Well that is the problem YES 1 OZ is 437gr but 1 oz in a volume is not the same. I dont know what they base it on. 1 oz of slug is 1 oz 1 oz of no2 is not close and 1oz of 9 is near . So I guess you fill to what ever ???
One ounce is not a volume measure but a weight measure. The same with grains of powder....the weight of powder varies a little in manufacturing so it behooves the reloader to check his weight of powder dropped and adjust the bushing (a volume measurement) to throw the desired weight.
OK? Weight and volume are two different measurement methods and we must correlate the desired weight with the appropriate volume (i.e. bushing).
The hole size in the bushing is designed to drop approximately 1 1/8 ounce of #8 shot BUT it is a volume, thus the size and weight of the individual shot pellets will influence the total weight in that volume. For example, if the lead balls were 1/4" in size, you couldn't put very many in the small chamber of your bushing (too much air space). If the shot were the size of grains of sand, it would weigh a lot more because lead is way heavier than air. If the shot was made of plastic, it would weight a lot less, but be a full volume in the bushing. If the shot was made of gold, it would weight more. Thus, the bushing is simply an approximation of the size you need.
I take a powder bushing and weight each powder drop and enlarge the bushing by drilling or sanding until it drops exactly what I want for weight - then mark the bushing to the approximate number (i.e. 30.4) so I know it is custom.
I do not care that much about the shot because I shoot 1 ounce loads in the 12 gauge except for handicap anyway.
Bushings were sized to drop the specified weight of soft, chilled shot. When dropping soft, uniformly-sized shot the bushing produce surprisingly accurate results. The harder shot that contains a higher percentage of lighter antimony doesn't weigh as much per unit volume.
The cheaper shot that contains some pellets one size on either side of the advertised size also screws up the weights by dropping inconsistent numbers of different sized pellets.
I liked the charge bar but found I got tired of changing it all the time. It's alot easier to drop a busing and a bar in. Although I have to say I got super accurate lead drops with the bar. Usually +or- a few pellets of the weight I was trying to drop.
got the answer 1 oz is not true 1 oz that is what I was getting at.
Its not a problem in a 12 but does become a problem in the 410. What is dropped and what is hand loaded and shook is way different
Yeah, Jason's got a point, batches of shot from different sources can weigh differently even though the "volume" is still there. I've had 20 grains or more difference in shot drops just going from one brand from another - especially if you're making your own or using that from a homemade shot maker......breakemall....Bob Dodd
ricks1, I think you are getting mixed up between fluid measure and mass ( weight) measure. Fluid measure is :- There are 20 fluid ounces in 1 Imperial pint or 16 fluid oz's in one American pint. There is no correlation between fluid measure and weight, fluid measure is volume and the weight of that volume depends on the specific gravity of the medium being measured. Maurice ( The Brit. )