I have an old Pact Model 1, not the XL, not the MKIII, not the timer/chrono unit, the original Model 1 from the 1980s. I've used this on and off over the years but it has sat in a box for probably over 20 years now. I took it out yesterday and got it all set up. Had to pry off the corroded 9v battery from the connector, but it cleaned up with a brass toothbrush well enough. Put the new battery in and everything powered up just like new. I got out a Red Ryder to test it and shot a bunch of BBs over the screens, and they all registered, a blazing 190 FPS on average. Great, now on to the centerfires!
A buddy brought over a couple rifles he wanted to shoot at 50 yards, so we lined everything up and had at it. First was his Winchester XTR in 6.5 Creedmore. Only read a couple of the six shots he took. Numbers looked to be about what we expected at 2650-2700 FPS. Then he shot his Savage Axis in .270, and we started seeing crazy readings. Some rounds were 2750-2800 where I thought they'd be, but also got some in the 1600s, and a couple over 6400, which can't be right. I know that sometimes the screen will pick up the muzzle blast, so we repositioned the screens, but it still gave erratic numbers.
Once he finished, I set it back up for my use, testing a couple loads through my .357 BBS. First 5 round string it read them all, first round was a bit slower, at about 1711 FPS, and the rest were up in the 1765-1785 range. Good data and that slower one was the flier from the group, so it was attributable. Second 5 shot group it only read one shot at 1577, which was as expected for that load.
So I'm wondering why I'm getting weird numbers with some shots, and missing the shot for others. Some shots would read the ERROR message, but others just missed completely. Shots were above the sensors by about 4-8", and I didn't have the skyscreens mounted at first, but put them on later, which did seem to help. (the BBs read fine without the skyscreens, even 12" to 18" over the sensors) The sensors are mounted on the PACT supplied 24" mounting bar, so that part is consistent. Start sensor was about 12 feet from the muzzle, but we could see it react occasionally with the .270 muzzle blast. Can the shots be too low, meaning too close to the sensors? Any other tips or tricks to share?
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PACT Model 1 Chronograph Issues
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Rifletom
- Deputy Marshal
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Re: PACT Model 1 Chronograph Issues
Hmm. On my old as well "Shooting Chrony", i put regular scotch tape over the sensors to keep out dust and id did seem to help with the readings as well, whether I had the shade screens on or not. [usually do]. But, these things are old, so, they may be acting up internally.
Oh, try your first sensor at 15' from muzzle. I also put a bit of electrical tape about 8-9" up the screen rods as a reference for getting over the sensor safely. Hope any of this helps.
Oh, try your first sensor at 15' from muzzle. I also put a bit of electrical tape about 8-9" up the screen rods as a reference for getting over the sensor safely. Hope any of this helps.
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Mr. Neutron
- Cowhand
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Re: PACT Model 1 Chronograph Issues
I have only been in the investigative/research stage" of looking into chronographs, so don't have any real world experience. Just what I've read or watched on the internet. My uncle wants one, and I'm his personal internet nerd, I guess. 
So my research ain't been to intensive lately......
One video I've watched (wish I could recall which one to be able to give a link....
) mentioned what I'll call a "sweet spot" triangle of sorts where the chrony is most accurate. A point where ya want all yer projectiles to pass through, slightly below the sunscreens, and slightly above the sensor/readout unit. This is pretty much done already in efforts to NOT shoot the crhony brain box or the sun screens. I just mention this in case your Pact is possibly slightly more "sensitive" to this sweet spot, and maybe some of the rounds went slightly high or low within that range?
Seems like the area of outdoor light and sunscreens "mishaps" has come up before as a possible reason for missed (not recorded) shots and weird high/low readings. What were the conditions like on the day you shot?
So my research ain't been to intensive lately......One video I've watched (wish I could recall which one to be able to give a link....
) mentioned what I'll call a "sweet spot" triangle of sorts where the chrony is most accurate. A point where ya want all yer projectiles to pass through, slightly below the sunscreens, and slightly above the sensor/readout unit. This is pretty much done already in efforts to NOT shoot the crhony brain box or the sun screens. I just mention this in case your Pact is possibly slightly more "sensitive" to this sweet spot, and maybe some of the rounds went slightly high or low within that range?Seems like the area of outdoor light and sunscreens "mishaps" has come up before as a possible reason for missed (not recorded) shots and weird high/low readings. What were the conditions like on the day you shot?
Jimmie
An Okie living in Oregon
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An Okie living in Oregon
H009G
H004
H009BG
"Never miss a good chance to shut up." Will Rogers
"It's better to eat yer fruit before ya shoot it." youtuber WHO_TEE_WHO
Re: PACT Model 1 Chronograph Issues
I have a Pact II chrono/timer and have issues at times. First problem is on totally clear sky days (blue sky no clouds). The bright sun at midday will give me crazy readings. I've had to set my sky screen in the shade of the range overhang to get proper readings. When I set up on the pistol range the sun travels from front to back. (East being behind the backstop.) I find I get the best results afternoon, usually in the 1-3 pm time frame and I typically tilt my sky screens to the left away from the sun.
When I set up on the rifle range the sun is moving left to right. So here again I tilt the screen away from the sun. Before noon I tilt the screens to the right. After noon I tilt them to the left.
My Pact doesn't seem to be bothered by muzzle blast, but I do set the screens at about 8 ft. for pistol and 12 ft. for rifle. I attribute a lot of the issues I get to the age of the sky screens.
Paul
When I set up on the rifle range the sun is moving left to right. So here again I tilt the screen away from the sun. Before noon I tilt the screens to the right. After noon I tilt them to the left.
My Pact doesn't seem to be bothered by muzzle blast, but I do set the screens at about 8 ft. for pistol and 12 ft. for rifle. I attribute a lot of the issues I get to the age of the sky screens.
Paul
Re: PACT Model 1 Chronograph Issues
Thanks for the responses guys.
The day when all this happened was a partly cloudy day, but mostly clear, and the internet searches I did looking up why this happened all made mention that sometimes clear blue skies give issues, which is what the sky screens are supposed to help with. I can remember standing behind my buddy, watching him shoot, and also watching some cloud shadows traversing the field out in the impact area while he shot. We started at about 12:30, so the sun was pretty much directly overhead, that's a definite possible contributor here. We both commented that we were going to get a tan, so it was mostly sunny. Seems like the sensors prefer flat light.
Distance to the screens is another high probability contributor. We both noticed the screens moving when he shot, due to the muzzle blast pushing tat far occasionally. I had the screens about 12 feet from my bench, (maybe it was 8 or 10) but I didn't have the mounting bar for the screens on a tripod. (going to be searching CL and marketplace for a cheap one) I used my GF's little white clothes drying rack since it was about the right height, and I had a board on top to lay the screens on top of. This whole arrangement reeked of jury-rigged disorganization, but I didn't want to miss the opportunity to get the chrony back in action again. I couldn't move it farther away because that monstrosity wouldn't be level enough. I'll do better with this part next time.
A parallel to the distance issue is muzzle blast. As mentioned previously, we saw the screens wobbling when he shot his rifles. It didn't move when I shot my .357 BBS, or my 6BR, neither of which have anywhere near the muzzle blast of a 6.5CM or a .270. It could be that the movement of the sensors on my rickety-ass apparatus added to the chrony's confusion. So the distance could be more important with more muzzle blast producing cartridges than with lesser ones.
I never thought about taping the sensors. I'm guessing that you tape over the slits where the optical sensor is positioned to look up for the passage of the projectile.......right? When the set up saw the BBs and read their speed while testing briefly, I figured all was OK. Looking inside the sensor housings wouldn't be a bad idea either. I've had spiders build their webs in small spaces on other things and since this unit has been in storage for decades, a little system prep should have preceded it's use. The sensors themselves are just tiny little clear glass/plastic looking bubbles, and a wet Q-tip should make quick work of wiping them off.
So a few action items going forward. I'm going to get a tripod for setting the sensors and their mounting bar up properly. Actually, that will simplify that part. I'll also be able to more easily adjust the distance from the muzzle to the screens that way too. I think I'm going to set up the screens in my basement and shoot a few airguns over them, if for no other reason than to refamiliarize myself with the process, and with the operation of the chronograph itself. I have a couple single-stroke pneumatics, and some PCPs that should be very reproducible for muzzle velocity, so it'll be a good learning experience.
Thanks again for the tips, I'll update this with anything additional I discover along the way.
The day when all this happened was a partly cloudy day, but mostly clear, and the internet searches I did looking up why this happened all made mention that sometimes clear blue skies give issues, which is what the sky screens are supposed to help with. I can remember standing behind my buddy, watching him shoot, and also watching some cloud shadows traversing the field out in the impact area while he shot. We started at about 12:30, so the sun was pretty much directly overhead, that's a definite possible contributor here. We both commented that we were going to get a tan, so it was mostly sunny. Seems like the sensors prefer flat light.
Distance to the screens is another high probability contributor. We both noticed the screens moving when he shot, due to the muzzle blast pushing tat far occasionally. I had the screens about 12 feet from my bench, (maybe it was 8 or 10) but I didn't have the mounting bar for the screens on a tripod. (going to be searching CL and marketplace for a cheap one) I used my GF's little white clothes drying rack since it was about the right height, and I had a board on top to lay the screens on top of. This whole arrangement reeked of jury-rigged disorganization, but I didn't want to miss the opportunity to get the chrony back in action again. I couldn't move it farther away because that monstrosity wouldn't be level enough. I'll do better with this part next time.
A parallel to the distance issue is muzzle blast. As mentioned previously, we saw the screens wobbling when he shot his rifles. It didn't move when I shot my .357 BBS, or my 6BR, neither of which have anywhere near the muzzle blast of a 6.5CM or a .270. It could be that the movement of the sensors on my rickety-ass apparatus added to the chrony's confusion. So the distance could be more important with more muzzle blast producing cartridges than with lesser ones.
I never thought about taping the sensors. I'm guessing that you tape over the slits where the optical sensor is positioned to look up for the passage of the projectile.......right? When the set up saw the BBs and read their speed while testing briefly, I figured all was OK. Looking inside the sensor housings wouldn't be a bad idea either. I've had spiders build their webs in small spaces on other things and since this unit has been in storage for decades, a little system prep should have preceded it's use. The sensors themselves are just tiny little clear glass/plastic looking bubbles, and a wet Q-tip should make quick work of wiping them off.
So a few action items going forward. I'm going to get a tripod for setting the sensors and their mounting bar up properly. Actually, that will simplify that part. I'll also be able to more easily adjust the distance from the muzzle to the screens that way too. I think I'm going to set up the screens in my basement and shoot a few airguns over them, if for no other reason than to refamiliarize myself with the process, and with the operation of the chronograph itself. I have a couple single-stroke pneumatics, and some PCPs that should be very reproducible for muzzle velocity, so it'll be a good learning experience.
Thanks again for the tips, I'll update this with anything additional I discover along the way.
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Rifletom
- Deputy Marshal
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Re: PACT Model 1 Chronograph Issues
Correct; tape right over the sensor slots and try 15' from muzzle. Yes, the tripod will help.
Re: PACT Model 1 Chronograph Issues
I tried a few different things yesterday, with little success.
The day was very bright and sunny, occasional breeze blowing, hardly any clouds at all. Gorgeous day for shooting actually. I got a tripod from a garage sale (good story there) and set up the screens on that. Put the tripod out about 15 feet from my bench, and got everything aligned. MUCH simpler set-up and adjustment with the tripod. With just the sensors and no diffuser screens, it read every BB that I shot over it, just like last time. Set up for some .357 reloads and it didn't see any of the 5 rounds that I shot. I then taped over the slits and tried 5 more shots.....nothing. I then put the diffuser screens on and now a couple of the shots show velocities of about 330 to 350, which is way, way lower than anticipated. These three strings were incrementally increasing powder charges, and that last group should be the fastest, well above upper 1700s that my prior loads clocked at. So the three different powder charges that I wanted to clock were all fired for groups, but I got no velocity data at all from them. Not happy.
I got a box of factory .357 ammo and put a large piece of cardboard over the diffuser screens so the sensors were in the shade, then fired another string of 5 over them. They read all 5 at about what I expect that ammo to do, except that it showed something over 5500 for the first shot, so that was an anomaly. I then removed the tape and left the sensors open (but still in the shade). Fired 5 more and every one of those read, with one showing about 1290, when all the others were about 1450-1500. That one could be real, but I have no confidence at this point.
Finally, after chasing down the cardboard every time it blew off the diffusers, I fired five shots of .45 Colt that I loaded up for my Blackhawk. I adjusted the tripod such that my shots were practically dead centered through that pizza-slice shape that the diffusers make above the sensors. Everything in the shade and now a giant 250 grain XTP flying downrange. All five shots didn't read. I got nothing from any of those five shots, and they grouped under 3" at 25 yards, so a good consistent load, but I have no idea how fast they were going, so I can't calculate energy.
That basement airgun idea probably needs to happen, if only to get some confidence that this chronograph thing isn't a POS to begin with.
The day was very bright and sunny, occasional breeze blowing, hardly any clouds at all. Gorgeous day for shooting actually. I got a tripod from a garage sale (good story there) and set up the screens on that. Put the tripod out about 15 feet from my bench, and got everything aligned. MUCH simpler set-up and adjustment with the tripod. With just the sensors and no diffuser screens, it read every BB that I shot over it, just like last time. Set up for some .357 reloads and it didn't see any of the 5 rounds that I shot. I then taped over the slits and tried 5 more shots.....nothing. I then put the diffuser screens on and now a couple of the shots show velocities of about 330 to 350, which is way, way lower than anticipated. These three strings were incrementally increasing powder charges, and that last group should be the fastest, well above upper 1700s that my prior loads clocked at. So the three different powder charges that I wanted to clock were all fired for groups, but I got no velocity data at all from them. Not happy.
I got a box of factory .357 ammo and put a large piece of cardboard over the diffuser screens so the sensors were in the shade, then fired another string of 5 over them. They read all 5 at about what I expect that ammo to do, except that it showed something over 5500 for the first shot, so that was an anomaly. I then removed the tape and left the sensors open (but still in the shade). Fired 5 more and every one of those read, with one showing about 1290, when all the others were about 1450-1500. That one could be real, but I have no confidence at this point.
Finally, after chasing down the cardboard every time it blew off the diffusers, I fired five shots of .45 Colt that I loaded up for my Blackhawk. I adjusted the tripod such that my shots were practically dead centered through that pizza-slice shape that the diffusers make above the sensors. Everything in the shade and now a giant 250 grain XTP flying downrange. All five shots didn't read. I got nothing from any of those five shots, and they grouped under 3" at 25 yards, so a good consistent load, but I have no idea how fast they were going, so I can't calculate energy.
That basement airgun idea probably needs to happen, if only to get some confidence that this chronograph thing isn't a POS to begin with.
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Rifletom
- Deputy Marshal
- Posts: 3971
- Joined: Tue Aug 21, 2018 11:26 pm
- Location: California Territory
Re: PACT Model 1 Chronograph Issues
Yeah, there is something amiss with that chrony. I dunno, maybe time for a new one.
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The Happy Kaboomer
- Cowhand
- Posts: 401
- Joined: Sun Apr 02, 2017 11:10 pm
Re: PACT Model 1 Chronograph Issues
I've owned and use an OEHLER 35P cronograph for over thirty years. It has a proof channel with 3 sky screens that give 2 velocities for each shot. It the 2 aren't close it flags that shot.......Never ever had a problem with it.
Re: PACT Model 1 Chronograph Issues
Well, I set everything up again yesterday for another try. I'm an optimist, so why not one more try. I had some fresh reloads I wanted some data for, and it was a gorgeous day, so why not?
Got my target frames all set up, chronograph positioned on the tripod perfectly aligned, and tested it again with the Red Ryder. It read every single BB I fired. Next I got out an old Diana 34 break barrel pellet rifle. Read every single pellet I fired. Because it was set up, I put my archery target downrange in line for the chronograph and fired a half dozen bolts through with my crossbow, read every single one of them. (all within 5 fps too)
So now I bust out the Big Boy .357 and my reloads for that. First five shots, didn't read a single one. I put pasters on the edge of the slits for the optic sensors so that their shadow would block direct sunlight from entering the housing for the sensors, then fired the next five shots for group. Again, not a single shot read. Then I decided to wait for a big cloud to cover the sun and I fired the last five shots in that condition, with no shadows due to that big cloud. Once again, nothing. This damn chronograph can't see Hornady bullets I guess.
Put all that stuff away and decided to try some .223 reloads I had on hand. Got my Rem 700V set up and had two targets at 100 yards, so I started again.....and once again, nothing reads. I tried shooting higher over the sensors up near the arch of the diffuser screens, nothing. I tried cranking up the tripod center to get the bullet path as low as possible over the sensors, nothing. These are little 50 grain bullets, so not as big of a shadow to detect, but it read BBs and .177 pellets, right? This load shoots little knots at 100 yards, but I'm curious what FPS I'm getting. I finally got one bullet to just tick the top of the sensor housing, so I cranked it back down after that. (you knew that was coming) So after 20 shots with the .223, and before putting everything away, I shot the Red Ryder, the pellet rifle, and my crossbow over it again, and it read all of them.
Might be time for me to price out one of those Lab Radar doppler units.
Got my target frames all set up, chronograph positioned on the tripod perfectly aligned, and tested it again with the Red Ryder. It read every single BB I fired. Next I got out an old Diana 34 break barrel pellet rifle. Read every single pellet I fired. Because it was set up, I put my archery target downrange in line for the chronograph and fired a half dozen bolts through with my crossbow, read every single one of them. (all within 5 fps too)
So now I bust out the Big Boy .357 and my reloads for that. First five shots, didn't read a single one. I put pasters on the edge of the slits for the optic sensors so that their shadow would block direct sunlight from entering the housing for the sensors, then fired the next five shots for group. Again, not a single shot read. Then I decided to wait for a big cloud to cover the sun and I fired the last five shots in that condition, with no shadows due to that big cloud. Once again, nothing. This damn chronograph can't see Hornady bullets I guess.
Put all that stuff away and decided to try some .223 reloads I had on hand. Got my Rem 700V set up and had two targets at 100 yards, so I started again.....and once again, nothing reads. I tried shooting higher over the sensors up near the arch of the diffuser screens, nothing. I tried cranking up the tripod center to get the bullet path as low as possible over the sensors, nothing. These are little 50 grain bullets, so not as big of a shadow to detect, but it read BBs and .177 pellets, right? This load shoots little knots at 100 yards, but I'm curious what FPS I'm getting. I finally got one bullet to just tick the top of the sensor housing, so I cranked it back down after that. (you knew that was coming) So after 20 shots with the .223, and before putting everything away, I shot the Red Ryder, the pellet rifle, and my crossbow over it again, and it read all of them.
Might be time for me to price out one of those Lab Radar doppler units.