Just to satisfy MY OWN CURIOUSITY I just put my 44 mag barrel on my Topper Deluxe (SB1) frame and shot a Remington factory loaded 240 gr. hollowpoint to check for primer flowback.
There was NONE.
The primer looked EXACTLY like when I fire it on it's own SB2 frame.
I'm not telling anyone it's OK, I'm just giving my results so please don't start flaming me.
If my post is out of line or against the rules, please delete it.
Spanky