Listed Weights Aren't True FWIW

[Frankly]

So I've assembled ("built" is an exaggeration of the skill required) my first dozen ARs and as I've gotten more experience I've started to go for lighter weight but middle-tier guns. No Titanium or exotic, expensive parts, guns around $1500 not $3500, Aero Precision not boutiques, etc. And I started a spreadsheets of weights of components including a margin for springs and tiny bits. And so far, out of 3 builds done this way, each has been 6-11 ounces more than calculated. Even if I round everything up and account for errors I've never beat 5%. 

 

I get it, there are lots of variables in manufacturing and materials, rounding errors, things I may have missed. And my scale isn't calibrated either. Those all easily account for the discrepancy. Except if there were all these variables in play then at least some of the builds should also be coming in underweight once in a while, am I right? 

 

Just something to bear in mind. If you think you're shaving a few grams by spending $90 on Titanium pins or something like that it's easily overshadowed by reality and that marketing stretches. If I were really serious, like building racing bicycles, I'd need to have a scale next to the workbench and weigh each part. 

 

And I'm not even an engineer! Manufacturing must be Hell, imagine what this does to Aerospace and things where it really matters!

Edited March 4, 2020 by Frankly

[Nolan]

11 hours ago, Frankly said:

So I've assembled ("built" is an exaggeration of the skill required) my first dozen ARs and as I've gotten more experience I've started to go for lighter weight but middle-tier guns. No Titanium or exotic, expensive parts, guns around $1500 not $3500, Aero Precision not boutiques, etc. And I started a spreadsheets of weights of components including a margin for springs and tiny bits. And so far, out of 3 builds done this way, each has been 6-11 ounces more than calculated. Even if I round everything up and account for errors I've never beat 5%. 

 

I get it, there are lots of variables in manufacturing and materials, rounding errors, things I may have missed. And my scale isn't calibrated either. Those all easily account for the discrepancy. Except if there were all these variables in play then at least some of the builds should also be coming in underweight once in a while, am I right? 

 

Just something to bear in mind. If you think you're shaving a few grams by spending $90 on Titanium pins or something like that it's easily overshadowed by reality and that marketing stretches. If I were really serious, like building racing bicycles, I'd need to have a scale next to the workbench and weigh each part. 

 

And I'm not even an engineer! Manufacturing must be Hell, imagine what this does to Aerospace and things where it really matters!

 

Generally speaking in aviation and aerospace, it's actually the engineering dept, not the marketing dept. that produce the dimensions and weight.

 

I suspect in the AR market, the published weights are rounded down, because light weight is a selling point.

 

Nolan

[Frankly]

Opps thought I put it in the rifle forum, apologies to mods if they see this.