Lube grooves....

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beltfed
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Re: Lube grooves....

Post by beltfed »

It is noted that the bore ride portion of the bullet is grooved (almost?) as deeply as the GG bands.
Leading????
beltfed/arnie
mdeland
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Re: Lube grooves....

Post by mdeland »

Thank you Gerald ever so much as that took a lot of effort and is very interesting to me. I noted the grooves seemed to expand linearly (width) toward the base in the fired bullet which is very unexpected and yet the cross section of the bullet body in the groove expanded as would be expected. It kind of looks like the lube supports and even expands the width of the groove but not so much the cross section. It seems to increasingly expand the groove width toward the base which is opposite of what I would think would happen. Fluid dynamics are not something I know very much about I'm afraid.
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JonnyV
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Re: Lube grooves....

Post by JonnyV »

The thing I do not see is any evidence that the lube circulated in the groove the way Fryxell describes…it looks to me like this lube just stayed in a solid mass and then some of it was ejected from the spinning bullet once it had left the bore (likely in an irregular/unbalanced fashion)…

This brings up other questions…

So if half a groove of lube flies off the bullet…and the other half sticks, you would now have a shockwave coming off one side of your bullet but not the other…am I wrong?

If your bullet is spinning at 58,000 rpm and you have a half lube groove full on one side, it’s now unbalanced and unstable….?

How do we make a lube that easily and completely flies off the bullet upon exiting the bore?

What role does the groove design play in this? The photos above show deep, straight grooves that seem very able to hold lube, some of the time anyway…would a round bottom groove work better?

Everything comes back to the lube and the grooves….
mdeland
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Re: Lube grooves....

Post by mdeland »

The problem I see is that we don't know when the lube left the groove as it could have been partially ejected at impact with snow or oiled saw dust. It's pretty obvious that grease bullets are not imbalanced from uneven lube expulsion or they wouldn't hold most if not all the national long range records. That cannot happen with wobbly bullet flight.
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DAVE ROELLE
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Re: Lube grooves....

Post by DAVE ROELLE »

Seems I remember a lube retention test , shooting thru the tube carpet was shipped on, but I'm not successful in finding the thread
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Etienne Brule
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Re: Lube grooves....

Post by Etienne Brule »

beltfed wrote: Tue Jul 20, 2021 5:38 pm It is noted that the bore ride portion of the bullet is grooved (almost?) as deeply as the GG bands.
Leading????
beltfed/arnie
HI Arnie,

No, I did not notice any leading with my boring scope.

Is that en evidence of nose slump ?

Gerald
beltfed
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Re: Lube grooves....

Post by beltfed »

Gerald,
Re Nose Slump??
Is the fit of the bore ride portion of the bullet a slip fit on the lands?
If so, the bullet bore ride section is bumping up/slumping? into the grooves
Glad you are not seeing leading
Arnie
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desert deuce
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Re: Lube grooves....

Post by desert deuce »

Making sure lube extends beyond front driving band on to the ogive and slip fitting the loaded cartridge into the chamber to where it is almost stopped by the lands contact with the bullet shank seems to give land marks onto the bullet as seen in the land marks in the lube seems to give overall good results, especially with higher intensity loads. Frequently, the land marks can be seen back to the third driving band. When this happens you may want to tinker with best seating depth for accuracy at distance and find as long as the shank is contacting the lands leading will be minimal to nonexistant. Sometimes you hit a point where a trade off is inevitable. Depends on rifle and load.

Of course, it does not seem to be necessary to put lube up on to the ogive but for initially determining the presence of slip fit of bullet to lands.

Always remember when reading this that the information is exclusively directed at match target ammunition designed to perform reliably under vastly varying match conditions, not ideal conditions while plinking around at the range days. :wink:
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desert deuce
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Re: Lube grooves....

Post by desert deuce »

I should have mentioned in the foregoing post that sometimes I actually have to seat the cartridge into the chamber with a breech seater, as much as the thickness of the rim on the case, to get the down range accuracy desired.

AND, sometimes the improvement is dramatic.
Sometimes you get the chicken, and sometimes you get the feathers!
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desert deuce
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Re: Lube grooves....

Post by desert deuce »

I should have mentioned in the foregoing post that sometimes I actually have to seat the cartridge into the chamber with a breech seater, as much as the thickness of the rim on the case, to get the down range accuracy desired.

AND, sometimes the improvement is dramatic.
Sometimes you get the chicken, and sometimes you get the feathers!
semtav
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Re: Lube grooves....

Post by semtav »

desert deuce wrote: Wed Jul 21, 2021 11:02 am sometimes I actually have to seat the cartridge into the chamber with a breech seater, as much as the thickness of the rim on the case,
I've heard tell that is sacriledge in some parts, kinda like duplex and smokeless !!
Kurt
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Re: Lube grooves....

Post by Kurt »

Mike,

I can assure you that the lube is out of the grooves inside 20' :D That is the closest I have shot GG bullets in the snow. You get snow and ice up your way, :D pick a clean spot and shoot over the snow at a target down range and look on top of the clean snow you will find unburned powder and strings of lube. I have never found lube in the grooves of recovered bullets even using the stickiest brands of lube.
As far as what the lube grooves look like, here is an example of different alloys.
The left is unfired and the first and third from the right is my lead/tin/antimony alloy.

And yes, I have shot through cardboard carpet tubing to weigh the spun off lube before and after fired. :D
IMG_1489 2.JPG
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DAVE ROELLE
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Re: Lube grooves....

Post by DAVE ROELLE »

Aha !!! Kurt did the cardboard tube test 👍

Hey Kurt, think you can find that thread 🤔

Dave
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JonnyV
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Re: Lube grooves....

Post by JonnyV »

Kurt....those are all the same mold right? If so, we are seeing different degrees of obturation/shortening of the bullet? Looks like the softer alloys shorten and change up the nose profile quite a bit....

Would be very interesting to see the results of your tube test, I did read about it on here a few weeks ago, will have to search it up again.

Looks like your lube grooves have a bevel cut to them, is that right? Maybe some grooves shed the lube better than others..
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DAVE ROELLE
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Re: Lube grooves....

Post by DAVE ROELLE »

your never lost, if ya don't care where ya are
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