I also had problems with open sights and got around it with a P/H peep sight.
18" barrel which came off a 9mm Manlicher and slugs out at exactly .357 and breech block bushed. Was originally a 22 R/F.
No more trying to align front and rear sights and so light to carry.
Real pussy cat to shoot and so accurate.
These little Martini actions must rate up there with the best or even better.
What other easily available rifle action can you take out the working parts by taking out one little screw.
OK so you are limited to calibre, no big booming Magnums but I have found my Martini 7mm Waters ok.
Looking forward to getting my hands on my next Martini in 5.6 x 50R
I used to be able to post a photo here from Photobucket but all I can come up with now is this.
http://i1223.photobucket.com/albums/dd514/velocette1/SAM_0557_zps4e9fe3c4.jpg