Powder scoops really aren't that much different than a powder throw. They can be incredibly consistent when they are used properly. More often than not the people using them DON'T know how to use them.
The idea predates smokeless powder. When you look at black powder load manuals, one of the things they mention is volume, rather than weight is important. Not so with black powder which is usually more precise with burn rates. We all know burn rates can and do differ from lot to lot with smokeless powder. With black powder that predates 1900, about the only thing that was consistent was granule size, not density. It's still very similar. Let me give you an example. I recently "weighed" black powder with the same designation from three different lots. FFG. I then poured each of the lots into a volume measure, one of those made of brass that telescope to desired volumes.
NONE OF THE THREE filled the measure to the same level. Even when I tapped them to settle the powder. I couldn't even compact them to the same level. When I shot the charges out of my Lyman 50 cal Plains rifle, which is close to 45 years old, there wasn't any noticeable difference in accuracy or point of impact that couldn't be attributed to my old eyes or hold. I did shoot from bags on a concrete bench, over open iron sights. I didn't bother to try the Magnetospeed.
One thing about modern smokeless powder is that its densities are much more consistent. The difference is in the burn rates, which are controlled by the exterior coatings for the most part. One noticeable difference is granule shape, which can even vary with the same designated powder from lot to lot. This will cause a few discrepancies when changing lots.
Once in a very blue moon, volume type powder measures will deliver excellent accuracy. They are also designed to give a specific volume with a specific powder from a specific lot, for a specific shape/weight bullet. The slight variance between lots won't cause any issues with safety. However, even using the same volume from the same lot can and will give significant velocity variation. WHY??
Because of the air spaces between the granules the weight of powder in each scoop is DIFFERENT. The difference will cause all sorts of accuracy issues.
Remember, these measures weren't intended to give sub minute of angle accuracy. They were initially intended for the LEE LOADER kits to my knowledge and they were intended to produce ammunition that was not only safe in all of the rifles on the market chambered in a certain cartridge with one bullet weight but also to produce what was considered to be acceptable hunting accuracy back in the fifties. 3-5 moa at 100 yards. They were also intended for folks on limited budgets and in reality produced ammo that was close to being as good and sometimes better than the commercial offerings available at the time. The ammo those simple LEE LOADERS produce today is still quite good and relatively cheap when comparing the price of components to that of factory loaded ammo.
There are ways to make your loads more consistent. One method is to tap the measure to pack the powder more densely. This isn't suggested in the instructions but it works. Then, pour a bit of powder on top of this and load that into your cases. It won't be perfect but it will usually be give or take a tenth of a grain in difference. Very close.
Now, for those of you that are more ambitious and experimental, pick up a complete set of measures. For each measure scoop up some powder, tap it down and top it up. Now weigh it and record it where you won't lose it. Do this with each scoop, with each different powder you plan to use.
These tables can be very handy when you want to cut down on time and equipment. If you can't afford a scale, borrow one and give a copy of your findings to whom you borrow it from. DON'T FORGET TO RETURN THE SCALE PROMPTLY.
There are many loads that can be varied with this method. You can also increase charge weights just by going to another ready made scoop by a few tenths of a grain.
I make up my own scoops from a cut down cartridge case. I found a bunch of 45-70 cases with split necks, that I cut down to give me a volume that is very close to the exact weight I want, for a specific load. Sharpie markers keep all the info on the case.
Now, just for full disclosure. I'm a bit anal about accuracy. I haven't competed for close to 20 years now. That's when I learned the value of scoop measures. Yes, I had and still have match quality powder throw units, adjustable to 2/10 of a grain. For the cartridges I was shooting, even in competition, I couldn't discern any noticeable difference in accuracy. NOW, that is with medium capacity cases and larger. Small capacity cases are a whole different story. I found it was quicker and handier just to carry the appropriate scoop and POUR the powder into it with a funnel Until it overflowed. This produced very accurate ammunition in combination with match primers and hand swaged bullets.
I seldom use the scoops for anything more than just a quick starting point. I generally weigh every charge I shoot our of a rifle. Not so for handgun ammo. I just load whatever the throw drops into the case. I weigh every tenth charge to make sure they stay in the ballpark.
One day that will be worth pain for the laugh alone! lol There's a gravy boat that's perfect I think.
