Lee Tumble lube grease grooves VERSUS Elmer Keith style grease grooves

[TheGuyOfSouthamerica]

Here the Nagant style Lee 148 grain Wadcutter in an 38 spl case loaded to "357 mag" pressures with 3.4 grain powder:



I just shot an cat with it again. Got him right trough the head. No tumbling to see. Once dead I shot him again through the ribs. Nice entrance and Exit hole. No tumbling to see. The bullet (next left to the Wadcutter reload in the photo) is the bullet of the second shot which got flattened out at my Wood stop behind the dead cat.
Seems to an lead bullet (no matter what design or meplat) does very well in soft media. But in hard media it soon looses Penetration due to Deformation and Expansion.
The other deformed lead bullets are all from shootin at Wood from an distance of 45 meters.

[Unclenick]

Those Nagent rounds press against a forcing cone surface to create a gas seal. The Nagent revolver (1895?) had a funny cylinder that backed up to rotated and then moved forward again to achieve the seal. The idea was to get more velocity by not having a barrel/cylinder gap. To me that was a little silly, as letting the bullet go slightly further forward and using more powder would accomplish the same thing with less complexity. The main real advantage to my mind is the presence of the seal should allow the shooter's weak hand to stabilize the barrel or wrap around the cylinder area without getting cut by escaping gas.

I thought a little more about Lee's friction claim. It occurred to me that with its shallow grooves, the Lee TLWC friction reduction is for the same reason bands on solid bullets reduce their friction: less bullet bearing surface is in contact with the bore. However, reducing friction is no guarantee of increased velocity. Indeed, with many rifle cartridges adding a lubricating coating to bullets actually reduces their velocity by giving up some of the resistance the powder needs to build pressure against. However, this will be more of a problem with slow powder than with fast powder. Also, because of the presence of the barrel/cylinder gap in a revolver, a revolver will see more gas vented when a bullet has more bore friction, so in that particular situation, the friction may matter more than in a sealed gun barrel. You'd have to try it and see.

The narrowed nose of a conventional bullet shape causes its center of pressure to be ahead of its center of gravity. That is, if you balanced the bullet between opposing needle points located at its center of gravity and blew on it from the side, the pointed end would catch more air than the base end and would be turned away from the air source, leaving the base facing into the wind. This is just the opposite of an arrow, for which the center of pressure is behind the center of gravity, so the feathers catch more air than the head and turn it into the wind. The exception with bullets is the hollow base wadcutter, whose center of pressure is behind its center of gravity. Some Minie ball designs may have their center of pressure and gravity co-located as does a double-ended wadcutter, so neither end favors the direction of the wind.

What that all means to bullet stability is that most bullets do not have what is called static stability in their direction of travel, like an arrow does. Without spinning fast enough for precession to correct their noses into the air stream, they will tumble. In theory, the hollow base wadcutter should be stable without spinning, but the center of pressure of such a bullet really isn't far enough behind itsr center of gravity for that be sure of stabilizing it, and I have seen them keyhole. They would also need fins to really get the air to stabilize them without spinning them.

The other factor is that when a bullet first leaves the muzzle, the gas escaping behind it accelerates to a higher velocity than the bullet has. So the bullet actually has this gas rush around it from behind and form the blast sphere you see in schlieren shadow graphs. They actually experience a tail wind from muzzle blast for the beginning of their trip and don't see a head wind until they break out of it. A hollow base wadcutter with too much powder behind it, for example, can have its skirt blown open as it exits the muzzle and be knocked off-axis before it even gets to the headwind.

The forces on the bullet in any fluid (air or water) have a lot of similarities. Indeed, Newton worked out the drag function shape coefficients by dropping shapes through water rather than air. Water cavitation eats up more energy than creating a partial vacuum behind a bullet in air does because the water goes through a high energy phase change in the process. Going through wood you run into fixed yield thresholds beyond which its resistance drops considerably. So there are differences in different media, but despite that, for short penetration and absent great deformation or turning of the bullet, they aren't so different that the ballistic coefficient still won't tell you something about relative penetration.

Incidentally, this photo of Keith's 45 Colt semi-wadcutter shows it is so close to the nose shape of a full wadcutter that it would be considerably more effective on game than a round nose.

(Attribution added to photo to fulfill Wikimedia Commons requirement.)

[TheGuyOfSouthamerica]

Dear Unclenick,

In one Video the tester Shows (7.62 Nagant Revolver test) that the gas seal rounds vs conventional modified 30-20 or something cases have up to 300 fps more velocity than non gas sealing modifications (same powder Charge).
I guess the opt to make the gun more complex in order to have an more efficient round (less powder for same velocity). Similar I do recreating in a way the Nagant seating method in the 38 spl case in order to use as less powder for same velocity. Considering the Wadcutter I get in those 38 spl an similar empty case Volumen than an 9mm Luger does (loaded with cast bullets which have to be seated to 1.044" OAL in order to go into battery reliably). So as well they tried probably to make the whole gun-ammo System as efficient as possible (adding complexity). Opposite road went the almost contemporary Samuel Colt SAA in 1873. (Maybe the Colt SAA model is more robust than the Nagant Revolver).

Well yes if the bullet glides too easy down the Barrel due to less friction or too much lube causing the powder to burn incomplete then that is bad News. Usually that can be remedied by a heavier bullet (since crimp is not much of a help in my Nagant type reloads) and by seating depth. I realised These 148 grain Lee Wadcutters cause incomplete powder burn if seated flush. That is the reason I seated them deeper ocasionally stumbled over the "Nagant seating" inadvertedly. as I realised later.
In my opinion if one gets incomplete combustion by reducing bearing Surface (Micro grooves) and more lube (with the Lee Tumble lube Micro groove design the bullet supposed to ride almost only on lube as I smear the whole side of the bullet full of the animal marker Crayon Raidl Raidex lipstick type lube I use for lube. The whole Barrel is after each shot lube and that protects it from rust as a positive sideeffect).
I believe the Lee microgroove made the bullet more efficient and so other variables have to be adjusted. For example for the same friction you can use a heavier bullet bacause MAYBE you get a trade off on sectional density-acceleration per grain of powder and less Barrel friction (less Barrel friction is almost equal to the slower acceleration of the bullet per powder unit and so one can use an heavier bullet getting similar velocities). Maybe!

I fear using an hollow Point Wadcutter will risk getting leading when the powder Charge is too high due to the hollow base presses with force against the Barrel.
Maybe the ballistics of an WC gets near to an "unsolvable equation" since there are too many variables.

The Ballistic Coefficient seems to be related to bullet shape and weight. That one can observe looking at the Lee table on their Website. Same bullet shape have different BC if the weight changes like the Lee 105 grain SWC and the 140 grain SWC (38 spl); as well the Lee 102 grain Round Nose and the 125 grain Round Nose (9mm Luger)

What worries me about the Elmer Keith 45 colt design is that only the last 60% of the bullet ride on the rifling and the nose floats in air in the Barrel. Seems to me the nose is pretty heavy and may get off centre in the Barrel while firing. But who am I to argue with Elmer Keith. As well some argue the lead bullet really just Needs on lube ring near the base. Supposedly that works fine (I lube mine completely as well sideways the whole bullet as well the base gets some lube).
With my "Nagant style" deep seating I will stick just to Wadcutters. I started to load them a Little hotter to about 3.4 grains to 3.5 grains of 700X type or Bullseye type shotgun powder.

[TheGuyOfSouthamerica]

I loaded yesterday again 7 shots of the "Nagant style" 148 grain Lee Wadcutter in the 38 spl and shot it today through my 357 mag SAA Revolver. This time I loaded These WC to 3.4 grains of 700X type shotgun powder (before I loaded them to 3.4 grains of Bullseye type powder which is a weaker load).

I shot again Wood at about 7 Yards and the results were again similar to the other Shooting at 45 meters.
The round kicked a lot more and I would not dare to load it hotter with this powder (since more powder I may get into the realm of compressed powder Charge). It still felt less recoil as an factory 357 mag round but considering the deep seated reduced empty Volumen of the 38 spl case I do not want to risk overpressure. I shot 3 shots.
It made an nasty Exit hole in the 1st Wood and tumbled slightly again in that way it has about 30 degrees sideways when it hit the 2nd Wood. This one it almost penetrated and probably would penetrate more if it would not had be lead and soft lead (as bullet media). So in hard media after Impact These WC will tumble allways but less if loaded hotter.

The effects was considerably more than the previous tests as it allmost got through 2 Woods but the destruction was devastating. It mushroomed to an Diameter of .767". This Diameter gets Close to an 12 ga slug I believe.
The whole Body mushroomd and basically only the base stayed intact. I guess with lead bullets ther is no Need whatsoever for hollow Points.
If it would have been an FMJ Wadcutter it may have made it through all Sheets of Wood.

Most important is there are no signs of overpressure whatsoever. The primers look nice. The cases were not sticky at all. No bulges nor rings to see as well neighter signs of unburnt powder.

[TheGuyOfSouthamerica]

Hi to all,

Today I got my Lee #4 Buckshot mold. Now I am able to make my own Buckshot and as well for my workers.

As well the local gun sho got finally the WSP primers in. I picked up 10000 of them and another 2000 when more will arrive this week. So for a long time I will have primers.
Each primer costs 0.07 US$ that is around 7 US$ per a pack of 100 WSP (with an discount already).

[Dozermonkey]

Do a google search for this book.
Guns , bullets ,and gunfights. By Jim Cirillo.
A Paladin press book. Isbn 0-87364-877-3.

He has real life experience shooting bad guys with 38/357 wadcutters.

[TheGuyOfSouthamerica]

dozermonkey,

I looked in the Internet and found no one free pdf book of Jim Cirillo.

You may send me the link for a free pdf of the book.