Chronograph shot loads?

[lar45]

Have any of you tried to chronograph shotshell loads?
I'm playing with some 410 stuff in brass cases and I'm getting some eratic readings, like 500 to 900fps.

Any input would be appreciated.

[upnorthwis]

I've only done 12 gage with #8 shot. Chronoed only two shots per load. FPS was close to book speed and didn't have the spread that you had. Does your recoil feel different between those large spreads?

[lar45]

The recoil seemed the same between the loads.
I'm shooting them out of a pistol. I thought that without a choke then the shot would start to spread fairly quickly so I'm getting about 3-4 feet from the chrony and shooting maybe a foot above the screens.
I know that if you get too close then the muzzle blast can give you some false readings.
Maybe I'll try shooting higher above the screens and see what that gives me.

I'm useing Magtech brass with a WLP primer and 11-13gns of Alliant 410 powder with 1/2 oz of no. 8 shot with 410 fiber wads. The 11-13gn loads would not expand the brass at the mouth of the case at all. I tried a 14gn load and it just started to expand the brass a very small amount. The cases will still go into and out of the chamber easily.

[upnorthwis]

Try backing up a bit. I don't remember how far back I was but think it was farther than 3-4 feet. Maybe closer to 6 feet. I wouldn't go any higher than a foot.

[FullTang]

This may be impossible to get right, because you're using a rifled barrel and the shot will spread much more quickly than from any smoothbore. You need to be far enough away that muzzle blast won't affect the readings, but close enough that the shot and wad are still together, and close enough that the wad won't kill your chrono if it peels off early. Try it on a cloudy day without the sky screen diffusers and you'll have a little more wiggle room.

[FullTang]

So I wrote this in the morning, went shooting this afternoon, and promptly proceeded to kill my Chrony with an errant wad petal while I was trying to chrono a slug load!

[lar45]

Oh, I am sorry to hear that.
I believe that they sell replacement parts for them that would be cheaper than just getting a new one.

[FullTang]

Oh, I am sorry to hear that.
I believe that they sell replacement parts for them that would be cheaper than just getting a new one.

I'm checking that out (though it's the LCD display that I wrecked, and that's soldered onto the main PC board), but I think it's probably best to use one with a remote display, so that you can put a big piece of wood in front of the chrono body. This one has been hit many times, but just never got the actual kill shot---until today!

[Larry Gibson]

So I wrote this in the morning, went shooting this afternoon, and promptly proceeded to kill my Chrony with an errant wad petal while I was trying to chrono a slug load!

I was just about to tell you that a shield to protect the screens from errant wads and shot is needed.......sorry I'm too late. I've chronographed shotshell/guns in the past with my Oehlers. I removed the diffusors and had a 3/4" steel plate in front of the screens at a 30 degree angle back. It stuck up about 4 -6" above the screens. That also protected the screens from the muzzle blast so I was able to have the muzzle 5' from the start screen for a tight bunch of shot shooting 6"+ over the top of the steel. Reliable readings were then taken.

Larry Gibson

[FullTang]

I really should have put a Lexan shield over the display (it was an F1 Chrony, the really basic model) but I never got around to it---the design is tricky because you need to be able to access the front panel, and you need to be able to see the display from a few feet back, especially on the rifle range. The company does sell some kind of clear shield, but I've only seen it on their web site, not in any of the other retail outlets. They certainly could have made the front panel out of heavier material---the only thing protecting the fragile LCD is a thin sheet of clear plastic film. A few square inches of 1/8" Lexan for the face of the control panel would have made all the difference and wouldn't cost much.

Well, I got it really cheap and got a lot of use out of it, and now I guess it's time to upgrade to one with a remote display that can't get hit by wad bits! I think I'll also make a nice, thick plywood shield in front of the unit to really protect it from anything short of an actual bullet.

The interesting thing is that I wasn't really shooting anywhere near the display---at least a foot over it from 8-10 feet away. But I was shooting a slug from a rifled shotgun barrel, and a wad petal must have sheared off and spun out from the slug's flight path. Just like we started out discussing in this thread, with the rifled pistol barrel spreading shot out really quickly.

[woody1]

I've chronographed 410 shot loads but out of a choked shotgun. I'm sure I was at least 6' mebe as far as 10' away. I even used the little rods that stick up on my Chrony. No harm, no foul. I do have a remote readout and a shield. I got what I thought were reasonable readings. YMMV Regards, Woody

[FullTang]

Got a replacement Chrony. This one is the Beta Master with a remote display; it costs a little more, but I don't have to worry about the display being in the line of fire (which is anywhere downrange of the muzzle with a shotgun!)

This one seems like it should be a lot sturdier, plus it figures all the stats automatically. Eventually, I'm sure all these things will work with smart phones via a wireless Bluetooth link, so all the data will saved and can be processed easily. I think this one will do for now, though.