Lubed J words in 5.56 (223)

[Zombie Whisperer]

In an attempt to seal ammunition ,improve barrel life, and increase velocity without increasing pressure. I coated M855 projectiles with LLA, and 45,45,10 then loaded them with 26.1grains of WC844 in Lake City brass with CCI #41 primers. After allowing the loaded rounds to sit for 48 hours I sealed up the primers with finger nail polish.

Out of a 15" ar15 barrel:

Unlubed:
2835FPS
SD21
ES73

LLA:
2791FPS
SD25
ES91

45-45-10:
2780FPS
SD26
ES71

About a 50 fps drop, and the primers were significantly flatter with the unlubed bullets.

In an Erlenmeyer flask 3/4 full of water the rounds were placed one at a time under 17 inhg vacuum, and the amount of time it took to leak was recorded.

The unlubed ammunition instantly formed bubbles, and the bubbles floated to the surface in a good stream. All Leaks formed at the case mouth.

The ones that were lubed with straight LLA had 2 out of the 10 tested that had enough of a leak to allow one bubble to float to the surface after at least a min. All leaks from primers.

Only 1 with the 45-45-10, but again after at least a min. All leaks from primers.

It would take many thousands of rounds through identical barrels with the only difference being the bullet lube to really be able to see any difference, so until I become rich that test will just have to wait.

As for the velocity increase I am going to increase the charge carefully, and bring the pressure back up to where it sits with the unlubed ammo.

[longbow]

Never chrono'd mine but I was trying out Federal factory rounds in my No. 5 Lee Enfield and they shot so poorly I was shocked. Cast boolits were shooting reasonably well. So I checked diameter and Federal must use a tight SAAMI spec because the boolits were 0.311" diameter. Well, the throat is 0.315" and groove diameter is 0.314" so 0.311" is just a tad undersize.

So, I decided to knurl the bullets with a tool I made to put annular rings on smooth sided boolits from cylindrical moulds. That brought diameter up to 0.314"+ which is about perfect. Since they now had "lube grooves" I decided to lube the copper jacketed bullets. Why not?

Group size shrunk from about 4" at 50 yards to about 1 1/2" so a significant improvement.

The bore seemed nice and clean after and no sign of flattened primers or other issues.

I figured the lube would reduce friction and increase velocity but since your results are showing reduced velocity then likely I would have seen that too. I guess less friction = less pressure which means less velocity. The differences are pretty small and you are right, it would take more than a few rounds and several sessions to sort it all out for sure.

Interesting though.

Longbow

[Zombie Whisperer]

I was going to do a thousand rounds, but the lube scrapping off, and filling the die up would require cleaning every 30 rounds, even with the case mouth belled.

Your tool sounds interesting if I can find an affordable method to quickly roll a cannalure into the bullet then run it through the star with some Carnuba Red then I may think about seriously turning this into a long term experiment.

My results were a lot like the results that I have read about with moly coating.

[NSP64]

I have used a single cut bastard file to put knurls on a smooth sided boolit I cast up for PP in my .270. May work for copper jacketed. I layed the boolits on a flat piece of steel and pressed the file down hard and rolled once.

I may have to try some speed green on some 55 gr FMJ's(in canalure only)

Also would Pressure be more appropriate than vacuum?

[Zombie Whisperer]

What I really want to do is something like the Lapua 30 cal 200 grain subsonic has, it is a real shallow lube groove, I will look and see if I have a sample that I can take a pic of.

I used vacuum because in order to put pressure inside of a loaded round to make it bubble in water I would have had to drill a hole some where which would sacrifice the case, so instead of pressurizing the inside I just drop the pressure all around it, then I can test every few rounds and still shoot them.

It is quite interesting to see how an unsealed round bubbles under vacuum.