 4 shotshell gauges to feed, I would need Bill Gates' revenue stream to refine my collection!