Lower range of Unique performance

[Pirate69]

Is there a minimum pressure that should be targeted to ensure that an effective burn of Unique will occur? Just looking for the lower pressure ranges for using Unique. Currently looking at a load with a max chamber pressure of about 11,000 psi.

Might as well as add 2400; looking at a 9,300 psi max chamber load.

Thanks,
Pirate69

[Outpost75]

I dislike Unique in the Star and Dillon machines because its larger particle size does not meter uniformly. It has also been my experience in the .455 Webley, .44-40 and .45 Colt that Unique does not ignite uniformly, burn completely or provide acceptable ballistic uniformity below about 13,000 psi, and unburned powder granules can get under the extractor of DA revolvers and cause malfunctions. I quit using Unique 20 years ago.

For low pressure smokeless revolver and cowboy rifle loads in the black powder calibers the powders of choice are Alliant Bullseye, Hodgdon TiteGroup and current Olin WST or the older 452AA, if you still have any.

I have been similarly unhappy with 231 in low pressure applications due to its excessive lot-to-lot variation such that it is necessary to work up loads again with each new 8-lb. caddy of powder, so I quit using 231 about ten years ago. For non-magnum loads the best powder is the fastest one which will uniformly provide the desired velocity at the lowest charge weight.

I would similarly forget about trying Alliant #2400 in any applications below about 18-20,000 psi for the same reasons. In the .32 S&W Long, for use in strong modern revolvers I've had much better results with IMR4227 than #2400, using case-capacity charges, without powder compression, at pressures approximating the .32 H&R Magnum <22,500 psi.

For standard-pressure loads in the .32 S&W Long not exceeding the SAAMI MAP of 14,000 psi the fast-burning powders listed above are also the powders of choice.

[1Papalote]

Your fired case will indicate the low end with Unique. Soot will be seen on the outside of the case. Increase charge to seal the chamber.
While Unique may not please everyone, it has a broad application. Hope I never run out of it.

[Pirate69]

Thanks Guys. This helps.

[Larry Gibson]

Depends on what is meant by "effective burn". Some think like 1Papalote that "efficient burn" isn't until the case obturates to seal the chamber.

Many others feel "efficient burn" means to just consistently gets the bullet out of the barrel enough to hit a 10" target at 10 yards or less.

Depends on the cartridge.

In thinner cases of small capacity such as the 22 Hornet and some small handgun cartridges lower psi loads of Unique can give an 'efficient burn". In other larger cases such as milsurp rifle cartridges Unique will not burn efficiently at the same psi as in the smaller cases.

That is why I agree with Outpost75 that for such lower pressure loads a faster burning, easily ignited powder is always the better option. I prefer Bullseye. However, in todays supply situation that may not be an option if Unique is what you have and can't get any other powder.

Knowing the firearm, cartridge and bullet to be used would help with, perhaps, a clearer answer?

[black mamba]

For your application I prefer fast and bulky powders that fill the case enough to detect a double charge. Some I have used and like for their accuracy and economy are Red Dot, 700X and American Select.

[jonp]

That is why I agree with Outpost75 that for such lower pressure loads a faster burning, easily ignited powder is always the better option.

Agree with Larry but my powder of choice is not BE but Promo (Red Dot). Same idea, though. I have no pressure gauge so can't give an answer on the pressure of Unique at the lower end except using math and a WAG but I'd say 10,000? Complete or adequate burn is in the eye of the beholder, though. I consider it to be where no unburnt granules exist the barrel or at the least where it is easy to clean up.
2400 I've not had good results dropping the loads way down. I tried some Blue Dot 38sp loads I got from an old manual I have and boy was it dirty with a bunch of unburnt powder.

I have some of the old powder and some of the new and improved variety. I'll load some 38sp up this weekend for a test using some cast in my Blackhawk test pistol and see how low until it is not working very well. I've not thought to try that.

[dverna]

I have used 231 with low level .38 loads but will differ to Outpost...my expectations may not be that high.

I have also used Clays in low level loads with good results. My. CAS load was 2.7 gr under the Magma 125 or 130 gr bullets in .38 cases. 1” groups at 30 yards. Good enough for CAS.

You can never go wrong with Bullseye for light pistol caliber loads.

[Cosmic_Charlie]

If those are the powders you have on hand........ But Bullseye, HP 38 or Titegroup would all perform better at lower pressures.

[Skipper]

Pirate69, take a look at the data on this page
http://www.gmdr.com/lever/lowveldata.htm

Scroll down on the left side

[USSR]

Also not a fan of Unique. Too many good fast burn rate powders out there that burn much cleaner at moderate pressure levels.

Don

[Wayne Smith]

I have six powder measures mostly collected on eBay years ago. Unique binds in all but two of them - my Belding and Mull and an old Pacific Rifle powder measure that operates in a similar way, the powder is poured into a separate measure. I discovered this after an excursion with my 32-20 (Rem. Model 25) of a significant undercharge and a boolit stuck in the barrel. I tested all my measures with the above result. Consequently I use Unique only in my Belding and Mull and continue to use it.

The measures where binding occured include my RCBS Uniflo and my Lyman 55.

[Walks]

I grew up on Unique, but never in "light" Loads.
Tried it just once, in the RCBS Little Dandy. Just when it came out. A light charge for .38 Wadcutter (out of Bullseye) Loads. Had 2 squib loads out of a 1,000. Never tried a light charge of Unique again.
When Clay's and then Titegroup came out I switched to them for My Cowboy Loads.

As much as I dislike Titegroup in a Plastic Hopper, it's really great for powder puff loads in large cases. Accurate too.
Never had case "blackening" even with bottom end loads out of the Hodgdon Cowboy Action Data handout; 1/03.

[robg]

i found true blue is similar in burn rate to unique but meters very well.

[Pirate69]

I am trying to do something that may not be advisable. If so, I need to hear that it is not advisable.

I want to load a 458 WM 300 grain boolit round. Objective is to load a round that is going to be going to be friendly to youth. I have RedDot, Unique and 2400 available. Velocity around 1,100 to 1,200 fps.

Will be using a filler to ensure that the prime flame has a chance of finding the powder in the large case.

Think I can get a higher chamber pressure with RedDot or Unique than 2400 to help seal the case.

Will this dog hunt?

[Outpost75]

Use Red Dot in the .458, try 13 grains with a 300-grain lubricated lead bullet. No filler is needed and I DON'T recommend using any as you will likely ring your chamber in doing so. Velocity should be very close to what you want and ignition no issue.

Probably will not seal the case, as pressure will be only about 13,000 psi.

[Harter66]

Unique cleans up about 14kpsi and is quit stable up to 20 kpsi as a rule . I've seen a notable amount of data going to 40+ .

Old Red Dot left target loaded 1000 fps 9mm sooty all over , like dangled over fire all night sooty .

I use both in all of the pistols mostly be cause it works and it's inexpensive . That I inherited a 12# can of Red Dot and Unique is also encouragement to use them .

To the 458 question Unique will allow a 45-70 to load down to a hot angry 45 Colts or start loads of 454 with appropriate bullets of 255,300,350 gr . Nominal Trapdoor start loads of 1200 fps 405s are quite nice in an 1895g with a 2010 factory recoil pad .
The Lyman 43 lists 12-16 gr for 405s in 45-70 .
458 probably goes on up to 18 or so . 10-14 should be pretty mild with a RB .