Weighing the Bullets.

[LRRPF52]

I did a quick back of envelope calc, and the variation of 0.3 grs in bullet weight means 0.0021, or .21% difference of your 143 gr bullet. Whereas a 0.2 gr difference in powder weight means a 0.006, or 0.6%, difference. So weight-wise, in terms of the physics, powder variations should cause more variation than bullet weight delta's... maybe 3X more than bullets'. I might even suggest that the best accuracy comes more from a repeatable, consistent pressure wave generation and propagation (ie, the firing of the powder charge) through the barrel, than a 0.21% delta of accelerated mass. In this propagation, micro-seconds matter.

Plus, perhaps point out that weighing brass is a method of comparative case volumes: since that shooter already uniforms the brand, even production date, and Oal of the brass... so weight is the proxy for uniform volume -- and volume is what will go into the pressure-progression of the powder when it fires.

My IMO from this is that, certainly weighing bullets might help...... but if so, it is one of the last, if not THE last, variable with the smallest ROI, for the shooter. This would be in line with comments that BR shooters are the ones who might want this step in their routine. I shoot mostly from the bench but am not a BR shooter... nor a Jedi master Lol!!).

You took most of the words out of my thoughts.

If there is one additional step you want to add to increase accuracy on top of the baseline of double-weighed or lab-grade scales for your charges, quality brass, and solid reloading presses/procedures, it is double-seating each projectile with a turn in between each stroke.

The concentricity runout has been proven to be a real thing with real results on-target, so it's the one step that I do when loading precision rifle. I don't uniform primer pockets, ream flash holes, or any of those steps that BR shooters use in tight chambers that don't require re-sizing because I won't see any practical improvements in my hit probability or groups for the kind of shooting I do (steel at distance).

If you are someone who is chasing group sizes on paper with a bag-riding bolt gun in the BR game, then you already know this and aren't constrained or enabled by the capabilities and limitations of the AR15.

Like the OP says, there are different ways to skin a cat.