My experience with free floated barrels vs. not free floated comes from shooting rimfire rifles in competitions. To give you an idea how much difference it can make I bought a Savage MkII with the F stock which is a cheap plastic stock. The barrel was floated but the second I put pressure on with a sling it wasn't floated any more. I soon replaced that stock and my group sizes became far more consistent. But be aware that just seating the barrel in the stock wrong can defeat free floating. You have to be careful to set it up right and in the case of rimfire rifles you have to have the action screws tight enough to keep it free floated.

I soon started winning competitions with that Savage. The thing is a rel shooter since I learned a few things like how to make sure it always free floated and how to get enough torque on the action screws to hold the barrel where I want it without crushing the wood on the stock I now have.

Here's an example of the kind of groups it can shoot now. It does not shoot this well all the time but it comes much closer than it did. Before I got it running right I would get a good group once in a while but after I got it running right I got a lot of them. I won 13 of the last 15 contests I was in with this rifle. Anyway this group is only 4 shots because I ran out of ammo. It's at 50 yards.



That hole is pretty much the size of a single bullet hole. Here's another example of what that rifle will do. This time 12 shots at 50 yards.



A free floated barrel certainly can make a huge difference in accuracy. A barrel heats up as you shoot it and that changes the way the harmonics work with the stock if it isn't free floated. Basically I cut my average group size down to about a third of what it was before on the Savage rifle.

That said the shooting I did was from a bench with a rest to get those groups. I never shoot my AR's that way. I see them as off hand type rifles. I know they can be made to shoot well from a bench but it is way easier to get a bolt action to shoot great groups. I have a .223 bolt action that will stay within an inch at 300 yards all day long. BTW it's also a Savage.

For people not interested in beating the competition I don't see a free floated barrel as being required. If your goal is to shoot a lot of targets quickly (which is what the AR is designed to do IMO) then missing by an extra half inch at 50 yards really won't matter that much. As others have said most people would benefit more from a better trigger and even more than that from practicing a whole lot. I'm not trying to insult anyone. It just takes practice to be able to take advantage of your equipment to the fullest.

I guess I'm about to find out how much a free floated barrel makes on an AR since I just got one with a free floated barrel (I believe it is anyway - maybe I'm wrong - I don't know how to tell short of taking the grip off but it appears to be free floated from what I see). It's a custom build using mostly Aero Precision parts. It says X15 on the lower and the builder apparently registered the whole gun as a single unit. I really haven't had a chance to shoot it yet except for a few tracer rounds at dusk. I guess I'll see what happens next.