Hi there read the posts with interest,Had the NS200 since autumn last year,made a couple of home made DSA"s but opted for the cobra/merlin dsa,you can use it straght off,but made a longer shim for the rear to get the best sight picture.Also use a 10amp li-ion battery waist pack and now have fitted a 4.2amp/hr battery to the stock,which is fantastic!Tried using gel filters found pale yellow best upto now,red killed the image to much.Been using the NS200 on the hmr and f.a.c air and achieved great success.With the hmr head shoot rabbits 100yds easily!longest shot in the neck was 179yds witnessed,so some of you may say " **** " but a lot i think depends on your scope,on all of my rifles i use a Simmons WTC 6-20x5owide angle and works a treat.Also tried it on an mtc viper 6x24 x 56 and no were near as good as the simmons,Brother tried on his hawk scope 3-12x40 i think and still not as good as the Simmons wtc.Lastly today got some double sided velcro and mounted a Yukon mpr on the rear of the camera unit for filming,fits just nice,so be interesting to see what scpoes guys are using to acheieve the best sight pictures....