Martin,
I don't think you will be harvesting much game at 50 yards with a 410, slug or shot. There is also no way, that I am aware of to attach a telescopicsight to the m6, and as you pointed out you will need pinpoint accuracy which the crude standard sights do not provide so the scope, in my opinion, is a must. The last m6 that I fooled much with the 410 barrel was not choked and threw a very wide, thin, pattern that was very poor for any but the closest targets. I don't mean to sound so critical, just my observations, but I know people who swear by them. I thought the combo guns never did as good a job as either a dedicated shotgun or rifle.

Now a pure shotgun has a lot of merit as survival firearm, of 20 gauge or larger, the only reason I went with the 22 was the amount of ammo I can carry compared to the shotgun. I have trained many people to shoot and hunt and have not seen anyone with a properly set up rifle, and scope, have a hard time hitting stationary game at reasonable ranges. Chris