742 jam issues usually tied to 4 things
1. dirty/rusty chamber
2. dirty/plugged gas port
3. soft shooting gun on a pillowy shoulder
4. chewed up bolt rails.
#4 usually from folks shooting the .30-06 and 180 gr or heavier bullets.
Reportedly not a problem in other chamberings.
The see through ring stuff........as funny as it is, might have some logic behind it.
Like a mini 14.........some shoot pretty decent iron sighted, but once scoped, the cold barrel first shot will be where it should be, the followups from the now hot barrel, will be elsewhere.
I got a minty 742 carbine in '06. Set it to shoot 1" high at 100. Cold bbl, no prob. But if I shot any without letting it cool, the group would be OK...........but 7 or 8" low.
If one used the irons, which would track with barrel warp.......it might hit where aimed.
