How to halve the powder throw variance on an Autotrickler

[PeteFox]

If you have an Autotrickler you are either trying to achive speed or accuracy or both and you probably have OCD.
The resolution of the AnD scale is 0.02 gn. The software in the Autotrickler uses this figure as a tolerance on the dialed in load. 0.02gn is pretty tight, but it can be made better with no effort on your part.

So if you dial in 51.5gn, the dispenser will stop at 51.48 or 51.50 or 51.52 grains. so from the highest to lowest load you have a variance of 0.04gn, or 2 kernels of say 2209.
Rumour has it that a kernel is worth about a 2pfs variance in velocity. I don't know if that's right, but if so then the powder thrower is responsible for 4fps of your ES.

The following works on my V4 Autotrickler and being the same software I think it should work on any Autotrickler

I discovered that if you set the powder charge to an odd number in the second decimal place, the variance is halved, with no noticable speed of throw drop off.

So if I set the Autotrickler to 51.51gn, it will throw either 51.50 or 52.52, a variance of 0.02gn, or equal to the resolution of the scale.

For those other obsessive compulsive types out there, this should help scratch that itch.

Pete

[bigjohn]

Thanks Pete I will try this tonight + see how it goes
Regards John

[CamoWhamo]

That's interesting and something I will test.

I load using Grams, not Grains, because the A&D's resolution is 0.001 grams which is 0.015432358 grains.
So loading to the 1000th of a gram is just a tad tighter tolerance than .02 grains.
Does it make a difference? I don't know, but it satisfies my OCD about this stuff.

[Tim L]

My trickler cuts out 0.02gns before the target weight ( I've never put the oddnumber in though ) Throwing target weight is actually an over throw.
With regards to the velocity value of a kernal, if it matters you're using the wrong node

[Weairy]

Jeez, I usually just add/subtract a kernel with a pair of pointy tweezers for accuracy with the AutoTrickler

[PeteFox]

Jeez, I usually just add/subtract a kernel with a pair of pointy tweezers for accuracy with the AutoTrickler

OK for those with OCD, here's the way to get it exactly on the money.

Enter the next lower value for your load into the app.
So if you are looking for 51.5gn, enter 51.49gn into the app. The trickler will then output either 51.48 or 51.50.

Now from the pinch of powder that you have spread on a flat surface (or previously spilt on your bench) you should be able to easily pickup a single kernel in your fingers and just drop onto the scale to bring throws of 51.48 up to 51.50.

Now you have the exact weight and you have reduced your ES by 4fps (in theory).

Pete

[BATattack]

4fps per kernal seems very high. What powder and case are you using it in?

From testing I've done 2208 in a 308 and 2209 in a 7saum it's closer to 1fps per kernal?

[macguru]

Are you really measuring powder wts to .01 grains ?? Thats your problem, you need to buy a scale that just measures to 0.1 grains, and then your stress level will decrease

[PeteFox]

4fps per kernal seems very high. What powder and case are you using it in?

From testing I've done 2208 in a 308 and 2209 in a 7saum it's closer to 1fps per kernal?

No its 2fps per kernel, read the entire thread
Pete

[PeteFox]

Are you really measuring powder wts to .01 grains ?? Thats your problem, you need to buy a scale that just measures to 0.1 grains, and then your stress level will decrease

No, I'm not stressing, I'm just showing how to do it.

Some people weigh primers and projectiles, I don't, but I know a whole lot better way to do it.

Pete

[Tim L]

If your 1 kernal IS worth 2fps then 0.25 grain variance in pill weight is worth the same.

[PeteFox]

I'm not saying there are absolutes here.
The point of the thread was to show an easy way of doing things, as there are obviously people using tweezers etc to get an exact load. This is better.

And also if the machine is capable of being more precise, why not take advantage of it?

As far as I can see, it's in the same vein as pointing bullets and weighing primers.

Pete

[BATattack]

Yep it's a great simple tip Pete thanks for sharing!

[Redhawk]

Thanks Peter, great share