Same problem for me with my 1972 SBH. I spoke directly to Ruger about it. The person on the phone didn't have the details to explain why they couldn't repair it, but said they didn't have the parts.
I wanted a shooter-not a collectible. So I have a 5.5" Stainless SBH on order. As soon as it is made, it will be shipped to me as an exchange. No fees [except my dealer for DROS and receiving: :evil: ]
So, this doesn't sound fishy to me.
It sounds like they are running out of conversion kits, or that they ran out. And they are not explaining this to anyone before the gun is sent in.
Mine was sent in for a Bullet Gap of .011" and an endshake/endplay of .007", when Ruger says the SBH numbers should be a BG of less than .010" and endshake/endplay of less than .003".
It was spitting lead significantly also, whatever caused that.
I am sad at the loss, but I only had it 6 months and will have something that will accomplish my goals just as well.
Too bad I have all the OM trigger parts in a drawer and can't put them back in.