No it's neither the only or best.
What I've used on most Contender barrels is the Weaver 92A or 92AS bases and used Burris Zee Rings or Burris Signature Zee Rings. The best is the SSK T'SOB for heavy recoiling barrels from those I've used. Back when VVGW was in business they made a similar base to the T'SOB from steel and perhaps aluminum as well. Part of that crew is now back in business as Match Grade Machine and they are also advertisers on this site and they are again making bases I believe.