As I was perusing Pearce's older article on the 45-270 SAA, I began thinking about the bullet design. He asserted that the lube slowed or prevented leading. Why is the lube groove on a traditional bullet so far to the rear of the bullet? Wouldn't it make more sense to have it closer to the front of the bullet, where it could grease the lead behind it?
Grease lubes on bullet
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troy fairweather
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Most bullets unless it's a bore rider don't touch the bore much in front on the groves, the lube helps seal the bore to. In would think a small amount of lube is pushed past the bullet.
Troy is correct, bullet lube not only aids in keeping the bore from leading, it is also a seal.
This is not my picture, several years ago I was having a conversation with someone on another website about round vs square lube grooves. He sent me this picture.
If you look at the lube grooves you'll see that they are compressed. This is that alloy/bhn/psi load pressure thing.
The watered down version:
You hit the loud button and "BANG" the bullets off to the races!!! As the bullet goes down the bbl the pressure of the load pushes on the bullet's base. This pressure compresses the lube groove causing the lube to press outward and forward. Some of the hot gasses get by the bullet's base (bottom drive band) and push the lube forward sealing the middle/top drive bands.
That's why it's a good thing when testing cast bullets to test the same bullet/load with soft and hard alloys over a chronograph. It extremely common to find that a softer alloy will have 30fps/40fps more velocity for the same load when testing +/- 20,000psi loads. The softer alloy compresses faster/better allowing the lube to seal better making better use of the pressure of the load, more efficient.
Not all bullets are created equal, I tested these bullets along with 2 other bullets not pictured in a snubnosed 38spl testing p+ loads.
There was as much as 70fps difference between the best bullet design and the worst bullet design. While 70fps doesn't sound like much it makes a huge difference with loads in a snubnosed 38spl. We are talking 880fps vs 950fps.
This is also where coated bullets really shine. Coated bullets don't need to have the correct alloy for the pressure of the load to get the most out of that load. The coating is already everywhere it needs to be and seals everything. In head to head testing with traditional cast/lubed bullets vs coated it's common to see +/- 50fps more velocity from a coated bullet.
This is not my picture, several years ago I was having a conversation with someone on another website about round vs square lube grooves. He sent me this picture.
If you look at the lube grooves you'll see that they are compressed. This is that alloy/bhn/psi load pressure thing.
The watered down version:
You hit the loud button and "BANG" the bullets off to the races!!! As the bullet goes down the bbl the pressure of the load pushes on the bullet's base. This pressure compresses the lube groove causing the lube to press outward and forward. Some of the hot gasses get by the bullet's base (bottom drive band) and push the lube forward sealing the middle/top drive bands.
That's why it's a good thing when testing cast bullets to test the same bullet/load with soft and hard alloys over a chronograph. It extremely common to find that a softer alloy will have 30fps/40fps more velocity for the same load when testing +/- 20,000psi loads. The softer alloy compresses faster/better allowing the lube to seal better making better use of the pressure of the load, more efficient.
Not all bullets are created equal, I tested these bullets along with 2 other bullets not pictured in a snubnosed 38spl testing p+ loads.
There was as much as 70fps difference between the best bullet design and the worst bullet design. While 70fps doesn't sound like much it makes a huge difference with loads in a snubnosed 38spl. We are talking 880fps vs 950fps.
This is also where coated bullets really shine. Coated bullets don't need to have the correct alloy for the pressure of the load to get the most out of that load. The coating is already everywhere it needs to be and seals everything. In head to head testing with traditional cast/lubed bullets vs coated it's common to see +/- 50fps more velocity from a coated bullet.
forrest r has explained it pretty much the way I understand it
Because the lube isn't spread along the bullet from the front, but from the rear
Hondo 60
Member
Hmmm learn somethin' new ever day!
Gee I have 2 chronographs & bullets with 100% Alox, "Rooster Lube", Alox 45/45/10 mix & Powder Coating.
Now I just have to find a new spot to do all this testing.
(I moved to ILL, and I do mean ill, when I got married 2 years ago, her family doesn't shoot
so I have no where to use my chrono)
Anyone in Northern IL have, or know of a spot?
For newbies - 45/45/10 is 45% Lee Liquid Alox, 45% Johnson Paste Wax & 10% Mineral Spirits.
Gee I have 2 chronographs & bullets with 100% Alox, "Rooster Lube", Alox 45/45/10 mix & Powder Coating.
Now I just have to find a new spot to do all this testing.
(I moved to ILL, and I do mean ill, when I got married 2 years ago, her family doesn't shoot
so I have no where to use my chrono)
Anyone in Northern IL have, or know of a spot?
For newbies - 45/45/10 is 45% Lee Liquid Alox, 45% Johnson Paste Wax & 10% Mineral Spirits.
tightgroup tiger
Member
I hadn't thought about that. I don't shoot a lot of lead but recently I found a box of 500, 124 gr, 9mm Missouri small balls that were hidden in my reloading room for I don't know how long, and decided to load them. I used 4.5 gr of AutoComp and there was no leading and hardly any smoke.
The next batch I loaded 4.9 gr of AutoComp and had bad leading and smoke clouds the size of a small car.
Does the heat of heavier loads defeat the effectiveness of the lube, maybe burn it up so to speak?
Never knew these things. It makes sense with compression and obduration for the lube to be squeezed forward, as well as lubing for the next round. Thanks all for sharing the results of your experimentation. I never knew there could be such a difference depending on lube. I also appreciate the sharing about the coated bullets. I like them for my 357 magnums.
I only shoot coated bullets in my revolvers because I need the extra velocity to make Power Factor. For everything else, I've standardized on RMR jacketed Matchwinners
My first thought would be the second load pushed them too hard and they skid over the rifling breaking the seal, causing smoke and leading.
Riomouse911
Member
A question on coated bullets for those much more in the know than I:
If the lube keeps gas from forcing past the sides of the bullet as it’s squeezed from the lube grooves as the bullet obturates the bore, do coated bullets with or without lube grooves let more gas slide by?
I have coated bullets from Ibeji Heads (165 gr RN .358) and Eggleston (200 gr RNFP .430) with no lube grooves but a sharp base, and a Missouri Bullet Co. 215 gr .411 SWC with lube grooves and a bevel base.
Just a wondering...
Stay safe.
If the lube keeps gas from forcing past the sides of the bullet as it’s squeezed from the lube grooves as the bullet obturates the bore, do coated bullets with or without lube grooves let more gas slide by?
I have coated bullets from Ibeji Heads (165 gr RN .358) and Eggleston (200 gr RNFP .430) with no lube grooves but a sharp base, and a Missouri Bullet Co. 215 gr .411 SWC with lube grooves and a bevel base.
Just a wondering...
Stay safe.
My guess is the coating is soft enough to do the same thing.
I have used home made wax (paraffin) gas checks and not only will they stop leading form very undersized bullets (.358 in a .361/2 grooved barrel/.38 S&W), but will blow heavy leading out and leave the barrel squeaky clean.
I have used home made wax (paraffin) gas checks and not only will they stop leading form very undersized bullets (.358 in a .361/2 grooved barrel/.38 S&W), but will blow heavy leading out and leave the barrel squeaky clean.
whughett
Member
Which is why if your going to push them fast use a bullet design with a gas check.
It's not so much how soft the coating is, it has more to do with how soft the alloy is and the bullet's fit/diameter.
A swaged lead bullet doesn't have lube grooves and relies on expansion to seal the bbl. The non-lube grooved coated bullets do the same thing. Bullet fit is also huge but relies on the cylinders being the correct size in revolvers when the alloys are too hard for the pressure of the load.
I shoot a lot of these modern version of the Himmilwright wc bullet in the 9mm's and 38spl's. They are cast out of 8/9bhn alloy and sized to .358" for everything.
I shoot a lot of these 125gr cast bullets in the 9mm's using the same 8/9bhn alloy..
For awhile I was sizing the bullets to be used in the 9mm's to .356". Had a couple firearms that had bbl.'s that slugged out at .358". I couldn't tell/see any difference with those 125gr bullets pictured above over a chronograph when using the .356" vs .358" bullets in the larger bbl'd (.358") firearms. When using the non-lube rooved bullet pictured above I was getting 20fps+ with the .358" bbulets vs the .356" bullets in the larger bbl'd firearms.
I believe the difference was from it took more pressure and bullet distance down the bbl (resistance to let the pressure build up) to get the non-lubed grooved (huge bottom drive band) to seal the bbl.'s (.356" bullet in a .358" bbl). The smaller bottom drive band of the 125gr bullets compressed faster/easier sealing the bbl more efficiently, hence no loss in velocity when using a .356" bullet in a .358" bbl.
Now accuracy was a whole different ball game. The .356" bullets looked like a shotgun pattern on the targets. When I switched over to the .358" bullets I started getting groups.
Now I use a .cast coated bullet sized to .358" for all my 9mm/38spl/357 needs.
A swaged lead bullet doesn't have lube grooves and relies on expansion to seal the bbl. The non-lube grooved coated bullets do the same thing. Bullet fit is also huge but relies on the cylinders being the correct size in revolvers when the alloys are too hard for the pressure of the load.
I shoot a lot of these modern version of the Himmilwright wc bullet in the 9mm's and 38spl's. They are cast out of 8/9bhn alloy and sized to .358" for everything.
I shoot a lot of these 125gr cast bullets in the 9mm's using the same 8/9bhn alloy..
For awhile I was sizing the bullets to be used in the 9mm's to .356". Had a couple firearms that had bbl.'s that slugged out at .358". I couldn't tell/see any difference with those 125gr bullets pictured above over a chronograph when using the .356" vs .358" bullets in the larger bbl'd (.358") firearms. When using the non-lube rooved bullet pictured above I was getting 20fps+ with the .358" bbulets vs the .356" bullets in the larger bbl'd firearms.
I believe the difference was from it took more pressure and bullet distance down the bbl (resistance to let the pressure build up) to get the non-lubed grooved (huge bottom drive band) to seal the bbl.'s (.356" bullet in a .358" bbl). The smaller bottom drive band of the 125gr bullets compressed faster/easier sealing the bbl more efficiently, hence no loss in velocity when using a .356" bullet in a .358" bbl.
Now accuracy was a whole different ball game. The .356" bullets looked like a shotgun pattern on the targets. When I switched over to the .358" bullets I started getting groups.
Now I use a .cast coated bullet sized to .358" for all my 9mm/38spl/357 needs.
Riomouse911
Member
Gotcha. The Eggleston 146 gr RN .358 has a profile sort of similar to the Himmilwright ones you have above (A long round-nose profile, a solid shank, single deep crimping groove) but the Eggleston nose is more rounded/less pointy. These, too, are coated but don’t have lube grooves.
The use of a gas check I get, the copper alloy cup prevents flame cutting and helps seal the bore as it’s smashed into the rifling under high pressure, and the same for soft lead wadcutters that are relatively mooshy and easily distort when fired at lower velocities. It would be neat if there was some way to slow motion video the higher BHN lead bullets as they are fired and as it hits the rifling to see how the lube and/or coatings actually work when moving down the bore.
Thanks for the responses, I learn something new here almost every day from you all.
Stay safe.
The use of a gas check I get, the copper alloy cup prevents flame cutting and helps seal the bore as it’s smashed into the rifling under high pressure, and the same for soft lead wadcutters that are relatively mooshy and easily distort when fired at lower velocities. It would be neat if there was some way to slow motion video the higher BHN lead bullets as they are fired and as it hits the rifling to see how the lube and/or coatings actually work when moving down the bore.
Thanks for the responses, I learn something new here almost every day from you all
.Stay safe.
Riomouse911
Member
And you could almost put out a cigar in the 9mm HP’s! Man those look like they expand like crazy .
Stay safe.
. Stay safe.
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