Scope Zero Check Thread

[ResearchinStuff]

egw 20 moa rail,

There's your known weak point, they don't have much material for the screws to hold them onto the action. It's interesting that increasing ring cap torque fixed the issue, if it starts shifting again I'd bond or replace the rail.

 

[Wacko]

You are assuming they were the same. Just in S2H classes, with everyone that swears that they have assembled their rifle and scope as I have laid out on here- I don’t believe there is one that didn’t have at least one thing off/ whether torque spec, or didn’t degrease every screw, or used blue loctite that was still wet, etc. I put rifles together constantly that don’t shift zero ever- it isn’t novel.


For your rifle- did you bond the rail to the action? Chassis have a very loose fit for the recoil lug, did you bed that? If those caps use 6x48 screws, 20in-lbs will probably let it slip at times.




That is how you do it until you have done so many that you know what it takes to keep them from moving.

That is exactly my question though too. What are ALL the steps to prevent movement? Especially if testing shows movement? Obviously now bedding has to be one of the steps. @Justin Crossley stated he has never bedded his chassis and it doesn't shift...but...I'm "Luckier"? no surprise there!

I use nail polish instead of loctite because I've had it stay wet. However, it doesn't make sense to me to apply a thread agent, then crack the screw to see if it stayed wet...only to have to reapply it and "hope" again that it dried correctly. I actually purchased some vibratite to test. It says you can reuse it up to 5 times and since it cleans up like nail polish I figure it has to be close, probably with some additives.

I will definitely check that I did bond the rail. If the rail is suspect as @ReasearchiStuff stated..what are other better options? Can I get away with just JB welding it or using Loctite 380 to the action?

They are the swfa 6 screw rings on the scope. Is the 30 inch pounds closer to where I should be on those ring caps?

I don't plan on hunting with this rifle in this configuration this year. I want something substantially lighter. However I will set it up again and test it. After confirming everything.

You say it isn't novel...yet here I am...LOL...I obviously will be "dropping it like it's hot" until I get adequate results. Is a big bag of bird seed still the recommended pad now to drop it on for consistency?

Thanks!

 

[Justin Crossley]

After reading through this whole thread....I have a couple questions and a couple observations.

Observations first....not trying to be an ass here...

If a rifle is "zero checked" it is supposed to be the same rifle, same ammo, same distance...nothing touched or remounted between. Using it is fine of course. As is travel, bumps, etc...

Using completely different ammo and shooting a group that is obviously off zero is of no useful data. Shooting a zero after changing stocks, scopes, ammo, etc is of no useful data for a "zero retention" test. IMHO of course.

Now for the questions.

It is apparent in many of these zero test groups that there has been a zero shift. Using all of the RS approved gear and mounting methods. How do you "fix" that so it doesn't happen? How do you diagnose the cause? Or is it just accepted that no matter what you will have some zero shift?

In reading Form's stuff and listening to the podcasts...Is the only solution to get "0" zero shift to glue frickin' everything together? Or can a guy get there some other way?

Just want to know. I have missed a few game animals now that have been traced back to a zero shift. I want to make it NOT happen again. @Justin Crossley makes a pretty good case for a chassis rifle and an Nightforce...heavy as all get out too I bet....

Looking for information...besides degrease, loctite, bond bases, and torque....I do that already. Bedding? Loctite on the ring caps?

My rifle is under 12 pounds with a triple pull and the sandbag mounted on the buttstock.

Can be under 10 pounds if I remove them.

 

[Schmo]

That is exactly my question though too. What are ALL the steps to prevent movement? Especially if testing shows movement? Obviously now bedding has to be one of the steps. @Justin Crossley stated he has never bedded his chassis and it doesn't shift...but...I'm "Luckier"? no surprise there!

I use nail polish instead of loctite because I've had it stay wet. However, it doesn't make sense to me to apply a thread agent, then crack the screw to see if it stayed wet...only to have to reapply it and "hope" again that it dried correctly. I actually purchased some vibratite to test. It says you can reuse it up to 5 times and since it cleans up like nail polish I figure it has to be close, probably with some additives.

I will definitely check that I did bond the rail. If the rail is suspect as @ReasearchiStuff stated..what are other better options? Can I get away with just JB welding it or using Loctite 380 to the action?

They are the swfa 6 screw rings on the scope. Is the 30 inch pounds closer to where I should be on those ring caps?

I don't plan on hunting with this rifle in this configuration this year. I want something substantially lighter. However I will set it up again and test it. After confirming everything.

You say it isn't novel...yet here I am...LOL...I obviously will be "dropping it like it's hot" until I get adequate results. Is a big bag of bird seed still the recommended pad now to drop it on for consistency?

Thanks!

3 points that jump out at me as possible problem spots. Your rail is a weak point. That definitely needs bonded with Loctite 380. Second, I’m not sure how SWFA rings hold up. Maybe they’re are fine, but that’s a possible issue. Not all rings are created equal. Third, barrel torque. Is this a factory barrel, or one that has been put on by you or a smith? If so, make sure its torqued to at least 100 ft lbs.

For example, here’s my post early in this thread. This rifle was a Tikka with barrel torqued to 100 ft lbs. UM Tikka rings. Stocky’s stock that was epoxy bedded by me, with action screws torqued to 65 in lbs. I wasn’t surprised that there was no drama.

 

[SteveAndTheCrigBoys]

After reading through this whole thread....I have a couple questions and a couple observations.

Observations first....not trying to be an ass here...

If a rifle is "zero checked" it is supposed to be the same rifle, same ammo, same distance...nothing touched or remounted between. Using it is fine of course. As is travel, bumps, etc...

Using completely different ammo and shooting a group that is obviously off zero is of no useful data. Shooting a zero after changing stocks, scopes, ammo, etc is of no useful data for a "zero retention" test. IMHO of course.

Now for the questions.

It is apparent in many of these zero test groups that there has been a zero shift. Using all of the RS approved gear and mounting methods. How do you "fix" that so it doesn't happen? How do you diagnose the cause? Or is it just accepted that no matter what you will have some zero shift?

Inspired me to put together an aggregate of my 100 yard groups with the 6.5 CM Tikka, RS1.2 and same lot of 143 ELD-X factory ammo. The only time the rifle was wrenched on was between the 04/26/2025 date and 05/17/2025 date to change the bolt knob/handle and adjust the trigger weight.

I did not follow all of the Form methods with this rifle, just the scope mounting and action screw recommendations. Not exactly sure what other screws need to be removed and degreased/torqued.

Based on the data I don't consider there to be a confirmed zero shift in the rifle system. Curious to see if others think differently.

I think I tried to compensate for wind on that 04/26/25 group and the 05/17/2025 group proved that. So since the initial zero adjustment, I've made a total of 0.1 MIL R adjustment. Within tolerance of what can be construed given the group sizes.

 

[pathnz]

I wouldn't say that I'm confident that you DON'T have a zero shift

 

[Castle Rock]

I’m with path, I think you do have a wandering zero, But I wouldn’t rule out that it is due to user inputs

 

[4th_point]

It is apparent in many of these zero test groups that there has been a zero shift. Using all of the RS approved gear and mounting methods. How do you "fix" that so it doesn't happen? How do you diagnose the cause? Or is it just accepted that no matter what you will have some zero shift?

This thread isn't the best format to judge the merits of formi's pre-flight checklist. It wasn't layed out for it, and that wasn't even the intention, but I can definitely understand why you are questioning some of the results against the claims.

As he stated, you don't know if all the steps were done, or done correctly.

I've seen it myself, even with technical people like mechanics, technicians, and engineers - all working in product dev/test, machining/assembly/fab/weld, and field service - so very hands-on people. Some could rebuild an engine blindfolded, but when it comes to rifles and scopes they get brain fog! And then there are other non-technical people who have a lot of common sense, patience, and natural troubleshooting ability that totally get it. And they might be a pencil pusher with no desire to wrench on anything, except their rifles.

The bigger issue though, is that we don't have enough information, especially how confident the shooter is of the original zero in terms of POA/POI and sample size.

Instead of true zero shift, you might just be seeing a clearer representation of the true dispersion (cone of shame). Except for those showing 15-30 round initial baselines, right? Confidence is higher with those.

It could also be shooter error. Like parallax that Jordan mentioned, or technique and follow through that someone else posted.

Plus wind - some documented it in their notes, while some others don't recall if they held wind or not. If you want to get down to the gnat's ass, you have to deal with it in one way or another.

Maybe most important is the fact that there can be issues that are not readily apparent.

For example, your 700 that experienced a shift - I would look towards an out of spec receiver before blaming the mount, lack of rail bedding, rings, etc.

Why?

Because, every 700 that I have looked at in recent years had the starboard portion of the receiver bridge over polished. When that is present and not accounted for, you can put the scope in a bind and the contact surfaces between the scope and rings are affected. The scope can move relative to the ring.

Using more torque may just bind the scope worse. That would be my biggest concern with your rifle in particular. I can probably dig up some photos to paint the picture.

If you need help checking it, I'd be happy to help but you should start a new thread. Or shoot me a PM.

 

[Schmo]

For example, your 700 that experienced a shift - I would look towards an out of spec receiver before blaming the mount, lack of rail bedding, rings, etc.

Why?

Because, every 700 that I have looked at in recent years had the starboard portion of the receiver bridge over polished. When that is present and not accounted for, you can put the scope in a bind and the contact surfaces between the scope and rings are affected. The scope can move relative to the ring.

Using more torque may just bind the scope worse. That would be my biggest concern with your rifle in particular. I can probably dig up some photos to paint the picture.

If you need help checking it, I'd be happy to help but you should start a new thread. Or shoot me a PM.

This would not be the case when he has a screwed-on EGW rail. This would only be feasible if integral bases were used

 

[4th_point]

This would not be the case when he has a screwed-on EGW rail. This would only be feasible if integral bases were used

Wrong - the tiny little base screws have sufficient clamping force that the rail deforms to match the receiver, and obviously not the other way around.

That's why it's easy to miss.

 

[Schmo]

Wrong - the tiny little base screws have sufficient clamping force that the rail deforms to match the receiver, and obviously not the other way around.

That's why it's easy to miss.

I seriously doubt that’s what’s going on. As I pointed out in my first post, we have a weak point in the rail attachment, possibly questionable rings, and unknown barrel torque. Any one of those things can lead to the issue.

 

[4th_point]

I've seen it and dealt with it personally, but if you want to question it, you should start a new thread.

 

[Wacko]

I won't clutter this thread anymore until I can post some zero tracking of my own. That won't be for a bit because I just moved to a new residence.

I stated the rifle seems to be holding zero now after testing it. All I had to do was increase ring cao torque to 30 inch pounds. If it blows up the swfa then so be it...it wasn't holding zero until then anyway.

While I appreciate everyone's help and "theories" it really doesn't go through all the steps a person can to ensure the system they are using holds zero. Since no one has added any additional steps I am going to list all the steps I know of here. Hopefully some people will find it interesting if nothing else.

The "degrease, loctite, and torque" is NOT the end period, full stop. It may not be "novel" but there are many things that can cause issues regardless of platform just due to tolerances that I have learned.

These are the steps....

Degrease all fasteners, all fastener holes, scope tube, inside the rings, inside stock action mounting areas

Check all fasteners for binding and fit. In other words, make sure your action screws don't bind on the barrel tennon or the bolt. Make sure your base screws don't touch the barrel tennon or bolt - adjust as needed.

Check the action to stock interface fit. Some form of bedding for "perfect" fit is always preferred. Float the barrel. Make sure the trigger, mag box, bottom metal are not binding or contacting anything.

Check the bottom metal fit and possibly bed it as well.

Check that the bolt lugs are actually making contact in the breech

Check the base to action fit. Bond and or bed to action as needed.

Make sure your rings are compatible with the base.

Assemble everything with a thread lock and torque to spec

Then rule number 1...test it.

If there is an issue I recommend increasing the scope ring cap torque first. In the majority of the drop tests doing that seems to stop issues or at least make them better. How high you go is up to you. On my swfa's I will go up to 30 inch pounds for sure.

If that doesn't help, then try a different scope.

If that doesn't work, then sell it and start over. Or send it to a competent gunsmith that can blueprint the action and replace the barrel. One that can also identify "unfixable" tolerances. Then re-bed, remount, and try again.

I'm sure there may be some things I have missed that are "easy".....I won't do any shimming or grinding myself beyond fitting and bedding the stock and shortening screws. I may try a different stock if the fit is bad enough.

JMHO on this of course. Hope it helps !

 

[Schmo]

I won't clutter this thread anymore until I can post some zero tracking of my own. That won't be for a bit because I just moved to a new residence.

I stated the rifle seems to be holding zero now after testing it. All I had to do was increase ring cao torque to 30 inch pounds. If it blows up the swfa then so be it...it wasn't holding zero until then anyway.

While I appreciate everyone's help and "theories" it really doesn't go through all the steps a person can to ensure the system they are using holds zero. Since no one has added any additional steps I am going to list all the steps I know of here. Hopefully some people will find it interesting if nothing else.

The "degrease, loctite, and torque" is NOT the end period, full stop. It may not be "novel" but there are many things that can cause issues regardless of platform just due to tolerances that I have learned.

These are the steps....

Degrease all fasteners, all fastener holes, scope tube, inside the rings, inside stock action mounting areas

Check all fasteners for binding and fit. In other words, make sure your action screws don't bind on the barrel tennon or the bolt. Make sure your base screws don't touch the barrel tennon or bolt - adjust as needed.

Check the action to stock interface fit. Some form of bedding for "perfect" fit is always preferred. Float the barrel. Make sure the trigger, mag box, bottom metal are not binding or contacting anything.

Check the bottom metal fit and possibly bed it as well.

Check that the bolt lugs are actually making contact in the breech

Check the base to action fit. Bond and or bed to action as needed.

Make sure your rings are compatible with the base.

Assemble everything with a thread lock and torque to spec

Then rule number 1...test it.

If there is an issue I recommend increasing the scope ring cap torque first. In the majority of the drop tests doing that seems to stop issues or at least make them better. How high you go is up to you. On my swfa's I will go up to 30 inch pounds for sure.

If that doesn't help, then try a different scope.

If that doesn't work, then sell it and start over. Or send it to a competent gunsmith that can blueprint the action and replace the barrel. One that can also identify "unfixable" tolerances. Then re-bed, remount, and try again.

I'm sure there may be some things I have missed that are "easy".....I won't do any shimming or grinding myself beyond fitting and bedding the stock and shortening screws. I may try a different stock if the fit is bad enough.

JMHO on this of course. Hope it helps !

Hey man,
A couple things that I mentioned, but haven’t seen them acknowledged.

1. I don’t know that SWFA rings have been proven durable during drops. Scope rings are definitely not created equal, and there are many that won’t hold zero. So strongly consider this.

2. Barrel torque is very important. Barrel nut setups, as in a Savage/Remage style, can be prone to shifts from drops. Fixed shoulder barrels are the most reliable, and need to be torqued to at least 100 ft lbs to ensure they don’t shift upon impact.

My impression from your last post is that it seems so many steps. I think some that you mentioned are either unnecessary, or excessive.

My list:
Bedding only improves fit and stability

Make sure barrels are free floated

Make sure barrel is torqued appropriately

If any action screws are blind screws, make sure they’re not too long and bottoming out.

Degrease, thread lock (whether you use locker or oil based paint pen, that’s your call), and torque all fasteners.

If a non-integral pic rail is used, bond it to the action.

Use scopes and rings that are proven to hold zero.

Test your individual setup. Just because that scope model has passed the drop eval and been great, doesn’t mean that your individual unit is bulletproof.

 

[pathnz]

Rifle: .223 Remington Model 7 action bedded in Manners EH8, Mullerworks 1:8" 18" 2B fluted, actions screws 50 inlb
Scope: March F 3-24x42
Rings: The much maligned Talley Ultralight, caps & base screws all torqued to 20inlb

March 5 zero set back to a handload after using factory ammo for work
View attachment 874426

March 8 zero confirm
View attachment 874427

Today May 2 zero check
View attachment 874428


Rifle has driven a couple thousand KM and shot 5 deer & a pig in that 2 month period. No issues. I have never had a zero shift with this combo of more than 0.1MRAD in 6 years.

Checked again today. Has been on a work trip and shot 129 wild goats since the zero check above. Still good within 0.1MRAD. Used a pretty shit aiming point. This March gets used heavily, not babied. It is reliable. No issues with the Talleys either

 

[Bluumoon]

Loss of Zero

Probably 200 rounds and 9-10 miles of riding in a pack, another couple miles on a 4wheeler, shooting my rifle course (gets bumped around pretty good).

Tikka c 6CM prefit, Maven 1.2, UM rings, AB Raptor 6


Rifle will be torn down and be drop tested on re assembly.

Barrel was only torqued to 80 lbs r/t barrel slipping in clamp. New clamp on hand, will be addressed.

Suppressor had been taken off (unsuccessfully tried to get end off to put reflex on). Don’t think this would have been the issue, but maybe.

Thought every thing was torqued and paint penned correctly. This is why I had been drop testing everything… got lazy, got bit

 

[Castle Rock]

Loss of zero combined with much worse accuracy is very likely the scope itself

 

[Bluumoon]

Loss of zero combined with much worse accuracy is very likely the scope itself

Ignore the black dots at the top, that's loctite from bolt handle install. Group size is on par for the load, right around 1.5" for 10 rounds

 

[Justin Crossley]

Another 600 mile road trip. This time the 25 CM road in a soft case sitting on the bed in my truck camper. Pulled it out of the case in Belt, MT and fired five shots to get power factor for the NRL match this weekend. I couldn't get pics because there were lots of people shooting but the rifle was still zeroed.

Saturday morning I was getting ready to drive down to the match and as I exited the camper, I accidentally dropped the rifle down onto the step and then to the ground in a soft case. Probably about 5-6' from my hand to the ground. The scope was the first part to hit the step on the way down.

Since I have had no issues with this scope shifting in over a year, I went ahead and shot both days of the match with it and didn't check zero.

View attachment 881912

Since the match in Montana, I drove home (about 676 miles) with the rifle sitting in the back seat of my truck on top of other gear.

Then another 120 highway miles in my Decked drawer before heading up a forest service road for 12 miles and then off-road for about 1 mile for some mountain shooting practice. I didn't check zero at 100 yards, but shot multiple targets out to 920 yards without issue. Back home again.



This weekend, I drove to Madras, Oregon (294 miles) for another match. I checked zero at check-in and I'm still right on. I didn't do well at this match finding targets and sucked it up but at least the rifle shot really well.

 

[Harvey_NW]

Tikka 6.5 PRC - 143 ELD-X hand loads.
Trijicon Credo HX 4-16x50
UM rings
AG Alpine hunter skim bedded
Assembled and torqued per Forms instructions.

Checked zero today, last zero adjustment was in December after adjusting powder charge to back off pressure with formed brass. POI shifted right a bit with the lesser charge, I recall giving it 2 clicks left and fussing with the turret cap while setting it back to 0 and questioning if I had given it an extra click. This was the zero confirmation group that day after setting turret.


Gun has ridden around in the truck and been tossed around moving stands while coyote hunting a few times since. This was today, 5 shots pretty much as fast as I could settle in and break because it's hotter than hell in the desert. Prone off Spartan bipod as I would be hunting.


Looks like I may have given it an extra click. I gave it one click right and reset the cap assuring it didn't move, and will verify again before the cold bore challenge.

But for all intents and purposes and based on sample sizes and past groups, no zero shift.