SWFA 3-9 possible tracking issue or something else?

[1000yards]

Guys I could use some help here with an issue that comes up when dialing for elevation.

System:
Sauer 100 6.5 creedmoor
SWFA 3-9x42 SS HD mil
Omega 300
130 TMK, 2715 fps, zeroed at 100 yards

Problem:
Three different ballistic apps (Hornady, Shooter, and Shooter's Calculator) all say I should be at 1.9 mils for 370 yards. My grouping at 1.9 mils was 2.4" high, and my grouping at 1.7 mils was 1.3" high. So to be zeroed at 370, I would have to set the elevation to 1.5 mils. What's going on? It's zeroed in at 100 yd and the wind was still.

Possible causes:
1. Scope not tracking correctly. I'm going to test tracking by firing ten shots at zero and ten shots at 5 mils (both at 100 yards) and measure the difference. I've never done that before so any advice is appreciated.

2. Range finder is incorrect. It's a Maven RF.1. I don't have another rangefinder on hand but two different mapping apps back up that reading. Also, three other rifles line up perfectly with that range and calculated adjustment.

3. Ballistic coefficient is incorrect. Sierra says the 130 TMK G7 is .272 and Litz says .273. That's all I really know about that.

4. Chronograph is incorrect. I'm using a Garmin. If the scope tracks correctly then I'll pull out the magnetospeed. But I can't imagine that 44 grains of H4350 would push this bullet past 2900, or that the chronograph error would be that great.

5. Parallax. I feel pretty well centered but I'm new to this long range game so maybe my head is not in the perfect spot.

If you guys can think of anything else, please let me know. Thanks!

 

[ChasingSqwach]

Following. I noticed my 3-9 shooting high at distance also. Haven’t gone through the steps to troubleshoot it. Could it be… a defective swfa?? Rokslide might ban me for suggesting that lol

 

[eric1115]

Do you have a different shooting position for the further target? Where I shoot most often, the further targets are higher and higher on the hillside and lots of guys (but NEVER me of course) have struggled with building a solid 100 yard position, then muscling/adjusting the gun up and ending up with compromised recoil management for further shots. It seems like data is iffy, but it's just higher POI due to that and sometimes a tailwind that results in an updraft.

 

[1000yards]

Following. I noticed my 3-9 shooting high at distance also. Haven’t gone through the steps to troubleshoot it. Could it be… a defective swfa?? Rokslide might ban me for suggesting that lol

Yessir I'll do my best to figure this out. I'm sure SWFA deserves its great reputation, but every product can have problems. I think the better parts of rokslide are more about following the path of speculations > testing > results > conclusions. And not the path of speculations > debates.

 

[1000yards]

Do you have a different shooting position for the further target? Where I shoot most often, the further targets are higher and higher on the hillside and lots of guys (but NEVER me of course) have struggled with building a solid 100 yard position, then muscling/adjusting the gun up and ending up with compromised recoil management for further shots. It seems like data is iffy, but it's just higher POI due to that and sometimes a tailwind that results in an updraft.

My range is perfectly flat. The only adjustment I make from shooting the 100-yard target versus the 370-yard target is aiming my rifle slightly to the right.

 

[eric1115]

My range is perfectly flat. The only adjustment I make from shooting the 100-yard target versus the 370-yard target is aiming my rifle slightly to the right.

Odd. I'd definitely shoot another 10 (20 preferably) round 100 yard zero group. You'll want that either way for the tracking test which would be my next step.

 

[rabbithuntr]

Could you be ranging in yards and then telling you ballistic app it was in meter, that would put you about .4 mils high at that distance

 

[Caseknife]

Something simple, is your scope height input accurately in the apps?

 

[1000yards]

Could you be ranging in yards and then telling you ballistic app it was in meter, that would put you about .4 mils high at that distance

I just double checked the rangefinder and the apps. Everything is in yards.

 

[Matt5266]

Guys I could use some help here with an issue that comes up when dialing for elevation.

System:
Sauer 100 6.5 creedmoor
SWFA 3-9x42 SS HD mil
Omega 300
130 TMK, 2715 fps, zeroed at 100 yards

Problem:
Three different ballistic apps (Hornady, Shooter, and Shooter's Calculator) all say I should be at 1.9 mils for 370 yards. My grouping at 1.9 mils was 2.4" high, and my grouping at 1.7 mils was 1.3" high. So to be zeroed at 370, I would have to set the elevation to 1.5 mils. What's going on? It's zeroed in at 100 yd and the wind was still.

Possible causes:
1. Scope not tracking correctly. I'm going to test tracking by firing ten shots at zero and ten shots at 5 mils (both at 100 yards) and measure the difference. I've never done that before so any advice is appreciated.

2. Range finder is incorrect. It's a Maven RF.1. I don't have another rangefinder on hand but two different mapping apps back up that reading. Also, three other rifles line up perfectly with that range and calculated adjustment.

3. Ballistic coefficient is incorrect. Sierra says the 130 TMK G7 is .272 and Litz says .273. That's all I really know about that.

4. Chronograph is incorrect. I'm using a Garmin. If the scope tracks correctly then I'll pull out the magnetospeed. But I can't imagine that 44 grains of H4350 would push this bullet past 2900, or that the chronograph error would be that great.

5. Parallax. I feel pretty well centered but I'm new to this long range game so maybe my head is not in the perfect spot.

If you guys can think of anything else, please let me know. Thanks!

1. Set up a tracking test.

2. Borrow a range finder to check

3. Either of those BCs is not going to matter at that distance.

4. Doubt thats it either but try to borrow one too.

5. This is my guess. Look up some videos of adjusting parallax and get it set.

Good luck. Let us know. And for the hell of it just check all your scope mounts and screws as well as make sure your action screws are torque down tight. I use 65 in lbs on my Tikkas

 

[1000yards]

Something simple, is your scope height input accurately in the apps?

I just measured that. It is 1.8" and not the 1.5" that I was using in the apps. That changed the correction from 1.88 mils to 1.82. So I'm getting closer but not there yet.

 

[HuntHarder]

Verify your 100 yard 0 again, verify scope height is correct. If those are good, I'd tall target test.

 

[1000yards]

1. Set up a tracking test.

2. Borrow a range finder to check

3. Either of those BCs is not going to matter at that distance.

4. Doubt thats it either but try to borrow one too.

5. This is my guess. Look up some videos of adjusting parallax and get it set.

Good luck. Let us know. And for the hell of it just check all your scope mounts and screws as well as make sure your action screws are torque down tight. I use 65 in lbs on my Tikkas

Thank you. The parallax is fixed on this scope, so am I looking for videos that show good head position? Everything is good and tight on all the screws, and I haven't seen any issues with bad groups or losing zero.

 

[Macintosh]

Do a tall target test. That is the one thing that will tell you if the scope is tracking properly.

 

[chizelhead]

Additional thing to check: Make sure your rings and bases are torqued correctly and the scope is not slipping. Make sure your action screws are torqued correctly.

Probably not your chrono or rangefinder.

 

[1000yards]

Do a tall target test. That is the one thing that will tell you if the scope is tracking properly.

So 10 mils, not 5?

 

[Macintosh]

So 10 mils, not 5?

Its pretty easy to do both. BUT my guess is you find the culprit before you even get that far.

1) verify action, bases, mounts are all properly torqued.
2) verify your zero is perfect. Unless this is a mega-accurate custom rifle that means a larger round count group. 3-round zero will lie to you, and it matters out at 400+ yards. Zero needs to be accurate to the nearest click. My guess is this is the majority of the problem.
3) for a tall target test, dial up enough that you can see a small difference per click. 10 mills will show twice the tracking error compared to 5, so thats what I’d lean toward just to make sure its measurable. Otherwise you dont usually have enough cumulative error to see it within the precision of your gun. The only exception being that I would stop before I maxed-out the erector—not sure how much travel is in that scope.

BUT, from the OP, 2.4” at 370 yards is .16mil, or a little less than 2 clicks, a bit more than 1 click. If your dialed solution should have been 1.9mils, you would need to have over 8% tracking error for that to be the culprit. Thats not impossible, but its a lot of error per click so I dont think its the most likely issue. My guess, just generalizing based on what I see “most guys” doing, is that your inputs are a little off (scope height, maybe others?) and your zero is about a click off. Which is VERY easy to do if you are zeroing off 3-round groups.

But, I think im seeing 10 round groups? Is one a zero group? Have you played with truing the BC in your app to see if that gets you close? Bc is velocity dependent so just because someone says its X doesnt mean your gun will have the same value.

 

[1000yards]

Its pretty easy to do both. BUT my guess is you find the culprit before you even get that far.

1) verify action, bases, mounts are all properly torqued.
2) verify your zero is perfect. Unless this is a mega-accurate custom rifle that means a larger round count group. 3-round zero will lie to you, and it matters out at 400+ yards. Zero needs to be accurate to the nearest click. My guess is this is the majority of the problem.
3) for a tall target test, dial up enough that you can see a small difference per click. 10 mills will show twice the tracking error compared to 5, so thats what I’d lean toward just to make sure its measurable. Otherwise you dont usually have enough cumulative error to see it within the precision of your gun. The only exception being that I would stop before I maxed-out the erector—not sure how much travel is in that scope.

BUT, from the OP, 2.4” at 370 yards is .16mil, or a little less than 2 clicks, a bit more than 1 click. If your dialed solution should have been 1.9mils, you would need to have over 8% tracking error for that to be the culprit. Thats not impossible, but its a lot of error per click so I dont think its the most likely issue. My guess, just generalizing based on what I see “most guys” doing, is that your inputs are a little off (scope height, maybe others?) and your zero is about a click off. Which is VERY easy to do if you are zeroing off 3-round groups.

But, I think im seeing 10 round groups? Is one a zero group?

I really appreciate all of that advice. I just realized I didn't explain this in my original post but the first picture I posted is a 10 shot group at 100 yards. I guess I could adjust it one click right, but I believe my elevation is spot on. Tell me if I'm wrong.

Also, everyone keeps telling me to check and make sure that the action and scope bases and rings are torqued correctly. I'm pretty sure I torqued everything correctly the first time. I have checked and everything appears to have stayed in place. On top of that, this rifle system is holding zero proved with multiple 10 shot groups at 100 yd on different days. I'm new at this so tell me again if I'm wrong, but how is it possible for loose screws to cause a ranging error even though my zero has stayed the same?

 

[Macintosh]

If everything is zeroed and your inputs are good(quadruple check), then play with truing the app and see where it gets you. Better done at longer range, but for sure it will make some difference. But if everything checks out Id do a tt test and just rule the scope out. Its always worth knowing if theres error, as you can build that into your app to account for it.