First time out with my chrono

[bossman]

I didn't shoot it, so yeah I'm happy. I was getting a lot of extreme reading at first and by trial and error finally got up and going. I found most of my loads were close to what I thought they would be.

I had one load of 45acp down lower than I wanted and one set of 9mm plated push 1200 fps, yikes. Great shooting round and very accurate but my gun would eject the brass to the next county. I thought they may be a little warm but found they're just hot. Next batch will be about 3gr lighter and will see how they work for accuracy.

I shot about 400 round and other than checking my POA and POI for each gun everything else went over the chrono.

How often do ya'll use your chrono? Just for checking new loads or everytime out?

I guess I'm getting soft, rubbed a blister on the inside of my thumb.

 

[Zach W.]

Dropping down 3 grains in 9mm might put you below the recommended starting load.

 

[bossman]

My bad how about .3 grs

 

[steve4102]

How far did you set the Chrony from the muzzle?

 

[steve4102]

Hey looky, looky, I just made 1000 posts.

 

[g.willikers]

Checking new loads is usually sufficient.
As long as the components and loading methods are consistent, and for the same gun, an occasional spot check is all that is needed.
As you discovered, if there's something amiss, it will be evident.

 

[David Bachelder]

I use mine only to research new loads. I've only shot it once

It did survive.

 

[bossman]

How far did you set the Chrony from the muzzle?

I end up 10 to 12 feet away. And congrats on that 1k post.

 

[Lost Sheep]

Muzzle blast can cause erratic readings, as well as pieces of unburnt powder being detected by the instrument. Sunlight can be problematic, too. Occasionally the odd angle of sun or a little reflective glint can cause a momentary inability to be accurate. Magic? Seems like it.

Sorry I can't be more help, but in general:

Set the instrument as far as possible from the muzzle of your gun.
In direct sunlight set the diffuser screens properly over the sensors.
In open shade with clear blue skies, try with and without sensors and see which seems to work best.
Under partly cloudy skies where the sunlight is intermittent, wait a while and hope the weather changes.
Under even, light overcast, count your blessings. That is the best light for your chronograph.

Good luck.

Lost Sheep

 

[steve4102]

I end up 10 to 12 feet away. And congrats on that 1k post.

That should be OK, but next time set it out at 15 feet and see what happens.

 

[Unclenick]

I had one load of 45acp down lower than I wanted and one set of 9mm plated push 1200 fps, yikes. Great shooting round and very accurate but my gun would eject the brass to the next county. I thought they may be a little warm but found they're just hot. Next batch will be about 3gr lighter and will see how they work for accuracy.

Just to make sure, you do understand that velocity is proportional to average pressure in the bore and not the peak pressure. So it can't tell you if the pressure is safe. Moreover, even if it could, its not that hard of circumstances to make a chronograph read off by 50 fps. Fine for comparing SD's and duplicating your own test load, but not accurate enough to be sure your peak pressure matches some other gun's peak pressure with the same velocity even using the same powder.

 

[bossman]

The good part is I now have a database for my powder, my bullet and my gun.

I know published velocity is a ballpark figure and every gun will be different. The published loads are like being in the upper deck with the chrono loads it's like being in the first row. I can see whats happening and get a better feel of the game.