Can a forcing cone reamer be used to lengthen a 20 ga. chamber from 2 1/2 to 3" or should a chamber ream be used?

ok, that should not be an issue here, but which do I use? the chamber ream or forcing cone ream?I am not concerned with forcing cone region as this is a rifled barrel for slugs
Thanks

I would use a chamber reamer...it has the correct taper out to 3 inch. 4D reamer rentals has one for rent...

http://www.4-dproducts.com/index.php

Ditto what Wayne said.

Good deal, yes we have used them before in a 12...good prices too.

I am curious as to what type of gun has a 2-1/2" chamber on a rifled barrel?

quote:

I am curious as to what type of gun has a 2-1/2" chamber on a rifled barrel?

If, and I don't know, this is a Manufrance Fusil Robust side-by-side (it probably isn't) then that rifles barrel is not for slug but for use on woodcock gam birds at short range with convetional #8 shot and a fibre wad cartridge.

Or a French Breton make o/u shot gun too.

To give a wide spread as the bird gets up at your feet and then starts to Jink to left and right. I don't think that the rifling would be of any use with a slug as it is not what it was designed to do.

So the bore may be too wide for a rifled slug to actually come int contact with that rifling.

OTOH this may be all irrelevant as it may not be that sort of gun at all!

are you getting the 2 1/2' measurement from the shot shell or from measuring the actual chamber?

most "2 3/4" shells are actually closer to 2 1/2" and most 3 inch shells are closer to 2 3/4.

They are 2 3/4 or 3" after they are shot; the folded crimp is opened.

Years ago I bought into longer forcing cones and bought reamers. I used each one (12, 16 & 20) exactly one time each and realized you don't take away metal where it's needed most in front of the chamber.

Should probably sell the damn things.