loading shells

[georgia hammer]

On some factory loads I notice they are harder to make the bolt (stiffer) close, and on other rounds and brands of the same grain they seem cycle better.

What's up with that?

[squirrelsniper]

It's due to headspace variances. Some manufacturers make their ammo toward the minimum SAAMI dimension and others more toward the middle of SAAMI dimensions. If you get a round that's made to SAAMI minimum and put it in the average factory chamber, the bolt will close like there's not even a round in there.