For LLA why would you want deep lube grooves?

[singleshot]

Here's a question I've been wondering: why not set lube grooves to a depth that is just under touching the rifling using the tumble lube method? Why not just set the lube grooves to be just under engaging the rifling? Wouldn't this make a stronger boolit? I know Lee Tumble Lube boolits have more shallow grooves, but still too deep in my opinion. That being said, I've never fired one with more shallow grooves.

The reason I ask, I'm considering a design where the lube groove depth is .012 under. In other words, for my 35 Rem, set the overall diameter at .360 (for MG rifling) and set groove depth at .348.

Somebody talk me out of this, please! :-)

(I guess this assumes the boolit starts out straight to within a few thou' which might be a bad assumption, but should still limit lateral travel.)

[btroj]

Need to leave some room for sizing, don't you? If a guy has a bullet with only .005 deep grooves and he sizes it down a bit he may be left with .002 deep grooves.

I think the fact Lee makes them as deep as they are is to ensure some groove is left after sizing. It doesn't hurt, does it?

[singleshot]

That's reasonable logic. Sizing down a solid boolit is certainly tougher. But there has to be a reason for the depth of the grooves, I would think lube volume more than anything else. Keith boolits are CRAZY in that respect. Some companies simply knurl solid lead boolits and lube them. They seem to work well too. Right? CH4D even sells a boolit knurl tool.

Wouldn't shallow grooves increase BC and structural integrity?

I don't know if it hurts. I don't know if it helps other than lube volume. I can see the benefit of decreased bearing surface.

Is there some rhyme or reason to lube groove depth? Or is it all arbitrary?

[btroj]

BC for cast bullets, particularly handgun bullets, isn't a big deal. Structural integrity? Huh? Alloy and velocity matter more in how the bullet behaves on impact than lube groove design ever will.

Knurling works on commercial bullets as they are already held to a precise size in manufacture. Cast bullets don't have that luxury. Diameter varies from mould to mould, alloy to alloy, user to user. That variation is what causes a need for sizers.

Knurled bullets work well for low velocity handgun rounds. I don't know that a knurled bullet coated with LLA would do so well at 2200 fps in a 30-30.

I hi k the deeper grooves found on Lee TL bullets also gives multiple locations for some lube to build up and seal the bore as the bullet travels down the barrel.

I just don't see where having 15 to 20 thousandths deep grooves hurts a thing. They certainly hold lube better than a smooth surfaces would. Those grooves also guarantee that some lube remains even if the case neck shaves some lube from the surface.

[williamwaco]

For LLA, you do not need deep lube grooves.
For LLA, you do not need shallow lube grooves.

The LLA lubes the surface of the bearing surface of the bullet.

You are over thinking and attempting to solve a problem that does not exist.
Stronger bullet? No. the bullet after the primer pops is like a wad of chewing gum under that pressure. Shallow grooves will not make any difference at all.

Your design would probably work OK. It might even work as well as a mass market design like this:

http://www.midwayusa.com/product/182947/rcbs-2-cavity-bullet-mold-35-250-sp-35-caliber-358-diameter-250-grain-semi-point-gas-check

Take a look at the Lyman, RCBS, or others or even better yet look at the custom mold makers that are members here.

To get the measurements you mention, you will need to buy a custom mold.
Buying a commercial is like a box of chocolates, you never know what will fall out of it.
If you want a custom mold because you want higher quality, by all means buy it.
If you want a custom mold because you want lube grooves exactly .012 deep, by all means forget it.

Talk you out of it? I tried. Did it work? :grin:

For my experience with LLA, see:

http://reloadingtips.com/pages/exp_111201a_lla_test.htm

[bhn22]

I'm a notorious multi-tasker. Everything I have must have multiple practical uses. I speak from annoyed experience about having a mold thats useful in only one gun. My experience has been that that one gun never stays long, because I get tired of bottle-feeding it. To answer your question, grease grooves do most emphatically not weaken a bullet. In fact, there's an entire science of matching lube grooves to the bullets intended velocities and purpose. We could start a rather dry ten page discussion of the principles and probably not cover everything. If you want a custom mold, by all means go for it, but what you propose really only has a basis in theory, and not practicality. Every feature must have a benefit, or it's not a practical exercise.

[singleshot]

Alright. You've all convinced me. As I was!

I do find mountainmolds.com fascinating since you can specify all kinds of boolit parameters. Will probably order one from him anyway. So....

Talk to me about the Keith vs. the Sensible Keith.

[btroj]

I don't know what a "sensible" Keith is.

[JonB_in_Glencoe]

In my non-casting world of friends, I have a Liberal friend named Keith, No sense to him at all !

with that said, I'd surely think theperfessor is a "sensible" Keith ;)

[white eagle]

In my non-casting world of friends, I have a Liberal friend named Keith, No sense to him at all !

with that said, I'd surely think theperfessor is a "sensible" Keith ;)
nicely done

[Airman Basic]

I don't know what a "sensible" Keith is.
http://mountainmolds.com/ has an original Keith and a Sensible Keith. Go figure

[btroj]

I saw that, what I don't see is a real description of what the differences are. What about a real Keith isn't sensible?

[Airman Basic]

I saw that, what I don't see is a real description of what the differences are. What about a real Keith isn't sensible?
Only difference I can see is a little less Lube groove in the "sensible"
9308593086

[btroj]

Doesn't make any sensible to me.......

Elmer made em just fine

[gundownunder]

Are they Keiths?
Didn't Keith draw his bullets with 3 EQUAL size driving bands?

[singleshot]

Guys, the difference is the depth of lube grooves. The "sensible" Keith has a more shallow lube groove which makes an overall shorter boolit for a given diameter and weight. Other than that, I can't discern any difference. You can get them with any number of lube grooves/driving bands you want. You can also specify driving band to lube groove ratio and the angle of the "face" of the bands.

[btroj]

That is a pretty darn minimal difference. Doesn't make much sense to me. Heck, Lyman makes bigger to changes than that......

[longbow]

I'm no expert here by any means but I do think the the Keith 429421 has a lube groove that is deeper than necessary which in turn weakens the "shank" of the boolit.

I have some 429421's, recovered from penetration testing, that collapsed at the lube groove. Never seen that before. They were cast of ACWW, loaded over Blue Dot and shot from my Marlin 1894. The collapse happened at firing not impact as there is rifling on what used to be the bottom of the lube groove.

I have several other designs with less lube groove than the Keith and they all work just fine.

So, to me the "sensible" design with shallower lube groove is indeed more sensible.

One man's opinion.

Longbow

[45 2.1]

Didn't Keith draw his bullets with 3 EQUAL size driving bands?

No, he did not...............

[turbo1889]

Think of it from the view of the mold cutter, shallower lube groove makes it easier to cut the mold. Thus from the mold makers point of view there is a "Real Keith" with a deep lube groove that makes the mold more of a PITA to cut regardless of cutting method (less room to get CNC digital cut tooling inside the cavity and maneuver it, weaker cherry if cherry cut, weaker cutting tool if single edge profile manual lathe cut) and then there is the "Sensible Keith" that with a shallower lube groove depth being the only difference is a very important difference to the mold cutter giving him more room for tooling and/or just that little bit of extra strength and stiffness that can make all the difference sometimes and reduce the PITA factor for him.

Thus from the mold cutter point of view those of his customers who want a Keith type boolit design will fall into the PITA "real Keith" category and the not such a big PITA "sensible Keith" category. It wouldn't surprise me either if there was a price difference between the two built into his online design program to cover the difference in the PITA factor. Been so long that I've ordered a mold from him I don't know for sure and I usually didn't order a Keith design anyway but it wouldn't surprise me one little bit if there is an extra price margin on the "real Keith" or a discount on the "sensible Keith" (depending on how you look at it).

[turbo1889]

Also, as to the OP's original question. Lube grooves aren't just for lube. They are also relief grooves and give the volume displaced from the driving bands when the rifling engraves in them somewhere to go without significantly distorting the boolit.

[Forrest r]

I'm no expert here by any means but I do think the the Keith 429421 has a lube groove that is deeper than necessary which in turn weakens the "shank" of the boolit.

I have some 429421's, recovered from penetration testing, that collapsed at the lube groove. Never seen that before. They were cast of ACWW, loaded over Blue Dot and shot from my Marlin 1894. The collapse happened at firing not impact as there is rifling on what used to be the bottom of the lube groove.

I have several other designs with less lube groove than the Keith and they all work just fine.

So, to me the "sensible" design with shallower lube groove is indeed more sensible.

One man's opinion.

Longbow

I've noticed the same thing decades ago when I had my marlin 1894 also. I had a newer 429421 (round lube grooves) & a rcbs 44-250 bullet molds and my brother had an older style 429421 (sq lube grooves). I cast bullets from all 3 molds from the same pot/alloy & loaded them with (like you) bluedot. And like you I found from the recovered bullets, the weaker the lube groove, the worse it collapsed.

[Baron von Trollwhack]

Think of LLA as KY jelly for the barrel, not testosterone for the bullet. Sometimes more lube is best for the barrel/bullet combination, othertimes, not so much.

BvT

[longbow]

Forrest:

Thanks for posting that. It is nice to have some confirmation and agreement. I had doubters when I posted my original results along with photos. Some said the groove collapsed at impact. Of course that would be impossible because there is less mass behind the groove than in front so yes, the nose would mushroom but the last driving band is not going to collapse the shank at impact. Also the dead giveaway was rifling on the collapsed over bore diameter "groove".

While this happened in rifle testing, the loads were same as handgun loads so I have to guess the same thing would happen in a handgun though I have seen no discussion about Keith (or other) boolits with deep lube grooves failing.

My 429421 has square lube grooves as well.

In any case, my view is that Lee's tumble lube grooves are a good idea and with regular lube groove designs I do not like overly deep lube grooves.

So, when your "trusted loob groove dealer" asks if you want regular or deep loob grooves, go with regular.

Longbow

[Forrest r]

Forrest:

Thanks for posting that. It is nice to have some confirmation and agreement. I had doubters when I posted my original results along with photos. Some said the groove collapsed at impact. Of course that would be impossible because there is less mass behind the groove than in front so yes, the nose would mushroom but the last driving band is not going to collapse the shank at impact. Also the dead giveaway was rifling on the collapsed over bore diameter "groove".

While this happened in rifle testing, the loads were same as handgun loads so I have to guess the same thing would happen in a handgun though I have seen no discussion about Keith (or other) boolits with deep lube grooves failing.

My 429421 has square lube grooves as well.

In any case, my view is that Lee's tumble lube grooves are a good idea and with regular lube groove designs I do not like overly deep lube grooves.

So, when your "trusted loob groove dealer" asks if you want regular or deep loob grooves, go with regular.

Longbow

Ya, the sq lube groove didn't do so well, the round lube groove did better & the rcbs was the best.

What got me to do the tests was recovering my own bullets & like you, seeing riflings where they shouldn't be.

I have the mihec #256, it's a h&g503 clone (h&g version of the 429421) & I have never saw this with that bullet.

You wouldn't happen to still have those pictures?

forrest r

[longbow]

Forrest:

Best I can find right now is attached.

I took this photo to show gas cutting more than anything but you can see 3 SWC's there:

93530

Left and right are 429421's and the middle one is an H&G #503 (Mihec). All are ACWW and were shot into end grain wood. You can see the lube groove collapse of the left and right boolits. Don't recall if loads were the same but I suspect the 429421's were the Blue Dot loads and the H&G #503 was 4227 so comparing for collapse is probably not fair.

I do have the boolits though so will take another photo. At least one completely collapsed resulting in rifling on what used to be lube groove.

Don't want to hijack the thread though (even this is a bit of a hijack) so I can e-mail the photo if you PM me your e-mail address. Or we could start another thread.

Longbow

[Good Cheer]

Big lube groove in the rear is fletching.
Richard Hoch made me a one big groove hemi-headed nose pour in 1981 for the rifling pattern in the carbon steel Security Six barrels that is the whoopie doopie. Saw a metallic silhouette shooter hit the ram three times in the first cylinder full.
I refused to sell. [smilie=l:

[w30wcf]

Interesting topic. Up until the time that Elmer Keith designed his famous single lube groove .44 bullet, most other .44 pistol bullets had two lube grooves. When Elmer designed the 429421 he obviously felt that a single lube groove which held about the same amount of lube that the 2 lube groove bullets carried sounded about right.

Back then, though, most 2 lube groove .44 revolver bullets were designed for use with b.p. and thus carried more lube capacity than necessary for smokeless.

By comparison, the Lee .45 Colt 255 RNFP has 2 shallow (.015" deep) and narrow lube grooves. At 1,700 f.p.s. in a rifle barrel (24") there is no leading with good accuracy which would indicate that there is enough lube to do the job.

Based on that, it would seem that reducing the lube groove depth on a single lube groove to .015"- .020", would certainly work, especially in a handgun. There is a possibility though that the lube may not be retained well in a wide shallow lube groove.

Here is another example.....shallow narrow grooved rifle bullets. At 2,200 f.p.s. they perform very well and carry enough lube for the 26" trip.

http://i116.photobucket.com/albums/o25/w30wcf/Collector%20Cartridges/301620301618.jpg

w30wcf

[turbo1889]

As far as whether a lube groove on a particular boolit design intended for a particular type of gun and cartridge has not enough lube capacity, just the right amount of lube capacity, or too much lube capacity. Well before you can even begin to answer that question you must first know what kind of lube you intend to use !!!

The two most extreme ends of the spectrum in my mind being that blue hard brittle wax crud that they lube some of the commercial cast with which your going to probably need more then one big fat deep lube groove to get enough of that stuff to get the job done even with modern smokeless. Compared to some of the better tumble lube mix recipes where you can coat solid smooth sided no lube groove boolits and have enough lube. Somewhere inbetween is the modern good lube groove lubes like "Speed Green" and "Canabara Red" which you do need at least one small lube groove to hold it but often you don't need much more then that unless your really pushing them hard.

Will this bullet hold enough lube, or will it be too much lube? The only proper way to answer that question is with another question = What Lube?

I've got several "hybrid" lube groove boolit designs that have tumble lube type lube grooves and/or micro-bands on the forward nose section (often set to engrave in the rifling upon seating of the cartridge in the chamber) and then one or two conventional but not too big lube grooves on the bottom of the boolit. For lighter loads I can get away with just tumble lubing, start building some high powered loads in high powered rifle velocity ranges (2,000+ fps) and then I start needing to also fill the regular lube grooves as well, in addition I seem to be able to get the best high end results by using two or more very different lubes to complement each other. A hard but elastic lube in the bottom lube groove that acts more like a gasket then a lube, and then soft very slick speed green in the second lube groove and load the boolits and then dip the exposed noses in a canabara based liquid dip lube that dries to a hard paint like varnish coating. Using that along with a triple layer load I was finally able to push plain base cast with 300 yard all in the pie-plate accuracy out of my 375-H&H at a full 2,300-fps muzzle velocity. And it wasn't just the triple layer load inside the case with a full case compressed charge duplex powder charge with a small amount of flowing gradual buffer right under the boolit in the very bottom of the neck, that alone with just using one of those types of lubes in the two lube grooves on the boolit didn't give me that much accuracy or velocity. Only by using two different lubes in the grooves of very different types so they complimented each other was I able to pull off the accuracy and then adding the third dip lube let me push the velocity up a little higher to that level without loosing the accuracy.

[longbow]

w30wcf:

Aren't those the Lyman PP boolits? Or are those full groove diameter?

On the note of multiple small grooves, I have also had some pretty good success with smooth boolits cast slightly undersize then knurled. I have not weight them to check on lube capacity but have to think that it is small compared to most conventional lube grooves.

Having said that I note that the Lyman 311299 has two very small lube grooves for the size and weight of the boolit. Mostly nose/bore rider but still small lube capacity.

Longbow

[w30wcf]

longbow,
Yes they started out that way but I had the last 3 driving bands opened up to .311" diameter on both bullets so they could be used as a normal cast bullet. The 301620 bullet, left in the pic is one that was cast prior to the mold being modified. The 301618 on the right is from the modified mold.

Thank you for the pic on the recoverd bullets. Interesting.

w30wcf