Point is, if you are going to do a custom with a super powerful cartridge, be aware that the gun was not designed for half of what you are using in it. I would NEVER pass on a custom max, since, other then Gary Reeder, there are no other max frames.
However, I'd have to give my self a real good exam, since I can often find a FA 83 for around 1000 dollars, and, likewise, the stronger, better made BFR short cylinder guns for around 500.
I have letters from Hamilton Bowen, and John Linebaugh that if you want to get a full throttle gun, buy a Freedom Arms....
As Bowen put it, even when he gets done with the gun, it's not going to be as tight, tolerance wise, as an FA, and, it's not going to be as strong.
I also see a bit of value in a custom S&@ .500, since it's the same length as the max frames, yet has a ton of ammo around, and, they make really neat little guns.
1500 for a max would have me thinking. 1000 or less and I'd buy it in a second. But, that's just me.
Makes sense 510 but if I can't kill it with my Bisley converts then I am in bad need of a really big bore rifle. Another reason I went with the conversion is I had it built exactly like I wanted it as far a grips, bicolor finish, sights, etc.. FAs are obviously well built and great looking guns but to my eyes if you've seen one, you've seen them all. Everyone to his own.
Shoot more, shoot more often.