FX Indexing Impact M4 barrel?

[encore209x50]

I've read a few places about indexing the barrel on an Impact M4, am I correct in thinking this is done to help correct windage out at distance? I know a lot of custom muzzleloader builders will Index their barrels to correct for this. I'm assuming the same is being done for the Impacts?
(Example: rifle shoots dead nuts at 50 yards, but at 100 will hit either left or right if the barrel has an extremely slight bend or bow to the barrel.)

 

[Frostbite]

Correct. This is also used to get your Point Of Impact at it's highest point so you can uses less of your scopes height adjustment range .

I insert a lazer bore sighter in the bore then rotate barrel around so I can see shift in P.O.I.
Saves a lot of time and ammo!

 

[encore209x50]

Ok yeah I figured that was it, good thing to know for future tinkering. And good idea with the laser bore sighter, that's one of those " why didn't I think of that" moments. So I'm assuming the liner is what's actually getting indexed and not the whole barrel assembly.

 

[Revoman]

Yes, liner only. However, the entire assembly needs to be in place in order to assure that it still will have the POI with all of the 'extra' weight in place.

mike

 

[encore209x50]

Yes, liner only. However, the entire assembly needs to be in place in order to assure that it still will have the POI with all of the 'extra' weight in place.

mike

Roger that