Okay, rest assured that gun didn’t blow up and kill or maim anyone. Except for the gun not cycling correctly and the report getting load in the covered rifle range shooting shed; there was no indication something went wrong. As 45workhorse said, he has put way more rounds through his and I would imagine he has cycled slugs through it as well.
I was shooting a mixture of Remington 1oz. slugs with rolled crimps and solid based Lyman 525 sabots with folded crimps (nothing was sky rocket fast by any means.) If you look at the picture of the target, all the shots in the top target are a combination of the two slugs. (Sighting in my red dot). The bottom target has a really nice group to upper left with the same load (with 1/2 grain less powder,) than what I was shooting at the time of the failure; which is the shots in the bottom target dead center and below.
I believe Cap’n has the most plausible answer, which is also been a known cause of rifle failures with low powered/low recoil ammunition. The wad, powder, primer and shell combination is listed for a 1 1/4- 1 3/8 shot loads in the Lyman manual but according to many this seems like a low dose of powder for the weight (565-575 gr.)
The shotgun was fairly new, I did not have many rounds through it yet as it’s a novelty to me and I was specifically setting it up for hog hunting if I where ever to get the chance to go.
The gun is being returned to RAI for warranty considerations when I get a chance to get it in the mail (I want to remove my collapsible stock before I send it in. I have already received shipping paperwork.)
I will keep you posted on the results.