10mm in GP100

[44Blam]

What boolits are y'all shooting?

I'm currently shooting the Accurate 40-180 H but without the lube grove. This makes them come out around 188 grain and I PC them.

I've been shooting them over a healthy AA#9 charge, but I think I'm going to tone my charge down a little. My current charge with this boolit is 13.1 grain and it sends that boolit about 1250 fps.

My goal for tomorrow is to test some lower powered AA9, Unique and AA7 charges. They should all be near 1000 fps.

But I am curious - does anyone else cast and load for the 10mm GP-100?

[Cosmic_Charlie]

How is the geometry on your revolver? Cylinder throats compared to groove diameter? Just curious......

[Outpost75]

I shoot these in a Blackhawk:

263868263869

[44Blam]

How is the geometry on your revolver? Cylinder throats compared to groove diameter? Just curious......

Cylinder throat is .403 (ish - used calipers) and the barrel slugs right around .3985.

[44Blam]

So, I made up 42 rounds with AA#9, AA#7 and Unique. All much milder than my current load...

I went to test the accuacy and velocity of said charges. However, my chrony was reading RIDICULOUS readings - but consistent ones. It was saying a 10grn load of AA#9 with a 188 grain boolit was going 1600 fps!

There is no way that is true. So, how do I go about troubleshooting a chrony???

[44Blam]

So, I made up 42 rounds with AA#9, AA#7 and Unique. All much milder than my current load...

I went to test the accuacy and velocity of said charges. However, my chrony was reading RIDICULOUS readings - but consistent ones. It was saying a 10grn load of AA#9 with a 188 grain boolit was going 1600 fps!

There is no way that is true. So, how do I go about troubleshooting a chrony???

I think it would be helpful to list the #s:

AA #9
11grm 1607 1608 1614 1622 1632
11.5grn 1632 1639 1637 1634 1637

Unique
5.5grn 1647 1659 1656 1653 1660
6.0grn 1693 1712 1697 1712 1707

AA #7
8.5 grn 1718 1725 1703 207 1700
9.0grn 1699 222 226 229 212
9.5grn 225 239 235 241 255


My current load: AA #9
13.1 grn 1274 1255 1277 1266 1269

[megasupermagnum]

How far away was it? Some strange readings happen if it is too close, reading muzzle blast and unburned powder.

[44Blam]

How far away was it? Some strange readings happen if it is too close, reading muzzle blast and unburned powder.

It was about 5 yards out. Usually, I put it 5-7 yards out with pistol rounds and probably closer to 10-15 yards with rifle rounds.

[megasupermagnum]

The next thing to try, is get it in the shade. Either move into the shade, or set a piece of cardboard on top of the sky screens.

[rking22]

First thing, put in a new battery. Electronics don’t like low voltage.

[rintinglen]

First thing, put in a new battery. Electronics don’t like low voltage.

+1 A few years back mine started giving wacky readings and I was ready to toss it until another shooter asked me when was the last time you changed batteries. Hint: if you can't remember, change them.
4 new Duracells and I was back in business.

[murf205]

After using every bad name I could think up, I have found that Chrony's have got to have fresh batteries, kept out of bright sunlight, and as far from the muzzle as the cable will allow-just like the advice you got previously. They will get you by but they AINT an Oehler by any stretch.

[Cosmic_Charlie]

Cylinder throat is .403 (ish - used calipers) and the barrel slugs right around .3985.

Try some sized boolits in the throats. Size for a snug push through fit.