Two years ago I started shooting rimfire PRS with my son. We struggled to get dope correct in AB but managed to get through 2 seasons. I built a much better rifle this winter (Vudoo 360) with Manners stock. I went out last weekend to get real world data. We shot 10 different distances and recorded elevation adjustments. Today I tried changing settings in AB to no avail. On average it shows elevation is too low (2-3 clicks) under 110 yards. At 60 yards it shows 6 clicks under actual. Over 110 yards, on average it 2-3 clicks over. I have adjust site height a couple times to no avail. I am using the Lapua Center X bullet in AB. Chrono speeds using labradar are average around 1080. Any help is appreciated. I dont want to guess anymore in competition.
- Thread starter bghartm
- Start date
either you have one setting off or you have a series of small errors stacking. You aren't using one of AB's private drag models for the Center X are you? That is specific to the barrel actually tested. I would try small adjustments to the speed and then slight adjustments to BC if necessary. You should be able to make it match within .1 or so. I was able to get Stelok, my Kestrel and actual to match to .1
I am not using a CDM for the first try but I have purchased them. I used the .172 G1 as Lapua advertises for their bullets.
I see alot of people are using Strelok but it's gone now from what I see in the app store.
Can you post all of your AB settings we might be able to see the issue from that.
Are you using a 25 or 50 yard zero?
Are you using a 25 or 50 yard zero?
50 yard 0. Verified 2x.
Barrel Twist 1:16
Twist Direction Right
Site Height 2.3 (Tried 2.3 to 1.9)
Sight offeset 0
All settings in MILS
Bullet diameter .224
Weight 40
Length .48
Muzzle Velocity 1080
Atmos Std ICAO
Drag Model G1
BC .172
Zero Range 50
Zero Height 0
Nero Offset 0
Enable Zero Atmosphere - Enabled
Usually use around 980 for Altitute and 28.8-29 for Station Pressure
I enable Spin Drift
I leave Corilis Effect disabled
Nothing jumps out at me. I would start by adjusting your BC down until it get very close to matching then play with the velocity to tweak. You may find yourself getting that BC down to .150's and even down to the .130's to get it to match what you are actually seeing. Basically your are truing your BC to the real world results. It could be off significantly.
I'll work on this some tonight. I think I have 130-250 yards within 0 to .1. The 60-120 yards is still significantly off. I'll report back tomorrow after I make adjustments. I have seen other threads where people have to make 2 profiles, I'd rather not have to do that.
25-250 shouldn't be an issue. confirm your sight height and then start walking your BC down to see when it all gets close and then see if dialing the velocity gets it to actual.
Have you confirmed that your scope adjusts as is advertised? That if it is .1 mils that it actually goes directly up .1? (tall target test) If you haven't, take a 48" piece of cardboard or paper and use a level to put a 36" perfectly verticle line on it. shoot at the bottom dot and move it up 1 mil each shot and make sure that your scope adjusts as it is supposed to ie 3.6" per mil at 100 or in your case, 1.6" at 50 yards. While relatively rare on a good scope, it could be stacking on the adjustment.
I can check that at some point soon. I'm running a Nightforce NX8. Used it the last 2 years with no suspicion of a problem.
I would do the tall target test last. Start with adjusting the bc to true against your real world results.
FWIW, if you look at the G1 values listed for other's CenterX PDM's in the AB app you will see values ranging from .120 to .135
If you have good tracking to 100 yards or more from your LabRadar sessions the labrabaco tool may give you more info.
This works great, used it on 22lr out to 500 and just entered my airgun into the 5700 tonight. First real world shot I got was a starling at 87 yards and the solution the 5700 gave me center punched him.
I see there are quite a few pdm's in the bullet library. How does one know which one to choose? There is probably 20-30 different options for Center X. I googled a couple different ones and couldnt find an explanation.
PDMs are AB Custom curves done for individual user's rifles, not for your rifle. Use the Center X that does not have PDM in the name.
I am running a Bergara B14r and SK ammo. SK lists a similar BC (.172) but when I true it up using data from my LabRadar it comes out closer to .140. Not perfect because the LR only gets quality data out to maybe 60yrds but I make adjustments from there based on actual drop at 100 and 200. I do use Strelok (until .gov force uninstalls it from my phone) but I think you do what others have said, start working the BC value down until you find something that fits better with what your target tells you
Edit: I noticed you are running a diameter of .224…I use .220 in Strelok. Not sure if I’m using the right value but it works for me…
Edit: I noticed you are running a diameter of .224…I use .220 in Strelok. Not sure if I’m using the right value but it works for me…
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Bullet diameter is not 224. I use 141 for most rimfire bc. Make sure every input is perfect then do a cal dsf at 100, 150, 200, 250, 300. Go near to far only. Shoot multiple shots to be sure. Works everytime
Just yesterday I did measurements on lapua Center x, Lapua Long Range and Lapua Super Long Range to find a more realistic BC. In all three cases I calculated a BC of 0.1458 G1.
I measured V0 then V at 50m and V at 100m. Incredibly, the calculation of the BC always settled on the value I indicated. Put that value, my Stelok Pro returns perfect corrections up to 150m. Beyond I haven't had a chance to check yet
I measured V0 then V at 50m and V at 100m. Incredibly, the calculation of the BC always settled on the value I indicated. Put that value, my Stelok Pro returns perfect corrections up to 150m. Beyond I haven't had a chance to check yet
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