commercial vs. canister unique

[corupter]

I recently got a great deal on bulk powder. It is supposed to be unique commercial powder. Same burn rate but finer flakes to meter better. I was given load data for several handgun rounds I plan to use this for.
I was curious about bulk difference between the two and found 1.3 cc's of the canister version came in at 11.4 grains. 1.3 cc's of the commercial powder came in at 14.5 grains. My question is how can I safely convert my load data for other rounds I use unique for? The guy I got the powder from only uses it for 2 handgun loads and has no other data.
Thanks for listening to me ramble. 1st time posting here. Will appreciate any feed back. thanks and have a Great day!

[Rocky Raab]

I don't use "conversion factors" to calculate charge weights. Instead, I do actual testing.

With most handgun "mystery" powders, I load a few test rounds as if it were Bullseye. I use .38 Special cartridges, 158 cast bullets and 3.5 grains of the mystery powder, then test-fire them in a strong .357 revolver. Then I compare the velocity I get versus what Bullseye would have given.

If the speed I got is slower than Bullseye gives, I repeat the test using data for Unique. Same round, same other components. Compare velocity again. If still slow, repeat using 2400 data.

In this instance, you could begin with the second step - although it would only cost you five shots to begin at the safe beginning.

Be very circumspect when working with any unknown powder. You are functioning as a ballistics lab here, and if ANY small detail of it gives you concern, it may be better to dispose of any mystery powder and buy commercial propellants.

[PB234]

Commercial Unique maybe $22 a pound or so. Losing an eye or finger priceless aside from the medical bills.

[felix]

Rocky's methodology is the correct solution. Powder obtains a surplus status when it does not meet a CURRENT specification for its intended purpose, being the powder is either brand-new or reclaimed from ammo. The home reloader always benefits provided the price is right for the seller to remarket. EVERY lot of powder must be examined no matter what its designation, canister or surplus. Labelling mistakes occur at random, even at 22 dollars per pound retail. ... felix

[corupter]

I will test as advised. The guy I got this powder from has been using it for quite a while. He loads 9mm & 45-acp for his sub guns with it. It works well for those 2 for me. I am wanting to use it in other loads I use unique for but want to be safe in doing so. the guy I got the powder from didn't want to advise on other loads he hasn't worked with and I understand that and respect that. I can get 50# @ $11 a # so I really want to make it work for other apps. Just don't want to hurt anyone while doing it.
Replies are much appreciated. I'll let you know how it goes. Thanks.

[BCB]

Rocky Raab…

I learned of your method of testing an unknown hundgun powder on this site and I have used it…

Sometimes things that are so dang simple are impossible for many to develop—me!!!...

But, isn’t it a pretty big jump in burning rates going directly from Bullseye to Unique powder…

I guess I would have thought maybe something in the middle—say maybe Green Dot or 231 before finally going to Unique…

Just curious…

BCB

[felix]

Of course you are correct, BCB! Rocky is working faster to come to a conclusion and taking bigger jumps to do so. Rocky's method is faster because it is TYPICALLY faster to hone in onto something by jumping over and under by a longer stretch, and then shortening the stretch per iteration. Engineering wise, this is called using the damped sine wave approach, i.e. clamping the outer limits to find the shortest stretch possible. This method is possible when there are quite a few powders on the bench to bounce back and forth with. ... felix

[runfiverun]

you can also cross check rocky's method by using commercial unique.
load it down to the first level and run that across the chrono.
if the numbers are similar to the suspected powder then the next [larger] step is more likely warranted.

[TCLouis]

Corupter

So if your buddy has been using it for years, how does his loading data compare to Unique loadings for those cartridges (weighed charges not volume. Either it is a denser powder, or due to grain size more will fit in the same volume. Either way, his loads either are, or are not the same as they would be with Unique.

That will give you the first hint.

His use in subguns may negate some of or most of that guesstamation value.

[Rocky Raab]

The main reason I use Bullseye, Unique, and 2400 data is because darn near every load book has data for them. Also because darn near every reloader has them, and can easily run an "in my gun" test to get real world velocity numbers. If all you have are Acme 100, 200, and 300 powders - and can find lab-tested load data for them - you can certainly use them instead.

The ultra-prudent tester will use START loads for each and every step of my method, of course. I quoted the classic .38 Special 3.5 gr Bullseye load above because it is universally known, produces under SAAMI-level pressures for the .38 - and I shoot mystery powder test loads in a Ruger .357 Mag Blackhawk.