Chronograph types and accuracy.

[Shooting Tigers]

Hi,

 

I have been reading this forum, and it seems like the police will give an airgun owner a hard time if they suspect the 12 ft. lb. limit has been breached without an FAC, and may even choose to do the ME tests using "their own choice" of pellets, to get the biggest numbers out of the chrono testing machine, even if the owner does not use that particular brand of pellet.

 

I have been looking for chronograph machines on the internet, and found two different types. One is a small, tubular one that clips onto the muzzle of the rifle. The other is a large, free-standing device with a large frontal area aperture that you have to aim the shot through. The free standing one can be used to measure the pellet speed at some distance from the muzzle , like 5 metres or 30 metres, or whatever.

 

Do any of you guys do muzzle energy checks with a chrono at home? What types of machines do you use? How accurate are they? Are they calibrated by an external test lab? Have you compared one against another, to see if they both read the same figures for one gun? Are they reading consistent figures for shot-after-shot on the same gun?

 

If anyone has got (or uses) a good chrono, I would like to know what make and model it is, where I can get one from, and how much I will be paying.

 

Any home-testers or tuners out there?

 

Cheers,

 

Rob

[andrewjames]

i use the combro cb-625 mk 4 (i think its called)

 

you can buy them for 39.99 from combros website... you can buy additional bits like the pc interface cables and bore alignment tool which is a nice feature. i use it all the time and its never let me down.

 

the great thing about cronos for me is the ability to record velocity... i like to see how consistant my rifles are, its the only way for me to see if (when i adjust the power) im actually making any difference to the rifles performance

 

one downside to the combro is that its consitantly mounted to the rifles barrel... you cant move it 30 yards away and continue to shoot through it like other cronos, but its not that much of a downside though because i use chairgun pro software to see what ftlb my pellets are doing at different distances.

[apache]

How accurate are they? Are they calibrated by an external test lab? Have you compared one against another, to see if they both read the same figures for one gun? Are they reading consistent figures for shot-after-shot on the same gun?

It's a bloody good question, that I have agonised over. How accurate is something costing £40 going to be?

 

Now I will bet someone will chip in with 'well if you can show the police you tried it will count in your favour' but I disagree. Imagine being pulled over by a policeman for doing 35mph in a 30 limit. Your £50 Aldi satnav says you were only doing 29.5mph - do you think they'll take your word for it and let you off? I don't.

 

I can see they are a good idea in theory, and I nearly bought one, BUT just how good are they?

[lineshooter]

I use a Cb 625 to regulary check my airguns, especially important when trying different pellets and my local gunshop will test for free using a Skan Chronograph which are supposed to be one of the best.

 

I suppose you can never be certain your results agree with the Police chrono so if you are arouond 11-11.5 ft/lb then you should have enough leeway to allow for the pellets the police use.

 

Many, many years ago I had the Police turn up when I was shooting with a couple of mates, they had a report of windows broken by pellets etc. It wasn`t us but they had an excuse and took the guns for testing, anyway two weeks later had a call to collect the guns, only a Webley Vulcan and a Meteor.

 

Nothing more was said or done and I did`nt get any paper work as to power results, so did they bother.

[Dekers]

It's a bloody good question, that I have agonised over. How accurate is something costing £40 going to be?

 

Now I will bet someone will chip in with 'well if you can show the police you tried it will count in your favour' but I disagree. Imagine being pulled over by a policeman for doing 35mph in a 30 limit. Your £50 Aldi satnav says you were only doing 29.5mph - do you think they'll take your word for it and let you off? I don't.

 

I can see they are a good idea in theory, and I nearly bought one, BUT just how good are they?

 

£40 buys you state of art technology these days, VERY VERY VERY accurate is the answer?

 

But that isn't really the question, there will inevitably be problems, failures and tolerance issues, as with even your Rolls Royce!!, so it would be a good idea to check any unit.

 

In principle the cb625 is very accurate!

 

Most would be advised to stay about 11.5ft lb or below anyway, so this should build in tolerance!

Edited July 17, 2010 by Dekers

[snipper]

i use a chrony F1

it can be used with anything from a bow n arrow to shotgun ....

no messing trying to fit it on your barrel

the only downside is they are light fussy ( cannot use them with floresent lights )

 

http://cgi.ebay.co.uk/SHOOTING-CHRONY-F1-C...=item588826734b

[Goldfinger]

I use the crony F-1 they are supposed to be very accurate,I find it easy to use,I got mine second hand £30 bargain from a gun dealer who didn't really know its true value.

[jackinbox99]

i use the combro cb-625 mk 4 (i think its called)

 

you can buy them for 39.99 from combros website... you can buy additional bits like the pc interface cables and bore alignment tool which is a nice feature. i use it all the time and its never let me down.

 

the great thing about cronos for me is the ability to record velocity... i like to see how consistant my rifles are, its the only way for me to see if (when i adjust the power) im actually making any difference to the rifles performance

 

one downside to the combro is that its consitantly mounted to the rifles barrel... you cant move it 30 yards away and continue to shoot through it like other cronos, but its not that much of a downside though because i use chairgun pro software to see what ftlb my pellets are doing at different distances.

 

I use one of these too. And its had loads of use chrono`ing mates and even other forum members rifles. Easy to use and accurate!

[Clubshot]

Many Clubs use Skan Pro's - as used to the Police before passing it on to Independant Labs

 

We have several @ Lea Valley - Club and Members - seem to keep most Gun's in Line

 

Available Direct or through good retailers

 

BOB/R

[minkhunter]

i use a shooting chrony f1 for all my airgun testing,i find they give accurate readings..use them out or indoors if the light is right..these read in fps so you have to do the math for converting to ftlb but all the info should come with the chrono,check it is if going down the second hand route..

[pintosal]

Chrony F1 do have the reputation for accuracy.

 

However, they can give a low reading unless you are careful. If you fire at an angle, either vertically or horizontally, the pellet takes a slightly longer journey between the 2 sensors, and hence the velocity reading will be understated. I have calculated that, worst case, it could give a 5% low reading. So, if you tune to the FAC limit, beware.

 

Follow the instructions that come with the unit, which tell you the height to shoot at etc, and then you should be OK.

[lottie Dave]

This is a piece of kit I would like. I am tending to go for the fire through such as the F1. Everything should be fine regards the readings. pellet grain. Providing it falls a few points under the 12ft lb limit for the rifles preffered pellet. I would check it with heavier in case of a pcp and lighter for a springer. Give it some leeway of a few %. That's on the upside.

You can bet on your bottom dollar if the police ever get hold of your gun, for whatever reason they will use a selection of their own pellets to give the highest power possible.

[drut]

Another vote for the F1 chrony from me,good for my shotgun reloads as well as airgun.I use one of "Stotts" interface cables to link to PC.Did have a cb625 till I clumsily broke it and in honesty could not fault it,seemed equally as accurate as F1 to me.

[carld41]

use my combro cb-625 mk 4 to keep my rifle on the 25ftlb mark. Handy bit of kit. But don't go trying to line it up with the barrel by eye unless your a squillion percent sure its not loaded. Better still use a 5.5 knitting needle to line it up like I do.

[THEINVISIBLESCARECROW]

Chrony F1.

Made in Canada not China.

Can be used not only for muzzle velocity but also at the POI.

There is a choice of different machine you could get & all recomendations useually are made by people who have just the one so no comparisons made.

I'm the same.

I chose the Chrony F1 due to good write ups & reviews from users.

For what I wanted It fitted the bill & the price was fair.