extension tube spacer?

[bigshooter]

where can i find a spacer to put into a rifle length receiver extension, so that i can run a carbine spring and weight?

thanks -

[Robb Jensen]

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=244

Part # 9MM0073 9mm Stock Spacer $8.00

[bigshooter]

well done sir!.