Inconsistent powder charge on 650

[Nimitz]

After a friend of mine who hadn't shot a match with me in a while commented on how "cute & soft" my gun sounded every time I fired it I decided to chrono my load & noticed it was around 120 PF. So, that night I starting checking every round & sure enough I was only throwing 3.8 g. So I reset the measure back to 4.2 where it should be & started checking rounds. I'd get 4.2 & then right back to 3.8-3.7. I'd reset the screw & get it to 4.2 & the same thing would happen. Couldn't get it to consistently throw 4.2 lke it's always done in the past.

I use WST which has always metered very consistently. i know you can get inconsistent throws if you don't keep the powder hopper full so that's not my issue. I remember reading about polishing something with the powder charging mechanism but couldn't find anything on a quick search? Also, should I be regularily cleaning the powder hopper even if I don't change powders or just keep it full? Thx

[mlmiller1]

Is the adjustment bolt moving? If you can't tell, put a sharpie mark on it to correspond with a mark on something that doesn't adjust. If it isn't moving, you need to clean out your powder drop, something inside is blocking it, whether it be a clump of powder or foreign material. I don't load with WST but I have never cleaned my powder hopper. I empty it when I'm done but have never since it was new, taken it apart & cleaned it.

[Pat Miles]

Living in Florida with the high humidity you should be emptying the powder hopper after every loading session.

Interesting that your 650 reverts back to 3.8 grains every time after you readjust to 4.2. If you are leaving the powder in the hopper between sessions I would think that the charges should become heavier after wicking in humidity. Clean the hopper and slide mechanism and then try dropping 10 charges in your pan and then weigh the total. Then divide by 10 and see what the average is. Do this several times to find what your machine is really dropping.

Try weighing the same 4.2 drop several times in a period of 30 minutes to see if the reading changes, could be a scale issue. What type of scale are you using?

Pat

[Nimitz]

It's a JS-100XV and when I weigh the 100g STD weight it shows 99.92g ...

I'll try those suggestions and see what happens ... thx