Velocity change (or lack of) with powder position in 30wcf

[earlmck]

a few days ago I posted about the considerable velocity difference I observed in 44mag loaded with Green Dot depending on whether the powder was forward or back in the case http://www.levergunscommunity.com/viewt ... =1&t=65533.
AJMD referenced some internet sites he'd located with additional info, and one of them (reloadingtips.com) had found no variation at all with a 38/55 and 9 grains Unique, CCI 200 primer, 250 grain cast bullet. I spouted off that I figured he had dry-labbed that since it just didn't jibe with my newfound knowledge. Ooops!

So today I proceeded to shoot that load as close as I could come: 30wcf (hey, it is the same basic case) with 9 grains Unique, CCI 200 primer, 180 grain cast bullet. One set of 10 cartridges with just enough crimp to remove the bell produced from the Lyman "M" die; one set of 10 with a heavy crimp via the Lee FC die.

Then just for grins I did the same set using my newly acquired can of Universal, which friend "Bill in Oregon" advises he has been using to replace Unique.

So here's what I got:
Unique, Light crimp Powder back: 1342+/- 17 fps
Unique, Light crimp, Powder forward: 1326 +/- 9 fps

Unique, Heavy crimp, powder back: 1337 +/- 13 fps
Unique, Heavy crimp, powder forward: 1330 +/- 15 fps

Universal, Light crimp, powder back: 1330 +/- 13 fps
Universal, Light crimp, powder forward: 1334 +/- 18 fps

Universal, Heavy crimp, powder back: 1337 +/- 9 fps
Universal, Heavy crimp, powder forward 1330 +/- 26 fps

This kid finds no appreciable influence of powder position in the 30wcf using either Unique or Universal powder and CCI 200 primers. Big appologies to the fellow who writes reloadingtips.com! And I couldn't even find his name on the site, and I'm not agonna let him know I ever questioned his veracity, anyway.

Also you will notice that Universal appears to be an absolutely perfect replacement for Unique in this application. Now that did surprise me (not that I was doubting Bill, but you'd expect different lots of Unique to show at least a slight bit of difference!) I also was surprised that I didn't see some crimp effect. Nope, nada.

Oh yeah -- this does not appear to be a particularly accurate load in my rifle, but I shot all this in a danged snowstorm and I seriously doubt I did the loads proper justice. The "heavy crimp Universal powder back" load with the low 9 fps SD did shoot about a 3" group (100 yd), but that was the best by quite a lot.

[milton]

Thank you very much for your work! I use a lot of Unique and what you show for lack of position sensitiveness is very interesting.I will have to store that information away for future reference.I wonder if Universal and Unique show the same relative relationship in handgun cartridges.

[M. M. Wright]

Thanks Earl. Always happy to hear this kind of research and the data it provides.

[Griff]

The coyotes were yippin' around my place yesterday, but staying outta sight. I knew somethin' was up! Not that I plan on loadin' up any light loads of .30-30, but good to know. If only I could get my full power loads in that cartridge down around the single digit SD numbers. But, I haven't loaded any up since my son bought the digital scale.

[stretch]

Well, Earl - it's good to know that jostling a hunting load like that around
some in the field won't hurt it's velocity!

But seriously, thanks for the information and the research.

-Tom

[earlmck]

Now to try the 44 mag load using Unique rather than Green Dot to see if that is indeed the big factor.

I have the loads ready to test -- would like to see a little nicer weather, though. Yesterday the snow had built up on the chronograph so that I lost one shot out of the last five, and one had a slightly funky reading which made for a big SD for the "Universal, Heavy Crimp, Powder forward" string...

[KWK]

Thanks for the well timed report. My son had asked me only the day before about a Hodgdon load for the .308 Win., a small charge of Clays under a 168 gn jacketed BT bullet. I warned him such charges can be position dependent, but perhaps I was too cautious. We'll watch for your progress reports.

Tiny charges and a jacketed bullet are unusual. Hodgdon seems to have backed away from recommending Trail Boss under jacketed bullets, yet the data is still in the manuals. Your approach, using lead bullets, sounds like a better bet.

Karl

[earlmck]

Thanks for the well timed report. My son had asked me only the day before about a Hodgdon load for the .308 Win., a small charge of Clays under a 168 gn jacketed BT bullet. I warned him such charges can be position dependent, but perhaps I was too cautious. We'll watch for your progress reports.

Tiny charges and a jacketed bullet are unusual. Hodgdon seems to have backed away from recommending Trail Boss under jacketed bullets, yet the data is still in the manuals. Your approach, using lead bullets, sounds like a better bet.

Karl

Ah, the main thing kinda' tricky about small powder charges in large cases is that it would be so easy to have a double-charge go undetected. You really have to be sure your loading procedure prevents that (I just don't load anything I haven't personally looked down into and checked to make sure the powder level looks normal, which isn't easy in a 308 sized case but can be done by getting the lighting set right). But you fellers "over there" have access to TrailBoss which is wonderful for those kind of loads and is so bulky you couldn't fit a double charge into the case.

I don't intend to do any exhaustive work on this powder position-sensitivity thing. For example, that "Clays" powder has been just as unobtainium as TrailBoss for the past few years here. Although I found 2 cans of TrailBoss at my LGS just last Monday so maybe the loooong drouth for Austrailian powders is coming to a close. Low-power loads in larger cases for grandkid's practice shooting is my main use of TrailBoss. I use cast bullets when "minute of tin-can" is all we need, jacketed when we need to try shooting a squirrel in the eye at 100 yards.

[JohndeFresno]

Despite all of the great new powders that have been made available to the public in the last 12 years, and even though I have several other brands on the shelf, Unique is still the powder that I use for most .38, .357, 9mm, .40SW, .44 Special, .44 Mag, .45 ACP, and .45 Colt loads - and one .45-70 load!

Your work helps to further validate that the powder is well named - Unique, indeed.

Your tests are most illuminating. Thank you, Earl.

[KWK]

The local powder-mongers say Universal has been in good supply but not Clays, so I'll watch for your reports with Universal. TrailBoss I've seen at several stores here in Illinois of late.

For loading reduced charges, we have one of those flashlights with a 90 degree light pipe to peer down in the case. However, I was thinking more about trying Universal in the .444, where my initial tests found TB to be very dirty, and visibility is much better in that case.

Have you ever tried 5744 in a cartridge similar to the .308? I saw Accurate had a load for it, running all the way to 61 ksi, along with a greatly reduced "starting" load.

Karl

[piller]

Thanks for the information. I will file it away for future use.

[w30wcf]

Earl,
Thank you for the info. Very informative!

w30wcf

[earlmck]

Have you ever tried 5744 in a cartridge similar to the .308? I saw Accurate had a load for it, running all the way to 61 ksi, along with a greatly reduced "starting" load.
Karl

I've only used 5744 for cast bullet loads in 30/30 and 30 Rem. where it makes one of my favorite loads. I was playing with it in QuickLoad after you asked this question, Karl. Looks like it would be perfect for making 30/30 power loads in the 308 using 25 to 27 grains and a 150 or 170 grain jacketed bullet. And I'd bet it would be a good candidate for making my 30/30 style 180 grain/1750 fps cast load using 20 to 22 grains. But no, I haven't ever done that.

Because of my shrinking wheelweight supply and my overstock on GreenDot most of my 30 caliber shooting has been with a gas-checked 32/20 bullet and that position-sensitive Green Dot powder. Which includes my 308.

[Lefty Dude]

My go-to powders for reduced lead loads in the 30WCF are SR4759, 5744 and Alliant RL 7. Also for the 30 US / AKA 30-40 Krag, 30-06 & 8mm Mauser.

[KWK]

Looks like it would be perfect for making 30/30 power loads in the 308 using 25 to 27 grains and a 150 or 170 grain jacketed bullet.

QuickLoad did a good job. Accurate's lab data is 168 gn starting with 25 gn of 5744.

Pity Accurate doesn't report the pressure of the starting loads, although it is sure to be low. It's tempting to use it in my .30-40 rolling block.

[earlmck]

QL thinks those are 30 to 31K psi loads at 25 grains/168 to 170 bullet, Karl. Slightly less in the Krag, so should be a right pleasant load for a roller.

[KWK]

Earl, my ancient copy of QL figures about 32 ksi, but it over estimates the speed by 100 fps, so the pressure is likely lower than that. On the other hand, the max charge of 35.8 gn, it gets the speed about right but puts the pressure at 12 ksi over the lab results. I really wish Accurate had reported the starting load pressures. The rolling block isn't a strong action, and my face is even less strong, so I try to limit pressures to about 30 ksi. Lyman publishes starting load pressures for the Krag, and I will depend on their data most of the time. However, QL reckons 5744 needs only 25 ksi to send a 125 gn BT out my 30" barrel at 2400 fps, and that should be good, clean fun. I might get around to trying it this summer, but I have several (light) 4895 loads to work up in that rifle this summer, plus all the .357 carbine loads for my son. Karl

[308magtip]

Reduced 30-30 loads in my H R singleshot are with XMP 5744.I use a 1/4 gr or so of polyester fiber fill on top of the powder and a 170 gr gascheck Lyman bullet.Allshoot well enough thru peep sights at 50 yds for deer.