magnetospeed v3 poi shift

[rhhudson]

Hey,

 

im looking at buying a new v3 chronograph i have read a lot of good things about them and they seem a lot eaiser to set up than a standard one with aerials and less risk of shooting them.

 

My question is that i have read on various forums people having trouble with POI shifting as much as 3moa when shooting with it fitted, has anyone else had this issue?

 

How do you go about load development with this? Or do you find the accuracy node and chronograph it after just to see what speed they are doing?

 

It will be used in conjunction with a moderator, i know it says on there site that it is suitable, but how good is it in the real world?

 

 

thanks

 

 

rhhudson

[dannywayoflife]

There is a poi shift on most rifles. But also from a armonics perspective I personally wouldn't shoot for accurate groups with a V3 hanging off the end. What I did was chrono a couple from each charge increment to get a rough idea of speed and pressure etc then when shooting fro groups the chrono came off once most accurate load established chrono back on to establish speed and es/sd. Simples there far far less hassle than traditional chronos

[simonl]

You wouldn't develop a load with one mod & then change it... that's what you're doing in essence.

It's the sole reason I haven't bought one.

[gbal]

The magnetospeed is an excellent choice of chrono-he basic sporter is excellent value too-unless you really,really need the extra featuresf the V3-it won't measure MV any better. Way better in use than screen (antennae) models in several ways-convenience,yes.but also crucially more valid/accurate and independent of light/atmosherics.

Anything added to muzzle is a potential change in MV and POI.But it might be near zero-varies with other factors-indeed interacts with some (Ie it very much depends...on barrel weight,harmonics,nodes etc).

IF the attachment (mod or magneto or brake,even) changes bullet release harmonics-unpredictable-there will be some POI efffect (3moa seems extreme,but not impossible?). It may/not affect POI-it's a rifle/muzzle weight/harmonics//ammo load complex interaction-but not a deal breaker at all-MV ignorance is a bit more so).

Safest option is to load develop without any muzzle attachment-or with the mod you intend to use. Check velocity with magneto on (if you are confident with moderator,and mag fits etc) or without mag on .

MV should not be too different.-but might not be exactly the same-check what difference 25 fps makes not much difference,at this stage!

Fine tune load.

If mag fits etc,test again with the actual shooting rig (rifle,+mod) if possible-mag seems fairly tolerant of dimensions (ie barrel and mod-but mods vary). I would not use mag with a pepper pot brake,with any gas going down...

 

Remember,chrono is to get good data on MV.

Almost inevitably,any final tune to eg ballistic solver will need some 'tweaking'-because there are quite a few rather sensitive measurements involved-the magneto is unlikely to cause much-but you dont ned to include it-except as a last check,maybe.

And remember,all this is not high up on 'hit' list...but mv is useful...I think I'd get the basic model-gives the crucial data,maybe less flexible with mods on...half the price-but that's another issue.

 

gbal

[DW58]

Please bear in mind that only the V3 offers the full versatiliy of use with muzzle brakes and varying diameters of moderator/suppressors - the Sporter model is limited in this way and also has a more basic display unit.

 

I've had my V3 for a couple of years now and have used it with various calibres from .22LR up to .300 WSM, with and without brakes and moderators - I cn't fault it.

 

I shoot for MV separately to shooting for accuracy.

[terryh]

Rhhudson,

 

I've used the V1 & currently use the V3.

 

The V3 works very well physically with suppressors or nude barrels, not had any problems if you put it on right. We purchased one for our club and all sorts use it with no issues to date.

 

Re. POI shift, there has been lots said about this, I have not found significant shift, if any, with the sensor on or off the barrel, if I had a rifle that moved its POI by 3moa (assuming this is at 100 yards) I'd probably look at the rifle!

 

Now using the Magneto speed or not during load devlopment, either really, I've not found a difference between the final load group size with or without i.e the 'good load' is still good the Magnetospeed makes no difference, but that is just me. friends who are very competitive (proven not verbally that is ) use this chrono with no issues.

 

Brgds

 

Terry

[MJR]

I own/ use a V2 and find it excellent. I cannot shoot the difference it makes when fitted to varmint contour barrels or heavier but it does effect a light weight sporter barrel I have. However I do not conduct load development with it fitted other than when initially testing for where pressure signs start to become apparent in my rifles and use the velocity obtained as guide to pressure and cross referenced with quick load. I then develop a load looking for accuracy first. Once that's obtained I use the V2 to establish the velocity and couldn't care less what accuracy is like whilst chronograping as its an already proven accurate load.

 

Do you shoot at Leek rifle club? If you do you are welcome to try mine.

[rhhudson]

I own/ use a V2 and find it excellent. I cannot shoot the difference it makes when fitted to varmint contour barrels or heavier but it does effect a light weight sporter barrel I have. However I do not conduct load development with it fitted other than when initially testing for where pressure signs start to become apparent in my rifles and use the velocity obtained as guide to pressure and cross referenced with quick load. I then develop a load looking for accuracy first. Once that's obtained I use the V2 to establish the velocity and couldn't care less what accuracy is like whilst chronograping as its an already proven accurate load.

Do you shoot at Leek rifle club? If you do you are welcome to try mine.

i dont yet no, i shoot mainly on my family farm ( near longnor).

 

I have looked into leek before but they only have 100m range and occasional access to 500. I can get 700 on the farm easy.

 

Maybe when i have more time might join

[Vermincinerator]

I develop a load and then see how fast its going, nothing could be simpler, why complicate matters.

 

Ian.

[MJR]

Ok. barrow moor ?

[rhhudson]

Ok. barrow moor ?

good guess.

[Colabear]

Have seen and used most other types of chrono and the versatility and ease of use of the V3 exceeds other options particularly 'screened' models. Mine gets used in and outside the real benefits being not having to wait to move forward of the firing point to make adjustments or recover the unit, the only annoying thing is everyone wants to borrow it. As mentioned here, if you are load developing then I would find your accuracy node and then establish the MV for use on ballistics tables or guides.

[OSOK]

I've seen either the V2 or V3 Version used in Leek tunnel on SR's 308 FTR rifle and the poi moved around an inch or just over . Strange how we all do things in a different way as when I load develope , I have a bullet and powder that I intend using and a velocity band that I need to be within . Once I'm around the middle of the band , I then try to make it group with good spreads so I couldn't load develope without using a chrono from start to finish . These barrel fitted chrono's whilst being useful and easy would put a doubt in my mind during load development so not for me .

 

I've collected a Labradar today for which i can see all the plus points of the barrel mounted but without the doubt issue ..... Hope i haven't just give it the kiss of death !

 

OSOK

[old_n07]

Our club in Uttoxeter has just bought a Ladradar, not had chance to try it yet but I'll be interested to compare it to the V2 I've been using

[rhhudson]

Our club in Uttoxeter has just bought a Ladradar, not had chance to try it yet but I'll be interested to compare it to the V2 I've been using

where is the club in uttoxeter? Is there a range too?

[old_n07]

Uttoxeter Rifle club, we have a 25 yard gallery range and also shoot at Thorpe out to 500 yards

[terryh]

Our club in Uttoxeter has just bought a Ladradar, not had chance to try it yet but I'll be interested to compare it to the V2 I've been using

Bit off OP but how does the radar 'know' you've shot and it's your bullet it is tracking if you are shooting shoulder to shoulder? Always made me wonder?

 

T

[old_n07]

Bit off OP but how does the radar 'know' you've shot and it's your bullet it is tracking if you are shooting shoulder to shoulder? Always made me wonder?

 

T

That's what I'm interested in trying out

[simonl]

Bit off OP but how does the radar 'know' you've shot and it's your bullet it is tracking if you are shooting shoulder to shoulder? Always made me wonder?

 

T

It listens for the bang IIRC. It'll never manage to be very selective about whose bullet it's tracking. Will probably tend to pick up the signal from the bullet with the biggest/flattest tail (eidt: which is most perpendicular)

[John MH]

I develop a load and then see how fast its going, nothing could be simpler, why complicate matters.

 

 

 

This

[Laurie]

The Labradar is sometimes falsely triggered by an adjacent shooter using something noisy, muzzle brake equipped jobs especially. The start emitting and recording trigger is sound - there are two small internal microphones about half way up the body, one on each side to allow placement either side of the firearm.

 

Even shooting off benches placed pretty close together, if a neighbour's shot triggers the radar, the other person's bullet track bullet is off the device's axis and so you get an error reading saying it cannot track the shot, press enter to reset. The trigger sensitivity can be altered so by keeping it just behind your rifle's muzzle only a couple of inches away from the edge of the barrel and reducing the sensitivity level, you can cut out false triggers. When mounted on a bench using the optional purchase bench stand, my experience of others using this placement is that the audible trigger mechanism doesn't pick up on moderated rifles even when set to maximum sensitivity. This set-up may need a tripod allowing the device to be placed closer to the muzzle. There is an alternative trigger method, but it doesn't seem to be as reliable.

 

On the original question re the MagnetoSpeed, I have seen the occasional rifle which gets away with little POI shift and no group changes - but I've yet to enjoy this myself having used all three main variants of the device during its life on maybe a dozen or so rifles. I have a shot 100 yard target somewhere that illustrates this graphically firing 15 rounds of the same 6.5-284 load in three 5-round groups. Fitting the bayo' on raised the POI around three-quarters MOA and moved it around half-MOA to one side. (Direction of change depends on the bayo' position in relation to the muzzle as it deflects exiting gasses which in turn slightly deflect the bullet.) Much more the the point, two 5-round groups shot with it off were in the 0.2 to 0.3 inch range in near perfect one-hole round patterns; with the bayo' on, the group was vertically strung and opened to somewhere between half and three quarter inch.

 

I have also had it the other way round with a series of test groups of a powder / bullet in 7mm-08 all producing really tight three-round groups. Take the bayo' off and the combination simply wouldn't perform with any charge weight. Not too surprising - if it weren't so, people making and selling barrel tuners would be in breach of the Trades Descriptions Act! I should also say, I'm talking heavy barrel match rifles, some with pretty stiff actions like the Barnard Model P fully Devcon bedded, so no skinny whippy barrel sporters that will presumably be more heavily affected.

 

So, I soon adopted the practice of load five or six rounds of everything new, use 1 shot per charge weight for a pressure / velocity test; then shoot the remainder in each batch for group. What I have found too is that shooting anything up to 10 or 12 velocity-finding shots over a large range of charges (2gn common, occasionally 3) at a single aiming mark, having the bayo' on seems to smooth POI and grouping out - sometimes the whole lot will go into a half-MOA group. What this has done for me is to overcome my past scepticism of the value of adjustable barrel tuners - my next rebarrel will have one installed to see how it works out.

 

I should say that I am still a fan of the MagnetoSpeed - a huge step forwards over optical devices. However, the Labradar is better still, but it is of course considerably more expensive, and you must either have mains power on the firing point or power it with a high-capacity power pack for anything other than short sessions. The device eats batteries, even if switching it off or putting it into stand-by mode for breaks in shooting.

[simonl]

, having the bayo' on seems to smooth POI and grouping out - sometimes the whole lot will go into a half-MOA group. What this has done for me is to overcome my past scepticism of the value of adjustable barrel tuners - my next rebarrel will have one installed to see how it works out.

So do you feel that load development might be unnecessary? i.e. Pick your required pressure-safe velocity & then just tune harmonically?

[Laurie]

That's the theory anyway. Whether it works in practice, we'd have to see. The bullet has to be a good fit/match to the barrel in any event. Some bullets just don't shoot in some barrels.

 

How I expect it'll work out is that you find something that is 'almost there' and also has a small ES/SD, and the tuner (hopefully!) does what it says on the tin and 'tunes' the load that last bit through a little adjustment to its setting.

[paddy]

i have no poi shift on my rifles with the v3 on . one is a tikka tac a1 20" barrel the other is a ai at with 26" barrel