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Chronograph Poll - Which one do you have?

Unread postPosted: Thu Jul 16, 2009 5:46 pm
Author: boyntonstu
How do you measure muzzle velocity?

Which brand/model chrony do you use?

Would you buy it again?

I'm in the market for a chrony and I am seeking reviews, etc..


BoyntonStu

Unread postPosted: Thu Jul 16, 2009 6:21 pm
Author: Moonbogg
I'm with you man. I will be needing one fairly soon myself. However, i'm not in the mood to spend $80-$100 for one. That money could be put toward a cannon. I would try the laptop method, but I am a little skeptical about how well it actually works.

Unread postPosted: Thu Jul 16, 2009 7:21 pm
Author: rna_duelers
I've got a chrono F1,cost me about $120 or so I think.Works wonders,but doesn't like cloudy days it finds the project hard to measure.

Sure they are fun to find out how fats your gun is,but thats about were it ends.

Unread postPosted: Thu Jul 16, 2009 7:33 pm
Author: gunzz
you can make a chrony with 2 microphones and some software from the internet. google diy chronograph or something

Unread postPosted: Thu Jul 16, 2009 8:12 pm
Author: boyntonstu
gunzz wrote:you can make a chrony with 2 microphones and some software from the internet. google diy chronograph or something


Only 1 mic is needed.

Place it midway between muzzle and target "thunk".


BoyntonStu

Unread postPosted: Thu Jul 16, 2009 11:58 pm
Author: skyjive
I have F1 Chrony, got it for like $80 on eBay, works great.

Unread postPosted: Fri Jul 17, 2009 12:07 am
Author: jackssmirkingrevenge
Another vote for the F1, reasonably priced, simple, compact and reliable :)

Unread postPosted: Fri Jul 17, 2009 8:40 am
Author: jeepkahn
jackssmirkingrevenge wrote:Another vote for the F1, reasonably priced, simple, compact and reliable :)


Another f1.... Reliability is good, accuracy is debatable(yet to be decided)...

Unread postPosted: Fri Jul 17, 2009 9:22 am
Author: jackssmirkingrevenge
jeepkahn wrote:accuracy is debatable(yet to be decided)


If you shoot massive clouds of CO<sub>2</sub> at it, you can hardly blame the chrony :roll: :D

Unread postPosted: Fri Jul 17, 2009 9:45 am
Author: jeepkahn
jackssmirkingrevenge wrote:
jeepkahn wrote:accuracy is debatable(yet to be decided)


If you shoot massive clouds of CO<sub>2</sub> at it, you can hardly blame the chrony :roll: :D


:twisted: And your point is??? :D

Unread postPosted: Fri Jul 17, 2009 10:01 am
Author: daberno123
Another vote for the F1, its simple and I personally haven't gotten any funny readings from mine using it with spuds, pellets, and airsoft bbs. However I don't use CO2 in any of my guns.

I would definitely buy another Shooting Chrony if this one broke, but I'd be tempted by one with some extra goodies like the Alpha Chrony.

However, I'd start with the F1 and if you feel the need for more features you can send your Chrony in for upgrades.

Unread postPosted: Fri Jul 17, 2009 4:00 pm
Author: jimmy101
Unless you are going to be using the Chrony pretty often then a homemade setup is the way to go.

Using a microphone is OK though it can be finicky to get it to work right. You need good strong audio signals and you'll have to do a bit of interpretation of the results. An advantage of a mic is it isn't confused by vapor clouds. Real Chronys and homebrew optical chronys sometime have problems with vapor clouds. The biggest advantage of the microphone technique is that you can probably do it for free. Any old laptop, or PC, will work even if it is ten years old or more. All it needs is a soundcard. Suitable mics are cheap and you probably already have one, or there is one built into the computer. If you are really cheap then any old speaker of piezo element can be used as a ghetto mic.

A homebuilt optical chrony is cheap and easy. (Most commercial Chronys are optical based.) About $5 for parts assuming you have a suitable PC or laptop laying around. Much simpler to interpret the data and the distance between the gates is a bit better defined than a sound based chrony. Pretty easy to make a gate holder that mounts directly to the barrel, that makes it easy to get the round to actually cross over the detectors. This type of detector can also be used with machine guns. A sound based chrony is tricky with a machine gun and basic commercial chronys like the F1 don't do ROF (IIRC).

You can also use a PC/laptop with induction coils as described by Technician. Need to add a small magnet to the ammo to get a signal.

Some have homebuilt a digital counter circuit that times the projectiles flight between two optical gates. It has been done with TTL and, probably a lot more simply, with a cheap single chip microcomputer like a Picaxe. If done with TTL then it is a fair amount of work to get a useable output from the timer since the output circuit has to be built as well. With a single chip computer it is usually much easier to get a useable output and easy to add an LCD display.

Unread postPosted: Fri Jul 17, 2009 5:36 pm
Author: boyntonstu
jimmy101 wrote:Unless you are going to be using the Chrony pretty often then a homemade setup is the way to go.

Using a microphone is OK though it can be finicky to get it to work right. You need good strong audio signals and you'll have to do a bit of interpretation of the results. An advantage of a mic is it isn't confused by vapor clouds. Real Chronys and homebrew optical chronys sometime have problems with vapor clouds. The biggest advantage of the microphone technique is that you can probably do it for free. Any old laptop, or PC, will work even if it is ten years old or more. All it needs is a soundcard. Suitable mics are cheap and you probably already have one, or there is one built into the computer. If you are really cheap then any old speaker of piezo element can be used as a ghetto mic.

A homebuilt optical chrony is cheap and easy. (Most commercial Chronys are optical based.) About $5 for parts assuming you have a suitable PC or laptop laying around. Much simpler to interpret the data and the distance between the gates is a bit better defined than a sound based chrony. Pretty easy to make a gate holder that mounts directly to the barrel, that makes it easy to get the round to actually cross over the detectors. This type of detector can also be used with machine guns. A sound based chrony is tricky with a machine gun and basic commercial chronys like the F1 don't do ROF (IIRC).

You can also use a PC/laptop with induction coils as described by Technician. Need to add a small magnet to the ammo to get a signal.

Some have homebuilt a digital counter circuit that times the projectiles flight between two optical gates. It has been done with TTL and, probably a lot more simply, with a cheap single chip microcomputer like a Picaxe. If done with TTL then it is a fair amount of work to get a useable output from the timer since the output circuit has to be built as well. With a single chip computer it is usually much easier to get a useable output and easy to add an LCD display.


2 pieces of paper spaced 10 feet apart would measure 1,000 fps if the 2 sound spikes were 1 millisecond apart.

IOW If your sound resolution was limited to 0.001 secon the paper spacing would have to be increased to let's say 20 feet.

2,000 fps could be measured this way.

Always place a single microphone midway between the sheets.

A bonus is that you can see the shape of the hole to determine how straight your projectile is flying.

BoyntonStu

Unread postPosted: Fri Jul 17, 2009 8:48 pm
Author: Gippeto
I have an F1 as well. The "factory" light kit is crap, you could build a better (although perhaps not as portable) one for less with basic light fixtures some wood, and a cheap extension cord.

You pretty much need some sort of light kit if you do any shooting indoors, especially under fluorescent lighting.

Otherwise, I like it and would still buy it if I had it to do over again. :)

Unread postPosted: Sat Jul 18, 2009 3:49 am
Author: jackssmirkingrevenge
Gippeto wrote:You pretty much need some sort of light kit if you do any shooting indoors, especially under fluorescent lighting


I find an ordinary incandescent bulb to be adequate for indoor shooting