Question on windage / trajectory

[littlepod]

Hi everyone, new to precision shooting and was curious about a few things with some questions that I've gathered while shooting.

1. Assuming everything is level, scope, action, etc. With zero wind, there should be no windage adjustment, from 25 - 100 - 200 yds? I've noticed that even when I really don't think there's any wind at all, I'm .2mil L at 100 yards, and .4mil L at 200 yards on both of my rifles (Tikka T1x, and PWS Summit).

2. Curious what people's adjustment is at 100yds and 200 yds. I'm running SK Standard Plus out of my 20" Tikka T1x, and noticing.
2.4 mil up for 100 yards.
8.4 mil up for 200 yards.

I should recheck my 25yd zero, now that I have 120 rounds through the rifle

We don't have 50/75 spots at my range, so I will need to guestimate for the local NRL22 comp. If people have their 50, 75 adjustments it'd be interesting to see so I can extrapolate.

Thanks!

 

[MarkCZ]

1. There is wind all the time. Even wind you can't feel, will move things around. You can take your known sight setting, and pug them into https://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi and get your 50 and 75 yd. settings. You can adjust your speed or BC and match your know settings.
You can adjust your zero at 100 yds, then check at 25 yds and 200yds.

Mark

 

[littlepod]

1. There is wind all the time. Even wind you can't feel, will move things around. You can take your known sight setting, and pug them into https://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi and get your 50 and 75 yd. settings. You can adjust your speed or BC and match your know settings.
You can adjust your zero at 100 yds, then check at 25 yds and 200yds.

Mark

Thanks! I just noticed the 22 LR trajectory thread, a lot of reading there as well.

 

[squirrelsniper]

As previously stated, there is always some degree of wind, so don't fret.

The free JBM ballistics site is usually very close in my experience (assuming correct data is entered). However, 22LRs are very sensitive to condition changes (baro, temp, altitude, etc), So a one-number-fits-all answer isn't going to help you much; at best it will just give a baseline to work from.

 

[littlepod]

The free JBM ballistics site is usually very close in my experience (assuming correct data is entered). However, 22LRs are very sensitive to condition changes (baro, temp, altitude, etc), So a one-number-fits-all answer isn't going to help you much; at best it will just give a baseline to work from.

The issue I had was not knowing the right BC... From SK's site, they had their SK Standard Plus as 0.172 which didn't fit any models. When I plugged in 0.132 which someone else was using, it was pretty spot on from what I noticed in real testing. 0.132 @ 1030 fps

 

[justin amateur]

Try this one

Ballistic Calculator GunData.org

Thanks for using the external ballistic calculator from GunData.org that accurately details all aspects of the bullets trajectory the millisecond it leaves the guns barrel.

gundata.org

Free, which is always nice.
Drop down selections, compare different bullets, speeds, wind, temp, pressure.
Has all the bc's in the selections.

 

[68hoyt]

Hey pod , are you canting the rifle ? my windage problems lessened when I started focusing on position

 

[squirrelsniper]

The issue I had was not knowing the right BC... From SK's site, they had their SK Standard Plus as 0.172 which didn't fit any models. W

SK was living in Dreamland if they think Standard Plus has a BC of 0.172

 

[littlepod]

Hey pod , are you canting the rifle ? my windage problems lessened when I started focusing on position

I don't think so... I'm getting my scope level in a few weeks just to be certain, and I have the bipod locked so it's not canting while I'm shooting. Assuming my platform is level, which I should also check, there should be no cant. I had the same .2 mil L and .4 mil L at 100,200 yards on my other rifle which had a non canting bipod... different scopes mounted multiple times using the weaver scope level mount system and I was exact as I could do it..

Looking at the trajectory charts, at 1030 fps for SK Standard, even 1 mph wind will be windage adjustment and I'm guessing there's generally probably at least 1-2 mph around the area I was shooting.

 

[45cal4life]

Bullet rotation is pulling it to the right, thus adjusting the scope to the left. For me the biggest variables are denisty altitude and temperature. Keep good records of both and the corrections on the scope. The scope itself is another variable. Just because you dail up 2.4 doesn't mean it is a true 2.4. Try to limit as many variables as you can, buy decent ammo, keep records (dope) and understand this is rimfire, a 40gr bullet at (probably) subsonic speeds
50 yard zero
100 yards = 2.1mil
200 yards = 8.1mil

 

[littlepod]

Bullet rotation is pulling it to the right, thus adjusting the scope to the left. For me the biggest variables are denisty altitude and temperature. Keep good records of both and the corrections on the scope. The scope itself is another variable. Just because you dail up 2.4 doesn't mean it is a true 2.4. Try to limit as many variables as you can, buy decent ammo, keep records (dope) and understand this is rimfire, a 40gr bullet at (probably) subsonic speeds
50 yard zero
100 yards = 2.1mil
200 yards = 8.1mil

Thanks. I wish I had a 50 yard spot at the range, we only have 25 and 100. I'd love to do a 6x5 @ 50 yard. I need to start taking notes on all this.

This is my JBM output using 0.132 and maps pretty well.