Troubleshooting an accuracy problem

[D4HighDesert]

Hey everyone, I have come up against a predicament with my first long range shooter and I was hoping to take advantage of the wealth of knowledge here. Any suggestions, advice or contacts for experts will be greatly appreciated.

As I said, Ive put together my first long range hunting rifle and Im having an accuracy issue not so far downrange. I obviously have not ruled out shooter error since thats generally the issue with all newbies, however I think I may have a problem outside of that.

 

Equipment info: Christensen Ridgeline 7mm rem mag, Nightforce NXS 5.5-22x56mm, Nightforce base and rings.

Load: 168 gr Berger VLD, 69 gr Retumbo, Norma brass, Federal 210M primers - 2990 FPS

 

So I finally got a load to group at just a hair over 1/4 inch (pictured). It is zeroed at 100 yds nearly exactly (about an eighth inch low and eighth inch right). Using the Shooter app, I entered all data and triple checked everything and shot at the range maximum distance of 375 yards. I shot about a half inch low but 3-3.5 inches right. I put about a 2 inch group of 4 bullets in that area. I made a 4.8 moa adjustment up but zero wind adjust as there was not even the slightest breeze and the range is down in a 15 ft hole.

 

So my question is, that outside of me possibly just being a terrible shooter (just based on the grouping), how could I be off by that much with such a tight zero at 100 yds? 375 yds seems awefully close to have so much error. I had Sportsmans Warehouse mount the scope, could this be a scope level issue? Or a scope centering issue? The NXS has a parallax adjustment but I suppose that could still be part of it?

 

Like I said, any help would be greatly appreciated. Has anyone else had this issue? Thank you all for assisting a newbie. Merry Christmas!

 

Randy

[dcshorthairs]

First things I would check is that there is no movement with any of the bolts. Tighten them to spec by the manufacturer. Second, I would make sure that when you are shooting the gun is level. I put a level under my scope so that I can see my gun is right where it should be. There are tons of factors and I know the load you are shooting as that was a load my 7mm liked too. Have you tried other loads at that range to see what they do?

[lancetkenyon]

Shooting position differences

Recoil management

Spin drift

Cheek weld

Sympathetic movement or rifle torque during trigger pull

Grip on stock

Zero imperfection (1/4" @ 100 = 1" @ 400)

Lack of loading bipod

Rifle not level/plumb

Reticle in scope not true vertical

Tracking not true in turrets/reticle shift during dialing

[pwrguy]

  On 12/14/2017 at 4:31 AM, lancetkenyon said:

Shooting position differences

Recoil management

Spin drift

Cheek weld

Sympathetic movement or rifle torque during trigger pull

Grip on stock

Zero imperfection (1/4" @ 100 = 1" @ 400)

Lack of loading bipod

Rifle not level/plumb

Reticle in scope not true vertical

Tracking not true in turrets/reticle shift during dialing

Well, like usual Lance pretty much covered all the bases Since a pro didn't mount your scope I would look there first. #1 for me would be reticle in scope not true vertical. If you are going to make it a long range gun consider doing your zeroing at 300 yards. It will help compensate for a lot of errors and you won't normally be more than an inch off on lesser yardages.

[ThomC]

  On 12/14/2017 at 4:31 AM, lancetkenyon said:

Shooting position differences

Recoil management

Spin drift

Cheek weld

Sympathetic movement or rifle torque during trigger pull

Grip on stock

Zero imperfection (1/4" @ 100 = 1" @ 400)

Lack of loading bipod

Rifle not level/plumb

Reticle in scope not true vertical

Tracking not true in turrets/reticle shift during dialing

Wow all that has to be perfect? I would guess that 90% of the people cant and shouldnt be doing it.

[STOMP442]

Lance pretty much nailed it. I would put my money on a canted reticle though. Double check the scope mounting to ensure its level and get a bubble level to check yourself when firing that you are holding the rifle correctly. After that, I would perform a tall target test to verify the scope is tracking properly.

[300RUM]

Is your scope positioned for proper eye relief? Are you stretching your neck forward a little or compressing it backwards a little to try and get a full view of the reticle in the scope? Doing either of those can lead to inconsistent shooting.

[lancetkenyon]

  On 12/14/2017 at 1:18 PM, ThomC said:

 

  On 12/14/2017 at 4:31 AM, lancetkenyon said:

Shooting position differences

Recoil management

Spin drift

Cheek weld

Sympathetic movement or rifle torque during trigger pull

Grip on stock

Zero imperfection (1/4" @ 100 = 1" @ 400)

Lack of loading bipod

Rifle not level/plumb

Reticle in scope not true vertical

Tracking not true in turrets/reticle shift during dialing

 

Wow all that has to be perfect? I would guess that 90% of the people cant and shouldnt be doing it.

Any and all of those can and will make a difference. Get half of them, the equipment possibles, corrected, and that leaves shooter input issues. Correct half of those or more, and stretch it out. To make first round hits a long ways out takes consistency. To get accurate impacts a long ways out (600-1400+) takes consistency, The key to long range accuracy.

 

I have seen people make a marginal 1st round hit, then fail to put shots 2/3/4 into an animal as an anchor, and away the game goes, never to be seen again.

[D4HighDesert]

Thank you all very much! I’m going to take it to a gunsmith tomorrow and make sure there’s no cant in the reticle and the eye relief is perfect. I’ll also have him make sure I’m still at factory torque specs on the screws and a bubble level put on.

This will be a big help in making sure my equipment is all sound so I can focus on improving my own shooting errors.

[SO I HUNT]

Get it on paper at 100 yds. finish sighting it in at 200 yds.

[forepaw]

  On 12/14/2017 at 3:02 AM, D4HighDesert said:

Hey everyone, I have come up against a predicament with my first long range shooter and I was hoping to take advantage of the wealth of knowledge here. Any suggestions, advice or contacts for experts will be greatly appreciated.

As I said, Ive put together my first long range hunting rifle and Im having an accuracy issue not so far downrange. I obviously have not ruled out shooter error since thats generally the issue with all newbies, however I think I may have a problem outside of that.

 

Equipment info: Christensen Ridgeline 7mm rem mag, Nightforce NXS 5.5-22x56mm, Nightforce base and rings.

Load: 168 gr Berger VLD, 69 gr Retumbo, Norma brass, Federal 210M primers - 2990 FPS

 

So I finally got a load to group at just a hair over 1/4 inch (pictured). It is zeroed at 100 yds nearly exactly (about an eighth inch low and eighth inch right). Using the Shooter app, I entered all data and triple checked everything and shot at the range maximum distance of 375 yards. I shot about a half inch low but 3-3.5 inches right. I put about a 2 inch group of 4 bullets in that area. I made a 4.8 moa adjustment up but zero wind adjust as there was not even the slightest breeze and the range is down in a 15 ft hole.

 

So my question is, that outside of me possibly just being a terrible shooter (just based on the grouping), how could I be off by that much with such a tight zero at 100 yds? 375 yds seems awefully close to have so much error. I had Sportsmans Warehouse mount the scope, could this be a scope level issue? Or a scope centering issue? The NXS has a parallax adjustment but I suppose that could still be part of it?

 

Like I said, any help would be greatly appreciated. Has anyone else had this issue? Thank you all for assisting a newbie. Merry Christmas!

 

Randy

 

https://video.search.yahoo.com/search/video?fr=yfp-t-s&p=youtube+brian+litz+tall+target+test#id=1&vid=7100e906e28d368be52658f7d18ea61a&action=click

 

Applied Ballistics is a little in depth, but the tall target test is pretty straightforward. It can be tedious, but you will need to make sure your rifle and scope are plumb before you try for accuracy at normal hunting ranges, or long range. The tall target will show you how much compensation is needed with your elevation turret. In other words, does it undertrack or overtrack by more than 1 or 2%. With your scope, I would be surprised if any is needed. You can also check windage to make sure your tracking is on. This can all be done at 100 yds.

 

forepaw

[300RUM]

There is a way to verify scope tracking that completely eliminates any shooter error. Measure the height of the target frame from top to bottom. Place the crosshairs on the bottom edge of the target frame and sandbag the rifle in place. Adjust a turret till the crosshairs are on the top edge of the target frame. Convert the number of clicks used in to inches and compare that to the actual measurement of the target frame. You can now calculate any tracking error as a percentage. I repeat the test several times to verify a consistent result. The same thing can be done for windage in the horizontal plane. I sometimes clamp a one by two to the Target frame so I can cover a longer distance and use the edge of the one by two as stopping point.

[ofdscooby]

Everyone is going after scope issues but I wanted to ask a couple questions. Were the groups in question with the same bullet lots and powder lots? Were they same day same temp and was there a cleaning in between groups? Have you checked bedding? What kind of bags are you using front bench rest and a rear bag with ears?

[D4HighDesert]

  On 12/15/2017 at 10:36 PM, ofdscooby said:

Everyone is going after scope issues but I wanted to ask a couple questions. Were the groups in question with the same bullet lots and powder lots? Were they same day same temp and was there a cleaning in between groups? Have you checked bedding? What kind of bags are you using front bench rest and a rear bag with ears?

Yes sir, everything was from the same lot. The group pictured above was shot first and then I shot the group at 375 immediately after with no cleaning in between. However, the gun was cleaned just prior to shooting. It was about 75 degrees the entire time. I am using Caldwell bags front and rear (rear bag has ears). I have done nothing with the bedding at all.

[D4HighDesert]

I took the rifle to the gunsmith today. My scope was canted about .75 degrees. I had him level it and put on a US Optics rail mounted level. I’ll be testing it out tomorrow and will post whether or not the problem is completely solved.