By Joe Berk
All right, all you Mini 14 and other rifle reloaders, the question du jour is this: Does it make a difference if you weigh each powder charge versus simply dropping them from the powder dispenser?
I always suspected the answer was no, but I want to answer the question more rigorously. I also want to try IMR 3031 in the Mini 14. I have an 8-lb bottle and I have not loaded .223 ammo with it.
For this experiment, I used my trusty RCBS Rockchucker (a tool I’ve been using for more than 50 years now), RCBS dies (with a neck size only die for the depriming and resizing step), an old RCBS balance beam scale (another tool I’ve been using for more than 50 years), my RCBS powder dispenser (ditto on the time in service), and an RCBS powder dribbler (yep, I’ve been using that one since I was in the Army, too).
The IMR 3031 load data came right out of the online Speer reloading page. For 55-grain bullets in the .223 Remington, Speer showed an IMR 3031 load ranging from 24.0 grains to 26.0 grains (a compressed load). I went with Lake City brass and Winchester small rifle primers. Cartridge overall length was set at 2.213 inches. I loaded one group of cartridges with 24.0 grains of IMR 3031 (dispensed directly from the powder dispenser to the cartridge, without weighing each charge), another group of cartridges with 25.5 grains of IMR 3031 (similarly dispensed from the powder dispenser), and a final group of cartridges with (again) 25.5 grains of IMR 3031, but this time I trickled the charge in to have exactly 25.5 grains.
IMR 3031 is a stick powder, and the individual sticks are relatively large. The powder dispenser was showing a variation of about 0.3 grains in the charges it threw. I didn’t know what that would do to accuracy and how it would affect velocity variation. I made that last batch weighing each charge to see if doing so (i.e., to get exactly 25.5 grains, with no variation in charge weight) would improve accuracy and reduce velocity variation. That’s what this experiment and this blog post are all about.
On that neck size only business, in the past while developing Mini 14 loads I found that the rifle groups much better if I don’t full length resize the cases, but instead neck size only. A guy on an internet forum wanted to go to war with me over that, responding angrily with NO NO NO!!! His comments emphasized the unsuitability of neck sized cartridges in a semi-automatic rifle, my stupidity, and my questionable ancestry. I told him I appreciated his inputs, but when I read them to my rifle, it ignored them completely and continued to function with 100% reliability. That ratcheted the guy up even more. I’ll tell you: The Internet brings out the worst in some people. Boorish behavior, the dumbing down of the human race, and online disinhibition have changed us, and not for the better. Anyway, I digress…back to the main topic.
As mentioned above, IMR 3031 is a stick powder, and the sticks are big enough to interfere with cycling the RCBS powder dispenser. Ball powders fall smoothly; stick powders want to catch in the rotary mechanism’s cavity. When I dispensed powder directly into each case, I saw significant variations in case fill.
I know that the case fill variations are more due to how the propellant falls in the case than anything else. I didn’t think they were driven by propellant weight variations. When I weighed each powder charge and added those to the cases, I observed the same kind of case fill variations (which I think supports my “let the sticks fall where they may” hypothesis).
With my ammo groups complete, I was ready to head to the West End Gun Club to test for accuracy and velocity. A few thoughts up front:
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- My accuracy tests should be taken with a very large grain of salt. My Mini 14 has iron sights and my vision is not what it used to be. Instead of shooting 5-shot groups at 100 yards, I’m going to shoot a single 20-shot group with each load at 50 yards. I’m an old guy and that’s my approach. If you don’t like it, start your own blog.
- The chrono results will be much more rigorous. I trust my Garmin chrono big time. It’s one of the best bits of gear I own.
- My Mini 14 is the same one you’ve seen before here on the ExNotes blog. It’s my least accurate rifle, and it is one of the most fun to shoot.
Well, this blog is getting a bit long, so I’ll call it a day and say that’s enough for now. I’m off to the range. Watch for the results in another day or two.