AHR Brno Trigger Installation

fourfive8

AH legend
Joined
Apr 27, 2017
Messages
2,847
Reaction score
5,953
Media
257
Hunted
USA, South Africa, Mozambique, Zimbabwe, Zambia, Botswana
Yes doable. I did mine with an AHR replacement for the factory set trigger that came on the rifle But I was not comfortable with how it was set up. So I had my gunsmith, who was also doing the tricky Winchester M70 safety conversion on the rifle, double check it. He said it was fine and said those triggers are what they are...

IMO, the issue with the BRNO design is the whole sear/ trigger mechanism is a Rube Goldberg funky doodle design from the get go. The sear mechanism is anchored to the action while the trigger mechanism is anchored to the stock! Study most any better and elegant trigger designs and both the sear and trigger will be part of the action group- not one attached to the action with the other attached to the stock! Any variation in the stock to action fit will also affect the trigger to sear fit. UGH

Long answer, sorry. But yes you can do it by simply removing the set trigger parts and replacing with the one-piece single trigger. The lobed end of the trigger should fit into the tear drop shaped slot in the bottom of the sear with minimum play but should also rotate freely within that tear drop shaped recess in the sear mechanism. If in doubt, take it to a decent gunsmith. :)

IMO, this is what a serious hunting rifle trigger should look like- robust, simple, fail safe. But that's for a different story.

Win 70 trigger.JPG
 

One Day...

Gold supporter
AH elite
Joined
Jan 7, 2018
Messages
1,669
Reaction score
5,690
Website
www.huntershillsafaris.co.za
Media
398
Articles
1
Hunting reports
Africa
3
Member of
PHASA
Hunted
Europe, America, Canada, Africa
Let us be clear, the trigger is one of the very few things that are genuinely different between a Brno ZKK 600/1/2 and a CZ 550.

The Brno ZKK trigger pivots on an axis located in the trigger guard; the CZ 550 has a more classic trigger group attached to the action.

I am saying this because the original post could be a little confusing to ZKK new comers, it mentions both "Brno", which hints at ZKK 600 (standard) / 601 (short) / 602 (long), and "set trigger", which hints at CZ 550 standard / magnum (long). To complicate things ZKK were available with single direct trigger, single set trigger, and double set trigger. Further, ZKK triggers came in rounded shape and in Glock-like flat shape with a built in safety paddle. Which one are we discussing?

I am not certain that replacement CZ 550 triggers currently available on the market are compatible with ZKK actions and can be affixed in the place of the ZKK sear group. To be verified... There used to be ZKK replacement triggers, but it has been a long time since I saw one.

ZKK 600/1/2 replacement triggers

To the best of my knowledge (?) currently available ZKK replacement curved triggers replace only the Glock-like flat trigger with a built in safety paddle\. They do not replace the sear group.

If this is the intent, replacing the trigger is very easy and consist only of punching out the axis in the trigger guard, replacing the trigger, and reinserting the axis. I have done it and it was very straightforward. In my case it did not involve replacing the sear group and adjusting the sear engagement or weight, mine were good

I never replaced ZKK sear groups.

CZ 550 replacement triggers

I have installed several Timney triggers on CZ 550 standard and magnum actions.

They are very simple to install and adjust, but as usual this is an issue of having the tools (in this case a trigger scale) and the knowledge (in this case the concept of sear engagement and appropriate trigger weight) to do it reliably and SAFELY.

Too many folks in their obsession to get a "trigger that breaks like a glass rod" have way too little sear engagement and way too little weight, resulting in a rifle that can fire accidentally when bumped (slam the rifle on the floor on its recoil pad to verify that this does not happen) or shouldered and touched off accidentally (a trigger weight less than 1.75 to 2 pounds does not belong on a hunting rifle -- this is not an Olympic event in a strictly controlled environment).

If memory serve Timney triggers come pre-set for reasonable sear engagement and trigger weight, but as usual best result is achieved by tuning it to a specific rifle to account for tolerances, etc.

I am perfectly comfortable with doing it it myself, but if you are not, and/or have never done it before, it is best left to a true gunsmith, which -- it must be said -- is not necessarily the same as a rifle salesman generally operating a gun shops these days...
 
Last edited:

CBH Australia

AH legend
Joined
Feb 10, 2019
Messages
3,095
Reaction score
6,262
Location
NSW Australia
Deals & offers
1
Media
18
Hunting reports
Africa
1
Member of
Sporting Shooters Association Australia, Africa Hunting website!!!
Hunted
Australia and now South Africa
Google it.

I've changed our a trigger group before and I have a Timney trigger for my CZ550.

I had a link saved once about removing the CZ550 trigger. I think there were a couple of springs or ball bearings that might come free when you dismantle it so the advice was to follow certain steps to be ready for it.
 

fourfive8

AH legend
Joined
Apr 27, 2017
Messages
2,847
Reaction score
5,953
Media
257
Hunted
USA, South Africa, Mozambique, Zimbabwe, Zambia, Botswana
OP clearly asked about putting an AHR single stage trigger into a “Brno” BRNO). I hate taking the barreled action out of the stock on my BRNO ZKK 602 but will when I get home, take a picture, post it and see if the OP is asking about the same deal
 
Last edited:

chslongrange8

AH member
Joined
Mar 28, 2022
Messages
43
Reaction score
43
Location
South Carolina
Yes doable. I did mine with an AHR replacement for the factory set trigger that came on the rifle But I was not comfortable with how it was set up. So I had my gunsmith, who was also doing the tricky Winchester M70 safety conversion on the rifle, double check it. He said it was fine and said those triggers are what they are...

IMO, the issue with the BRNO design is the whole sear/ trigger mechanism is a Rube Goldberg funky doodle design from the get go. The sear mechanism is anchored to the action while the trigger mechanism is anchored to the stock! Study most any better and elegant trigger designs and both the sear and trigger will be part of the action group- not one attached to the action with the other attached to the stock! Any variation in the stock to action fit will also affect the trigger to sear fit. UGH

Long answer, sorry. But yes you can do it by simply removing the set trigger parts and replacing with the one-piece single trigger. The lobed end of the trigger should fit into the tear drop shaped slot in the bottom of the sear with minimum play but should also rotate freely within that tear drop shaped recess in the sear mechanism. If in doubt, take it to a decent gunsmith. :)

IMO, this is what a serious hunting rifle trigger should look like- robust, simple, fail safe. But that's for a different story.

View attachment 502725
Good to know it can be done! Better to know that I'm better off just giving it to a gunsmith to do. Thank you!!
 

chslongrange8

AH member
Joined
Mar 28, 2022
Messages
43
Reaction score
43
Location
South Carolina
Let us be clear, the trigger is one of the very few things that are genuinely different between a Brno ZKK 600/1/2 and a CZ 550.

The Brno ZKK trigger pivots on an axis located in the trigger guard; the CZ 550 has a more classic trigger group attached to the action.

I am saying this because the original post could be a little confusing to ZKK new comers, it mentions both "Brno", which hints at ZKK 600 (standard) / 601 (short) / 602 (long), and "set trigger", which hints at CZ 550 standard / magnum (long). To complicate things ZKK were available with single direct trigger, single set trigger, and double set trigger. Further, ZKK triggers came in rounded shape and in Glock-like flat shape with a built in safety paddle. Which one are we discussing?
Wow - thank you for the thought out response, I appreciate it. It is a Brno ZKK 602 with the flat faced Glock-like trigger, and does have the safety paddle. It sounds like a smith is the best route.
 

chslongrange8

AH member
Joined
Mar 28, 2022
Messages
43
Reaction score
43
Location
South Carolina
Let us be clear, the trigger is one of the very few things that are genuinely different between a Brno ZKK 600/1/2 and a CZ 550.
Would you recommend sticking with the factory trigger, or doing the conversion? There is certainly no negative performance, as she's a shooter. BUT I don't love the ergonomics.
 

colorado

AH elite
Joined
May 8, 2011
Messages
1,658
Reaction score
2,395
Media
59
I had Wayne at AHR do mine along with the M70 type 3 pos safety and straighten and fill bolt. I love all of his work!
 

One Day...

Gold supporter
AH elite
Joined
Jan 7, 2018
Messages
1,669
Reaction score
5,690
Website
www.huntershillsafaris.co.za
Media
398
Articles
1
Hunting reports
Africa
3
Member of
PHASA
Hunted
Europe, America, Canada, Africa
You are correct fourfive8, I was probably using an abundance of caution...

The 5 parts that need to come out of the trigger guard are:

1669757948882.png

Single set trigger parts for ZKK 602 in the original factory "blue bag"


The one part that need to go in the trigger guard is

1669758091543.png

Direct trigger for ZKK 602

When the direct trigger is installed, the two rear pins that hold the set trigger springs in place in the trigger guard are not needed. You can either leave the holes empty (they will be hidden after the stock is put back in place) or you can put the pins back to simply fill the holes.

There is typically no spring included with the replacement triggers to hold the direct trigger in contact within the sear round notch. Some replacement triggers allow for the use of the original lighter spring for that purpose, others do not. I do not know for the AHR.

Typically the better replacement triggers do not rattle inside the sear round notch and do not need spring tension. Given the fact that Wayne knows what he is doing, I would expect the AHR trigger to be purposely ever so slightly oversized so that it can be carefully stoned to fit just so, without any binding but without any rattling (one of your wife's disposal sandpaper nail files will do just fine if you do not have gunsmithing / sharpening stones).

Also, if the steel pillars are used (as they should!) to assemble the rifle in the stock, they hold tightly the trigger guard at the proper distance from the action and there is no play whatsoever in the system.

Admittedly, the ZKK trigger was unorthodox, but it was both flexible with 3 options (single set, single direct, double set), utterly reliable, and quite good with neither drag nor creep.

Most DG caliber ZKK (typically the magnum length 602) have a direct trigger, and many 600 or 601 (standard and short) have a set trigger, because this makes the best sense in either case.
 
Last edited:

fourfive8

AH legend
Joined
Apr 27, 2017
Messages
2,847
Reaction score
5,953
Media
257
Hunted
USA, South Africa, Mozambique, Zimbabwe, Zambia, Botswana
As promised
Here is a BRNO ZKK 602 with AHR single stage trigger installed after removal of factory set trigger showing tear drop recess in sear toggle where the trigger end lobe fits when rifle is assembled.

IMG_3768.JPG


IMG_3767.JPG
 

fourfive8

AH legend
Joined
Apr 27, 2017
Messages
2,847
Reaction score
5,953
Media
257
Hunted
USA, South Africa, Mozambique, Zimbabwe, Zambia, Botswana
Sure. Hope it helps! After removing all the parts of the set trigger it seems too simple to install the one piece trigger with that single pin. But basically that’s all there is to it. The only thing I did was hone down the contact, fore and aft, sides of the lobe, trial error, until it slipped easily into the sear recess.

The contact lobe of the trigger should fit into the teardrop recess in the sear toggle with minimal play fore and aft once the rifle is completely re-assembled. I say minimal because there must be a tiny bit of play for the trigger end lobe to move with minimum friction within the teardrop recess as the trigger is pulled and the sear trips. I do not know the nominal clearance between the lobe and inside surface of the recess but I’d guess something less than .010”. One of those sneak up on it by feel things. :)
 

Forum statistics

Threads
46,772
Messages
953,160
Members
80,464
Latest member
wildmantn
 

 

 

Latest posts

Latest profile posts

Inline6 wrote on Chris Sells's profile.
PM me when you get a chance, have a few questions for you.
steve white wrote on Pheroze's profile.
Pheroze: I was intrigued by the blog on 400, 465 H&H in which you stated you were having a rifle reamed out to accomodate the larger bore. Who is doing the work for you, do they then provide cut rifling or buttoned. Will a 375 H&H rechamber to the 400 H&H. Is there much ballistic difference between it and the 404/375
My Most beautiful Trophy

IMG_20230125_071102_530.jpg
Bush Duiker shot in the free state just shy of 6 inch

1674577328003.jpg
DonT wrote on OLB's profile.
Just checking to see if you got the second package of shells I sent you?
Don
 
Top