I've had a look at the reamers on Brownells, can anyone tell me what size they are(12 Gauge),
ie start size and finish size, also are they a 1-50 taper..
And what is the reccomendation of how much to take out?

regards
griff

I have 12 gauge and 20 gauge reamers.They will only take out so much metat then they stop.
Well worth it in my opnion,the shotguns that I have done have shot tighter and better paterns after.
I have the carbide in 12 gauge and the sprial in 20 gauge.

There is only one type per gauge. If you can, get a scrap barrel to practice on, it's easy to do once you get the hang of it. You remove enough metal to completely remove the old forcing cone. Once you do it and see how the metal removal progresses it will become clear to you how far you need to go.