Had my h&r topper 20 ga threaded by Mike Orlen. I had mine threaded for winchoke/ invector threads. My gun is the youth turkey gun with 22" barrel, there was just enough "meat" on the barrel to have it threaded for remchoke. But I elected to go with winchoke to leave more meat on the barrel, just as added insurance shooting heavy tss loads. He does great job threading with quick turnaround. My topper patterns great with a kicks .560 choke shooting #9 TSS.