I will be using the AR i bought for varmints, primarily coyotes.  After some extensive research I have decided I will probably be shooting a 60ish grain bullet for a few reasons.  I don't understand the whole barrel twist thing.  The gun I ordered from Model1 has a 1-9 twist.  I hope I made the right decision as I should have researched this more before making the order.  What is the main difference between say a 1-8 and a 1-12 twist barrel?

You'll be fine with a 1/9 twist and 60-ish grain bullets.  Don't sweat it.

Basically, a slower twist (like 1/12) won't properly stabilize a longer (read: heavier) bullet.  60gr or 62gr bullets and a 1/9 twist were practically made for each other. Conversely, a faster twist (say 1/7) is too much for short (read: lighter) bullets like 40gr, etc.

With 1/9, your rifle should be reasonably accurate with practically any bullet, though less accurate with 40gr or 80gr than with 55/62/69gr.

You can search and read about this subject for hours.  Trust me.

My search feature does not work on this website for some reason.  Every time i enter a "keyword" i get the "page not found" error.  Not sure what is up.  I have emailed technical support.  Thanks for helping me out with these questions.  I'm sure the majority of the questions i ask are very novice.

Quoted: You'll be fine with a 1/9 twist and 60-ish grain bullets.  Don't sweat it. Basically, a slower twist (like 1/12) won't properly stabilize a longer (read: heavierlonger) bullet.  60gr or 62gr bullets and a 1/9 twist were practically made for each other. Conversely, a faster twist (say 1/7) is too much for short (read: lightershorter) bullets like 40gr, etc. With 1/9, your rifle should be reasonably accurate with practically any bullet, though less accurate with 40gr or 80gr than with 55/62/69gr. You can search and read about this subject for hours.  Trust me.

it's not the weight it's the length.

Uh, thanks.  I know it's the length.  I was trying to explain it to someone who didn't (hence the original question).  Since they don't market ammo with the bullet length marked clearly on the outside of the package, one can (usually) assume that a longer bullet is a heavier bullet.  62gr steel core ammo is the exception, not the rule.

Apparently my explanation was unclear.