Home Forums Hunting & Shooting Ask The Gunwriters Chronograph issue

I went earlier today and ran some loads through the chrony,I brought one box of 22 rimfire 36 gr winchester hollowoints that are advertised to run 1330 fps and shot them through my Ruger carbine, I beleive it has an 18 inch barrel. With no shadow and the sun at three oclock they averaged 1310, with sun at about the same position and black carboard placed on both sides completely shadowng the photo eyes I got an average of 1297 fps, not much difference. I then fired a 223 handload using the black cardboard to shadow the photo eyes, that load read 2890,I then removed the cardboard and turned the chrony slightly so that the photo eyes were completely shadowed by the diffusers, same load read 2945, all the rounds read higher than the rounds fired with the black cardboard and the exreme spread was much lower also.

I then tried another different load using the diffusers to shadow the photo eyes, it averaged 2962, then I went back to using the cardboard to create the shadow and fired the same load, it read 2954, this time the average velocity difference was much smaller with this load however the extreme spread again was much smaller when using the diffusers to create the shadow, I fired another string about twenty minutes later using this load using the diffusers to create the shadow and the average velocity dropped 32 fps, I noticed that the sun had moved and was slightly higher in the sky. Both methods seem to work but I like the carboard method best because I think it keeps a consistant shadow regardless where the sun is located however which method produces the correct velocity is the question that I would like to know the answer to, any advice or opinions would be appreciated.

I don't have lighting problems with my Oehler 35P. Also, I like to evaluate grouping while I work up velocity.

Yeah, I've never had any problem with getting consistent readings with my 35P either--and there are other inexpensive light-screen chronographs that are more consistent than Shooting Chronys.

I've got a Magnetospeed and if I shot a lot on public ranges I'd probably rig some sort of stand for it, so I could test velocities at the same time as groups--or sighting-in. But the only time I shoot on a public range much is after I've worked up a load, and want to take advantage of a bunch of gongs out to 1000 yards. Consequently I loaned a friend my Magnetospeed after his old Pact broke down. That was several months ago and I haven't missed the Magnetospeed enough to ask for it back.

Setting up the Oehler isn't nearly the ordeal some ADD types would have you believe either.

I dont find it hard at all. But some just want instant gratification.