Truing Strelok Pro Question.

[Just Chuck]

I'm not sure if this belongs here or in the 'Dumb Questions' thread, but I'll throw it out here.

I'm using Strelok Pro for calculations on 22lr out to 235 yards or so. I've selected the correct ammo - Center X, input DA, and ranged distances.

My question is; if I range the longest distance - 235 yards, Strelok will generate a firing solution of say 9 mils. Now I fire three shots and determine the actual hold should be 8.5 mils. Now, I go to the truing function and I can either true by BC or Velocity. I decide to true by BC and that is now part of the Strelok calculation data.

Are the Strelok calculations for shorter distances - ie. 200, 180, 140, 85 yards, going to be correct? My gut feel and logic says they should be corrected because I've trued at the longest distance.

Am I off base on this assumption?

 

[DownhillFromHere]

There are quite a few threads on this issue, which, in my experience, has no absolutely correct answer - because it's a bleeping .22. Today is Monday. A trued solution for today might not work on Tuesday. Or if it gets cloudy later.

What I'm finding with Center-X out of my Vudoo is that what works out to 150 yards or so usually falls short at 200-300, and especially at 400. So if I true for 300-400 yards, I hit as much as a mil or two high at shorter ranges.

It's important to note that I true using BC, not velocity. While others who chime in on this may have really good reason to allow Strelok to calculate an adjusted velocity - and I pay attention to all experience-based comments - it makes me crazy to have the tool change velocities I know to be consistent and accurate.

Depending on range and environmental conditions, calculated BCs run from 0.132 to 0.172. Right now, I'm using 0.153, with the knowledge that I have to dial or hold under at ranges up to 150 yards and dial up or hold over at ranges 200-300.

I tried using Strelok's multi-BC capability with data from Exterior Ballistics. No joy.

I'm just now reaching the point of recording "trust the bullet" dope. I've fired a couple thousand rounds out of my Vudoo since early this year, trying to find the ammo it likes best. I could have saved myself a lot of cost (but not necessarily the fun of experimenting) if I had just paid attention to Vudoo designer @RAVAGE88's advice and used Center-X from the get-go. I just need to make myself get out and record actual observations every 15 yards or so out to 300 and see if I can get a Strelok setup to match it.

 

[Lowlight]

Make two tracks,

One that is good 150 yards and in, the second for 150 yards and out.

Find where the middle ground falls and split the tracks cause .22s can be weird compared to centerfire data.

Mainly it's all subsonic so that is part of the problem.

 

[Just Chuck]

I understand the truing function is not a one-time deal. It needs to be done at almost every session depending on atmospherics. And may need corrections throughout the day. If I start a shoot at 0900 at 42*F - that truing will not be the same at 1300 at 70*F. But for some period of time it should be accurate.

 

[Jefe's Dope]

Did you find the Center X under 'Drag Function'? I think it's fairly new. I just found it while messing with the other Drag Functions to find one that worked best. The .22 specific Drag Function was fairly accurate too. The Center X Drag Function seems to work well for me at all the distances we usually shoot.

As a side note, I used the Strelok when shooting at 354 last week and it was very close if not spot on. I don't recall tweaking it more than ½ a MIL.

 

[Jefe's Dope]

I understand the truing function is not a one-time deal. It needs to be done at almost every session depending on atmospherics. And may need corrections throughout the day. If I start a shoot at 0900 at 42*F - that truing will not be the same at 1300 at 70*F. But for some period of time it should be accurate.

You can update the current weather using either the local forecast or linking a WeatherMeter. You can also manually input new weather conditions. It's important to enter the actual zeroing conditions when zeroing.

 

[Just Chuck]

I've got an app that will give DA - so I use that for weather. Not sure if one - weather data or DA is better for this.

I use the Center X ammo data (velocity, BC, etc.) provide by Strelok.

 

[Lowlight]

You should not have to true multiple times, that is the whole point of software

Once the computer is trued, it should adjust for conditions if you did it right

 

[Dthomas3523]

.22 gets a little tricky because it’s subsonic immediately. I’ve had the best luck with the DSF function in kestrel 5700 elite.

@lowlight suggestion of two curves is probably your best bet for StrelokPro with a .22

 

[firas]

I would suggest playing around with the RA4 Ballistic Coefficient. I have been able to get my CCI Blazer (dont laugh, this stuff is very impressive) trued using the actual measured velocity and the BC of .107 RA4 (1251fps). It was nearly perfect for 100m-300m. I'm going to try this method with my Center-X and Polar Biathlon sometime this week.

 

[John Glidewell]

I am running RA4 drag function, 50 yard zero and trued velocity at 150 and 200. I did not have to true BC past that, it was dead on. Shooting RPR 22 with Eley Edge.

Edit: I used the velocity on the box, I could not get labradar to pick it up. When I trued velocity it is was off by less than 100 fps so I just went with it. If I can get a good velocity from labradar I leave it alone and true the BC. Lots of good advice here.

 

[akxx]

It's important to note that I true using BC, not velocity. While others who chime in on this may have really good reason to allow Strelok to calculate an adjusted velocity - and I pay attention to all experience-based comments - it makes me crazy to have the tool change velocities I know to be consistent and accurate.

This is great advice. It also drives me crazy to know that I am manipulating a known and trusted velocity number to try to get the data to true up to DOPE. Thanks for the suggestion.

 

[seansmd]

It should also drive you crazy to adjust BC that has little effect inside 600 yards, as @Dthomas3523 and other shave stated you need to lie to the solver to get it to line up its a curve that needs to align to a starting point. Accurate MV is great but it doesn't equate to the MV and ballistics of the gun they created the BC and curve with.

You need to true with MV at the short distance or you are making HUGE changes to the BC, and your curve will be off out past 800 yards. This is what Litz and the AB folks tell you to do, and Hornady and the 4dof folks and they tell you to do it in a video with a labradar and measurement equipment better that available to you and I.

 

[DownhillFromHere]

It should also drive you crazy to adjust BC that has little effect inside 600 yards, as @Dthomas3523 and other shave stated you need to lie to the solver to get it to line up its a curve that needs to align to a starting point. Accurate MV is great but it doesn't equate to the MV and ballistics of the gun they created the BC and curve with.

You need to true with MV at the short distance or you are making HUGE changes to the BC, and your curve will be off out past 800 yards. This is what Litz and the AB folks tell you to do, and Hornady and the 4dof folks and they tell you to do it in a video with a labradar and measurement equipment better that available to you and I.

This thread is about .22LR. Different beast.

 

[seansmd]

oh shit, my bad