Which Chrony to believe?

[Ralpharama]

Some time back I used a friend's Chrony to give me an idea of my MV before taking my .308 to Warminste IR2 1000yards. We used it in the 50 metre tunnel at MNTSC. He had some led lights rigged, though I suspect the lights were only borderline strong enough as it was quite temperamental. The 'hot load' I had made (45.5gr RS52, Lapua Scenar 167gr, S&B primer) gave an MV of 2905 fps which seemed great. I dialled all the data into StrelokPro on my iPhone and was on the paper with elevation. Well chuffed!

I have since joined Offas Dyke and had signed up for Sennybridge J3A, which was sadly cancelled. In an attempt to get my bullets to stay supersonic at 1000metres I made some new rounds using Lapua Scenar-L 175gr and upped the propellant to 145gr. Rather than bothering my friend I invested in a new Chrony Alpha Master. I fabricated up a set of lights to run off a motorcycle battery for use in the rather dark 50metre tunnel. On Sunday morning I took my new hot loads and new toys to the tunnel Andy was disappointed to find my MV to be only averaging 2450fps. Last night I took my original loads up to club and measured them and they averaged 2665.5fps, somewhat lower than the measurements by my friend.

I would have assumed that the original measurement was spurious, were it not that using it with StrelokPro put me on the paper at Warminster IR2.

Can anyone make any suggestions?

[No i deer]

Chronographs can be temperamental in certain light conditions especially low light but when the light is fine there no different to the muzzle mounted ones that don't work using the light cells.

I've used the muzzle mounted chronos and fired shots over my F1 chrono and fps measurements were nion identical.

Shooting in tunnels with anything else bar the V3 type chrono would probaly be inconclusive.chronos don't like strip/fluorescent lights at all.

[Ralpharama]

Thanks for the reply.

Both chronographs were Chronys, not sure which model my mates is, but is essentially the same. We have LED lighting in the tunnel, though it's pretty dim in front of the firing point. We were both using LED 'extra' lighting so there shouldn't be any pulsing or flickering associated with fluorescent lighting. Mine seemed to be giving consistent readings. I fired five rounds of SK Match .22 RF though my Anchulz 54 Super Match which read average as 1043 fps before using the .308; if it wasn't set up 100% 12p a round is more palatable than the cost of .308 rounds :) Do those readings sound about right?

[Deserttech Europe]

Isnt IR2 1000 Yards not metres, could that be part of the problem?

 

[Ralpharama]

9 minutes ago, Deserttech Europe said:

Isnt IR2 1000 Yards not metres, could that be part of the problem?

 

IR2 is 1000 yards and my 167gr Scenars worked a treat there. I am trying to pep up my rounds to shoot 1000 metres at Sennybridge J3A and hopefully get them to the target before going transsonic.

[jcampbellsmith]

Bin the Chronys would be my recommendation. Also note that each time you go out with the chronograph, the weather will be different, so I'd expect different results in terms of measured velocity and point of impact on the target.

I use a MagnetoSpeed and am very pleased with that.

Regards

JCS

[20series]

The lighting is probaly the cause of your issues another Critical factor is getting the distance from the barrel to the chrono consistent. 3 metres or 10 foot as a rule, I use a piece of string to make sure it's in the same place.  

 

Alan

[Ralpharama]

39 minutes ago, 20series said:

The lighting is probaly the cause of your issues another Critical factor is getting the distance from the barrel to the chrono consistent. 3 metres or 10 foot as a rule, I use a piece of string to make sure it's in the same place.  

 

Alan

Following the instructions with my new Chrony, I carefully measured the 10' to the front of the chronograph. When my mate measured my gun before I think he had his Chrony much closer than 10' and was using different lighting.

[Mick Miller]

Having used a few (caldwell, pro chrono and chrony) only the magnetospeed and labradar seem any good. The labradar isn't worth having in the UK as it's been emasculated by the authorities and from what I've observed can be a complete faff to set up and get to register shots. That leaves just one option.

Both labradar and magnetospeed registered the same velocities within +-5fps of each other, whereas when compared to traditional chronos there was a large difference in results.

Magnetospeed – buy once, cry once. This is only one mans opinion.

[No i deer]

2 hours ago, Deserttech Europe said:

Isnt IR2 1000 Yards not metres, could that be part of the problem?

 

I think it's 900 metres.

Which is 990yds ?.

I've not been there but a mate goes there with his 338 lapua magnum 

[DaveT]

It defo is 900 metres.

I used to shoot my 338 there untilI figured I was wasting expensive 338lm ammo at such short range!

[DaveT]

19 minutes ago, Mick Miller said:

Having used a few (caldwell, pro chrono and chrony) only the magnetospeed and labradar seem any good. The labradar isn't worth having in the UK as it's been emasculated by the authorities and from what I've observed can be a complete faff to set up and get to register shots. That leaves just one option.

Both labradar and magnetospeed registered the same velocities within +-5fps of each other, whereas when compared to traditional chronos there was a large difference in results.

Magnetospeed – buy once, cry once. This is only one mans opinion.

Nowt wrong with the Labradar... it will measure MV just as well as the US version... it simply won't track bullets downrange much past 50 yards whereas the US version goes further.

[Gandy]

I shot rounds over a pro chrono, a fold out F1 (I think) steinart Accoustic chrono and magneto speed. 

 

They all gave different results...  

 

Litz measured them scientifically and said the magneto was the most accurate so that’s what I trumped for.

 

I would reccomend you you stick with the chrono you have and change ballistic app the inputs until it lines up with what you see on paper. 

[Mick Miller]

52 minutes ago, DaveT said:

Nowt wrong with the Labradar... it will measure MV just as well as the US version... it simply won't track bullets downrange much past 50 yards whereas the US version goes further.

Every time I see someone using one, and when I had someone set one up for me, it was endless faff getting it set and getting it to register every shot. Just seems to me that the Magnetospeed wins hands down on user friendliness. Strap it on and away you go.

[20series]

2 hours ago, Ralpharama said:

Following the instructions with my new Chrony, I carefully measured the 10' to the front of the chronograph. When my mate measured my gun before I think he had his Chrony much closer than 10' and was using different lighting.

Anything much closer will be affected by muzzle blast even with a Moderator on.

[DaveT]

1 hour ago, Mick Miller said:

Every time I see someone using one, and when I had someone set one up for me, it was endless faff getting it set and getting it to register every shot. Just seems to me that the Magnetospeed wins hands down on user friendliness. Strap it on and away you go.

Nowt wrong with the Magnetospeed either... but watch out for the strap loosening and it will be a faff to get the spacers right and the bayonet properly just under the bore.

They all have foibles but having both Magnetospeed & Labradar its Labradar for me.

Shots being missed are usually due to incorrect trigger settings in the unit user setup or having the muzzle too far away.

[Mick Miller]

9 minutes ago, DaveT said:

Nowt wrong with the Magnetospeed either... but watch out for the strap loosening and it will be a faff to get the spacers right and the bayonet properly just under the bore.

They all have foibles but having both Magnetospeed & Labradar its Labradar for me.

Shots being missed are usually due to incorrect trigger settings in the unit user setup or having the muzzle too far away.

Don't forget the 'didn't check the bayonet height' terminal user error either...

[DaveT]

4 hours ago, Mick Miller said:

Don't forget the 'didn't check the bayonet height' terminal user error either...

Shooting the bayonet is a WTF error!

[Bangbangman]

I like the magnetospeed but it does influence POI and, presumably, therefore harmonics. So load Dev with it attached could mislead.

[No i deer]

Ive witnessed one being shot off the end of a mates 338 lapua magnum barrel. You could safely the 250gr lockbase blew it to smithereens 

[DaveT]

Ouch..... as expensive as it is embarrasing!

I can picture him furtively looking around and hoping nobody noticed!

[Ralpharama]

"magnetospeed" is bit bit pricey for me! The Chrony will have to do. I used it again last and found that the information was useful. 

ON my load development for 1000m, I had to stop at 45.5gr of RS52 as the bolt started to get slightly tighter opening and a very slight polishing of the back if the case, which gives me a safe maximum of 45gr it seems, regardless of MV. I'll have to empty out the 46s!

 

I'll have to save my pennies for a .300win mag, certainly can't afford to feed a .338 lap !

 

[No i deer]

It was somebody else's chrony and this somebody else fitted it before my mate blew it up ?

[GT3_richy]

5 hours ago, No i deer said:

It was somebody else's chrony and this somebody else fitted it before my mate blew it up ?

Ooops! ?

Re. the UK Labradar being a bit impotent compared to the US version - as others have said the only shortcoming is how far away it will accurately keep returning velocity readings.

Personally, once you grasp how to locate it correctly for brakes, mods, large cals, small cals its very reliable. Mine *might* miss one shot in a session, shooting projectiles as small as .17s, V3 is no better at best with trigger errors. Set up takes about a minute including taking it out of the bag, takes longer to strap on (oo er) the Magnetospeed. I've only compared them side by side once, they were 4-5fps different across a few shots from a 223 running lights bullets at 3600fps+

I have both in the truck, but really only use the V3 if the USB power packs for the Lab is dead - Lab running on batteries is a piss take, 6 AAs last no time, cheap USB power pack lasts aaaages fortunately.

 

[No i deer]

So it was you Richy who incorrectly fitted your V3 for Rob on f range at Sennybridge to blow it into dust.Rob laid they're looking at what was left thinking WTF happened there.£300 worth of chrony bit the dust ??.