While it is a simple idea to have an over the counter class, there are big troubles in the actual implementation of it.
First, if you allow shooters to shoot a T/C contender (the most common silhouette gun) in the class you will create a rush for used guns and barrels as T/C no longer makes a barrel shorter than 12". The top gun in a standard class would be a used contender with a 10" bull barrel with T/C silhouette sights(tough to find) on it. All other guns would not be competitive. To not allow the T/C contender would limit many of your new members who already own one.
Second, it be like the old days, the best shooters will buy 10-20 guns of the same model, shoot them for groups, keep the best one , and sell the rest. Don't fool yourself, if you want to start a competition, you will get people who are competitive and they will push the rules but not break the letter of the rules. With a 5 year moratorium on rule changes, you could do nothing for 5 years, while the membership whines about how unfair it is.
Third, there will be a large turn over in guns. As soon a manufacture comes out with a better gun or upgraded one, everyone will have to get that one to be competitive again. Heres an example: If Ruger comes out with upgraded sights (Bomar) on their 10" Mark II, every has to sell their old Mark II's and buy the new one to remain competitive.
IHMSA has been through this and the members have rejected this old thinking (they voted the aftermarket sight rule in). It has proven to be a better system to allow shooters to upgrade their grips, sights and triggers as their ability and needs warrant. More guns will remain competitive with upgraded sights.
Fourth, Each "standard, over the counter" class will become a single model gun class, just as Production Air has become. You shoot a Daisy 747 or you put yourself in a big hole. The new shooter will know what gun they need to get to reach the top of the class. Without the C,B,A,AA,AAA classes the shooter will have no option, but to buy the top gun the winners are shooting if they ever want to make it to the top.
How are you going to address these and other problems?

??