Trigger Scale Accuracy

[AlanG]

I bought a new populated lower today. It came with a Mil-Spec-ish trigger. Before replacing it, I wanted to check the current pull weight. I have two digital scales. I bought a Wheeler Engineering Digital Trigger Gauge some years back, and then mislaid it in moving so I bought a Lyman Trigger Pull Gauge. Then found the Wheeler gauge. So I checked the lower with both gauges. Ten pulls with each. The Wheeler average was 7# 5oz. The Lyman average was 5# 14oz. Any suggestions as to which I should believe?

Thanks,
Alan

 

[Evintos]

Fishing weights in a variety of weights (sinkers, split shot), fishing line or string, gravity. Find out which one is the closest, return for refund or warranty or throw away the one that is not accurate.

If you don't fish but you reload, string, cup, bullets.

 

[Rocketvapor]

Calibrate with a bag of bullets
OR,
A real calibration weight. Note that pounds of FORCE will be slightly different than pounds of WEIGHT.

 

[AlanG]

Fishing weights in a variety of weights (sinkers, split shot), fishing line or string, gravity. Find out which one is the closest, return for refund or warranty or throw away the one that is not accurate.

If you don't fish but you reload, string, cup, bullets.

Duh….. Thanks for jogging my brain cells.

 

[AlanG]

I think you are referring to the difference between indicated force and actual force.

 

[Rocketvapor]

A 6 pound mass (weight) will still be a 6 pound mass on the moon but will only indicate 1 pound on a force gauge or earth calibrated scale. Recalibrate the scale and it will read correct.
Slight variations will be seen between a calibrated Mass and the FORCE applied due to SLIGHT variations in local gravity.
Usually not enough to be worried about unless making somewhat precision measurements.

 

[sinister]

Real weights, calibrated, may or may not be more useful and consistent:

 

[AlanG]

A 6 pound mass (weight) will still be a 6 pound mass on the moon but will only indicate 1 pound on a force gauge or earth calibrated scale. Recalibrate the scale and it will read correct.
Slight variations will be seen between a calibrated Mass and the FORCE applied due to SLIGHT variations in local gravity.
Usually not enough to be worried about unless making somewhat precision measurements.

Absolutely true, but I won’t be making my trigger pull gauge calibrations on the moon.

 

[Rocketvapor]

Local gravity won't make much difference but you can check online to see how much it varies.
I made the comment in my trigger pull calibration, just because
Local gravity does impact precision scale calibrations, in the order of 0.1%.
7 pound trigger pull, 0.1% is close to an ounce. Of course, if you are CALIBRATING force gauges you want to be more accurate than the device you are calibrating.
Pull the two against each other to verify they are different. Some times trigger release sends a little shock wave that a digital scale can see as extra force.
Pick one and add bullets to a bag. Most good bullets are within a fraction of a percent of nominal.
Like 77grain +/- 0.1 grains (about a tenth of a percent). A box of 500 would be really close to 5 lb 8oz.

Try this:
bathroom scale, add a gallon bucket of water, tare or record indicated weight, lift, slowly with the trigger gauge,
3 pounds 4 lbs, 5lbs, etc. Force will show as weight loss on the scale.