New Toy In My Loading Room

[JamesnTN]

Can I suggest that people run the FX-120i scale in its native gram mode... This will give the reloader better resolution than running in grain mode.

For example, the resolution in grain mode is 0.02 grains. This equates to increments of approximately 1.296mg rather than increments of 1.0mg in gram mode.

This means an error of +/- 1 digit in gram mode equates to a charge error of +/- 0.154 grains rather than a charge error of +/- 0.2 grains for the same +/- 1 digit error when measuring in grain mode, that's a 23% improvement for nothing..!

Google is very helpful in converting grains to grams; my standard load of 38.5 grains of Reloader 17 converted to 2.49475804 grams; this I rounded to 2.495 grans or the equivalent of 38.5037341grains... (38.504 grains).

What kind of improvement did you see in your groups using the more accurate grams instead of grains in your weighing?

I have two digital scales one will measure .01 grains and the other will measure .002 grains in all my testing over the years and shooting I can not see any accuracy enhancement with using the scale that measures down to .002 grains over the one that measures .01 grains. There are more variables beyond cutting kernels of powder into tiny pieces to get an exact measurement. I think I'm as anal as they come with my loads but I'm not so anal to start slicing and dicing powder.

 

[Jet]

Another check I do with my FX-120i or any other digital scale I use is to check the indicated weight in the digital readout after you remove the pan with your powder. The weight of my powder pan is 101.12 gr which you re-zero/tare to zero. After you remove the pan with your weighed powder from the scale it should read -101.12 gr until you put the empty powder pan back on the scale and then it should read zero. If not your next measurement may be off. The first thing I look for when this happens is a piece of powder that may have fallen on the scale pan while I was trickling powder.

Exact same for me.

Rich

 

[Macropod]

I use an fx120i and while I haven't seen definitive group improvements at 100m the confidence of accurate charge weights is priceless.

I do seem to have better elevation at long ranges with an almost flat 'waterline' if conditions don't induce vertical.

Again, confidence in your ammo and equipment is paramount to good shooting. You can't beat that feeling.

 

[RallyFan]

Snakepit,

I'm not in a position to comment on score improvements or vertical dispersion effects resulting from the weighing charges using grains or the more accurate grams setting as I have not done the experiment.

Why not? Three reasons.
1. I first went digital with a GemPro 250, and just like the FX-120i, it is also more accurate on the grams setting, so being an engineer, this is the way I ran it from the start. Just logical to me.
2. Greater consistency in your charge weights will always give you greater consistency in your velocities. Granted, the improvement will be tiny, but in a worse case scenario errors can be cumulative.
3. I figured that using valuable barrel life to prove this hypotheses wasn't really necessary.

What I can say is that I did see an improvement in my on target vertical dispersion (at 1000 yards) when going from an untuned and basic model balance scale to a GemPro 250. I cannot tell you about velocity consistency between the 'value' scale I originally used and the GemPro as I did not get regular access to a chronograph until after my switch to the GemPro.

I can say that with both the GemPro and the FX-120i, my extreme spreads and standard deviations are both single digit (velocities running in the 2800fps range). Achieving these figures is much easier on the FX-120i than the GemPro simply because of the drift characteristic differences between systems using a strain gauge type sensor and a magnetic force restoration system that measures electrical current.

 

[Martin52]

Not to highjack but I have a question regarding trickling on a gempro-

I will use a dipper to get "about" close to my charge weight, and then trickle in to the actual weight, or use tweezers to place in individual kernels if I'm within .06. As stated earlier bigger powders like H4350 are usually .02 per kernel, where smaller powders can be 2 kernels per .02. I then pour about half of measured charges back onto the scale to verify, and am within .02-.04, is this not recommended?

My experience with the Gempro 250 indicated that whilst the scale did not accurately measure small increments when trickling, it did measure static load very well. So, after trickling and before dumping the trickled load into the case I always put it back onto the Gempro for a final check - sometimes it was the same sometimes it was +/- >0.02. If it was above or below, it was usually within 0.06 so easy, but time consuming, to add/remove kernels with plastic tweezers, hence my eventual shift to the FX.

Martin

 

[dixieppc]

Got the two 50 gram weights back from my Smith's pharmacist friend. He was able to get both weights to come out to a total weight of 99.998 grams. I don't know how he was able to do it but I'm impressed to say the least. So, rounding it to 2 places, that's a 100.00 gram calibration weight.

I had also asked that the 20 gram calibration weight that came with the Gempro 250 scale be weighed on the certified scales so I could see how close the A&D scales would come to that after calibrating them. The Gempro calibration weight came out to 20.012 grams on the certified scales and came out exactly the same on the A&D scales after they were calibrated with the two 50 gram or 99.998 gram total calibration weights.

But as said before, accuracy of exact weight is second to repeatability. My biggest complaint against digital scales before getting the A&D was poor repeatability, drifting, having to zero them every few weighings and poor sensitivity to trickling. As far as strain gauge scales go, the only one that semi-impressed me was the Gempro and it still needed constant attention to going off the reservation after so many cycles thus needing a rezero and a problem with trickling.

Regards....

 

[JamesnTN]

Glad to hear you got your check weights to spec. Now get some lint free gloves of some sort and never handle the check weights with you bare hands always wrap it in the glove to place on the scale for calibration. Believe it or not over time your weights will gain weight by handling them with your bare hands l.