Chronograph can't record pistol loads.

wogpotter · March 7, 2011, 12:38 PM

Its an older "PACT model 1" & it has never had a problem with 30 cal rifle bullets so I've just kept & used it with complete satisfaction. I did have an issue with muzzle blast jumping the plugs once, but sitting a sandbag on the cables solved that & it only happened with a muzzle break fitted.

Then I tried using it to check some 125 Gr .357 ammo from a 6" revolver. What a disaster! it seems to be reading blast or something as the velocities vary between 300 & 2000 fps. for every cylinder fired

I've tried it with & without the diffusion screens & at several different distances 10' & 15' mostly, but the problem persists.

Any clever ideas other than buying a new chronograph?

Dr. Strangelove · March 7, 2011, 06:51 PM

Boolits or bullets?

If you're shooting lead with no plating or jacket, it could be having a hard time reading bullet pass of the sensors.

k4swb · March 7, 2011, 07:29 PM

Move it a little further away from the muzzle.

Win_94 · March 8, 2011, 03:22 AM

Quote:

at several different distances 10' & 15' mostly,

I first started noticing false chronograph readings with my 357, I moved it out to 20 yards and never had a problem after. I take all my reading at 20 yards now, just in case.

wogpotter · March 8, 2011, 08:28 AM

Dr. Strangelove:
It failed with both plated & jacketed bullets. I haven't tried boolitt tips yet though. It is recording something, otherwise I'd not be getting readings at all or a shot number in the string.

k4swb:
"with & without the diffusion screens & at several different distances 10' & 15' mostly"

Win_94:
Do you have a conversion back for MV? I haven't seen any numbers for 20' corrected to muzzle.

Clay · March 8, 2011, 09:34 AM

I had the same issues with my 38spl loads. I read the manual *gasp* and it said this can commonly happen with subsonic rounds. The "blast wave" reaches the chrony before the bullet does, and it ends up registering or messing it up.

If you were doing full house magnum loads then I also don't doubt that the concussion could be causing issues. As suggested, move back a little more and try again.

OH... also don't forget to change the battery. If the battery is getting low it can cause funky readings as well.

wogpotter · March 8, 2011, 11:52 AM

Good point about the battery, thanks, I hadn't thought of that.
In theory my loads should be running about 1250 FPS, well above mach 1, but without the chrony data I can't really tell.

steveno · March 8, 2011, 05:38 PM

if you are getting strange readings with the screens over 15 feet away you other problems. I don't have any muzzle blast problems with my Oehler 33 using magnums and the screens are usually set around 6 or 7 feet.
I would change batterys & chronograph on cloudy days.

wogpotter · March 8, 2011, 07:04 PM

It ONLY happens with pistol bullets, both 158 Gr plated & 125 Gr JHPs, rifle bullets work fine at either 10' or 15' depending on the rifle's muzzle blast.
I don't think the problem is distance per se, or nothing would work.

Caboclo · March 16, 2011, 04:50 PM

Wog, try snooping around the reloading forum. They're big on chrono's over there. And +1 on moving farther away.

wogpotter · March 16, 2011, 04:55 PM

I'll try there, thanks.
I'm also gettinga chance to test over a different chronograph, lets see if that gives me more info. It would at least eliminate a possibility if that one had similar problems.

eviltravis · March 16, 2011, 05:07 PM

Move it back further.

rjrivero · March 16, 2011, 08:23 PM

I had this issue with my Pact as well. I used a second target stand with a piece of cardboard on it about 2-3 feet IN FRONT of the first screen. It blocks the blast and allows for more accurate readings.

It helps if you cut the cardboard to the same shape as the screen and supports so you can see the outline of the chronograph.

wogpotter · March 17, 2011, 07:17 AM

OK, I wondered about that.
I'll head to the range next time with a cardboard blast screen.

March 7, 2011, 12:38 PM	#1
wogpotter Senior Member Join Date: September 27, 2004 Posts: 4,811	Chronograph can't record pistol loads. Its an older "PACT model 1" & it has never had a problem with 30 cal rifle bullets so I've just kept & used it with complete satisfaction. I did have an issue with muzzle blast jumping the plugs once, but sitting a sandbag on the cables solved that & it only happened with a muzzle break fitted. Then I tried using it to check some 125 Gr .357 ammo from a 6" revolver. What a disaster! it seems to be reading blast or something as the velocities vary between 300 & 2000 fps. for every cylinder fired I've tried it with & without the diffusion screens & at several different distances 10' & 15' mostly, but the problem persists. Any clever ideas other than buying a new chronograph? __________________ Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”? Elderly Hunter: “That's dashed unsporting. Probably Belgium.”

March 7, 2011, 06:51 PM	#2
Dr. Strangelove Senior Member Join Date: August 1, 2008 Location: Athens, GA Posts: 1,436	Boolits or bullets? If you're shooting lead with no plating or jacket, it could be having a hard time reading bullet pass of the sensors. __________________ Just remember, when you pull the trigger, the bullets come out going very, very fast. So make sure to keep the weapon pointing away from you.

March 7, 2011, 07:29 PM	#3
k4swb Senior Member Join Date: July 11, 2009 Posts: 389	Move it a little further away from the muzzle. __________________ My posts are things I have tried or experienced. You may or may not wish to emulate them so read them with this in mind. Compromise means that both sides give something, but they never give, they just take. I'm The NRA!

March 8, 2011, 08:28 AM	#5
wogpotter Senior Member Join Date: September 27, 2004 Posts: 4,811	Dr. Strangelove: It failed with both plated & jacketed bullets. I haven't tried boolitt tips yet though. It is recording something, otherwise I'd not be getting readings at all or a shot number in the string. k4swb: "with & without the diffusion screens & at several different distances 10' & 15' mostly" Win_94: Do you have a conversion back for MV? I haven't seen any numbers for 20' corrected to muzzle. __________________ Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”? Elderly Hunter: “That's dashed unsporting. Probably Belgium.”

March 8, 2011, 11:52 AM	#7
wogpotter Senior Member Join Date: September 27, 2004 Posts: 4,811	Good point about the battery, thanks, I hadn't thought of that. In theory my loads should be running about 1250 FPS, well above mach 1, but without the chrony data I can't really tell. __________________ Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”? Elderly Hunter: “That's dashed unsporting. Probably Belgium.”

March 8, 2011, 09:34 AM	#6
Clay Senior Member Join Date: November 11, 2009 Posts: 166	I had the same issues with my 38spl loads. I read the manual gasp and it said this can commonly happen with subsonic rounds. The "blast wave" reaches the chrony before the bullet does, and it ends up registering or messing it up. If you were doing full house magnum loads then I also don't doubt that the concussion could be causing issues. As suggested, move back a little more and try again. OH... also don't forget to change the battery. If the battery is getting low it can cause funky readings as well.

March 8, 2011, 05:38 PM	#8
steveno Senior Member Join Date: June 18, 2004 Location: Minden , Nebraska Posts: 1,407	if you are getting strange readings with the screens over 15 feet away you other problems. I don't have any muzzle blast problems with my Oehler 33 using magnums and the screens are usually set around 6 or 7 feet. I would change batterys & chronograph on cloudy days.

March 8, 2011, 07:04 PM	#9
wogpotter Senior Member Join Date: September 27, 2004 Posts: 4,811	It ONLY happens with pistol bullets, both 158 Gr plated & 125 Gr JHPs, rifle bullets work fine at either 10' or 15' depending on the rifle's muzzle blast. I don't think the problem is distance per se, or nothing would work. __________________ Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”? Elderly Hunter: “That's dashed unsporting. Probably Belgium.”

March 16, 2011, 04:50 PM	#10
Caboclo Senior Member Join Date: November 2, 2009 Posts: 212	Wog, try snooping around the reloading forum. They're big on chrono's over there. And +1 on moving farther away. Last edited by Caboclo; March 16, 2011 at 04:59 PM.

March 16, 2011, 04:55 PM	#11
wogpotter Senior Member Join Date: September 27, 2004 Posts: 4,811	I'll try there, thanks. I'm also gettinga chance to test over a different chronograph, lets see if that gives me more info. It would at least eliminate a possibility if that one had similar problems. __________________ Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”? Elderly Hunter: “That's dashed unsporting. Probably Belgium.”

March 16, 2011, 05:07 PM	#12
eviltravis Senior Member Join Date: June 18, 2001 Location: montana Posts: 283	Move it back further.

March 16, 2011, 08:23 PM	#13
rjrivero Senior Member Join Date: November 17, 2008 Location: NW Ohio Posts: 1,399	I had this issue with my Pact as well. I used a second target stand with a piece of cardboard on it about 2-3 feet IN FRONT of the first screen. It blocks the blast and allows for more accurate readings. It helps if you cut the cardboard to the same shape as the screen and supports so you can see the outline of the chronograph.

March 17, 2011, 07:17 AM	#14
wogpotter Senior Member Join Date: September 27, 2004 Posts: 4,811	OK, I wondered about that. I'll head to the range next time with a cardboard blast screen. __________________ Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”? Elderly Hunter: “That's dashed unsporting. Probably Belgium.”