Re: question on ar bolt
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mrs.Lazy21</div><div class="ubbcode-body">wanted to know what is the difference on a semi auto and a full auto bolt for an ar15, any info is much appreciated and thanks in advance
another? can you run a ar15 bolt/carrier in multiple ar's or do you have to swap out the bolt from the carrier for each ar </div></div>
As for the bolt itself - none.
Second question - you can swap carriers universally with any in spec carrier and upper.
However I think you are really asking something else - can one swap a carrier and a bolt between uppers? Generally headspace is not an issue with a new bolt and a new barrel / extension. However it can happen. In order to check headspace you really need a field gauge or a gauge that shows headspace beyond spec. The other thing to know is that one bolt and one extension mate and wear together. That wear pattern may not be the same from extension to extension and running just one bolt in several uppers may cause problems.
At minimum you should have one bolt that is dedicated to one barrel / complete upper.
Back to carriers for a second - FA carriers are a little heavier and can help retard the timing a bit. This can promote reliability. Many better quality ARs come stock with FA carriers. Retarding the timing becomes more critical as the barrel gets shorter. In the case of 10.5" /10.3" you need to pay a lot of attention to the timing in order to set up a reliable gun, and will likely need to try either a heavy or a heavy + buffer.(This already assumes your gas port is the correct size)
Lastly, if one has concerns about FA carriers and running afoul of the BATFE - BARFcom and M4Carbine both have some tacked threads that will run through it exhaustively.
Good luck
