B yond
I'm pretty sure all the pistol version's pistol grip frames are cast into the frame. At least I know mine is. However, mine is a Charter Arms, both the rifle and the explorer II pistol, and seems like the AR7 changes makers about every five years or something.
I'm not sure the Explorer II pistol was even built by anyone, but Charter, though. It's pretty ugly, big, and useless, LOL, just got mine cause a friend with an FFL said he was getting one for seventy bucks and did I want one? For seventy bucks, why not? LOL. It came with 8" and 6" barrels. It shoots well, accurate, but the same aweful AR7 trigger. Larry liked it because for some odd reason, he likes broom handles and thought it looked like a broom handle.
I've seen folks bad mouth function of these little guns, but mine work great. I think the deal is nobody understands the way they work. These things have the feed ramp in the magazine. If it's nosing up bullets and jamming, or hanging below the chamber, just bend the feed ramp part of the magazine in or out as needed to adjust it with a pair of needle noses and you can make it work 100 percent.
The little guns are a lot of fun to play with and shoot and what I got my first AR7 for was because it'd disassemble and fit in a motorcycle saddle bag.