.45 SWC load data does not jive

[TES]

So I loaded up some .45 acp with cast swc to spec and used starting data only to see my FPS's way to high.

1.225 oal
Bullet Dia. 4515 - .452
Bullet weights avg. 204 grains
5.8 grains Comercial #1 / universal data used / #1 data is the same starting load 5.8 grains.
All powder charges are hand weighed.
Light (very light) crimp just enough for it to slide into a chamber checker.
I checked for push back and col is same after cycling the ammo so no head spacing issues.

Velocities should be between 889 - 962 FPS

What I got was

lo - 1410
high - 2185
avg - 1670

2185
1442
1410
1451
1828
1474
1897

Yes there were signs of over pressure so I do not think it was a faulty reading on the chrony.

Have I missed something?

Thanks,

TES

[marvelshooter]

Something is wrong with your chronograph. You may be a little over pressure but you are not shooting a 200 grain swc any where near 2000 fps out of a 1911.

[TES]

When I saw 2185 I nearly crapped my pants and stopped shooting. Because the 9mm string I got before the .45 string was spot on....I don't get it. The light conditions did get a little darker than when I started shooting but I don't see how that would affect the speeds so much. However the last strings I tried to shoot would not register at all.

[35remington]

Given 2000 fps loads would probably blow case heads and wreck the gun completely, there's no doubt your chrono is not working right.

[5.7 MAN]

Change your battery and/or increase the distance between you and the chronograph.

[JRR]

Does your chronograph have a metric function? 2000 fps divided by 2.54 = 787.40 fps. I might have my ft/metric conversion messed up. Perhaps you hit the wrong button on the chrony.

[Char-Gar]

Frankly, I am surprised you needed to ask this question. If you did indeed have a load that was running between 1,400 fps and 2,000 fps, you would have would have a damaged if not destroyed handgun.

[TES]

Frankly, I am surprised you needed to ask this question. If you did indeed have a load that was running between 1,400 fps and 2,000 fps, you would have would have a damaged if not destroyed handgun.

I have experienced odd things with chrony's before but never consistently like this. I would maybe get a 2500 fps and then the others where spot on. But the whole string kinda threw me a bit. I was just trying to see if anyone else experienced this before and if they could help. Or if I in fact did something horribly wrong. Never hurts to ask.

[CPL Lou]

I would replace the battery, then try again.
Pressure = Velocity, all things considered.

CPL Lou

[orrwdd]

Did you make sure that the chrono was AT LEAST 10ft from the muzzle? If closer, muzzle blast could interfere with the readings. I am not familiar with Commercial #1 powder, but 5.8 sounds a little hot.

Bill

[TES]

It uses the same data for universal. Every caliber I have tested using universal data has been spot on....probably just a chrony issue.