Brno 602 416 Rigby shoots low with scope

[Aleksj89]

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.

 

[mark-hunter]

I have number of rifles including zkk 602.
20 moa low (or in any direction) is not normal.
But it is not disaster either.
20 moa is cca 58 cm at 100 meters
or 20 inches at 100 yards. (50.8 cm)
This can be compensated by scope elevation adjustement.

Possible causes:
1. Barrel harmonics. Most likely.
Channge the bullet and cartridge, and see what you will get.

If that is not the cause:
2. Tightness of the screws, and mounts
Check

3. next suspect is alligment of the rings, unlikely because they are on dove tails
For gunsmith to check

4. Non aligmnet of action (with dove tail) with barrel. But I find it unlikely.
for gunsmith to check

5. Damaged muzzle crown
Check.

6. Wrong way of shooting. (not sure how you check the rifle)
Barrel should not touch any object, while shooting, pay attention to trigger tecnicques, breathing, etc)
But this could be unlikely as wellif you are experienced.

7. Screws slack - screws which connect stock and action (not sure what is the name) but it was the cause for one of my rifle loosing zero. Check crossbolts as well.

My guess, causes 1 or 2, and 5 are probable.

BTW - zkk rifles as many of that time are not with free floating barrel, so this may result in a bit wierd POA/POI, or a bit reduced accuracy.

Later edit:
iron sights are weak point. many times they are not regulated in factory. for example my new tikka, was shooting 60 cm low, at 50 meters, brand new from factory. (wrong front site installed)

What I want to say, comparing alignment with factory iron sights is not proper way to align.
What you need to do, is take out the bolt, look through the barrel and aim to target through barrel at 50 meters. Bring you scope to the center of barrel. Then you have rough alignment. then compare MOA.
If you want more accurate: remove the primer from one of casings, and look through barrel via primer hole to aim to target. In technological manner, you can also use a laser to aim to the target, then bring crosshairs to it. Then you can see actual differences in MOA, although not absolute perfect.

 

[Shootist43]

Alexj89, IMHO something is definitely wrong. First place I'd look is the mounts and rings. BRNO(s) require a proprietary / unique set. Make sure you have a matched pair. The second place I'd look is the scope itself. Do you know that it is good? Another thing that might be possible is to look at the scope when mounted to see if the "barrel" of the scope appears to be parallel to the rifle.

BRNO(s) and CZ(s) often have feeding issues, but I've never heard of any having your current problem.

 

[Berettaco]

As @Shootist43 said - mounts/ bases are most likely not correct. I would start there.

 

[PHOENIX PHIL]

Which of the Warne QD rings are you using? Low, medium or high? If medium or high, could you go lower?

 

[xausa]

Has anyone suggested to you that a scope with a 56 mm objective lens might not be appropriate for a .416 Rigby rifle? I, personally, would not go beyond a straight tube, in order to keep the scope mounted as low as possible. If you insist on a variable power, 1.5-5X should do nicely.

My African plains game scope was a 4X, and I never thought of myself as handicapped by it. You might occasionally find yourself taking a running shot, and anything over 4X would be an impediment, in my opinion.

You should also consider eye relief. You will not want your eye in close proximity to the rear of the scope in the case of a .416 Rigby. The Noske scope on my .450/.400NE has close to 5" of eye relief, so I don't need to concern myself with the possibility of a crescent shaped cut above my eye.

Does your .416 have a recoil lug under the barrel and is it held down with a screw? My early 602 in .375 H&H has such an arrangement, and I would think that it was even more essential for a heavier caliber. Such a screw can be too loose or too tight and have an effect on point of impact.

Finally, is your BRNO's barrel factory original, or is it an after-market barrel? That can make a difference.

 

[PHOENIX PHIL]

Has anyone suggested to you that a scope with a 56 mm objective lens might not be appropriate for a .416 Rigby rifle? I, personally, would not go beyond a straight tube, in order to keep the scope mounted as low as possible. If you insist on a variable power, 1.5-5X should do nicely.

I didn't even notice the 56mm scope part. @Aleksj89 I would have to concur with xausa. A smaller scope mounted closer to the barrel and I'll bet your problems go away.

 

[mark-hunter]

First to do, is bore sighting.
He must confirm that bore sighting is done.

 

[Berettaco]

Never owned a BRNO - just trying to do some basic trouble shooting. Is the action higher or lower on the front? Are the bases different heights? Thinking you may need to switch front to back?

 

[mark-hunter]

nuff said. lets wait for comments by op, after reading responses on his first post.

 

[DougBrümmer]

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.

Does the rifle group low constantly? Or no grouping?

I have a brno 602 375h&h. Battled to group. Turned out my scope bases/mounts were loose

 

[Aleksj89]

Thanks for all the great answers, english isn't my native language and im without power due to storm but ill try my best to answer you all.
I did initially think it was the rings that were the problem, so started to look at those. They are even in height and looks good, it's the warne rings that is for the CZ/Brno rifles with the recoil lug.
The reason I went with that scope is because i'm mostly gonna use it for deer and wildboar hunts that takes place at dawn or evening/night time.I got alot of other scopes i could try out but i dont think a brand new zeiss scope would be the reason why i have maxed out the scopes elevation at 100m, but i will try to switch it out if i cant find out were the problem is.

It is the original barrel, almost unused.
I have checked all three screws that connect it to the stock, its an aftermarket stock that is bedded and fitted vel by a gunsmith. Grouping isn't the problem, it shoots well with cast bullets, 350 gr speer, 340 sonic brass bullets, 400 grain woodleigh etc It's just weird that a scope with so much elevation has to be maxed out at a 100m, and when googling around i came over the thread on this site that brought up the problem with the barrel/action alignment.

When i get power back will i take a closer look at the rings, but they look good and even in hight. I did boresight it before shooting with the scope in "the middle" on both elevation and windage and could see that i had to screw alot up to get onto the target. I'll take another scope with me on tuesday when the range opens to check if it can be the scope.

I dont think that the scope is too high above the barrel to be the issue, but im no expert. I have to use the high mounts to stay clear of the rear sights on the barrel.

 

[mark-hunter]

Partial explanation to forum members:
Part of Norway is in polar circle. This means they have polar night 24 hrs dark per day half a year, etc.
So, depending of hunting season, large light gathering scope could be useful.

@Aleksj89
Did you try bore sighting?

How did you deteremine that you have 20 MOA bullet drop with scope?

Is it based on shooting by iron sights, and then with scope, when you get 20 moa down?

Is your scope brand new, out of box, or it was zeroed before on some other rifle?

 

[Aleksj89]

The 20MOA was what the other guy on this forum was low, might have been bad writing by me in the first post.

The scope is new, i just made sure that i was in the "middle" of the elevation and windage adjustments before boresighting, and as i wrote earlier i could see already then that i was way to low. So after i had used up all the 120clicks in the scope was i still a few cm low at 100m.
I will try to change it for another scope if i cant see anything wrong, but after reading other posts on this forum about poor fit between the barrel and action did i want to ask if that was a common issue before switching out the scope.

There were no problem with the elevation when using the peepsight or the sights on the barrel, thats why i thought it might have been the rings that were the issue. If the barrel was so far of from the action that im not able dial in that scope i dont think i would be able to use the peep sight that is in the back squarebridge togeather with the front sight without having to adjust it all the way in one direction.

 

[DWB]

There have been a few issues with Warne rings and Zeiss scopes as well. The rings squeeze the scopes too much and it affects functionality.

 

[mark-hunter]

There were no problem with the elevation when using the peepsight or the sights on the barrel, thats why i thought it might have been the rings that were the issue.

Ok, I am trying to play Sherlock Holmes, here, or giving the diagnosis without seeing the actual patient.
So, with peep sights you are alligned, iron sights alligned, and with scope, you drop down, significatanly but still within elevation range of the scope.

I had similar issue with one of my 22lr. Here is the story:
I fitted a piccatiny rail. This piccatiny was marked as 20 MOA. (I wanted to maximise the range)
So, I fitted the scope (which was good for another 22).
When going for first sighting on the range, i was not able to zero at 50 m.
The best was at the end of elevation to shoot, 5 cm plus, above point of aim.
All my calculations were in order, this issue defined the logic, and math.
I went to gunsmith.
We removed the rail, and made the measurement.
The measurment gave - rail was 40 MOA, and not 20 as certified.
He worked it out on rail by removing excessive material, down to actual 20 moa, and all was fine later. In this case mounting system was faulty. I suspect similar issue with yours

The point of the story.
Your rifle is alligned with peep sight, and most probably barrel alligned with action.
Zeiss is high end scope, unlikley to be faulty. But can be.

Suggestions:
1. change the scope for testing, and verify too much drop of bullet with another scope
If other scope is alligned, then Zeiss is problem,

2. Somethning wrong with scope mounts. as in my case.
Change the mounts if possible, but eliminate the scope as first suspect.

 

[BC.Pat]

I have three 602s and I am surprised at this, like others have said I would ensure your using the correct 19mm dove tail rings.

 

[Hunter4752001]

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).

 

[450 Dakota]

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.

 

[DWB]

There have been a few issues with Warne rings and Zeiss scopes as well. The rings squeeze the scopes too much and it affects functionality.

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.