3 shots, 600m.
Should I true my result from the ballistic app? How and what?
what is your thought process, for those that subscribe to the practise?
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3 shots, 600m.
Should I true my result from the ballistic app? How and what?
what is your thought process, for those that subscribe to the practise?
Attachment 247374
I'd just true speed from app and check it again at various ranges. What app do you use?
Your elevation looks fine to me. If you're aiming the center of the plate, your dope seems correct.
I verify the BC with the following process
1. Measure the muzzle velocity
2. Use muzzle velocity with bullet BC to estimate the drop and terminal velocity at a known distance.
3. Use silvermountain/shotmarker to measure the terminal velcity and the actual drop.
Although the electronic targets are considered not accutate enough, I'm usually getting averaged < 10fps difference between the predicted terminal velocity from Applied Ballistic, versus the measurement from the electronic targets at 600-900yds.
i do, shoot at 4 different rangers and can use the app to make a nice average shooter has a bit that you punch in and it works out your curve.
edit to add that you use real-world drop so it accounts for, speed, bc & scope adjustment all in one
Futch i cant see that far,nice shooting.Quote:
Originally Posted by gimp
That’s a very tidy group at 600yd. What was your POA? Assuming it was centre of gong then your vertical dispersion looks pretty small - maybe 1-2 in high at most ? I guess it depends on how big the steel plate is? If it’s 1.5 in high at 600 then that’s a 1/4 moa correction. Pretty minor. You certainly could increase muzzle velocity in app to see what speed equals 0.25 moa less than your dial up.
There’s appears to be more horizontal dispersion - right to left wind ? This might also mean a slightly high poi.
I use a small centre dot or square on the gong to ensure a precise pos.
I’d be tempted to repeat the excercise on another day with different conditions to see if you need to dope & how much
I suspect Gimp has adjusted dope to get to where he is and now is asking if he should adjust either BC or Speed to line upQuote:
Originally Posted by eamars
To be clear, I'm setting up a strawman to test other's thinking, not genuinely asking for adviceQuote:
Originally Posted by Gibo
Greetings @eamars and all,Quote:
Originally Posted by eamars
That is exactly what I have done and found measured velocity at the target was very close to estimated, less than 10 fps. I did not measure the drop as I had done a rough zero using a tall target for 600 yards. I am a beginner at F-class and this was my first attempt at 600 yards so I was quite pleased.
Regards Grandpamac.
If there is any vertical discrepancy I cant attribute to wind then I adjust velocity in app untill it matches results.
My reasoning is as follows.
Bryan Litz bcs are probably pretty accurate.
My shooting chrony is probably within 100fps on a good day.
Greetings @gimp,Quote:
Originally Posted by gimp
Assuming you have a half decent chronograph I suggest you use your measured velocity. If you want to measure your down range velocity you may want to consider joining your local NRA club so you can use the Silver mountain kit. This will either correct or validate the predicted velocity. If the downrange velocity checks out then any difference in trajectory in likely to be operator error (sorry). If you can't measure down range velocity and wanted to change your predicted trajectory then I would adjust the BC and not the velocity. In spite of what some believe BC varies from shot to shot and day to day. I would also do some test firing at 300 metres to see how trajectory matches prediction. Last as mentioned above a decent aiming mark on you 600 metre target would help.
Regards Grandpamac.
My reasoning is : they are fairly close to the edge of the gong. How many shots did you fire ? No one shoots real 4cm groups at 600m.
Should use at least a double sheet of newspaper and not seriously true off a gong.
40cm square plate. Holding for R-L wind with intent to hit centre plate (POA). Did not call wind correctly but held consistent wind hold to shoot 3 shot group.Quote:
Originally Posted by chainsaw
E: actually 38cm sq plate.
Fired 3 shots.Quote:
Originally Posted by Bagheera
Haters gona hate :D
Quote:
Originally Posted by grandpamac
I have a magnetospeed v3.
All the more reason not to fiddle with the velocity then.Quote:
Originally Posted by gimp
GPM.
600m? The group looks to be 60mm or so, scaled from 400mm edge length. That is exceptional shooting, well done. (Not trying to sound condescending, it's hard to say that otherwise)
I wouldn't adjust anything on the app - I'd call it good and go hunting, or practise wind calls to get POI nearer the POA.
So if you have a 9g bullet with mv about 2500 fps and a 4500g rifle that will Be recoiling backward at about 5 fps by the time the bullet passes the magnetospeed you would need to subtract 5 from the measured velocity ?Quote:
Originally Posted by gimp
Pray tell @gimp is this the infamous model 7? If so even more impressive at 600m
Remember this is not real. I dont really hate Gimp. 🙂Quote:
Originally Posted by Gibo
Watch/listen to hornady 4dof app pretty much explains why trueing is a shot yarn if you ahbe a reliable chrono and will at something lead to significant erro at some range.Quote:
Originally Posted by gimp
See it's a question starter not an actual question stand by those podcasts very good
Yes, Model 7 .223. I don't really shoot anything else anymore.Quote:
Originally Posted by Preacher
First bounce or second ? :yaeh am not durnk: :DQuote:
Originally Posted by gimp
600 yrds - Sporter weight .223 Rifle - 2-3 inch group .
Personally I wouldn’t be asking for advice, I’d be giving it .
I tend to get that sort of shift through the difference in shooting position between zeroing and then at the other distances. Dope could well be spot—on.
Not to start a calibre debate but what sort of range are you limiting yourself too with the little 223. Its a great little caseQuote:
Originally Posted by gimp
I find that there is very rarely any need for me to shoot a deer beyond 400 metres or so.Quote:
Originally Posted by Stocky
He's not seriously asking for advice though :thumbsup:Quote:
Originally Posted by Ground Control
Advice: Tordon at label rates would tidy that gorse up nicely, metsulfuron if you were on a budget and happy wait longer.
Nice shooting.
Quote:
Originally Posted by Moutere
Met will tidy a lot of things up
Further to this, all of the podcasts that are about external ballistics and drag are well worth a watch (or listen). Though I think that starting with 'Your groups are too small' parts 1 and 2 gives the useful grounding on statistical significance. Once you understand the importance of statistical significance the rest of the discussion (including critiques of load methodologies) makes a lot more sense.Quote:
Originally Posted by Stocky
If you are running a pretty std velocity for the bullet ie a 140 6.5 where you are in that 2750-2900 fps then the BC in your app will be pretty right and just adjust the velocity to correct your drop. If you happen to be running it in a caliber that is going quite a bit faster then you might increase bc slightly and if going a lot slower ie in a Grendel or very short barrel then you would drop the BC. Some bullet manufacturers like Sierra have banded (different velocity thresholds) BC listed. Using a good app with good actual bc data like Applied ballistics BC are more accurate. Running some apps where they use the manufacturers no.s like nosler or Barnes where they maybe slightly over stated you may need to adjust. For std hunting we usually shoot 800m and use that drop for adjusting velocity. Some apps allow you to put in actual drop and will work out velocity for you. Snipers hide has a new app called gravity balistics that will do your dope without using velocity or BC and uses a multiplier but you need targets every 100m. You can true your drop at 600m. Works fine, the closer to your transonic about 1400 fps the better for further accurate drop prediction. Make sure settings are all correct such as scope height above bore and zero range as those 2 factors make a difference. Once getting out to distance atmospheric inputs on day of doing data may make a bit of difference when you shoot again also. Aswell as shooting direction as shooting north south makes a windage error and east west makes a elevation error. Depending on whether your app has a calculation worked in for that. Inside 500m a lot of these factors are minimal. I like to write my drop data in a book when truing a rifle so I can reference if I have trouble with an app or get another one and want the correct inputs.
We do run shooting schools at Sparrowhawknz that teach this, check out the website.
Using g7 bc will give you better longer range data than g1. If you have a modern boat tail bullet use the g7 bc.
Insufficient data to comment.
Multiple 5 shot groups required to improve quality and quality of data set.
Physics is fascinating, but most people can’t be bothered to generate sufficient quality data to formulate quality outputs. Even if they do understand most of the factors involved.
Me, I’d just end up calling it a 1/4 Moa gun and probably sell it :)
Just get applied ballistics and use a custom curve. BC is not a static number over different velocities
I agree. Tune mv to match real world. Should only be a few tenths out, otherwise something more serious is wrong e.g. zero or environmentalsQuote:
Originally Posted by veitnamcam
True BC if I have access to significant sub-sonic range (e.g. 1k+)
Are you bloody kidding Gimp!!
It's a pretty easy process. What you do is write down how many clicks it was to 600m on your wrist mounted diary, or failing that inside your scope caps next to you punisher sticker.
Then when you are next out hunting, find a deer check your wrist diary, apply a Little more face paint and dial up your nightforce then walk backwards until you are 600 yards away and send it.
Easy
What he said.Quote:
Originally Posted by Cowboy06
Bullshit in bullshit out.
Perfect zero is a very good start.
Watch some litz or todd and Colby hodnett videos on truing.
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