As I understand it, ammo manufacturers use "cannister" powders or something like that?  And we can't get them.  I'm just picking up what I heard.  They don't use the same powders we can get.  I was just wondering why.  Not because I'm jealous -- more for my own edification.

"Canister grade powders" are what we get.  They are tremendously consistent.  Manufacturers use powders that are potentially LESS consistent, but the manufacturers can test each batch in very involved ways that we can't (got a "bomb calorimeter" in your shop?), so that lack of consistency isn't a problem for them.  They just adjust their loads for the appropriate velocity and pressure and they're golden.

What's the real drive to get those powders, anyway?  They aren't really that much less expensive, even in surplus channels.

I am sure that they only difference in powders is the product quality and packaging specifications.  When it comes to powders, many of them are sold by quality grade.  The tighter the distribution, the more expensive the powder.  It is the difference between target grades and more "general" grades of powder, other than the burn rate.

I don't think you are missing much.

Thanks guys.  As I said, I was just curious and was interested for my own personal knowledge.  I'm perfectly satisfied with the powders I can get right now and had no interest in buying these commercial powders.

Liability is the reason.  Cannister grades are easy to produce with acceptable lot to lot variances.  

Surplus powder is cheaper I would think than "commercial powder".  I would think commercial  powder is sold in humongous containers, bigger than 8lb jugs - containers heavier than the 70lb UPS limit, with no hazmat fee.

More speculation here: manufacturers of commercial powders in commercial quanities are probably obligated to provide a product that meets the buyer's needs.  Not somethng that would be consistent with published load data from a 15 year old reloading manual.

Note the abundance of weasle words

Interesting replies....

GHPorter is closest to being correct to the OP's question.

Cannister powders are held to very tight tolerances for burn rate from lot to lot so that they can meet the characteristics needed for published load data for guys like us.  This, plus the needed "small packaging" (i.e. "cannisters".) that us end use shooters buy at the local gun shop makes cannister powders more expensive on a per pound basis.

Bulk lot commercial powders have much looser tolerances from lot to lot.... which is both cheaper to produce and no big deal anyway to the commercial ammo makers.  They have the equipment to test each lot of powder to determine the correct charge weights needed to give the published mv of the loads they are making with it.

For this reason as well commercial powders are not sold on the open market......  There is no load data that corresponds to them.   Can you just see the legal weenies of the powder makers going into convulsions at the idea of selling a powder on the open market that doesn't have any valid published load data???

Just my 2 bits,
Swampy

Garands forever
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Quoted: For this reason as well commercial powders are not sold on the open market......  There is no load data that corresponds to them.   Can you just see the legal weenies of the powder makers going into convulsions at the idea of selling a powder on the open market that doesn't have any valid published load data???

They are available sometimes.
The data is usually limited to the mil calibers the powder was developed for with some very basic starting loads.
They are NOT for the inexperienced reloader.

Some of the manufacturers make odd lots available also.
Accurate Arms 'data powders' are likely batches that do not meet the canister requirements but are otherwise fine.