I think it was Europe that made a post on here about factory ammunition. I along with some others made the comment that decent factory ammo is a good indicator of how your rifle is shooting. It's pretty consistent ammo. I can really only speak of Remington as that's the typical factory ammo I ever shot.
Here's a good example. Underneath my boxes of loaded ammo was a partial box of 100 gr Remington's that has to be pushing 20 yrs old. I shot 1 fouling shot on the target beside it then shot 3 more for group. This is from a 6mm Model 7 with a short and thin 18" barrel. The gun can be finicky on reloads......it likes what it likes and will pretty much puke with anything outside the lines of it's tastes. But it spit out this run of the mill factory ammo in a group that measures just a tick under 3/4" at 100 yds.
Here's a good example. Underneath my boxes of loaded ammo was a partial box of 100 gr Remington's that has to be pushing 20 yrs old. I shot 1 fouling shot on the target beside it then shot 3 more for group. This is from a 6mm Model 7 with a short and thin 18" barrel. The gun can be finicky on reloads......it likes what it likes and will pretty much puke with anything outside the lines of it's tastes. But it spit out this run of the mill factory ammo in a group that measures just a tick under 3/4" at 100 yds.