Chrongraphs

S&L7x57

Well-Known Member
Been looking to buy a chronograph to work out new loadings and assess my factory ammo (which is often old stock bought at auction). Can one comfortably make do with the Chrony products or is the Caldwell product worth the extra cost? Any other recommended options? Thanks in advance for your help.
 

hammo

Well-Known Member
Hi

Crony F1 will do you fine, little point in spending more. I struggled with a small airgun type crono, shot it once with the .243 - small aperture to get your bullet through!! Polish supplier repaired it for a fair price, but shot it again with my Hornet; so bought a crony f1 off fleabay.

Hammo
 

Laurie

Well-Known Member
Yes, it does so in most rifles. A few seem immune. So, although you regularly see people doing it, it's not a great idea to do load development with the MagnetoSpeed 'bayo' attached. Either get get a load that groups well sorted first, then chronograph it, or do initial testing with one or two extra rounds loaded per charge weight to obtain MVs. When I used this model a lot, my initial batches were often 3+1, the '+1's all fired together with MagnetoSpeed attached on a single aiming mark to identify MVs / MV incremental increase per 1gn weight powder / look for hard bolt lift and other over-pressure signs before removing the 'bayo' and shooting groups with the 3-round batches.

Quite often, a fair number of single shots in rising charge weights covering up to 3gn in 260 / 308 size cartridges would group amazingly well with the 'bayo' on. With one F-Class rifle in 7mm-08 Rem throated for long / heavy bullets, I tried load development with the device on having just got it and not realising how much effect it can have. Nearly every charge weight of an early bullet-powder combination shot a tiny group. Fantastic! thinks I. Of course, when I took the MagnetoSpeed off, nothing grouped worth a damn. (It certainly changed my views about barrel tuners for competition rifles!)

If the straps slip under recoil, this usually causes a significant POI change too.

There are many pluses to the MagnetoSpeed models, but these are downsides.
 

deeangeo

Well-Known Member
I use a Chrony F1 & have done for many years. I always found it good enough for 'field test' conditions.

Trying to replicate lab tested data in manuals is not what it's about for me, it's more about finding close enough MV and ES for my own loads, from my own rifle, to give good information that I can rely on, for my hunting.
The Chrony provides that data.
 

timbrayford

Well-Known Member
I have always wondered about these. I use a crony to measure SD when working loads up for accuracy. Does something strapped to the barrel not change the harmonics and make the exercise a bit pointless? POI must change.
From my own perspective the POI does change, not least of which because I test without the mod fitted, but I develop loads for accuracy first and having got a range of tight groups then velocity test.

My rifle is .243 and with the 90 & 95 grn bullets that it shoots best I am loading towards the upper end of safe loads to obtain a good England deer legal round, for target/practice shooting I use a slightly less quick round which falls just a little short of deer legal ME.

The main advantages of a strap on chrono is that light & wind conditions are no longer of significance and unlike the shoot through types of chronos there is much less chance of a mishap with it being impacted by a flying bullet.
 

Yorric

Well-Known Member
I use my Chrony for all load development. A couple of shots over it at each steps adds invaluable cross checks to the process.
What is important with this two sensor type of chronograph is to ensure that you always shoot over it in the square on axis & that the Chrony is fully opened out.
The case on the Chrony can catch on a tripod head as you open it up & not fully unfolded flat if you are not careful. This leaves the sensors out of line & this will result in variable readings depending on the height of the bullet path over them.
If the chrono is not aligned square sideways or up & down to the bullet path, the reading will be wrong again. (Not by much but it will vary depending on amount of misalignment.
If you keep the above in mind the Chrony will do a good job providing reliable results which are accurate enough. As long as you don't shoot the machine it will last many years.

Ian
 

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