[Dean]

Thanks Ron, You just saved me alot of headache.

However, Ignoring the "return to battery" problem, If the mass of the new barrel is at issue would not a ligher recoil spring be in order?

I think the "return to battery" problem comes about because the weight of the barrel causes a torque on the frame rails, thus adding extra friction to the motion.

I can think of a few ways to deal with this. Good lubrication, hone the frame rails, smooth the action up.

It's might be possible to add a lightly spring loaded roller in the forearm to push up on the bottom of the barrel and ease the torque on the rails. Granted, we no longer have a "full floating" barrel, but if it means that we can now have a carbine that is able to shoot regular ammo without cycling issue then it might be worth the small loss in accuracy.

I believe the above items can be addressed after the carbine is completed. Only after test firing the gun will I be able to evaluate these issues. To play it safe, I will install Wollfe's heaviest recoil spring and, if required, move to a lighter spring.