Those mosin's WILL shoot if you are able to do your part!! At our club we have had two mosin shoots: We shot prone at 200, 300 and 600 yards. You gotta remember, Mosins are not bench rest target rifles. They are minute of man battle rifles!!! They will put holes in paper at 600!!! With iron sights!!
The big problem with these rifles is most shooters are not iron sight proficient!!
Takes practice, proper position, rock steady NPOA and knowing come-ups!! Get thee to an Appleseed to learn the fundamentals and be surprised how effective irons are!!!