.45 speeds

JoKa

JoKa

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Hey All,

Thought I would pick your brains.

I just bought a crony and tried to test it out the other day...... because it was fricken cold I was not able to do much in the ways of testing..... but the numbers I pulled where different then expected.

I am shooting .45 ACP LSWC 200gr. w/ 5gr bullseye CCI#300 LPPrimer.
Expected vel was 800-900 FPS..... crony was saying 1300-1400 FPS.

So what do you think was off? The Crony or my expected velosity?
 
.

The muzzle was about 5ft from the first sensor.

Anyone know what the vel should be? Anyone have any data to compaire to?




acrashb said:
If the velocities were accurate, your wrist would know it. Gun might even blow up.

Most likely the muzzle blast is messing with your chrony. Try setting it back further.
Click to expand...
 
It could be picking up particles of unburnt powder. This has happened to me before.

Move the chrony down range a minimum of 10 ft from the muzzle and try again.

CS45
 
Perfect

Thanks for the tip...... will try again and let y'all know.

(Might be a little bit though...... when the weather gets a little better)



cansoldier45 said:
It could be picking up particles of unburnt powder. This has happened to me before.

Move the chrony down range a minimum of 10 ft from the muzzle and try again.

CS45
Click to expand...
 
Outside temp has a lot to do with your chrony too. I don't think they suggest using it for any kind of accurate figures below 0 degress? Yes, no?
 
Unless you're running 45-08 or some super, I'd say your chrony is to blame here. You'd have massively flattened primers I think, and as noted, recoil would be retarded.
 
JoKa said:
The muzzle was about 5ft from the first sensor.

Anyone know what the vel should be? Anyone have any data to compaire to?
Click to expand...

Couldn't find my data for Bullseye, don't use it much as I find 231 and Unique give me better results but for a comparison 5.4 grs of 231 with a lead 200 gr. SWC gives me an average velocity of 896 fps. 7.0 grs of Unique with a 200 gr. JHP gives me an average velocity of 845 fps. Finally 4.7 grs of 700-X with the 200 gr. lead SWC gives me an average velocity of 858 at -16. This was done with an Oehler Model 33 chronograph with a minimum of 10 shots per configuration. This data was developed with a Colt Model 1911, Series 70 w/5 inch barrel. I would say that you are either getting unburnt powder interfering with your chrony (as per CS45) or there is something wrong with it but I suspect unburnt powder. I haven't found cold weather to be an issue with my Oehler, on the other hand if you are too close to the sensors, especially with handguns, it can cause problems.

Cheers
 
Last edited:
How cold was it? The user's manual of my Chrony F-1 says that it doesn't work if it's below freezing. It's what's stopped me from measuring my new Unique 4.9 grain .45 ACP loads that I've started shooting for the last couple weeks. I can't wait for spring weather.
 
Well, standing temp was prolly around the 0 mark....... but the wind chill def made it a LOT colder...... couldnt feel my fingers or face.

And I am using the Chrony F-1 as well....... guess I should have looked at the specs on it first. (I didnt think it was going to be that cold at the range...... standing out on my drive way it FELT nice)

Skyhawk said:
How cold was it? The user's manual of my Chrony F-1 says that it doesn't work if it's below freezing. It's what's stopped me from measuring my new Unique 4.9 grain .45 ACP loads that I've started shooting for the last couple weeks. I can't wait for spring weather.
Click to expand...
 
There is no way that 5 grains of Bullseye would give a muzzle velocity of 1300-1400 fps; 900 fps is more believable. It would be pretty obvious if the bullets were really going that fast.

Something is wonky with your chronograph.
 
Oh yeah, as other posters have said you have to watch the distance... but especially for "sub-sonic" loads as stated somewhere in the manual. 5 feet is fine for pistols, but it says you have to be further for handguns that shoot their load slower than the speed of sound. Something about the muzzle blast getting there first or something? I took that to mean further than 5 feet...

I try 7 to 10 feet with a rest on the table with a tripod in front of it lined up with the target. Over 10 feet the probability of me shooting the darn thing increases exponentially :redface:
 
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