cowboy
Well-Known Member
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Absolute best scale.
- Thread starter Bear cat
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Grim Reaper
Active Member
- Joined
- Sep 29, 2015
- Messages
- 44
Is the gem pro as bad to drift as rcbs digital are??I know that changing Temps from no heat to heated room is a real big drift but even so mine never stops drifting no matter how long the loading session.Granted it does seem better if the scale is plugged up and on for a couple hours before use.Just wondering what you guys have found if you don't mind sharing your findings.
gempro really needs to be turned on for 24 hrs before using. It is very stable then. Lots of people leave theirs plugged in all the time.
you don't want air conditioning blowing on it and I would think you would want stable temps.
Grim Reaper
Active Member
- Joined
- Sep 29, 2015
- Messages
- 44
Thanks for the heads up on the gem pro I really got one in mind for sure
The only time I have any issues with drift is when the Furnace Blower is on. Closing the lid eliminates drift in that condition. Otherwise I never see any drift at all.
I turn mine on when I get ready to use it. I calibrate it and use the gr weights I have to make sure it's spot on.
For the money it's hard to beat.
I turn mine on when I get ready to use it. I calibrate it and use the gr weights I have to make sure it's spot on.
For the money it's hard to beat.
Grim Reaper
Active Member
- Joined
- Sep 29, 2015
- Messages
- 44
When I get a few more coins I will definitely own one of them Thanks for the responses.The one I have now is a royal pain
There's a greater spread in primer output for a given lot of them than a 1/10th grain (.1) of powder causes. And that's ten times the spread of 1/100th grain (.01) grain of powder. Some powders have 3 to 6 granules per 1/10th grain of weight, so how does one measure to the nearest .01 grain if that covers 3 granules: cut one in thirds or fourths?
To say nothing of the variables humans have that influence the accuracy of a given load that's 10 times bigger than what those powder charge variables cause. For example, several people shooting the same rifle and ammo will have a muzzle velocity average somewhere in a 100 fps range. If they're hand holding the rifle against their shoulder, the muzzle velocity will be slower and the spread will be 3 to 4 times that the barreled action will have clamped solid in a vice so it doesn't move at all. Newton's laws prevail.
Sierra Bullets throws charges direct from measures that have a spread of 2/10ths grain or more. Their best match bullets shoot 1/4 MOA 10-shot groups in their 200 yard range. They don't work up new loads for different lots of components nor for a new test barrel; the recipie that worked well with the old stuff does as well as the new stuff.
It doesn't matter if a beam scale is 2/10ths grain off exact. As long as it's repeatable to 1/10th grain, that's good enough. There's typically a grain or two difference across powder lots to produce the same exact pressure with a given load in a given barrel anyway.
Having bullet diameters at least .0003" larger in diameter than the barrel's groove diameter is 10 times more important thatn exact charge weights.
But it's easy to see errors in charge weight. Much more so than the other elements of accuracy that are not considered that have a much greater impact. How many of you who've watched a benchrest match notice the people shooting do not hold onto their rifles? They're fired in free recoil untouched by humans except for a finger on their 2-ounce trigger. Rifles shoot much more accurate when they're not held by a human against their shoulder; rested on bags or not.
To say nothing of the variables humans have that influence the accuracy of a given load that's 10 times bigger than what those powder charge variables cause. For example, several people shooting the same rifle and ammo will have a muzzle velocity average somewhere in a 100 fps range. If they're hand holding the rifle against their shoulder, the muzzle velocity will be slower and the spread will be 3 to 4 times that the barreled action will have clamped solid in a vice so it doesn't move at all. Newton's laws prevail.
Sierra Bullets throws charges direct from measures that have a spread of 2/10ths grain or more. Their best match bullets shoot 1/4 MOA 10-shot groups in their 200 yard range. They don't work up new loads for different lots of components nor for a new test barrel; the recipie that worked well with the old stuff does as well as the new stuff.
It doesn't matter if a beam scale is 2/10ths grain off exact. As long as it's repeatable to 1/10th grain, that's good enough. There's typically a grain or two difference across powder lots to produce the same exact pressure with a given load in a given barrel anyway.
Having bullet diameters at least .0003" larger in diameter than the barrel's groove diameter is 10 times more important thatn exact charge weights.
But it's easy to see errors in charge weight. Much more so than the other elements of accuracy that are not considered that have a much greater impact. How many of you who've watched a benchrest match notice the people shooting do not hold onto their rifles? They're fired in free recoil untouched by humans except for a finger on their 2-ounce trigger. Rifles shoot much more accurate when they're not held by a human against their shoulder; rested on bags or not.
Okanogan
Well-Known Member
It has been reported that 96% of the top 100 PRS competitive shooters weigh their charges in some fashion and approximately half of those use high precision weighing equipment costing more than $500. I'm take that as an indication that some very talented shooters believe accurate powder weight control for reloading is important.
The gem pro is moderately priced and can differentiate when one or two kernels of extruded powder is added, which is less than 0.1 gr - typically 0.02-0.03gr/ kernel for rifle powders I use. Weighing this closely costs me time, but in my personal case it is worth the effort to me to remove at least one variable where I want to work on precision shooting. (e.g., I'm not as tempted to blame my SD/ES on powder charge variance)
I think everyone will have to decide for themselves how much effort they want to put into weighing charges depending on the particular objectives they have for the loads. I certainly don't do it for my 6.8 SPC AR that doesn't have a scope.
The gem pro is moderately priced and can differentiate when one or two kernels of extruded powder is added, which is less than 0.1 gr - typically 0.02-0.03gr/ kernel for rifle powders I use. Weighing this closely costs me time, but in my personal case it is worth the effort to me to remove at least one variable where I want to work on precision shooting. (e.g., I'm not as tempted to blame my SD/ES on powder charge variance)
I think everyone will have to decide for themselves how much effort they want to put into weighing charges depending on the particular objectives they have for the loads. I certainly don't do it for my 6.8 SPC AR that doesn't have a scope.
The other 4% always win.
engineer40
Well-Known Member
Well said Bart.
I trust Bart has reached the sensible conclusion. I think a guy could spend his entire life attempting to document the difference that 0.02 grains of powder would cause on MV, ES, and SD. And on his death bed, he will still have never demonstrated a statistically valid conclusion. There are too many other factors that will affect MV, ES, and SD, above and beyond a 0.02 grain difference in powder charge weight. A guy would have to have absolute control over all the other variables affecting MV, ES, and SD. And that's not humanly possible. Different lots of powder, bore wear over time, temperature differences of the bore depending on the rate of fire and the outdoor ambient temperature, variance in case neck tension over time, throat erosion, variance in differing lots of primers, error associated with the MV measuring instrument, and so on and so on...
This coming from a guy with a significant degree of obsessive compulsive disorder. As Bart said, just because powder charges can be measured down to 0.02 grains, doesn't mean that powder charges differing by 0.02 grains will have a significant affect on MV, ES, and SD. Your MV measuring tool will likely have more variance associated with it than the small variance in MV caused by such minor variations in powder charges. So how does one propose to measure and document the affects of such a small difference in powder charge weights???
Okanogan
Well-Known Member
I don't believe anyone on the thread has suggested powder charge weight variance of 0.02gr would be a significant one of the many variables affecting MV, ES & SD.
In my case, agreeing that 0.02gr isn't a significant factor allows me to comfortably move on to work on other variables to try and bring my ES/SD down. It also avoids the need to workout what is a reasonable tolerance on powder weight control if 0.02gr is already accepted as below the meaningful threshold. Once I get my ES/SD where I want it, I have the option to back off weight control until it has some measured effect if I want/need to save some time. While working to improve my reloading though, I want to be working with one variable at a time so I have some means of measuring results objectively. I understand there are difference in approach by others, and that is fine with me.
Agree completely with the earlier comment about not staying locked on weighing accuracy as the sole key to precision reloading. If weighing to tight tolerances had produced ES/SD I want, I'd be saying so. What I like about the Gem Pro is I didn't pay $500+ to get me to where I personally feel comfortable eliminating weighing accuracy as a significant factor in my load development efforts. For those on the forum who have found that equipment throwing charges to 0.1gr or 1.0gr meets your needs with quicker/ cheaper equipment that represents the absolute best scale, it is great that you too are offering up your opinions on scales that might meet the OPs needs.
If the thread has morphed from what is the absolute best scale, which I took to mean precision, to what accuracy tolerance is required for weighing powder charges, then I apologize if my comments tended to divert the thread.
In my case, agreeing that 0.02gr isn't a significant factor allows me to comfortably move on to work on other variables to try and bring my ES/SD down. It also avoids the need to workout what is a reasonable tolerance on powder weight control if 0.02gr is already accepted as below the meaningful threshold. Once I get my ES/SD where I want it, I have the option to back off weight control until it has some measured effect if I want/need to save some time. While working to improve my reloading though, I want to be working with one variable at a time so I have some means of measuring results objectively. I understand there are difference in approach by others, and that is fine with me.
Agree completely with the earlier comment about not staying locked on weighing accuracy as the sole key to precision reloading. If weighing to tight tolerances had produced ES/SD I want, I'd be saying so. What I like about the Gem Pro is I didn't pay $500+ to get me to where I personally feel comfortable eliminating weighing accuracy as a significant factor in my load development efforts. For those on the forum who have found that equipment throwing charges to 0.1gr or 1.0gr meets your needs with quicker/ cheaper equipment that represents the absolute best scale, it is great that you too are offering up your opinions on scales that might meet the OPs needs.
If the thread has morphed from what is the absolute best scale, which I took to mean precision, to what accuracy tolerance is required for weighing powder charges, then I apologize if my comments tended to divert the thread.
