what is the best chronograph to buy?

[Amleto63]

POI change isn't only caused by the 'bayo' weight hanging on the end of the barrel, but by its affecting the muzzle blast and deflecting the bullet slightly, in the direction of 180-deg from the 'bayo' position. You can mount the device at any point around the barrel but most people will put it on at the 6 o'clock position. (I do.)This therefore tends to deflect shots upwards.

 

Using it on a new 6BR barrel last week running the barrel in and doing initial load development, there was around three-quarters inch vertical difference between 'bayo' on and off at 100 yards, the first 'off' group low.

 

The method I usually use now in initial load development is to load one extra round per charge weight batch (usually making it 4 rounds) and shoot one round from each with the Magnetospeed on to see MVs and check on pressure signs - ease of extraction or otherwise, primers, case-heads being marked etc. The 'bayo' is then removed and the remaining 3 rounds in each charge weight fired to see how they group and if required rezero. This doesn't tell you about velocity ES / SD of course, this having to be done subsequently, but I usually fine-tune charges around initially promising loads anyway.

Happy knowing I do same method :-)

[dorg]

Mik how much are the Labradars going to cost, I use a V3 but struggle to get my head around the fact you cannot do accuracy tests and velocity tests at the same time. With limited round counts on the F class barrels we use the less round used in load development the better .

[stu47]

Stu47 15" high and 3" right!! At what distance was that? Surely not 100? Got to say on my DTA the v3 makes no difference at all to the poi or the accuracy: but I think that might be due to the uber short 16" barrel and the fact that the first 7" of the barrel are engaged by the action.

Sorry - forgot to add "at 500yds".

 

Having said that my poi does seem to move a lot more than the others are reporting.

[Swarovski1]

I shot a v3 through my f1 chrony, figures were nion identical,

[DeerOzzy]

Nick,that's a very sensible question.Most user reports seem not to be concerned-or much with POI issues.

But as with any change on/off barrel,you would be very wise to just check with a couple of shots,with the load,with it off-it should not invalidate the load development.

Gbal

I have been using the Magnetospeed V3 on a custom .284, 28" heavy fluted barrel for load development (still ongoing) and have not noticed any shift in POI, but suspect this is more to do with the barrel dimensions being simular to a scafold pole, than the effect not being there. It to has crossed my mind as to how valid a load developed will be with this straped to the barrel, compared to when removed in use. I suspect the optimal load with it on will cease to be the exact optimal load when removed as the harmonics will change, what are others thoughts on this?

[Swarovski1]

I would be intrested in your load development velocities and the bullets you are testing, post them on this thread or pm me them, cheers swaro

[DeerOzzy]

I would be intrested in your load development velocities and the bullets you are testing, post them on this thread or pm me them, cheers swaro

Hi Swaroski1,

 

Not sure if you are refering to my last if so:

Rifle is 0.284 with Nesika V repeater action, Bartlein 9t 28" barrel,Jewel trigger, Christensen carbon stock,Wyatt outdoor bottom metal and mag, Lawrence precision "Zodiac" mod, all finished in a fetching Ral 8000 sand and black to match the PMII sat on top (Yep bought scope first, sent Mik into a tizz, but looks awesome now) all put together by Mik Mak's deft paws.

 

All development so far using Berger 180gn Hybrid and RS 60 powder, CCI BR2 primers, Lapua 6.5-284 brass re-sized to .284 and neck turned and prepped.

 

Barrel has been bedded in with Mik's recommended cleaning process as I went.

 

5 x 50gn -average - 2748fps SD 8.8

5 x 51gn- average - 2808fps SD11

5 x 51.5 - average - 2845fps SD10

5 x 52gn - average - 2874fps SD7.0

5 x 52.2 - average -2895fps (showing minor head marking of ejector pawl ejector pocket on some cases, no other sign) SD 17.7

3 X 52.4 - average - 2907fps (showing minor head marking of ejector pawl pocket on some case, some minor squaring of primer) SD1.7

 

Next series has shown slight increase in speed e.g 52.2 average now 2904 as barrel beds but SD increased from single/low teens to LOW/MID teens but over 10 shots at each charge.

 

So far the 52 Gn is showing most promise, though this has been hampered by Century crosswind variability @: 300yds only printing 0.7-1 MOA over 10 shots per charge, on last outing, though I think some of that is my inconsistency in technique, poor target with ill defined aimpoint (homemade).

 

The V3 has stuck fast strapped to a Lawrence precision Zodiac mod throughout is very easy to use, recall data, review later and has been very consistent never missing a beat, but that is a big lump passing by so it shouldn't, just waiting for a calmer day to allow better grouping! I have tested it against my competition electronics CE3800 and it was very close, though of course that took a heap of aligning and messing with a tripod to get all working as it should.

[Swarovski1]

Fanx for the info,0.7 to 1 inch 10 shots groups is superb accuracy,2900fps is very quick, this is hme past 2884fps with 180 grainer just incase you didnt know, I use to ammo test at 300yds prone with a rear bag, it was my old tikka continental master in 30-06,I put 4 into 0.6 and let the last one go that gave me 0,960 oai group, still got the target on my gunroom wall, load was 155gr scenar sat on 49.8grs of n140 if my memory serves me right, its viht data I used.i only sold it because I wanted 10 shot mag capability, doing 200yds mcqueens with a magazine change was a pain.sometimes I did it flawless, other times not so.not sure how much you can improve on 0.7 ten shot groups but if you do post a picture, went out with my 22 lr safternoon and printed around 0.7 oai ten shot groups at 80yds with eley subs, kinder on the ears too

[Dunc]

I have and use a V3, I have tested it versus our indoor Commercial Chrono system and its within 1% of a £20K calibrated system, so I can safely vouch that its a quality piece of equipment. I fact we tested these for the Importer and every one we tested was accurate to with 1%

Was it consistently 1% low / high? Thanks.

[DeerOzzy]

Fanx for the info,0.7 to 1 inch 10 shots groups is superb accuracy,2900fps is very quick, this is hme past 2884fps with 180 grainer just incase you didnt know, I use to ammo test at 300yds prone with a rear bag, it was my old tikka continental master in 30-06,I put 4 into 0.6 and let the last one go that gave me 0,960 oai group, still got the target on my gunroom wall, load was 155gr scenar sat on 49.8grs of n140 if my memory serves me right, its viht data I used.i only sold it because I wanted 10 shot mag capability, doing 200yds mcqueens with a magazine change was a pain.sometimes I did it flawless, other times not so.not sure how much you can improve on 0.7 ten shot groups but if you do post a picture, went out with my 22 lr safternoon and printed around 0.7 oai ten shot groups at 80yds with eley subs, kinder on the ears too

Hi Swarosvski1,

 

Sadly this is 0.7-1 MOA (1 MOA is 1.0472" @100yds) not inch, therefore tightest group little over 2" @ 300 so not quite so great!, I did have some good sub groups within that best 3 shot @ 14mm (yeh I know inches-mm, but that's what I had!), with a best 4 shot @ 34mm, so as you can see its not so good as you thought, but I have to keep working on it as I need it to be sub 1/2 MOA to have a chance @ 1000Yds. The prob was I was doing grouping and not offsetting for wind as a result, cant ever seem to find a decent day @ Bisley for this. Sorry for the Hijack of thread, just answering a question, still I did use the V3!

 

ATB

[Luther1]

I fully expected a bit of sight adjustment, more likely a lot at this distance, would be needed

 

 

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