I charge $350 plus return shipping to do my work on CZ Sharptails that are shipped here. Its no secret to email or call for pricing. I don't know where you're finding new CZ Sharptail coachguns for $800-$900?¿ Thats not even wholesale cost, and you can't ever compete with a gunsmith buddy doing work for free.
Ken Griner
Check the ramp on the carrier, an aluminum carrier can develop a groove/ding/gouge where it pushes the cartridge back in the tube and lock up the carrier.
If you only need a few, check out these https://www.toxictargets.com/ I have used a few and they work good. Without breaking the bank
They hang on a T post and come in 1/4" and 3/8" AR500
This one is ~ 12 x 20. They come in different sizes, etc