Question on Lube Grooves

[standles]

Got a quick question.

My buddy and I both bought 45-70's and are messing around with casting our own.

I lean toward the Black Powder loads but afte rtrying them he swore off BP and went smokeless.

Now, some deisgns have 1 - 4 lube grooves. He claims that 1 or 2 grooves are sufficient for smokeless since the lube is higher performance than bore butter and SPG.

His other argument is that less grooves means more bullet to engage rifling and therefore more accurate.


Looking for comments on these matters. I am not trying to win a testosterone game just wanting others more knowledgeable opinions before I squash him under the fist of truth. :mrgreen:



Steven.

[Pathfinder1cav]

Steven,
FWIW, there are a LOT of things involved in getting an accurate load going for your .45-70s. However, I will say that I was able to place 4th in a two day 1000Yd National BPCR match using a single lube groove bullet & Black Powder.
A good rifle with proper Soule sights & bullet should group under Moa @ 200Y. (after that you need to be a good wind doper also). ....Dennis

[montana_charlie]

He claims that 1 or 2 grooves are sufficient for smokeless since the lube is higher performance than bore butter and SPG.
That depends on how he defines 'higher performance'. Lubes meant for use in smokeless loads are usually designed to operate at higher pressures and velocities. Is that what he means? They may not do well (at all) at lower pressures.
Then, there is the fact that bullet lube (in a cartridge loaded with black) is not just a 'lubricant'. It also has the responsibility of keeping the fouling soft.
A light charge (of powder) might only need a single groove-full of 'softener'...but a heavy charge will usually need more.

Your friend is mixing his apples and oranges. Apples need apple wax, and oranges need orange oil. How much depends on how fast you throw the fruit.

His other argument is that less grooves means more bullet to engage rifling and therefore more accurate.
If the bullet doesn't strip, the number of grooves (actually bands) gripping the rifling make no difference in getting the bullet to spin.

However, in very long range shooting, fewer grooves - or very shallow grooves - can improve the B.C.
CM

[Bass Ackward]

Steven,

I can make different scenarios for both size and shape of lube grooves depending on the use for the bullet. Performance at a desired metal hardness or velocity can also alter calculations. Another thing to consider is that lube grooves and band with can be used or positioned for determining the center of balance location for a particular design and have absolutely nothing to do with lube capacity.

Other reasons that come to mind may be that you want small bands so that you can control the amount of lube as opposed to having to fill everything to get the bullet to carry enough. And multiple smaller grooves can allow the case to cover all groves with lube in them when seated so nothing is exposed. This is very important to some people. You may want wide bands particularly in the front if the bullet has to jump to avoid stripping. Or if your rifling height is short or low, you may need more lead contact to prevent stripping than someone else running taller rifling.

So there is no easy answer and why you will see virtually everything under the sun when you look at factory designs. Everything was created by someone who at least THOUGHT that he was logical in what he wanted his design to do. And I am sure there are more reasons that I haven't covered. Just so you know.

[Buckshot]

................standles, look at the old original BP era grease groove boolits for what the REAL BP shooters used when that was the only propellant.

Lube for smokless has one great big positive going for it. It doesn't have to help soften a half pound of powder residue left on he barrel wall as a result of BP's burning. In that case then yes you don't need as much. See the Lee TL designs as proof positive of this.

However it really isn't a simple question to answer as to how much is enough. It's predicated on alloy, pressure, bore condition, plus the makeup of the lube itself. I'm sure there are other issues. As an illustration I have a shooting buddy who is big time into SASS. He has a Pedersoli Creemore rolling block in 45-70 he uses for side matches. Naturally he shoots case, but he doesn't pour his own. He buys commercial so you're at their whim.

He was buying his 45 cal rifle slugs from Dillon. They were 405 gr boolits and (naturally) lubed with a pretty blue hi temp lube contained in 3 normal looking and spaced lube grooves. No issues, no problems. Then he got an order in where he ordered just like before and the boolits had ONE lube groove only, and with the same (looking) blue lube.

They leaded his barrel to a fare-thee-well, and no doubt about it :-). His loads were typical light SASS type stuff. So I was gifted with about 200 commercial cast 405 gr slugs to melt down and pour as I wished. Just looking at them would lead a person to wonder just 'What were they thinking'?

Now on the other hand, for my 58 cal P58 Enfield ML'er I have a Raphine mould that drops a 580gr Pritchit Minie'. This design has no, zero, nada, zilch, so far as lube grooves go. I have certainly shot it probably within 100 fps of what my buddy had shot his 45 cal one lube groove boolits at. I don't get any leading (lube is in the base cavity) so why did he?

For one thing it may have to do with how the different propellants burn. BP burns about as fast just lying in a pile on the ground as it does in a gun barrel. What this means is that at the moment of ignition (for our purposes) the BP charge is all in, and all done. It has achieved it's maximum pressure at that moment. Smokless on the other hand builds it's pressure gradually (by comparison) and the boolit may not experience maximum pressure until it is some distance down the barrel.

The skirts of the Minie' expands as far as possible to conform to the bore form at the moment of the powder's explosion, and then see's a decreasing pressure as it moves away. Certainly the skirts don't 'spring back' away from the bore, but the lessening pressure is less demanding. The boolit has achieved it's max expansion and it expands no further anywhere else in the barrel (Proven by Metford back in the 1860's).

Smokless on the other hand places increasing demands upon the boolit for some distance as it moves up the bore. Assuming rifle type powders. An example is what happens to a boolit fired from a revolver with the barrel removed.

Speaking of revolvers, for my 38 Special target loads I use 148gr WC's cast of pure lead. I also only put lube in the very bottom lube groove. The lube doesn't seem to matter as I've used the fairly soft NRA alox (Javalina) and the last I loaded used Lars Carnauba Red heat lube. I get zero leading in the barrel. The load is the very original 2.7grs of Bullseye. Max pressure is reached about the time the base of the slug clears the casemouth.

Load that same slug of pure lead and one lube groove filled in a 357 Mag and see what happens.

There is no simple answer. Your friend will be right some of the time, and wrong to varying degrees the rest of the time. It's a balancing act of several things, as even more lube then required can cause problems.

..............Buckshot

[joeb33050]

For smokeless loads in 45/70 just about any of the current Lyman designs work fine. I don't use Lee or any aluminum mold unless forced to.
Leading is caused, 99% of the time, by a bullet that's too small in diameter for the gun.
If your bullet is large enough, then the lube type and number of grooves and how many are filled just doesn't matter. Until you're a wizard shot, and probably not then.
We shot the Lyman 457191 at ~300 grains with Darr lube, unsized, in 45/70s from trap doors to Martinis to Sharps at 200 yards and were able to average 4" or less for 10 shots. At longer range the 457193? 405 grain bullet shot equally well. Then on to the NGG and Postell and Gould 330 grain hollow point and so on.
You can fill all the grooves or some of the grooves or one groove and almost always have no problem, and you can use no lube with a Cream Of Wheat filler.
Now let me tell you this. You'll hear a lot about accuracy and the 45/70. If you can shoot five 5 shot groups at 100 yards and average under 2", you're doing very well. Also, under 4" at 200 yards, that's great. I've never seen anyone average 1" at 100 yards with a 45/70 for five 5 shot groups-but I've occasionally shot ONE group well under 1" at 100 and under 2" at 200 yards-proving nothing.
With aperture front and rear sights, best with an adjustable Hadley style or Parker Hale style or Merit rear aperture, my experience is that we can shoot ALMOST as well as with any scope including my 20 and 30 X STS. However, over about 40 and without a great deal of luck, talent, skill and experience; it is very hard to do well with anything but an aperture = round hole front sight.
So, don't worry about the grease or grease grooves. Get a mold for a bullet that's big enough = .002" or so bigger than groove, grease it with Darr or any reasonable grease, use ~14 grains of Unique with a little ball of toilet paper firmly on top, seat the bullet out as far as you can and get the cartridge in the gun; you're good to go.
joe brennan

[standles]

Thanks for the input folks. Basically his point was that he was going to use smokless powder exclusively in his. To lazy to clean up the rifle every 5-10 shots. In that case his point was he was happy with a design that had one groove and used a high temp lube.

I am more of a traditionalist and was leaning toward a BP design that had multiple grooves and used a lube such as SPG. My thinking is more lube keeps the fouling soft for easier cleaning.

The battle was settled in good fashion. I had him bring 10 of his best rounds and I brought my 10 best BP loads.

Lets just say I got a free lunch out of the deal and we decided he will get a mould design to cast his and I will get one to my liking. Then we can swap/trade as needed.

I really appreciate all of your willingness to help and post suggestions/comments. It is nice to feel like you have a community to lean on and learn from.


Steven