Equipment failure or hot load?

A

albog

Regular
Rating - 100%
79   0   0
Location
North GTA
I reloaded 3 sets of trial 40SW loads to check on the newly purchased chronograph (Alpha Chrony), hoping to get and select something just above the Major PF of 160. I had 180 gr. Truncated Cone Bullets from Aim Projectiles and 4.6, 4.8 and 5.0 gr. of Titegroup respectively for the three load sets. OAL was 1.167 in.

The minimum load with 4.6 gr. clocked at an average of 1837 f/s (I fired 5 shots and took an average), which makes a PF of 313. The recoil was I would say as usual, nothing special. Could it be a real actual hot load or do you think it was a malfunction of the chrono? From what I read, this type of load should give you just under the PF of 160.

Any input would be appreciated.
 
albog said:
I reloaded 3 sets of trial 40SW loads to check on the newly purchased chronograph (Alpha Chrony), hoping to get and select something just above the Major PF of 160. I had 180 gr. Truncated Cone Bullets from Aim Projectiles and 4.6, 4.8 and 5.0 gr. of Titegroup respectively for the three load sets. OAL was 1.167 in.

The minimum load with 4.6 gr. clocked at an average of 1837 f/s (I fired 5 shots and took an average), which makes a PF of 313. The recoil was I would say as usual, nothing special. Could it be a real actual hot load or do you think it was a malfunction of the chrono? From what I read, this type of load should give you just under the PF of 160.

Any input would be appreciated.
Click to expand...
I'd go back and check the scale, and the load, item by item first. The reloader is far more likely to screw up than the chronograph. But it does happen.
The only way I know of for the layman to check a chronograph is to fire the same load under the same conditions over another one, and compare. For safeties sake, use a known safe load for this test, or even a factory load.
 
If yur chrono was right and you were pushing 1800+fps you wont be for long. That'd be waaaay above the pressure curve with 40SW already being a high pressure cartridge..Hodgdons shows the max as 4.7g (33,300CUP)with a real jktd bullet and it is still sub 1000fps so something is outa whack for sure..
dB
 
hot load?

Hi albog,

Chonographs are sensitive to different lighting. I know from experience that fluorescent lighting really throws them for a loop. I've seen shooters use incandescent(read old-style globe) lighting over the diffusers even when shooting outdoors.
Try to ensure that the lighting is consistent when you do your next test. This will leave lighting out of the equation.

Let us know what the results are.

Phil
 
It sounds to me like maybe you had your chrony a bit close. If you have the model with the remote display, run that ##### out to 10 meters and try again.
 
You'd def know if your load was THAT hot. Even loaded to PF195 (I did once) would be waaay different from factory loads.
 
Your cases would fail long before you got that kind of performance. Even out of a 6" barrel my best load with 180s in 10mm auto are only running about 1450 fps. They are HOT.
 
Likely a false reading by the chrono. Was your lighting OK (see manual for suggestions)? Was your muzzle close to the chrono, did it "see" the shock wave from the muzzle blast rather than the bullet?
 
Equipment failure or a hot load?

I should have pointed out in my original post that the chrono was approximately 2.5 m away from the muzzle and that "Error 1" was being continuously displayed on the monitor following the shots; however, the readings were still provided after the shots (albeit, unrealistic ones). So, at this point I'm pretty sure it was the chrono malfunction rather than a hot load as it felt quite normal recoil and sound wise. What is the right distance of the chrono from the muzzle? My chrono has a remote display unit connected to the main unit by a phone cable which can probably stretch to a max. of 3 - 3.5 m.

Thanks everybody for your input.

albog said:
I reloaded 3 sets of trial 40SW loads to check on the newly purchased chronograph (Alpha Chrony), hoping to get and select something just above the Major PF of 160. I had 180 gr. Truncated Cone Bullets from Aim Projectiles and 4.6, 4.8 and 5.0 gr. of Titegroup respectively for the three load sets. OAL was 1.167 in.

The minimum load with 4.6 gr. clocked at an average of 1837 f/s (I fired 5 shots and took an average), which makes a PF of 313. The recoil was I would say as usual, nothing special. Could it be a real actual hot load or do you think it was a malfunction of the chrono? From what I read, this type of load should give you just under the PF of 160.

Any input would be appreciated.
Click to expand...
 
albog said:
I reloaded 3 sets of trial 40SW loads to check on the newly purchased chronograph (Alpha Chrony), hoping to get and select something just above the Major PF of 160. I had 180 gr. Truncated Cone Bullets from Aim Projectiles and 4.6, 4.8 and 5.0 gr. of Titegroup respectively for the three load sets. OAL was 1.167 in.
Click to expand...
If you're shooting 180s, I assume you're shooting for Standard Division IPSC and major power factor in that division is 170.
See P76 - http://www.ipsc.org/pdf/RulesHandgun.pdf

I load Titegroup too. In a 5" Barrelled Edge, I'm in the 5.3 gr range for major myself.

Your conclusion and a few of the guys above is correct; the chrony's not working right.
 
2.5m is a reasonable distance.

"Err1" on a Chrony either means that only sensor #1 saw the shot, or sensor #1 missed the shot (I forget which; look up the manual).

This would be due to either a bullet placement error, or a lighting condition problem. Read the manual w.r.t. where the bullet should go (4" to 12" over the sensors, over both of them (line them up front-to-back)). Read the manual w.r.t. lighting conditions (e.g. clear skies are actually quite dark, and benefit from using the supplied translucent white plastic sky screens; bright sunlight falling on the sensors can cause problems; sunlight at low angles can cause erroneous "glints" to be seen from shiny bullets; fluourescent lights cause problems but incandescent don't, etc, etc).

Take a .22 rifle with you and use that to verify your setup. With target ammo you ought to get readings in the 1100s fps, with high velocity ammo you ought to get readings in the 1200s. And with a .22 rifle it's cheap to shoot a lot of test shots, and easy to accurately line it up and aim it through the sensor zone.
 
You must log in or register to reply here.
Back
Top Bottom