WTS JP Rifles Recoil Eliminator.
This a 1" outside diameter stainless model for bull barrels. It was originally threaded in 3/4-28. Since my barrel was threaded at 1/2-28, I had my gunsmith who specializes in threading barrels permanently install a 1/2-28 adapter. The adapter is not going anywhere - not sure how he did it, but it is there to stay, and was a job well done - the threads are straight and clean. Has a final exit hole of .281" and will accommodate bores up to .243/6mm. The final exit hole of the JPRE-9S can be enlarged to accommodate bores up to .500.
See the manufacturer's website here: