Thread: "Trueing" BC/Velocity

Originally Posted by grandpamac

Greetings @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.

I have a magnetospeed v3.

Originally Posted by gimp

I have a magnetospeed v3.

All the more reason not to fiddle with the velocity then.
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.

Originally Posted by gimp

I have a magnetospeed v3.

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 ?

Pray tell @gimp is this the infamous model 7? If so even more impressive at 600m

Originally Posted by Gibo

Haters gona hate

Remember this is not real. I dont really hate Gimp. 🙂

Originally Posted by gimp

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

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.

See it's a question starter not an actual question stand by those podcasts very good

Originally Posted by Preacher

Pray tell @gimp is this the infamous model 7? If so even more impressive at 600m

Yes, Model 7 .223. I don't really shoot anything else anymore.

Originally Posted by gimp

Yes, Model 7 .223. I don't really shoot anything else anymore.

First bounce or second ?

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.

Originally Posted by gimp

Yes, Model 7 .223. I don't really shoot anything else anymore.

Not to start a calibre debate but what sort of range are you limiting yourself too with the little 223. Its a great little case

Originally Posted by Stocky

Not to start a calibre debate but what sort of range are you limiting yourself too with the little 223. Its a great little case

I find that there is very rarely any need for me to shoot a deer beyond 400 metres or so.

Originally Posted by Ground Control

600 yrds - Sporter weight .223 Rifle - 2-3 inch group .

Personally I wouldn’t be asking for advice, I’d be giving it .

He's not seriously asking for advice though

Advice: Tordon at label rates would tidy that gorse up nicely, metsulfuron if you were on a budget and happy wait longer.

Nice shooting.