Question on ballistic app data inputs

[Klem]

Klem, the Strelok app says 3.92 MRAD /70.55''/ 39.2 clicks I dialed this in initially but never saw any signs of impact, instead of wasting ammo I went back to zero on the scope and held at the 4 mil mark ( SWFA 10X42) so none of my hits were dialed. When I held at the very tip of the triangle at 4 mil mark I was hitting every time. Precision...probably not, acceptable to me...yep

Jack, is your SWFA a Mils/Mils scope or a Mils/MOA? if you are using a SWFA 10*42 which has a Mildot reticle and 1/4MOA clicks on the turrets that might explain why you can hit with the reticle but not when using the turrets.

I understand you dialled-up but missed the target at 500. Then dialled back to zero and used the Mils reticle to hit the target. Strelok's Mils and inches are correct but the 39.2 clicks are configured for a 0.1Mil scope. Your Strelok is configured for a Mils/Mils scope and you might have a Mils/MOA model.

[bj139]

Klem,
SWFA scopes are available in MIL/MIL. I have two as well as one MIL/MOA.
Maybe you already know Jack has a MIL/MOA. I couldn't find anything in his post to indicate he does.

[Klem]

Klem,
SWFA scopes are available in MIL/MIL. I have two as well as one MIL/MOA.
Maybe you already know Jack has a MIL/MOA. I couldn't find anything in his post to indicate he does.

I don't know for certain what model he has. No doubt he will chime in when he reads this. A Mils/MOA scope would explain why he hit the target using the reticle but could not if he dialled up the 39.2clicks on an 1/4MOA MOA turret.

[JASmith]

Harking back to the OP -- there are calculators to estimate change in barrel length. I created the referenced chart using the velocity estimator app I wrote a few years ago.

You can get to it through the Grendel load data in ammoguide.com using reference load data already existing in the data base. The over 600 loads for the Grendel there cover almost all reasonable powder and bullet combinations. (yes there are a few not there!!!)

Alternatively, you can enter your own reference load here: Velocity Estimator

[jackwagon]

Jack, is your SWFA a Mils/Mils scope or a Mils/MOA? if you are using a SWFA 10*42 which has a Mildot reticle and 1/4MOA clicks on the turrets that might explain why you can hit with the reticle but not when using the turrets.

I understand you dialled-up but missed the target at 500. Then dialled back to zero and used the Mils reticle to hit the target. Strelok's Mils and inches are correct but the 39.2 clicks are configured for a 0.1Mil scope. Your Strelok is configured for a Mils/Mils scope and you might have a Mils/MOA model.

So I do have the mil/mil scope, and I used 2475fps. I think that I may have found part of the problem
as I went back over the strelok data I have 2.25'' scope height on my phone, and 2.5'' input on my tablet which I took to the range last time, I don't remember off the top of my head which is right( possibly neither since I think I got the info from u tube) will have to research this more.

So I think when I dialed the scope it was possibly just high - probably why I didn't see anything. I did consider dialing the scope again but with no zero stop/no spotter I was afraid of getting lost...

[terrywick4]

+1 to LR1955. I use 22 fps per inch and usually it is close to the labradar.

Boyette:

I think you are confusing elevation changes with barrel length.

I believe that barrel length is something like 25 or 30 fps per inch and isn't linear.

It is generally considered that a 50 - 60 fps difference in velocity equate to one minute of elevation.

LR55

[Klem]

A difference of .25" for sight height is not going to make much difference. If you enter both heights into your program; 2.25" and 2.5' and keep everything else the same, the difference in drop is only 1" at 500yards. I use 2.5" as a default for AR's.

If you hit the target using a 4mil hold-over on the reticle but missed when you dialled the same on the turrets then maybe the wind got you, or dare I say it, a more ordinary reason.

How big is your target?

[jackwagon]

A difference of .25" for sight height is not going to make much difference. If you enter both heights into your program; 2.25" and 2.5' and keep everything else the same, the difference in drop is only 1" at 500yards. I use 2.5" as a default for AR's.

If you hit the target using a 4mil hold-over on the reticle but missed when you dialled the same on the turrets then maybe the wind got you, or dare I say it, a more ordinary reason.

How big is your target?

You can say it... I certainly thought it. The target was 8''

[Klem]

You can say it... I certainly thought it. The target was 8''

There's your answer. An 8" target at 500yards is way too small for load development. Great for target practise when you square away your sights and ammo but right now you need a target that is as big as possible to see what's going on.

Especially when starting out with new loads and gun. The gun may only be capable of 2MOA which means the average group size at 500yards will be 10". Some bullets will always miss the target and there's not a damn thing you can do about it. Plus you don't yet know the velocity of your bullets.

I would suggest a minimum of 3ft square at that range. You can always 'borrow' a Corflute plastic sign on the side of a road if looking for something that big. Retailers sometimes leave them out at night...

[bj139]

There's your answer. An 8" target at 500yards is way too small for load development. Great for target practise when you square away your sights and ammo but right now you need a target that is as big as possible to see what's going on.

Especially when starting out with new loads and gun. The gun may only be capable of 2MOA which means the average group size at 500yards will be 10". Some bullets will always miss the target and there's not a damn thing you can do about it. Plus you don't yet know the velocity of your bullets.

I would suggest a minimum of 3ft square at that range. You can always 'borrow' a Corflute plastic sign on the side of a road if looking for something that big. Retailers sometimes leave them out at night...

There are a few election signs around here that need removing.

[jackwagon]

There's your answer. An 8" target at 500yards is way too small for load development. Great for target practise when you square away your sights and ammo but right now you need a target that is as big as possible to see what's going on.

Especially when starting out with new loads and gun. The gun may only be capable of 2MOA which means the average group size at 500yards will be 10". Some bullets will always miss the target and there's not a damn thing you can do about it. Plus you don't yet know the velocity of your bullets.

I would suggest a minimum of 3ft square at that range. You can always 'borrow' a Corflute plastic sign on the side of a road if looking for something that big. Retailers sometimes leave them out at night...

Klem, You have disproved all my theories on what I did wrong with math, that was very cool, thank you. This is a work in progress and as long as i am on the right track I can work on the rest.
I have already purchased new scope VViper HST 6x24x50 mil/mil . Santa has my order for a chrono.
I am going to do a tall target test to get scope as correct as possible, might be good for drop data also?
I am going to stop second guessing myself and buy LARGER TARGETS.......OH, and work on the mil math.

[jackwagon]

There are a few election signs around here that need removing.

That is for sure....

[Sticks]

.... Santa has my order for a chrono.....

Magneto speed I hope. LabRadar if you have been a really good boy.

[bj139]

Magneto speed I hope. LabRadar if you have been a really good boy.

I heard Santa uses Lab Radar to determine his speed.

[grayfox]

I heard Santa uses Lab Radar to determine his speed.

O come on!!! everyone knows he uses a Garmin - LOL!!!
Needs that map and gps to hit the houses w/ good boys n girls... !!!

[jackwagon]

Magneto speed I hope. LabRadar if you have been a really good boy.

Sticks, I typically get coal from Santa. I take it that the magneto speed is the one I should want? would the one designated sporter barrel be acceptable, cause I certainly wont be getting the V3...YIKES.

[Klem]

The different types of chrono's work but all seem to have their peculiar disadvantages. Mine is an old fold-out optical Chrony with sky screens. It's cheap, and works, mostly (except on cloudy days, or late in the day, or when you don't open it out completely, or when you don't shoot exactly over the sensors, etc). I save my chronoing for night-time with lights. Fewer error readings and wasted loads.

If Santa is dishing out Lab Radars then he knows who's been 'naughty and nice'...I'm stuck with the Chrony.

[NugginFutz]

Group Buy for LabRadars!!!

[Sticks]

The only down side that I can see with a Magneto speed is the POI shift. Ergo - I cheated and put a long rail on the end of my handguard and it's not an issue. The only difference that there is between the V3 and the sporter is the accessories (extra shims, hard case, second cord....) With the sporter, you will have to probably adjust the sensitivity to get a reading, especially on a bull barrel.

The different types of chrono's work but all seem to have their peculiar disadvantages. Mine is an old fold-out optical Chrony with sky screens. It's cheap, and works, mostly (except on cloudy days, or late in the day, or when you don't open it out completely, or when you don't shoot exactly over the sensors, etc). I save my chronoing for night-time with lights. Fewer error readings and wasted loads.

If Santa is dishing out Lab Radars then he knows who's been 'naughty and nice'...I'm stuck with the Chrony.

You forgot the potential to shoot your Chrony.

FWIW - it is possible to shoot a magneto speed...I've grazed mine. That is all I have to say about that.

[grayfox]

I have one of the version 1's when they first came out - not an early adopter but it just looked like what I could really use. Not a bunch of accessories but very functional. No down-range setup needed just do it all at the bench. First few times you do it, take the bolt out and look through to ensure it doesn't stick into the flight path...
plus, every 4-5 shots take a minute to make sure it remains tightly cinched up to the barrel.
It shifts my poi but I don't shoot for accuracy with it, I do it for the data. Then when I've identified a good load I come back and zero in for poi.
Typically it shifts poi up 1.5-2" but like I said no biggie to me.
ps, for bringing on an indoor range it's great.

Long ar15 handguards with only 1 or 2" of barrel sticking out don't work so well for it IMO. But sun/clouds etc don't bother it a bit.