Based on the excellent counsel I received from members of the forum, I purchased a chronograph to use with my doubles. I purchased a Chrony Beta Master.

The first trip to the range with the chrony was yesterday. The chronograph worked fine with one exception. I probably had four or five instances where I got an error code "Err2" meaning that the second electronic eye was not picking up the round. This seemed to be more common with the right barrel than the left barrel. I surmised, perhaps wrongly, that this was a function of the fact that with a double the sight is in the middle but the barrels are offset to the right and left, hence sighting down the middle might have the bullet traveling to the left or right of the electronic eye.

If this is the case, since the unit is picking up the first electronic eye and not the second, should I move the chrono closer to the bench? I had the unit between 10 and 12 feet in front of the muzzle. Is there another fix? Am I off base on the problem?

Thanks.

I doubt it's related to the relative location of the bullet's path to the sights... just not a lot of distance there.

Doesn't sound like anything you did wrong to me... none of these are fool-proof... they all seem to miss shots sometimes.

How was the ligting outside? Bright sunlight? Overcast?

I get alot of error messages on bright sunny days. I've don't have a double (yet) so I have the same trouble with single barrels. I've found the are most reliable on light overcast days or when the sun is lower on the horizon.
Sam

Run a black "Magic Marker" felt pen over the bullet before firing to blacken it and your readings should improve, .....most of the time you're not getting enough shadow off the bullet.~Arctic~

It was an overcast day, probably a bit on the darker side. Was shooting at 9:00 a.m.

The marker on the bullet sounds like an interesting trick. Although you would think that the damn thing could pick up a 400 grain boulder flying across the electronic eyes.

quote:

Originally posted by MJines:
It was an overcast day, probably a bit on the darker side. Was shooting at 9:00 a.m.

The marker on the bullet sounds like an interesting trick. Although you would think that the damn thing could pick up a 400 grain boulder flying across the electronic eyes.

I've had problems on days like this with My Oehler 35P. Removing the sky screens was the answer, probably didn't have enough light to work reliably.

If it is a difference in the bullet paths, and if the bullets from the left barrel are just getting "better light", the solution would be to tilt the screens a little to the left.

When shooting an expensive cartridge, I generally bring a 22 to the range also. I get the screen oriented (fresh batteries is a good thing, too) so that those tiny cheap bullets register consistently, and then I start shooting the big gun. Well, generally, I have a 22 with me anyway. It's something to do while the barrel cools.

H. C.

HC470, That is GOOD info, Thanks.

I had the same problem with a .54 Kodiak SXS. I started moving the rifle to one side or the other, as necessary, by about 1/2" or so when chronoing each barrel..Problem eliminated.

quote:

Originally posted by new_guy:
I doubt it's related to the relative location of the bullet's path to the sights... just not a lot of distance there.

Sorry! It IS related to the bullet's path over the screens. Bullet needs to pass as close to the centerline of BOTH screens as you can get it! BT, DT!!

I used the same chronograph under similar situation for my first go at it about two weeks ago.

I didn't use the skyscreens because of the heavy overcast. Only set up the longer rods and not the extensions. I did use a 22lr to confirm setup and shooting height etc. Result was no problem. I made sure to shoot at the height Chrony recomended in the directions. This is lower than I would have guessed without reading the directions.

Shot at 15ft then tried at ten, again, no problems. No need to adjust for the barrel offset and ten to fifteen feet is what Chrony recomends.

22lr, 375H&H and 458wm DR all produced good readouts.

Second try was a very bright day a couple of days later, but in later afternoon. I used the sky screens, as recomended and the long rods without the extensions. Again, good readings with 22lr, 375H&H and 458wm DR at 10' and no need to offset for the DR barrels.

Hope this helps,

JPK

Always use the skyscreens... always....

missed shots go down from 3 in 20 (or more) to totally user err (err2 - you missed the rear lens)

jeffe