Have a polite conversation with S&W's service dept, & tell them of your attempt(s) to eliminate a poor shooter &/or incompatible ammo. See if they think they should have a look. And, depending on the age of the gun, I might be wanting a prepaid shipping label as well.
4" @25 is not acceptable accuracy for most decent handguns in the hands of a capable shooter, & Tier II or custom is not necessary to achieve better.
Edit: I read my reply this morning & didn't like it. It could seem like I've called the OP a poor shooter by my wording, that was not my intention. Only thinking the manufacturer might wonder about the shooter and the OP has eliminated that variable by having other shooters try it.. Hope this clears the mud.
No problem, I wonder about my shooting sometimes too!
