The Ammos

For what twist does to a given bullet weight in 5.56.

It really wouldn't be an issue except, like he says, small changes in mass make large changes in length on a 0.224" diameter bullet.

Pic taken from the above linked article.

Of note is two columns for 62 grain projectiles.

This is because M855 ball weighs 62 grains, but because of the steel penetrator it's as long as a 69 grain bullet with an all-lead core.

That underscores that bullet construction matters.

Some of the up and down from this table also relates quality.  M855 and M193 aren't match ammo.  They are bulk made ammunition for the military, where 3 MOA is just fine.  You can see it on the chart where 62gr lead and 69gr are more accurate.

I've made a couple of other posts on this...

Here.

The effect that changing weights can have on point of impact.