20/28 swap with Unique

[jonp]

On another thread someone did some testing and found Alliant 20/28 to be almost identical to Unique in terms of velocity.
Anybody have any experience with this powder?

[kir_kenix]

I've seen alot of stuff that says Hodgdon's Universal Clays is nearly identical to Unique, but never another Alliant product. Would seem like a waste for them to make 2, nearly identical powders.
For any given cartridge, there may be multiple powders that yield the same velocity with nearly identical loads. The trick would be duplicating this accross the board with various cartridges, and as far as I've seen, this is probably not likely. Even lot to lot, identical powders can vary quite a bit. 2 different lots of Varget in my 6mmBR can vary by as much as 60-80fps with the same load. This can be disasterous to accuracy (and brass life) when one is already opperating on the upper edge. This is why I usually try and buy either multiple (identical) lots of a given powder, or an 8lb jug. Its always a good idea to work ones way back up to maximum if the powder lot is switched (if a top end load is being used).

I would be very leery of substituting powders, especially based on internet here-say. I can't even find Alliant 20/28 on my powder burn rate chart, so that would turn me off to the idea even more.

[kir_kenix]

After looking it up, I see that Alliant 20/28 is a fairly new powder. Only load data I see is for sub-guage shotgun loads. It is very likely that this powder will have alot of useful applications in cast boolits. Hopefully usable load data becomes available in the near future, because this looks like a pretty inexpensive powder with a burn rate in the Unique range. Maybe it will end up being a (cleaner) alternative to Unique, Universal Clays, or WSL.

[jonp]

You can find his testing in the "alternatives to standard powders" in the wheelgun, handcannons forum. It is quite interesting as Unique is hard to come by and I just bought a 45 Colt so this caught my eye. I've been playing around with Promo as a Red Dot sub because I can find it and its cheaper. Originally I was thinking of Alliant 410 but 20/28 seems ok to me. If it works in this application I will give it a try. Someone else also tried it and found it worked in 38sp if reduced .3 or .4gr under a Unique load.

[jonp]

Sorry, I bought a 45 colt and was looking for a powder and saw this sub for 44sp so thought it might work for me.

[GSaltzman]

I've only used it for 28 gauge skeet loads but did talk with an Alliant rep. It is very close to Unique and the load charge was similar but it does not take up as much room in the shell case. I'm sure they could help you out if you sent an email.

[GabbyM]

I did notice the other day an online catalog had plenty of 20/28 and no Unique or about any other standard 9mm powder.

I’ve tried it in a 9mm. I can say that I like it far better than Power Pistol. Which I don’t like at all. I’ve never shot it side by side with Unique. But the one fellow that did didn’t see any gain in accuracy. 20/28 may be cleaner than Unique at 38 Special r 45 acp pressure levels but at 9mm levels new Unique is pretty clean and the 20/28 is still far dirtier than say AA#5 ,which is still my favorite 9mm powder. I check for pressure by using an accurate micrometer to measure for head expansion. Loads listed below showed zero case head expansion but I consider them max. Power Pistol along with WW231 always gave case head expansion before reaching published max loads. Plus velocity was below published.

Powders , as we know, acted different in different cases. In the 9mm these loads are near case full. In a 38 or 45 you’ll have a lot of air space in the case. So 20/28 may not give similar results to Unique in those cases. Pressure will be more shotgun level so maybe 20/28 would be cleaner in a 38 or 45 than Unique.

I should point out that 9mm cases vary widely in capacity. Even among American manufacture. These loads are Fed cases.

Saeco 122-TC #377 , CCI500, Fed case, 20/28, 5.0gr, 1.045” COL, 1142 fps.
Lee 125gr RNFP, CCI500, Fed, 20/28, 5.0gr. , 1.020”, 1119 fps.
Lee 125gr RNFP, CCI500, Fed, 20/28, 4.5gr. , 1.020”, 1081 fps.
Used 4.9gr to load a thousand. Mostly to stay below the speed of sound. Note the 122 grain load is right at the speed of sound so is leaving the barrel in transition. Lee bullet weighed 128grains.

[jonp]

I was not looking at accuracy.as you mentioned but rather a sub for unique without pressure increases. He did say that in 38,44sp and 45acp he noticed no signsvof pressure but he did not say he used a strain guage or what volume the powder filled the case with.

[jonp]

From Ben Amonette, Alliante Powder: "We have not tested 20/28 in handgun applications but the burn speed is similar to Unique. Thanks for your note. "