is having a bolt matched or fitted to your barrel necessary?

[adrenaline151]

I see some barrels on Rainier Arms come with a matching bolt... so it seems that should obviously be the best choice, but for carrying a backup bolt, say, in the MIAD, can you just buy a quality bolt and be all set, or should the extra bolt also be matched? Is there a way for an average non-gunsmith type of person to match to bolt, and what is actually involved in this matching?

[Stickman]

For maximum accuracy, a fitted bolt is the best way to go. However, the level of accuracy we are talking about is almost mandated to be using top of the line scopes with ammunition tailored to your barrel. The skill level required to see the benefit is probably more than I will ever notice.

A spare quality bolt will serve you well.

[Eric]

For precision rigs and those who are able to due them justice, a fitted bolt is the way to go. There really isn't a downside to using one, but for the type of shooting I do, I most likely would not experience any benefit.

[John Hwang]

A fitted bolt is basically checked for head spacing with the barrel extension. Many factory bolts will close with both the GO & NO-GO gauge which will function fine as long as it don't close in with the Field gauge. However, the tighter everything fits, the better. A fitted bolt is one of many items that need to fit well for a precision rifle.

[adrenaline151]

Can a person with basic gunsmithing knowledge "fit" a bolt to a barrel?

[Klutched]

AR-15 Bolts will fit themselves to a chamber, they are pretty dummy-proof. After a couple of hundred rounds, the bolt will be thoroughly "fitted" to your chamber.
Headspacing is not necessary. Of course if you are looking for an ultra-accurate AR, a fitted bolt is a good idea.