OK so I almost never shoot anything other than surplus 55 grains FMJ. So I decided to make a semi auto M16 A4 with a 1/12 twist on a flatop. on top of a preban Colt A2 pushpin lower.

Now I wonder if the TA11 will work out OK with this bullet twist combo?

Should I leave the 1/7 twist barrel in place?

Or it wont matter under 300 yards?

Any responses appreciated.

Why would the twist have anything to do with the effectiveness of a scope?  Am I missing something?  It will work as well as a 1/7 twist and 55 grain ammo.  If you are asking will it be off from using 62 grain ammo then yes it will but it will be a very minor difference and the only thing you need to know is where the bullet strikes in relation to the 300 yard tic on the reticle which will be a very very small adjustment.

That is what I was on about the bullet impact difference.