I started with a new 100% stock H&R Pardner Protector
I knew I was going to get one, so I had already ordered TacStar furniture
and a AIM (not TacStar) side saddle
The side saddle turned out to be junk (it broke after about 25 rounds of target loads)
After watching some videos on youtube I learned you can make the OEM tube 6+1 with a little work. It took more work than in the video, I had to grind down the dimples and trim the spring, but I got it to work (it's a tight fit).
And I also put in a Wolff magazine spring because I cut the one that came with my extension a little short and moved the rail/light back so I can activate it without taking my hand off the grip (at least until I get the rest of my permanent light setup)