PC vs Alox velocity

[petroid]

Sitting at my backyard range and just shot these two groups. Both are 308 win loaded with 26gr h322. Bullet is lee C309-170F cast of 50/50 with copper gas check.
Left group is Alox lubed, right is powder coated. Velocity of Alox lubed is just over 1800fps. Powder coated is 1900 (pic says 1860 and is wrong)
I'm very happy with both but curious about the velocity change. 190067

[runfiverun]

slickness.

[44man]

Slow the PC to match the alox.

[Tackleberry41]

PC goes down the barrel easier. In some cases, seems like low pressure, its the opposite. That a PC coated bullet is slower than lubed. Thats what I have seen in 45 colt and 45 ACP. But with more pressure they speed up.

[petroid]

slickness.

so the PC is slicker and therefore faster?

[petroid]

Slow the PC to match the alox.

The same PC bullet with lower powder charge at velocity virtually matching the Alox bullet had same POI as the Alox bulet and excellent accuracy. I may just have to load the PC bullets with 1 grain less powder

[OS OK]

I've seen 2 to 3% speed increase PC over conventional lube size in the .45 ACP...same load. (870 & 850 FPS)

[petroid]

This group is the pc bullet at 24gr h322. Virtually same poi and velocity as alox at 26 gr. Guess I'll load each bullet at its own powder charge and should shoot the same190106

[Gohon]

That a PC coated bullet is slower than lubed.

I found just the opposite. That's five shots in each target. Not only were the PC bullets a tad faster they were a tad more accurate. Target was at 50 yards.
190109

[racepres]

I found just the opposite. That's five shots in each target. Not only were the PC bullets a tad faster they were a tad more accurate. Target was at 50 yards.
190109

Welp...Just shows you maybe should speed the Alox Boolits up a Bit...

[Gohon]

Welp...Just shows you maybe should speed the Alox Boolits up a Bit...

And prove what?...apparently you don't get the point of the discussion the OP's thread is about.

[runfiverun]

your looking for a node.
if it's at 1932 fps it's probably at 1932 fps with the different lube.

your idea of finding a load for each lube type is a good one.

[racepres]

And prove what?...apparently you don't get the point of the discussion the OP's thread is about.

Maybe Not...is your point that PC is faster and more accurate???
And non PC is just simply slower and less Accurate??
OR

your looking for a node.
if it's at 1932 fps it's probably at 1932 fps with the different lube.

your idea of finding a load for each lube type is a good one.

Does the Firearm exhibit a Preference for a Given velocity for a given Projectile shape/weight??

[flyingmonkey35]

Every gun shoots a little bit different. Nice results

Sent from my LGLS675 using Tapatalk

[Larry Gibson]

The responses and conjectures to the OPs curiosity regarding the velocity "change", while interesting, are meaningless. Given just single 5 shot test strings and not knowing the test procedure the velocity variation is meaningless. Having chronographed thousands of test strings since '75, including comparison of PC bullets vs lubed bullets, I have seen close to that variation with back to back tests of the same load. It's not unusual and w/o further testing of larger samples inconclusive. Kind of akin to looking at two 5 shot groups with a .2 gr difference of the same powder and proclaiming the load giving the 1.15" group is amore accurate than the load with the .2 gr difference's 1.25" group.........

More testing would probably give us a better idea if there was a real difference.

Larry Gibson

[OS OK]

Elvis Ammo just did a little comparison...cursory, but gives a general idea of comparing the same weight rounds...PC'd, lubed and Jacketed.

Powder Coated Bullet "VELOCITY" Vs. Jacketed Vs. Lubed (Pistol + Rifle) (https://www.youtube.com/watch?v=40pTJxDZEfU)

The results are interesting.
Tests were a GLOCK 30 and .45 ACP-231g.-RN profile in PC, tumble lube alox & "THE J-WORDS" <OMG!
He used the same ammo in a carbine to compare barrel lengths.

Then he did a comparison in a 300 BO with 165g.

[Smk SHoe]

With only two groups you could be chasing a rabbit down a bottomless hole. So many variables to try to contend with. Did the weather warm up while you were shooting ( PC bullets in the sun on the bench while shooting other group). Did the sun position change and affect the chrono? Is it a good chrono? Did you shoot the second group right after the first ( barrel warmed up vs a dead cold barrel). Did the PC add any weight to the bullets. Were they seated to exact same COAL ( addition of PC would change load length if you measured to Ogive) Did you clean the barrel between groups? some times a fouled barrel shoots faster than a clean barrel. I know this is a short list of variables and I don't think anyone of these would explain the change in velocity but tolerance stacking may explain it.

[Forrest r]

I noticed the same thing when I first started pc'ing bullets. Started with a 308 and pistol powders that ended up being an extremely enjoyable project. Nothing more than scrap range lead, pc, home made al gc's, ben's red and 45/45/10 lube.

I cast bullets out of range scrap and used traditional ben's red lube + a al gc + coated the bullets with 45/45/10 + sized then to .311" and shot test groups (10-shot groups) over a chronograph.
I used the same cast bullets and simply pc'd them. No gc just sized to .311" and using the same powder/powder charge shot 10-shot groups.
Traditional lubed/sized/gc'd bullets
http://i162.photobucket.com/albums/t242/forrestr-photo/bens311291_zpsfc0dcb8f.jpg (http://s162.photobucket.com/user/forrestr-photo/media/bens311291_zpsfc0dcb8f.jpg.html)

Same bullet/load just a pc'd bullet this time.
http://i162.photobucket.com/albums/t242/forrestr-photo/pc311291_zpsea11d496.jpg (http://s162.photobucket.com/user/forrestr-photo/media/pc311291_zpsea11d496.jpg.html)

It isn't comparing 2 10-shot groups and proclaiming a difference. The groups actually didn't mean much to me, a pulled shot or seating a bullet wrong or casting errors will ruin a group. The same theme kept coming up after shooting/testing 50+ 10-shot groups of traditional vs pc'd bullets.

The pc'd bullets consistently had higher velocities than their traditional sized/lubed counterparts for the same load. At least that's what I found with head to head testing of pc'd vs traditional lubed bullets in 2 different 308w's.

[lotech]

Despite the deterioration of the AMERICAN RIFLEMAN, that publication still has the best method of evaluating rifles and ammo for accuracy and velocity. There are rare exceptions, but generally results are based on five, five-shot groups fired at 100 yards. That tells you a lot.

[Smk SHoe]

Just spitballing here. If the PC is slicker wouldn't it slide easier down the barrel which wouldn't build pressure as fast or as much compared to the a lox. Or since the time in the barrel is so short and the area for the gas to expand is the same maybe it wouldn't matter. This is one of the reasons load development can be a hair pulling endeavor. Just like a load one day is perfect and the exact same load next day wouldn't work for shoot skeet.

[petroid]

All I know for sure is that for this rifle, the pc bullet shots to similar poi and similar group size at similar velocity to the alox lubed with 2gr lower powder charge