Any time you have semi-auto firearms that throw perfectly good brass away and makes you go look for it you can end up with scratched dies. When your cases hit the ground they pick up dirt and grit that can become embedded in the die, And wet tumbling with stainless steel media will scrub the cases clean before sizing.
If your dies starts scratching your cases you can polish them with a drill and a snug fitting bore cleaning mop. Just use a short section of cleaning rod and chuck the mop in the drill. Then apply J&B Bore paste, automotive rubbing compound, Mothers Mag and Wheel Polish, etc to the mop and clean and polish the die.
If you are lazy and have a vibratory tumbler with treated walnut media you can polish a die. Just take the die apart and put the die body in the vibratory tumbler and let it tumble over night. The die will come out looking better than new and the inside should have been scrubbed clean of any dirt and grit. The polishing time will vary depending on how new the treated walnut media is and its polishing compound.
NOTE, if you are shooting a standard type AR15 carbine the cheaper Lee dies below with their ridged and "centered" expander will produce concentric cases. And if they become badly scratched you will not cry as much.
Below the Lee clamping expander collet centers the expander in the die, and dies like RCBS and Redding will let the expander be tightened down off center. On top of this if the extractor on a semi-auto chews up your case rims any ding in the rim will cause the case to tilt on the down stroke of the ram. And the only cure for this is a Forster die or a expander die that expands the neck on the up stroke of the ram.
You can use a Lyman type "M" expander with any type die and increase your bullet grip. And just bumping the case mouth on to the .226 section of the expander will aid in straight inline bullet seating. If you do not have enough brass spring back after expanding the case mouth you can use a taper crimp die to aid feeding.
Below I fitted all my older RCBS dies with Forster expander and spindle assemblies to reduce neck runout.
Below a Redding full length .243 die fitted with a modified Forster expander to reduce neck runout. Why drag the much longer Redding expander through the case necks with their increased drag. And a simple neck thickness gauge and a runout gauge will tell you a great deal about where the runout is coming from.