ridgeway said:
in2deep said:
Devil's advocate:
Sam Hall shoots little bitty 600 yard records at Williamsport using an old beam scale. Most are accurate to within a couple individual grains of powder once you get used to them.
A digital may help you load a little faster but probably won't make you shoot any more accurately.
I totally agree with you! I use a gem pro digital currently, but have a tuned beam scale in the works. The price of the lab grade scales is ridiculous. Sure, they are accurate, but how accurate do you truthfully need to weigh powder?
At 600 yards, it depends on what you are doing and the cartridge you are firing. If you are shooting a cartridge that uses, say, 25 grains of powder then your RCBS scale is only accurate to 0.4% of your charge. If you are using a 47 grain charge, then you are 0.21% of the total charge. What difference does that make? in a 308 (47 grains) it makes about 5 fps for a charge difference of 0.1 grain (+ or - .05 grains accuracy). In a 223, the difference is about twice that.
Here is the hard part: If we take the velocity variation from not being able to tell the exact charge and compute it with the velocity variation caused by other issues (variations in case volume, primer flash differences, bullet variations, etc.) we can estimate the realistic best ES and SD we will get.
For example if we had an extreme spread of 5 fps from cases and 3 fps from primers, 2 from bullets, and 1 from seating depths, then the ES prediction would look like this:
ES = Sqrt(5^2+5^2+3^2+2^2+1^2) = sqrt(25+25+9+4+1) = sqrt(64) = 8
Without any variance from powder charges: sqrt(39) = 6.25
As this is an example with made-up numbers, let's look at real world numbers: my 155 grain load runs about 47 grains of powder and the ES (as measured over a 10 shot string ) is 10 fps with an SD of a touch over 4.
In my case, an ES of 10 is plenty good enough for that load (I don't shoot it past 600 yards and only for F-class), so the lab-grade scale isn't going to make a huge difference.
If I were shooting a smaller target, or for group it would be worth the expense of the lab scale even though it will only likely make a 1-2 fps difference in my ES. Likewise, if I were shooting a 223, then the ES prediction would reduce from about 11.8 to 6.25. That kind of difference would keep me up at night!
Truthfully, I've struggled with the question of "how accurate do my charges have to be?" My answer is this: I have bigger fish to fry before I invest 900+ dollars into a scale. I don't measure my case volumes, I don't weigh my primers, and I don't have a really good setup, but my rifle and ammo are more than capable of shooting cleans in my chosen game, and, for that matter, they are accurate enough to clean X's. I just wish I were!
Whatever you decide, in the end, it is your faith in your rifle and ammo that can make or break you. In my case, I know from repeated experience that I have everything I need to shoot outstanding scores, I just need to learn how to shoot more consistently.
