Cutting The Choke Off An FX Slug Liner ?

This isn't quite an accurate statement. The crown does offer a protection to the rifling indeed. But as to having little to no affect on accuracy, myself and every F class shooter will disagree. The crown provides a square / perpendicular departure in relationship to the rear of the projectile. This can be even more influential with regard to pellets. If a crown isn't square, the gas will escape on one side of the projectile, acting like a thrust vector. The projectile will wagg for a bit until the gyroscopic spin or drag stabilizes it. By that time the deviation in flight path has been established. This can be a benefit to the use of related bullets. Pellets that are out of square or have bent skirt will exhibit these characteristics. I've made blocks with reamed hole to fit pellets really precisely load the pellets into the holes and move in a figure eighton a peice of paper, until you see an even shine around the skirt, with crisp edge. 

You did say properly prepared but offered no detail as to what proper is. 
 
This isn't quite an accurate statement. The crown does offer a protection to the rifling indeed. But as to having little to no affect on accuracy, myself and every F class shooter will disagree. The crown provides a square / perpendicular departure in relationship to the rear of the projectile. This can be even more influential with regard to pellets. If a crown isn't square, the gas will escape on one side of the projectile, acting like a thrust vector. The projectile will wagg for a bit until the gyroscopic spin or drag stabilizes it. By that time the deviation in flight path has been established. This can be a benefit to the use of related bullets. Pellets that are out of square or have bent skirt will exhibit these characteristics. I've made blocks with reamed hole to fit pellets really precisely load the pellets into the holes and move in a figure eighton a peice of paper, until you see an even shine around the skirt, with crisp edge. 

You did say properly prepared but offered no detail as to what proper is.

No it was a completely accurate and factual statement. Properly cut is just that and I did offer detail. I said " As long as a barrel is cut clean with no burrs at the end of the riffling there is no need for a crown." There is nothing else to say about it... no ifs, ands or buts. No one is thinking they can chop off a barrel at an angle and all boogered up and a crown will fix it.
 
You have to make a lapping tool if you cut the choke all the way off .You can start with an 1'\/8 inch increments. Get on extreme airguns on you tube . exactly the way it is spelled .There is a video that says cg slug barrel with choke cut off .My phone auto corrected when i put in fx.The gun put for slugs in the same hole and 2 slight flyers.I then did more barrel work and im waiting to get more slugs.Also what my video on slug liners .