Bought a Franchi Affinity 20 gauge and a Marlin 336 mount to install a Vortex Venom. The Franchi is drilled and tapped but the two back holes on the shotgun don’t match the longitudinal holes on the mount. Also, the mount doesn't match the curvature on the top of the shotgun. It looks like it would rock even if I could mount the bracket on the shotgun. I thought this was the mount to buy?

Call sumtoy custom they make a great mount that fits perfect.

Just got a sumtoy mount this week. Perfect fit for my Remington V3. His mounts will fit whatever's you got.

Dont over tighten it. I'd you do the nipples on mount wont match up to the ff3 or venom. Great mount otherwise.

How long did it take? Will it match the holes and curvature of the gun?

The center of his mounts has one hole and then a long slide so the other screw can move up and down. Call William. Tell him what gun and optic. He sent me mine and said if it didn't fit he would make me another one. Yes it fits the top curve of the gun.took less than a week to get here.

Weaver 1-Piece Multi Slot Tactical Weaver-Style Scope Base for Benelli SBE II, Franchi Affinity Matte $15 on midway USA

You bought the correct mount, but you have to pay a gunsmith $10-20 to tap new holes that match that base

Just buy William's and be done with it. Then you dont have to do any tapping or anything. Just put it on and your good to go.

I really don’t want to drill more holes in my new shotgun when it’s already drilled and tapped. I guess I assumed that if the 336 would fit the Venom that it would also fit a drilled and tapped gun. Figured they would somehow be standardized.

I’m going to call Sumtoy on Monday and see if they can build me a custom mount that will fit the holes I already have.

I understand that. I haven’t seen sumtoys mount up close. When you get yours, could you put it next to the 336 and post a pic of the difference?

I will. I held the 336 up to the shotgun and it seemed like it would extend over the edge like it didn’t match the contour of the gun.

If it’s drilled and tapped from the factory (mine is an affinity 3), then you can buy the rail that fits a Benelli. It will fit the contour and screw pattern.

You can but it sits much higher than the sumtoy. Sumtoy will be the lowest and best fit to the contour of the barrel.

I agree. I wouldn’t want any extra pieces elevating the sight. I want it as low as possible.

Sumtoy is what I have on my daughter’s Affinity as well.

The Weaver 336 for a Benelli lined up perfect and follows contour of gun. Plus it’s $15 on line

Is it available for 20 gauge?

Yep. I got one on mine. I should add mine was factory drilled.