I have a .45-70 Sharps replica (admittedly a cheapo uberti) and thought it would be neat to play around with it a bit with black powder.

It shoots reasonably well (for me with buckhorn irons) and I am thinking of putting a tang peep on it.

My first attempt with BP reloads for it have been not so good. However, how I am loading it is by using one of those cheap brass "powder measures" that is basically a dipper that you can set the volumetric amount in 5 grain clicks.

I recall there being a Harrel black powder measure but they don't even have it on their web site anymore. Doing a web search just brings up more of the brass jobs like I already have.

Any thoughts on what is the current way to get accurate measure dispensing? My smokeless stuff is all either electric or has plastic (ie static electricity risk)

Is there any somewhat midlevel or higher level advanced book that you guys who are experienced with it might recommend?

As an aside, I do use BP for muzzleloading hunting, I have a couple BP percussion pistols, and do load some brass shotgun shells with BP for the odd clay target or hunting day for the hell of it, so I am not wholly inexperienced with black powder, but the cartridge load was pretty sorry- 70 gr of FFG with a commercial cast 405 gr LSWC (.458 dia) gave a group that was 4x larger than my smokeless round with the same bullet...

A good place to start is the SPG Blackpowder Reloading Primer. As to loads, I throw slightly under weight loads with a Lyman Classic 55 blackpowder measure and then trickle onto a pan on my scale. I use a 24" drop tube to put powder into the case. You also generally need an over powder wad. Blackpowder cartridge rifles are somewhat sensitive to lead alloy and bullet lube. I have good results using 16:1 lead to tin alloy for bullets and SPG lube. You also need some kind of fowling control between shots, either blow tubing or wiping the bore between each shot. Hope this helps for a start.

CR, Dave -- a highly experienced BPCR shooter and a very fine guy -- is giving you great advice.
I load by weighing my charge on a scale, then trickling into the case with a 30-inch drop tube. May or may not use a wad, but you want to compress the load 0.10 inch or more, preferably with something besides the bullet base; your rifle will tell you how much. You want a softer rather than harder bullet alloy -- 20:1 is a good target to aim for -- and a quality BP lube like the aforementioned SPG, which I have used since Steve Garbe invented it decades ago. (Look up Matthews lube for a home-made product.)
The actual bullet used is critical. If it just has very shallow lube rings for smokeless applications, it likely won't deliver enough lube to the fouling in the upper half of your barrel and you'll want a mold designed specifically to hold BP lube and sized a thousandth or two over groove diameter to be successful. That Uberti probably has a very decent barrel and would reward you with pleasing accuracy if you you feed it what it wants.
Dunno which powder you are using, but the gold standard is Swiss -- more powerful and more consistent while much cleaner burning -- vs. garden-variety Goex. The latter can be made to shoot just fine but takes more attention to fouling control to maximize performance.
Garbe and Mike Venturino's SPG BP Primer is an excellent resource, as is Venturino's "Shooting Buffalo Rifles of the Old West." I've read that one a half-dozen times.
You have a good rifle in a very fine choice of chambering and it will make you smile if you do the work. Best!

Thanks for the info!

Trying to find the powder measure is kind of challenging at the moment.