@GhostMutt the pins I bought are from Lantac where I bought the trigger from. They are supposed to be for the 15-22 as the pins that come with the trigger are the ar-15 ones. When I say they are "too long" it is literally only a fraction. The screws, when done up don't touch the sides snugly allowing slight sideways movement in the pins. With regards to the trigger I have noticed on the bolt under the firing pin where the hammer comes into contact with the bolt when it moves backwards, there is some wear and a slight lip. I am guessing that because the radius on the top of the hammer on the CMC is sharper compared to the original this is what it is catching on. I will try and polish this bit smooth and see if it makes a difference.
@Rob1 I would love a set of KNS anti rotation pins but don't know where to source them without the usual kerfuffle or paying a King's ransom. If you were able to point me in the right direction it would be appreciated. They would have to be FDE ones though!