I had my Stevens 301 20ga compact drilled and tapped for a scope base and I like the idea so much I'm thinking of doing my 870 20ga.  I looked at Weaver and a 48454 or a 429M is what it calls for BUT, considering a 12ga receiver is a wee bit wider than the 20ga will this still fit?. 
thanks in advance
			
			
			
				20 and 12 use the same scope base.
			
			
			
				I have just had a 870 20 gauge drilled for the weaver mount (48454) and it works great with a Vortex red dot.
			
			
			
				thanks y'all.   I just ordered a Weaver 429M.  gonna strip out the receiver and get it drilled and tapped as soon as the base arrives.
			
			
			
				done deal.  I already have one 2x32 Pro Diamond for the 301 but haven't mounted it yet and I have another on the way.  scopes on shotguns is a strange world for me right now but I'm thinking I'll be happy.
			
			
			
				Is there a difference between the 48454 and the 429m. Do they have the same hole pattern ?
			
			
			
				I may be wrong but I think the 48454 is gloss black and I know for a fact the 429M is matt black.