Brno 602 416 Rigby shoots low with scope

[Aleksj89]

I dont have problems with the rings disturbing any of functioning of the scope, as i can dial in all directions without a problem and the point of impact changes.
I never over tightened the screws on the rings but i'll keep the comments about those rings in mind if im going to change out the current scope i have on it.

The rings looks like the correct ones, i will attach a few photos.

I will try to switch the scope out for one of my Swarovski Z8 or a Leupold too see if is the scope that is damaged or as 450 Dakota writes, not enough elevation in the scope.
As the Z8 should have 60cm more elevation at 100m.
There is no L shaped steel piece at the forestock, it's just bedded in. Maybe they dident need it in the aftermarket stock?

Thanks again for the good advice, if the darkness don't settle before im of work on tuesday ill give it a go with a few different scopes.

 

[fourfive8]

Bore sight first. Secure the ring bases to the rifle. Check for alignment between rings with a bar (called lapping bar) the diameter of the scope tube. Use a scope of known functionality. Count the adjustment clicks from one stop to opposite stop for both windage and elevation. Set both at their respective midpoints of adjustment. With rifle in cradle or gun vise, remove bolt and look down bore at a 6 inch black bull at 50 yards. Lay the scope in the bottom half of the bases, rotate to plumb and lightly secure scope to ring bases. See relationship between where scope cross hairs are pointing vs where bore is pointing. Likely some deviation. Adjust scope so both bore and scope are on same point. You should be able to tell very quickly if something is amiss or if scope won't adjust enough to point to same spot as bore. I know this sounds silly simple but it's surprising how many don't use this technique when first mounting a scope and sighting in.

If there is really a lot of variation between where scope is pointing and where bore is pointing you can many times just look down the side of both from a rear angle and see the divergence without even looking through either.

 

[Aleksj89]

That is what i usually do, except the lapping bars. Might need to get my hands on a pair. I could already see when boresighting with the scope in the "middle" of the available adjustments that i was far to low.
I guess i will see next week if the scope is damaged, lacking the necessary elevation for the rifle or there is something ells thats wrong.

 

[PeteG]

Just to clarify, the issue is when Warne rings are used on specifically on Zeiss scopes. Had a few friends experiencing the issues with the Warne+Zeiss combo.

This is interesting.
I have had to shim the scope mounted on my fathers 458wm, for the exact problem as the OP is having.
ZEISS scope, warne mounts.

 

[Aleksj89]

That is what im planning to do if I find out im just lacking elevation. I already have some shims cut out of beer cans ready to try out. The only way we know how to do it in Norway.

 

[fourfive8]

The most obvious potential is either ring bases of different height, mounted incorrectly or scope out of whack. If the front and rear ring bases are same height and if shims are required then the front and rear mounts are not going to be in same plane and will bind scope when tightened. There is a difference between mounts that have elevation built into them for long range shooting purposes and regular mounts that are supposed to be on same plane as action and barrel... then shimmed to make this type of correction. Something is not right up to and including barrel not threaded correctly to action or even a bent barrel.???

 

[Mark Biggerstaff]

Its your scope. 120 cm when converted to MOA is just a hair over 45 MOA adjustment. I had a leupold 1.75-6 which has 53 MOA on my CZ 416 Rigby and could just get it sighted in with a couple clicks left at 100 yards. I swapped it out with a Leupold 2.5-8 which has 58 MOA of adjustment. Not an uncommon problem from what I have read on CZs and no one that I know of makes rings with 20 MOA built into them. Need to find a scope with at least 55 MOA of adjustment. Nightforce has 100 MOA adjustment on their 2.5-10x42 Which will get you on target easy.

I have had the same issue with CZ 550 458 Lott. Wayne at AHR did a number 2 to it and still was unable to get it to sight in with a Swarovski Z6 1-6. It was shooting low at 100 with scope bottomed out. Using Talley QD rings. I switched to a Leupold VX5 HD 1-5 and have plenty of adjustment to sight in and enough CDS in it to go to 200 yards. You need a scope with the most MOA adjustment in it you can find. The issue is barrel and reciever alignment. I think, that is what issue is with my Lott. Even CZ admitted it was the issue but the only person that used to fix that problem for them passed away. Wayne said he had seen this issue several times in the CZs.

 

[Dewald]

It is a well known problem on a few of the ZKK602 rifles. I sold my .458 Lott for that reason. Tried everything then eventually realized the axis of the barrel wasn’t true to the axis of the action because the thread in the action was skew. In effect the barrel pointed downward out of the action, causing that 40 MOA difference.

 

[Aleksj89]

At least there seems to be an explanation to why im having the problem. Guess i'll let the local gunsmith take a look at it, he does jobs like that with rifles from other manufacturers so i'll see if he can do something with mine.

 

[Hunter4752001]

@Aleksj89 Your rifle is fitted with an aftermarket stock which has been setup in way which doesn't use the barrel screw as originally designed. That may be a good thing or, more likely, the cause of your problem. Easiest way to find out is to reassemble the rifle without the barrel screw fitted. Fire it and find out if the point of impact has changed. If it hasn't then its off to a gunsmith for investigation. If the point of impact has risen then it confirms that the problem was too much downwards pressure on the barrel.

 

[sestoppelman]

Unless I missed it, but one critical issue hasn't been mentioned. The 602 has a system in which, in addition to the the two action screws, there is a third screw (part 18) holding the barrel into the forestock. The barrel lug (part 19) bears on a L shaped piece of steel (part 79) which sits in the forestock. I've seen occasions where previous owners have lost the L shaped steel and tightened the barrel directly to the wood hence putting too much downwards tension hence causing it to shoot low. Long term warping of the stock can cause a similar effect. Try undoing screw (18) entirely and a fire a group. Also check that the rifle still has the front action screw spacer (part 20).

The diagram is a little goofy to me. It shows two different methods for the forward screw. I have not seen the L clamp before but only the nut that fits in a dovetail below the rear sight boss.
If that nut is missing there is nothing to screw into so that wouldnt be the issue.
What is the purpose of the L clamp? Does the screw thread into it? In the diagram it appears the L is too far aft for the screw.

 

[425SCHADE]

The diagram is a little goofy to me. It shows two different methods for the forward screw. I have not seen the L clamp before but only the nut that fits in a dovetail below the rear sight boss.
If that nut is missing there is nothing to screw into so that wouldnt be the issue.
What is the purpose of the L clamp? Does the screw thread into it? In the diagram it appears the L is too far aft for the screw.

A squared off machined face at the rear of the sight base bears against the "L" block to create a second recoil lug arrangement. See the integral sight base included in the barrel made for my CZ550. The 550 has a block resembling an "F" compared to the 602's "L"

 

[375 Ruger Fan]

Years ago, I had this type of issue with a rifle/scope. Shot low and ran out of scope adjustment. I placed a shim under the scope on the rear ring only and the problem was solved.

 

[Desperatezulu]

I

View attachment 449699View attachment 449700

Maybe nothing but those rings looks quite battered and maybe even repainted when I look at the second pic. A build up of paint could cause misalignment.

If you haven't done so already - take the rings off and give them a really good clean with a solvent. Clean the underside of the rings where they contact the mounts - there may be old dried grease/oil built up that causes the misalignment.
Also clean the top surfaces of the mounts for the same reason.

The inner surfaces of the rings look like they could use a clean up by lapping but this may be a job for your gunsmith. The uneven inner surfaces are likely to mark your scope too, even if they maybe aren't the source of your problem.

If the problem still persists then the simplest solution will be to lap the front ring - there should be enough travel in the ring screws to take up the additional 'play' created by lapping, but if not your smith should be able to solve it easily.
The beer can shim thing is temporary fix - the 416 is a big recoiler and lots of forces passing through the mountings and scope. Just get it done properly;-)

 

[ARod]

Hi

I bought a Brno 602 416 Rigby from 1967 with a peep sight a year ago, but due to alot of work I just got around to mount a scope on it after shooting with the open sights until now. It shoots really low with the scope mounted, i have maxed out just to get it in the right height at 100m.
Im using the Warne QD rings and a Zeiss HT 3-12x56 ASV+
It should be more than enough with the 120cm adjustments I have in the scope to get well past a 100m, but after searching this forum I found a thread were someone mentioned that their 602 wasn't aligned between the barrel and the action so it kept firing 20 MOA low, is this a common "well known" issue? I havent had a gunsmith look at it yet, but i guess i'll have to get it looked at if i cant find any faults with the mounts.

Aleksander.

The front site come in various sizes. Contact Top Gun Gun smith in Warsaw, MO. in the USA. Here is their email. topgunwarsaw@outlook.com

 

[Scrumbag]

Hi @Aleksj89

If it we me, I would do the following. (largely building on @mark-hunter 's list).

1) Check your dovetails are free of debris or burrs, dents, machining marks etc
2) Have a look at the underside of your mounts and see if they are planar, free of marks, burrs, dents etc
3) Do the above particularly around the recoil lug and check it hasn't bent / distorted the mount (I have seen this on other CZ / Brno rifles)
4) Check your folding rear peep is sittint low enough so it doesn't interfere with your mount

Your scope has not a huge amount of elevation change in in (120cm at 100m is ~40 moa by my reckoning) so that might not help.

As a short term solution is to shim your mounts (Beer can cut to shape under the rear of the scope).

More long term after a gunsmith checking would be to talk to sets of people.

1) Kozap - Czech mount maker https://www.kozap.cz/ (Website is in Czech but they email you back in English so be worth explaining your issue)
2) https://www.optics-trade.eu/ Huge range of mounts and experienced with former Yugo and Eastern bloc rifles

Hope that helps.

Scrummy

 

[mark-hunter]

@Aleksj89

if you will be ordering from optics trade, Then I can recommend Rusan german swing mounts - for magnums. (we are talking about 416 rigby after all)
They are made and reinforced with 6 screws on front ring.
They are made of steel, and they are indestructible.
For installing Rusan pivot mounts gunsmith is required because iron sights will need to be raised, and zeroed. (check the steel doubler on rear sight on photo attached)

 

[fourfive8]

Wen mounting a scope on a rifle with front and rear mounting surfaces on same plane and using two piece ring bases of same height, this is the type of stress induced to scope tube by shimming either the front or rear ring base.

 

[Tra3]

I’ve had a similar problems on a different rifle. The rings were the culprit. You could try putting a different scope on the rings and see if it is also low. Hopefully that is the answer.

 

[nztimb]

Wen mounting a scope on a rifle with front and rear mounting surfaces on same plane and using two piece ring bases of same height, this is the type of stress induced to scope tube by shimming either the front or rear ring base.

View attachment 450481

If you shim under the base then lapping is essential to return the rings to stress free mounting of the scope.