Problem with bases.

Mach Two · 05-06-2021 3:31pm #1

I have Leopold Quick Release Bases set up on my rifle only they don't seem to be holding zero. The point of impact is moving left and right after removing the sight and replacing it. Any suggestions on how to fix it.

Richard308 · 05-06-2021 3:48pm

Are they return to zero bases? Only ever heard of return to zero on blaser rail and a.r.m.s rings mounted on a fixed picatinny rail.

Mach Two · 05-06-2021 4:27pm

Pictures of similar setup. I have different bases but rings are identical. They operate with a cam pushing forward and pulling down the ring.

Richard308 · 05-06-2021 4:32pm

Mach Two wrote: »

Pictures of similar setup. I have different bases but rings are identical. They operate with a cam pushing forward and pulling down the ring.

Don’t think they’re guaranteed return to zero

Mach Two · 05-06-2021 5:37pm

Guaranteed to within a half moa.

cookimonster · 05-06-2021 5:49pm

Are these them-

https://youtu.be/eVdIVDv2Yxc

A few comments-

How much shift are you getting?
If you can live with the reported 1/2 MOA then they could be ok. It would be well within acceptable tolerances if it's on a deer rifle. I'm quite happy to have that sort of deviation on a zero day. On a rim fire I'd be looking for a bit tighter, but then again that 1/2 MOA may be smaller at usual .22 zero range.

Are the bases and rings matching?
I've seen this recently, were the bases and rings were reported to be compatible but in reality it wasn't so. The rifle was zeroed dead on, then begins to wander with each shot. Bases were replaced to excat match of the rings.

Have you tried various combinations of the ring and bases?
On one of my set ups the whole lot comes into line if I have the rings placed in a particular way, otherwise any other orientation shots the scope off centre.

Mach Two · 05-06-2021 5:56pm

They are the base and rings. I have my bases in such a way that when I put the sight on the tabs are pushing the sight towards me. Would that make a difference.
Have you theses bases Cooki?

GooseB · 05-06-2021 6:06pm

I have my bases in such a way that when I put the sight on the tabs are pushing the sight towards me. Would that make a difference.

I'm not familiar with these rings (I looked at your photos) but just in regard to the above statement - When I put a scope on a normal Picatinny rail, I push the scope away from me (towards the muzzle). When the gun recoils, the inertia of the scope is going to want to make it stay where it is and the rest of the rifle will try to move backwards. This gives the appearance of the scope moving forwards under recoil. Does your ring system ensure any play in front of the rings is removed as opposed to play behind them?

cookimonster · 05-06-2021 6:07pm

[QUOTE=Mach ...pushing the sight towards me. Would that make a difference.
Have you theses bases Cooki?[/QUOTE]

Push Forward....

When mounting rings / bases and there's some forward / rearward play in the position, it is advisable to push everything forward to the muzzle. This will counteract the rearward force of the recoil. The locking mechanism may be flinching under recoil.... what calibre by the way?

Edit - Sorry missed your question.

No I don't have them. The issue was with Burris / Leopold bases and rings. The rings lock into the bases in a rotating fashion.
My set ups are or were on either receiver dovetails/dedicated rings or picatanny bases / rails with matching rings ( QD in these cases)

Mach Two · 05-06-2021 6:10pm

I have them on a .22 LR. I would think that recoil would be minimal.

Mach Two · 05-06-2021 6:21pm

So you had quick release weaver type rings?

cookimonster · 05-06-2021 6:33pm

Mach Two wrote: »

I have them on a .22 LR. I would think that recoil would be minimal.

Ok, to save yourself a hugh nightmare proceed carefully and slowly and don't get a rush of poo to the head.

Firstly check your scope (what make?), ensure the cross hairs are fairly centred and not way off the axis. If theres an issue, bore sight and see if there is a massive difference between the bore sighting and the centre of the scope. This would indicate a misalignment of the bases. Go look at the bases.
Without dismantling everything, check all your screws are tight. If you find something wrong then fix that one thing and check zero.
If all is tight, remount your rings - start by removing them, placing the bottom halves into the bases and mount the scope from there doing the usual procedures. Ensure that the screws are cross tightened and repeat even when torque is reached, as each adjust ment on opposite screws can effect its partner. Check zero and continuity.
If your still having issues, remove bases, clean reciever and bases well and remount. Some locktite solution can be used on the base screws. Reassemble and check zero and continuity

Mach Two · 05-06-2021 6:41pm

Leupold scope. How do you mean way off the axis? I had to move the crosshairs a good bit when I changed rings and bases. Would that affect the ability for the sight to hold it's zero?

I am actually using Leupold Gunmakers Bases. I had to make theses bases for the gun. The bases are very well secured.

cookimonster · 05-06-2021 6:45pm

Mach Two wrote: »

So you had quick release weaver type rings?

I had Waever bases on my Mauser with steal Burris QD rings. The receiver mounting system is the same as the Remington 700 configuration. These worked fine but Ichanged the bases to a full length Picatanny rail to accommodate different set ups. It's a good solid set up and doesn't give me any hassle

cookimonster · 05-06-2021 7:06pm

Mach Two wrote: »

Leupold scope. How do you mean way off the axis? I had to move the crosshairs a good bit when I changed rings and bases. Would that affect the ability for the sight to hold it's zero?

If the bases are not in line with the bore and off centre then the scope will be off centre to the bore. If this deviation is severe enough you can end up adjusting windage so much that your vertical cross hair could be all the way to the left or right of its adjustment plain. This can put strain on the internals or not give you a good sight picture.

Mach Two wrote: »

I am actually using Leupold Gunmakers Bases. I had to make theses bases for the gun. The bases are very well secured.

That's a whole different ball of wax and way out of my omelette and pancake realm, you obviously had to machine / cut / shape the block to fit the receiver and then drill the mounts to fit the exsisting tapped reciver holes etc. There's a huge amount of things that could be off, no insult to your skills.

Mach Two · 05-06-2021 7:19pm

That's a whole different ball of wax and way out of my omelette and pancake realm, you obviously had to machine / cut / shape the block to fit the receiver and then drill the mounts to fit the exsisting tapped reciver holes etc. There's a huge amount of things that could be off, no insult to your skills.

The bases are 100% in line with each other which is I presume correct. They are tight fitting without any movement.
I have a standard dovetail rail that is on most rimfire rifles.

How do I check the sight to get it centred. It is keeping its poi between shots it is only when the sight is removed and replaced that poi changes.

cookimonster · 05-06-2021 7:58pm

Remove the scope (handy with the QD mounts) and place the tube of the scope on something that will allow you to evenly and smoothly rotate it 360. Crank the power down if you can and look through the scope at a fixed point - small dot on the wall etc. While looking through the scope slowly rotate the tube in one direction if the cross hairs are fairly centred then there will be little deviations between the aim point and the point on the wall. If the cross hairs are way out of line then after abouts 90 degree rotation you should start seeming a massive difference between the aim point and the spot on the wall.

Remove turret caps and dial your turrets all the way out to the right or left, then up or down. Now slowly click back the opposite direction, counting the clicks as you go. If you max out a say 80 clicks dial back 40 click, then repeat with the opposite turret. Try the rotation trick again and your scope should be centred.

Put the scope back on the rifle and check the bore sighting. If you find your way off then theres a problem.

Re holding zero, obviously you are rezeroing to get it back on each time you remount the scope - this could be a tension problem, if the mounts and rings aren't aligned it may be torqueing the scope tube and causing loss in zero. Check the rings are in line and not out of place.

Again, when you lose zero is the point of impact consistent or is it random and moving. In other words loss of zero but all are going in the same hole.

Re the fit of the mounts, do you have a retaining system ie side clamp, vertical screws down onto the reciever etc or is it just a friction fit. I ask because a few of my rifles (CZ, Brno and BSA) had dovetail reciver mounts but all rings or bases were fixed in place by side clamps or in the case of picatanny to dove tail fittings downward torquing screws.

Mach Two · 05-06-2021 10:39pm

Thanks for that Cooki. A lot to do there.
I just took a few shots there. Fired 5 shots and removed sight after each shot. All shots almost touching each other. Problem fixed I thought. A miracle. Fired another few shots. Hoping for the same results. Back to the start again. Probably 2" spread. This is at 40yds.

I will post a picture of my setup tomorrow.

Mach Two · 06-06-2021 11:20am

Photos of rifle.

Mach Two · 06-06-2021 6:00pm

Photos of base. I have drilled and threaded a hole to take a grub screw in the middle to help keep it in position since theses photos were taken.

cookimonster · 06-06-2021 6:39pm

Forgive my ignorance, what rifle is it?

...again, since we are chatting, was there a particular reason to go with this mounting set up?

One thing you could try to eliminate the elephant in the room, is to mount the scope with conventional dove tail rings - test fire that then you'll know that the scope is good.if you don't have extra rings, test the scope on another rifle.

I always loved the simplicity of dove dail rings - rings to receiver. I have a unmoderated 270 that uses a dove tail receiver with a single recoil pin in the rear mount - no issues with it at all.

Mach Two · 06-06-2021 8:25pm

Sako Quad. It has interchangeable barrels. I was hoping to use nightvision at some stage so this set up would be ideal for me. I have also discovered that when I squeeze down the front ring first the rear ring lifts 0.2 mm. I checked this with a feeler gauge. I will have to put a shim on it. If I turn the sight around it fits flatter on the bases so changing the rings around might be a good idea.

I don't want to remove the bases on it as they are a tight fit and if I take them off and refit them they probably won't fit as well. Good idea actually to change the rings to check the sight. I could fit it to another rifle.
If this system works I would be very happy with it.

cookimonster · 06-06-2021 8:36pm

Fitting night vision was the reason I got rid of the two seperate bases, the full length picatanny gave me better mounting options. Some of the NV can be a b*tch to get a good eye relief and suitable LOP.

I ended up setting up a dedicated NV rifle with a picatanny on a dove tail reciver so I have the option for fitting a day scope.

Mach Two · 06-06-2021 9:22pm

How well do the weaver type quick release base hold poi?

cookimonster · 06-06-2021 9:42pm

Mach Two wrote: »

How well do the weaver type quick release base hold poi?

I never got to that stage of removing the scope off on a regular basis, but they did hold usable zero, slight shift of about 1/4 inch to the right (?). I would recommend the picatanny rails as they are more compatable with other mounting systems then weaver.

Mach Two · 06-06-2021 11:00pm

I checked out other people's thoughts on your system and the system I am hoping to use. My one came out tops providing I get it up and working.

Mach Two · 06-06-2021 11:11pm

What kind of rings have you on that set up?

cookimonster · 06-06-2021 11:30pm

Mach Two wrote: »

I checked out other people's thoughts on your system and the system I am hoping to use. My one came out tops providing I get it up and working.

Fair enough, but have a look at various NV units and how they attach to the rifle, often requiring some sort of step back mounts to allow proper eye relief. Some of the thermal units that are more traditional in terms of scope design may allow fairly conventional mounting but many still utilize oversized housing where traditionally elevation and windage turrets are located. Rings may need to be spaced out beyond the range allowed with normal reciever positions. Scope / Unit housing may come in contact with iron sights, barrel and receiver profiles etc, etc so a multi slot rail can help over come these situations.

Some people get hung up with full rails thinking they may cause obstructions, its simply not true. I've used two centrefure rifles with blind magazines both fitted with full length rails with no issues loading, unloading or ejection, one of them a straight pull and it operates smoothly as fast as I can cycle it. I've also shot two controlled feed rifles with rails, again no issues. While my .22 fitted with a rail worked flawlessly.

cookimonster · 06-06-2021 11:33pm

Mach Two wrote: »

What kind of rings have you on that set up?

Burris Steal QD (1 inch) on the Mauser and Hawke Steal QD (30mm) on the CZ

Mach Two · 07-06-2021 6:24pm

The problem with the likes of Burris Steal QD rings and similar rings from what I could read was that they were not returning to zero. Or not as good as the Leopold Quick Release Bases.
I am of course open to correction.

cookimonster · 07-06-2021 7:37pm

I've indexed the throw levers and tested the I've torque using a fat wrench, but prior to that I tested the set up just using indexing.

For the .22LR I got good repeatablity on initial testing but I have since changed rifle to a .22 centre fire and haven't removed the NV scope since zeroing.

I use the steal rings for longevity and robustness.

Wadi14 · 07-06-2021 7:55pm

Mach Two wrote: »

The problem with the likes of Burris Steal QD rings and similar rings from what I could read was that they were not returning to zero. Or not as good as the Leopold Quick Release Bases.
I am of course open to correction.

Don't believe every thing you read as your having bother with your rings and the Burris seems to be working very well.

Change them rings and base as there not working for you.

Mach Two · 08-06-2021 12:59pm

If I have to I think I should be able to put a dovetail clamp/bracket on it.

Mach Two · 10-06-2021 7:32pm

I have removed sight from rifle and put it on another rifle. It is grouping alright. No holes all over the place. I even adjusted the windage and bullet drop. Still held good groups. I also checked to see how centred it is. As I rotated it,it might move about 18 inches from centre when rotated at 30 yds.

How good is this?

cookimonster · 10-06-2021 8:49pm

You have eliminated two elements- the scope and the shooter.

Now look at the rifle - check action screws, stock to action /barrel fit, mounts etc, etc.
Also look at any similarities or not between one rifle and the other. Are scopes mounted at the same height, are you getting consistent cheek weld etc, if all check out then what evers left is the problem.

"when you have eliminated the impossible, whatever remains, however improbable, must be the truth?"
Sherlock Holmes(1890)

Mach Two · 11-06-2021 1:48pm

It must be a mounts problem. The rifle was shooting very well before I changed the mounts. You said to centre the crosshairs. How much off centre can a sight move its reticle before problems occur. I hope to check the amount of clicks it will move in either direction.

cookimonster · 11-06-2021 2:58pm

Re Centreing the Reticle.

Ok, sorry no time for computer graphics, drawings will have to do . A lot of assumptions and a bit of balistic heresy.

Just pretend the scope has a full range of 80 clicks windage and elevation. That's 40 clicks to centre the reticle. Each click is 1/4 inch (I'm beyond middle aged).

Diagram 1
The scope reticle is centred and the is bore sighted, in this case is close as be damned to same point of aim (POA).

Diagram 2
First group on target at 100 yards is 2.5 inches up and 2.5 inches right from point of aim.

Diagram 3
That equates to 10 clicks up and 10 clicks right to zero POA and Ponit of Inpact. The scope reticle is now off centre. But there are 50/30 clicks adjustment to play around with.

Diagram 4
Shows you what you actually see in the eye piece, theres no discernable off centering.

Diagram 5
Shows extreme dialing / zero setting were the reticle has been dialed to the maximum values. On some scopes this can be noticeable (drawing depicts location of reticle in the housing not sight picture) with a poor ocular view, but not always. It can put strain on the erector system as well as drastically reducing useable adjustments in the scope.

Now as I said, some assumptions were made, so imagine if the scope was not in line with the bore and you needed to dial in a good bit just to bore sight it then you are starting out with a limited amount of adjustments for zeroing. Think a standard scope on a 20MOA base this is going to shave a lot of adjustment off your elevation for standard hunting ranges of less then 200 yards. Your POI could be 12 or more inches above POA and you could have very little left in the way of adjustment on your dial.

_______________________________________________________

There's definitely something going on with the bases.

clivej · 11-06-2021 9:39pm

Maybe your looking at the movies? And your expecting the same? Where the sniper gets the center fire break down rifle out of the suitcase, put it all together, swings on the scope and still gets the head shot at 200y.

I have picatinny rails on all my rifles, medium priced good scopes, €400 on my rimfire rifles and €1200 on my center fire rifles. I have ALWAYS had to re-zero after taking a scope off and putting it back on. It's not out by a lot, maybe a couple of MOA but not good enough to go target shooting with and expect good results.

Just think for a minute, back at school and the plastic protractor you used to measure angles with. That very small 1 degree mark from the zero line is sub-divided into 60 minutes segments. 1 MOA each segment. Each 1 minute is now sub-divided into 60 seconds.
So now think that when 1 click of the turret = 1/4 MOA, that is 15 seconds of movement.
Now think when you re-mount your scope it only has to be off just a very small amount to throw your original zero off quite a lot.

And now my head hurts, after all this thinking.

11-06-2021 10:10pm

I've considered using quick release mounts so I can have 2 different scopes for different uses from the same rifle. I might just alternate between removing and reattaching different scopes, but have each scope with their own mounts fixed on and ready to attach by a nut fixture rather than quick release, ie not remove the mounts off the scopes. I had thought a good quality quick release might be a viable option, but I'd always expect to have to do some work to zero again. Yours sounds off in a different way.

I had problems when setting up the same rifle originally so I think I may have problems ahead, but know how to fix them.
When I fitted existing mounts, no matter what I did, I couldn't get it zeroed and the scope adjustments were at their limits and still not sorting things (I didn't like being a bit off, let alone way off).
I got fully adjustable mounts (windage & elevation), used a laser borsecope, centred the scope as cookimonster mentioned previously, that got me on target/paper, made small adjustments again and fine tuned with the scope, rifle was spot on after that.
I only removed the scope recently as I put a picattinny rail on as part of a new buttstock, my problem now is, I can't find a fully adjustable 1" mounts to fit a picatinny rail and it would be my preference to torque up everything (need to acquire a suitable small torque screwdriver or wrench).

In my experience, I needed the fully adjustable mounts, the laser boresighter helped a lot (done at short range indoors first). That would be my route to resolve.

Mach Two · 12-06-2021 9:26am

Not really expecting to have a setup where I can remove my sights and expect a complete return to zero. Anything would be an improvement on my current setup of changing sights. The poi could be anywhere.

minktrapper · 15-07-2021 12:15pm

We seem to be up and running again. Any update on this.

Mach Two · 11-11-2021 10:23pm

Just a quick update on this. I have fired 4 different 3 shot groups. I removed the sight after each group and replaced it. Needless to say I am very happy with the results. I have marked the different groups as an indicator as to how well the rifle performed. The target was at a measured 50 yds. I am using Leupold Quick Release Bases.

Cass · 13-11-2021 10:58pm

Good result.

Quick question. You said when you removed the sights and refitted it would shift left or right. Is it constantly holding that left favoring? Of did you shoot the groups then finish off zeroing by adjusting that last 15mm to the right?

Mach Two · 14-11-2021 11:49am

I should have explained how I fixed the problem. The point of impact was moving because the sight was not sitting dead flat on the two bases. So I put a shim in to fill the gap. It was only 0.2mm but was sufficient to cause a problem.

It would put you thinking as to how many sights are twisted/bent by only a fraction using traditional mounting systems.

When I was finished I just moved the poi to the right. The photographs were just to show the repeatability of the quick release mounts I am using.

Cass · 14-11-2021 12:19pm

I found out some time back how little of a "fault" can make a big difference at the target when I had a similar problem and was given shimming brass. It was something like 0.25mm thick yet placing a piece front and back of my scope gave me, iirc, something like 12"+ of adjustment at 100yds, so I completely believe what you're saying.

Well glad you got sorted and thanks for updating the thread.

keith s · 14-11-2021 2:29pm

Was reading through this thread too.

Sorry for the silly question, but when you said:

"The point of impact was moving because the sight was not sitting dead flat on the two bases."

Is that the bottom U of the two rings were not level with each other, so when the scope sat in two them it was not sitting dead square in them.

Then putting the top of the rings on and tighting down bends the scope or at least puts strain on the tube?

If so, where did the problem lie or start, is it with the receiver, the rail or the rings?

Cheers

Mach Two · 15-11-2021 6:48pm

The picture of my rifle seems to have been lost in the change over. So here it is again. Also I have a photo of the quick release mount I have used.

The mount had to be machined so as to fit the dovetail rail on the rifle. The rings are fitted to the sight so in order to remove the sight you also remove the rings. Essentially I am lifting the sight and the rings off as a single unit and leaving the bases behind. The problem was with the base of the rings not sitting flat on the two bases when downward pressure was applied. So when I locked one base down the other would be lifted off the base so that a gap would left. When downward pressure was applied on the second ring to lock it in I was actually bending the sight. So a shim had to be inserted to fill the gap.

Mach Two · 17-11-2021 12:54am

https://www.boards.ie/discussion/comment/118164142#Comment_118164142

Out of curiosity where did you put the shims to give the adjustment.

Cass · 17-11-2021 1:39am

Between the scope tube and the inside of the ring. Bottom on the rear ring and top on the front. Didn't leave it there long, it was a simple test. I then tried under the rings and while this was more secure I could only use either the front or back, not both. So had to double up on shims which presented a secure mounting to the rail issue.

Very soon after I bought my first 20moa rail. About 13 years ago now.

Mach Two · 17-11-2021 6:33pm

Would putting a shim between the tube and the ring not affect the tightening of the rings on to the tube.

Cass · 17-11-2021 7:39pm

Yup, hence the reason I only tested it. It prevented a secure tightening of the rings from the point of view that the ring was not clasping the scope tube, but rather the shim. It added additional pressure when tightening the rings which could have lead to crimping the scope tube, plus the shim would allow a certain amount of "slippage" of the scope in the rings if not fully tightened.

So tighten normally and I rish crimping, don't tighten fully and I risk the scope being loose in the rings.

The shim on the bases worked better and I could get, iirc, up to three shims in (at 0.25mm per shim) at a time, but it got to the point after say three where the rings would sit up higher on the rail and I'm back facing proper/secure mounting of the ring on the rail.

As said above these were all trial and error missions. I had only just started into long range stuff so it was all new to me. The 20moa rial eliminated all that with no mounting/secure issues.

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Problem with bases.

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