40 S&W reloading thread

[BuffCyclist]

Discovered the reason I'm spilling so much powder.

Here is my powder measure.



The top pipe is just long enough to hold the cap on, but small enough that I don't have to force it on and off each time. I didn't think it through, but it worked out perfectly. EXCEPT, if I put the cap on quickly enough, the air inside the feeder tube doesn't have time to equalize, and it blows powder out the side of the base. Shown as this tiny crack on the left side in this picture.



So each time I remove and replace the cap, which is a lot when I'm dialing in a load, it blasts about 1 grain out the side. I can just put the cap on slowly and it doesn't happen. However, if I want to not worry about it, I could seal this gap in some way. I don't want to use a sealant for many reasons, such as risk contaminating the powder, want to be able to remove the pipe, etc. I could wrap a rubber band around the base of the pipe, but even that thickness will make it difficult to place the pipe in the stand. My options are a gasket at the bottom (which requires me going and shopping for one), or drill a small vent hole on the side of the cap. How important is it to keep the powder sealed? If I drill a 1/8" hole on each side of the cap to help equalize the pressure without blowing powder out, will I have to worry about the powder going flat or some other adverse reaction to contact with the air?

Drill a hole in the cap. If you're worried about dust falling in and contaminating powder (which you shouldn't, see below), then drill the hole in the side of the cap, but above where it rests on the pipe.

You should never leave powder stored in a powder measure when you aren't actively reloading, as in, at the end of each reloading session you should put the powder back into the powder containers. And yes, that's what the powder jug says, but if you live dangerously and don't follow directions, carry on.

eta: For what its worth, I was loading my pet 40 load with 3.9gr WST behind a 180gr Xtreme plated bullet. That was the best grouping I had when I did my initial 5rd groups last year. This year, when I got a chrono, I decided to retest and found that 4.3gr was the optimal load (5FPS StdDev in my Glock 23, 7FPS StdDev in my M&P40c) and had the smallest grouping. Since the StdDev's don't lie, I switched my pet load. But I still had my target from last year when I did my initial loads and the 4.3gr load was almost identical in size to the 3.9gr load, I just chose the 3.9gr load last year due to it using less powder.