New help/Advice... is it my Chrony or my reloads data??

The ROC

The ROC

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Hello,

I don't have any reloading books that are current, my latest is 11 years old and doesn't have the info I need. I did extensive on-line search for the data I needed as well as this forum and others.

I have a Chorny but shot at the second sensor with a pellet, the black plastic housing was protected with a thick metal plate but I'm not sure if the impact of the 950fps .22cal pellet may have jarred the internals. I did a visual and the internals "look" fine, battery is brand new and the case open fully when I used it today.

Back on track, I loaded up some 9mm for my M&P9 with once fired brass, Frontier 147gr TMJ, 3.5grs of W231 and Federal #100 primers, OAL was 1.154". With this load I've read that the fps should average about 850fps giving my a power factor of 125 for IPSC.

When I chornied these loads this morning it read 565fps average :eek:.

I double checked and triple checked the grains I was dropping and rechecked my OAL. Could the data I've read have been incorrect or is it possible my Chrony needs to be recalibrated?

That's for the help.
 
Ditto, try something else you know the velocity of.

How much damage to the Chrony? Can you show a picture? If the black plastic is broken it might be letting light (actually shadow) in early or late that is triggering the sensor.


Fudd
 
Already tried that. Yes I get over 1000fps but if it's off by 200 to 300 fps I wouldnkt know. Need advuce from the 9mm reloaders.
 
to be that far off i'd definately question the chrony- even the data from 11 years ago doesn't vary by all that much- my speer is a 1991 issue and if anything , the maximum loads are a little "warmer " than the lawyerized loads of todays manuals- i don't have a load for the 147 but i get 1096 using the 125 grain fmj slug at 5 grains of 231- checked winchesters own data( you can do that too- just type in 9mm load data in your search engine) and they give 3.5 of 231 and the 147 as giving 905 fps-
 
If you're getting over 1000fps with a .22, then it would seem that your Chrony is reporting believable figures. Which would make me suspect maybe your 9mm handloads really might be going that slow. Do you have any different ammo, or factory ammo, that you can fire as a sanity check? If your 147 TMJ was a bit undersize, it might end up going out slower like this.

The direction that the Chrony's sensors point is quite critical. It is important that the unit be fully opened, otherwise the sensors will point "together" a bit rather than parallel (this isn't your problem though - this would result is falsely high readings). The sensors are fairly well located in the housing with metal tabs. As a result of your nicking the sensor, has it changed orientation, so that instead of looking perpendicular to the axis of the Chrony it is actually looking slightly farther downrange? (unlikely, but check this while you are checking to see whether the photocell is seeing a wider "picture" than it should be)
 
ElmerFudd said:
Ditto, try something else you know the velocity of.

How much damage to the Chrony? Can you show a picture? If the black plastic is broken it might be letting light (actually shadow) in early or late that is triggering the sensor.


Fudd
Click to expand...

What do you think... is it bad enough to cause a read error for the velocity?

P6260083.jpg


P6260084.jpg


P6260085.jpg
 
t-star said:
... checked winchesters own data( you can do that too- just type in 9mm load data in your search engine) and they give 3.5 of 231 and the 147 as giving 905 fps-
Click to expand...

I've tried their website and can't find the info you're mentioning... can you provide a direct link?
 
Gosh, that is a big chunk you knocked out. Don't really know if it would cause problems or not. You could try carefully taping over it, to more or less duplicate the size and shape of the original viewing port, and see if that makes a difference.

Another way to check, if you (or a friend) has another Chrony available, is to set up one Chrony in front of another, and have both of them measure the same shot - see if they agree or disagree
 
t-star said:
www.handloads.org/loaddata- that takes you TO A MASTER LIST- THEN select winchester from the top line, and it'll roll to a winchester page- then plug in your powder and bullet weight and it'll give you 4 loads for that bullet
Click to expand...

Thank you.

I'm reading all the data and it's looking like the chrony is reading incorrectly. I did call Shooting Chrony for a replacement part, not expensive, but they're closed all of next week so I'll have to wait till they open again.
 
P6260083.jpg


Well there's your problem! :rolleyes:

That will do it alright. The chrony basically waits for the end of the bullet shadow to pass. So without that plastic it still "sees" the shadow till the bullet has gone much further. Everything should read low.

Now if you really try hard you might be able to repair it yourself. You have to replace the plastic you removed with something else that will block the light. And it has to be straight right where the edge was. See this picture:

shot-Chrony-Fix.jpg


You should be able to take it apart and just work with that one piece of plastic thus making the job easier and preventing anything from getting on the other parts.

If you go to Revy or maybe Home Depot you should be able to find some kind of gunk to fill it with. When it is hard cut or file a new edge right where the old one was.

I don't know what a replacement part will cost but if you do it yourself you don't need to wait for it.

I hope this helps! Keep us posted! :D


PS - did your Chrony come with that metal protector in front of the sensor? Mine didn't.


Fudd
 
^^^^

Thanks Fudd,

Makes sense but I didn't think the sensors where that sensitive. I called Shooting Chrony and the black plastic cases are cheap. To replace both fornt and back complete sensors and black case would be about $40 she said but the US to CAN exchange rate she told me sounded alittle high... 15%. We're almost at par.

As for the metal plate... just luck that we where throwing out junk at the in-law's house when I came apon these plates. They didn't need them so I took them off there hands. Originally I was going to cut to size junction box plate covers x 2 and stick them together. Next time I'm using velcro to stick the plate to the plastic case... I can't fold the chrony completely closed.
 
Shooting Chrony is Canadian made back east. I bought my Chrony from the US for much less than it would have been buying direct or from a Canadian store. A few years ago when the US dollar cost about $1.15 or so Chrony still wanted to screw me with a $1.40 exchange. And they sell it in US dollars. They didn't have a fixed Canadian price. The lower our dollar the more they make.

We're not close to par at the moment. Last night I saw it was $0.867 or so. Better than a few years ago sure but not at par.

So you're going to be charged about C$46 plus shipping (or was that included?) plus tax plus you have to wait. I would try to fix it myself. It'll be a fun little exercise too! ;)

Good idea with the protective metal. What was the hit on it made with?

Maybe I will try something like that too. But try something in between the metal and sensor to reduce shock damage. Won't protect from a centerfire rifle but smaller stuff might be ok. And it doesn't cost much to do.


Fudd
 
^^^

I live only a 45min drive from Shooting Chrony in Mississauga. Not only did I shoot out the housing but I also nick the wires so I had to do a quick fix but because the wires are so thin I didn't solder them but twisted them together and then shrink wraped each wire. I'm going to get the replacement parts that I need and that way I know all is working.

Thank goodness I went with my gut feeling and kept my loads to 4gr max or I could have been in trouble some way some how.

I shot out the housing as well as the plate with my AirForce Condor at about 3 feet away.... 950fps with a 21gr .22cal pellet.
 
I just checked my books and on line sites. It looks to me that 231 is not listed by anyone as a load for the 147 gr bullet. powder is too fast.

I use IMR 7625 as a general purpose powder. A mid-speed powder, so it works well with all bullet weights. meters very well.
 
Ganderite said:
I just checked my books and on line sites. It looks to me that 231 is not listed by anyone as a load for the 147 gr bullet. powder is too fast.

I use IMR 7625 as a general purpose powder. A mid-speed powder, so it works well with all bullet weights. meters very well.
Click to expand...

funny how the rest of us found it???-
 
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