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Post by RAF on Jun 7, 2007 23:00:30 GMT -5
This evening I was at the range and took my 22-250 with me to shoot along with a 30-06. I had to re-zero the 22-250 'cause I used that scope to work up a load for my new 300 WSM. Anyway, I was also interested to see what velocity I was getting with it. I'm shooting 40 grain V-Max over 41.5 grains of H380. I guessing it's about 4000 but want to make sure. Well, the Chrony wouldn't give me a reading on these. Any ideas why. Seems I tried this years ago, with another Chrony, and got the same results. I did shoot some larger 55 grain bullets over it and they registered but not these little and faster ones. I should point out that these are moly coated but can's see how that would make a difference. Anyway, any help would be appreciated.
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Post by herman on Jun 8, 2007 6:09:18 GMT -5
Looks like it would pick up the moly colored better.In one of my 22/250 I shoot the 40 v-max and bt around 4200 useing 10x,That is out of a savage with 26 in barrel.
In a remington the BT will shoot one holes but the 40 v-max and 52 amax won't even shoot. In the 40 gr or the 52 gr a-max.I think they are blowing up in the barrel.The rem is a 24 in barrel.
I use a pact but haven't had a problem with it picking up the reg 40's.
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Post by bubba on Jun 8, 2007 10:06:59 GMT -5
are you doing it on a sunny or overcast day? if its sunny, you might need to use some type of sun shade.
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Post by RAF on Jun 8, 2007 22:23:44 GMT -5
Bubba, it was sunny but this was about 7pm and it wasn't bright. I wasn't using the sky screens and haven't since the first time I had this chrony out. I have it set up on a tri pod at about 10 feet and the muzzle blast was blowing the screens off from time to time. Yesterday I was shooting with my 30-06 first and it was fine. After it didn't work for my 22-250, my friend shot his 7mm rem mag over it and it was fine.
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Post by bubba on Jun 9, 2007 6:25:50 GMT -5
perhaps you could move the chrony alittle further from the muzzle - it would be slower then.......
perhaps there is an issue over 4000 fps with the chrony ?
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Post by E.T. on Jun 9, 2007 14:35:32 GMT -5
RAF
Took a quick look through the Chrony manual and they are supposed to detect speeds up to 7000fps. They also say 4”-6” above sensors to be used. One last item you might want to check is the battery or replace it with a new strong one. Other than the possibility of a light layer of dust on your sensors I have no other suggestions to offer as to the possible cause of why you are not registering velocity for that particular load.
Ed
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Post by mike3132 on Jun 9, 2007 16:55:50 GMT -5
If i don't use the sun shades with my chrony using small caliber bullets it will give me error or erratic readings. mike
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Post by RAF on Jun 10, 2007 8:45:49 GMT -5
ET the unit and battery is only a couple of months old and used 3 times should battery should be good. As I said it read the bullets before and after I shot the 22-250. I'll check the lenses. YOu never know.
I'll the the screnes a try next time I'm out.
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Post by E.T. on Jun 10, 2007 16:35:24 GMT -5
RAF
There is reference to a minimum 7.5-volts required for accurate function of the unit. This statement suggest to me if it should fall below this level then the unit will not function fully. If this is the battery that came with the unit then who knows how long it’s been in the box and if any deterioration has occurred. For the price of a fresh 9-volt battery to confirm this, then this isn’t a major cost to eliminate this possibility. I always replace my battery every year with a spare I have on hand and then get a new one for a backup.
To get a strong enough signal reflected off a smaller diameter bullet I would also make sure the bullets path does at least cross-over no more than 5” above the sensors. I know there’s always the concern of tagging the unit unless you can set some barrier in front of it.
One thing you might want to try is your pellet gun over the unit and see how that works because it is supposed to be able to register a velocity for this small a bullet and speed. This might reveal something.
Ed
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Post by RAF on Jun 10, 2007 17:11:38 GMT -5
E.T. I'll take a look at that battery. I don't recall if it came with the unit or I bought it. In any case next time out to the garage I'll grab my battery tester and check.
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Post by herman on Jun 10, 2007 20:09:33 GMT -5
Re read your post and you said it worked fine with the 30/06 before and the 7 mag after,so it sounds like it just isn,t picking up the moly colored ones,you can try this and see if it works Take a magic marker and color the small bullet and see if it will pick it up.With it working for the 55's and the 30/06,7mag don't sould like anything wrong with the battery or the chrony.
I have a pact and if I forget to take my battery out it is dead the next week I go to the range.And if I try useing anything but a duracell it won't work.
I have blowed my sky screens off so many times I started tapeing them down with duct tape.
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