I almost bought one in .325 WSM but I didn't like the trigger pull and wasn't confident I could get it fixed. The .325 WSM really hasn't caught on either. I also hate detachable box mags in regular hunting rifles. Other than that I loved it and wanted it.
A good friend of mine has a takedown and has a scope mounted on teh reciever. We did thorough testing with regard to the point of impact changing when removing the barrel and replacing it.
We found that the point of impact would move about an inch to inch and a half every time and not in a predictable manner.
This wasn't an issue for the type of hunting we were doing as we were shooting pigs at reasonably close range.
But for me personally it's a bit of a deal breaker.
I do not know the range you say you shot at, and/or if the scope was mounted properly. Mine, with iron sights does not have that problem, but my use is different. It was bought to for Bear Protection in Alaska, and for my son to carry on small aircraft for other travels about Alaska for protection.
The convenience of breaking down versus a small change is point of impact is the priority! This is why they do make models that DON'T TAKEDOWN!
Everything cannot be everything. Without the small size he may not have any rifle at all ... this is the Crown Jewel of the takedown models! NOT being able to takedown is a deal breaker for me in these scenarios!
I don't consider an inch in point of impact change a problem either. The rifle my friend has is a 308 so most of the game that my friend hunts with it is such size and ranges short enough that an inch is not going to be the difference between missing or not as with you and your son's situation.
Using it with iron sights I would say is the best option IMO because the irons come off with the barrel and therefore i don't know for a fact but I'd assume the point of impact change would probably not occur. or alternatively the user could mount a scope in a scout configuration if they'd prefer a scope they're probably the best two options.
It's a great rifle I'm not disagreeing with you at all in that regard, however I thought that point regarding the point of impact change with a receiver mounted scope was definitely worth mentioning to the op.
I understand there was always going to be a small sacrifice with a rifle that can be taken down so quickly and easily and as you said it's convenience far outweighs a minor change in POI.
I have the BLR stainless takedown in 450. Yes, the point of impact moves a bit and typically requires a set shot, but on what I got the gun for (big animals in brush country), who cares about an inch left or right at under 100 yards. If it's big enough to justify a 450, its vitals cover more than an inch.
As for the mechanics, never had a failure on it. Compared to my Marlin it's as reliable as a Mauser 98.