Charge weighing issues

[Minnesnotashooter]

So I just picked up a can of red dot today and I got home started weighing the charges with the correct powder bushing in my Lee load All 2 press. It was supposed to be dropping 18 grains but my scale said it was 16.5 or a little lower. When I was using a different powder in my press it threw the correct charge but now my scale says its light for red dot, do you think it's my scale( the lee safety scale) or the press, I think it's the scale because I've heard it's a little off sometimes but it worked fine for my last powder(American select) so I'm not sure

[EJSG19]

Sounds like you best get your hands on some known weight scale check weights. Lyman makes a nice little set for not much money from Midway etc. How do you know your scale was ever "fine"?

[wrench]

I never had those bushings throw what they should, according to the chart. I trust my scale, more than the Lee chart.
You do need some check weights, though, so you can have confidence in your scale.

[Sigfan220]

I use kegs of red dot in my MEC loaders. The bushings charts are way off. I'd step it up to the next bushing and check. Also throw a bunch of charges, make sure the powder has settled. The first couple are usually off, then it settles in.

[Minnesnotashooter]

Alright thanks everybody, I made sure my scale is ok I forgot that when I got my scale I made sure it was on with a calibrating weight. But for my press I bumped it up to the next bushing, settled the powder with 4 or 5 drops the weighed it and it was barely under 18 grains so that's good enough for me.
Thanks for everybody's help!

[Seismic Sam]

Measuring powder by volume instead of weight is an inherently faulty process, and with EVERY bump and vibration to the system the charge weight will get heavier because the powder will settle more. There are some machinist guys in here who have connected their throw handles to mechanical servos to reproduce the throwing motion precisely, and even then they will tell you that it's still not perfect.

[grousemaster]

I never had those bushings throw what they should, according to the chart. I trust my scale, more than the Lee chart.
You do need some check weights, though, so you can have confidence in your scale.

The Lee Powder Disk is never correct, it is always "light"....you need to use a scale and figure out what the lee disk is actually weighing out with the powder you are using.

[Pat Cannon]

I never had those bushings throw what they should, according to the chart. I trust my scale, more than the Lee chart.
You do need some check weights, though, so you can have confidence in your scale.

The Lee Powder Disk is never correct, it is always "light"....you need to use a scale and figure out what the lee disk is actually weighing out with the powder you are using.

This. I think they play it safe on their chart so we don't blow ourselves up.

[LarryFlew]

When I was using a different powder in my press it threw the correct charge but now my scale says its light for red dot..........................

Don't forget you are converting weight to volume so every different powder will have a different volume for a given weight and will need a different bushing. IE if you go to a powder similar to what you are using the volume will be greater or lessor for the same weight required. Your bushing that throws 18 gn with blue dot may not be the bushing that throws unique in 18 gn.

[farmerj]

I never had those bushings throw what they should, according to the chart. I trust my scale, more than the Lee chart.
You do need some check weights, though, so you can have confidence in your scale.

The Lee Powder Disk is never correct, it is always "light"....you need to use a scale and figure out what the lee disk is actually weighing out with the powder you are using.

This. I think they play it safe on their chart so we don't blow ourselves up.

light charges can be as deadly as an overcharge too.

[Pat Cannon]

I think they play it safe on their chart so we don't blow ourselves up.

light charges can be as deadly as an overcharge too.

This is true. Go with what the scale says!