CZ 550 9.3x62 second recoil lug?

kayaker

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Hi all.

I just replaced the full length stock on my CZ 550 FS 9.3x62 with an older CZ 550 American stock, also from a 9.3x62.


The CZ's use a second under barrel recoil lug dovetailed into the barrel. CZ obviously changed the location of the lug as the 'new' stock has the lug recess a bit further back so I had to remove the second under-barrel to get it to work (just slides out). The rest fits well.


The stock as a steel recoil lug plate and 2 cross bolts. The CZ action also has a large recoil lug, bigger than a M98.


Is this second under-barrel lug really necessary on a 9.3x62? Many 9.3's don't have this feature, including M98 actioned rifles which have smaller recoil lugs than the CZ. 9.3x62 has fairly stiff recoil but its not a real hard kicking cartridge, as many of you know.


Opinions? Has anyone else removed this second recoil lug (the aftermarket B&C stock that some people buy don't accommodate the second under barrel lug).


Thanks
 
I can't really talk about the CZ rifles, but I can talk about the elder brother - the Brno ZKK60x series.

I have 4 of these rebarelled to various calibres - 2 x 601s converted to 7x57 and .260 Rem, a .375H&H in 602 and a 600 in 9.3x62.

ALL of these have been stocked without the front lug. The 7x57 and 375 are in other stocks so they may not count - but the 9.3 and the .260 are back in Brno stocks where they came from and are showing no adverse effects.

I admit I have only fired about 250 rounds out of the 9.3, but there are no indications that it's coming to harm - and it shoots acceptably at 100m - about 1.5" with an old Weaver K2.5 on it.
 
No Brno experience either, but my Sako 9.3x62 doesn't even have a cross-bolt, just a loose recoil lug (held in place by the front action screw - see picture link below) that fits into a recess in the wood. I was a bit surprised at this, as it kicks more than just a little, but the stock doesn't seem to have started cracking yet.

https://www.usedguns.com.au/pics/1-106560-2017-07-24_10-07-51-AM.jpg

/cmk
 

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So I had a specific conversation about this with the owner of Triple River Gunsmithing. MY 550 in 9.3 came from the factory with the Kevlar B&C stock and NO barrel mounted recoil lug. Apparently they aren’t necessary on a 9.3. So if I want to get that factory walnut stock, I’ll have to go with fake cross bolts I guess.
 
Thanks all,

As I suspected. I mean Tikka has one single lug and its small and not very robust. I was sanding out the barrel channel on the new stock and the recoil lug surface in the stock has a substantial steel plate on it and 2 cross bolts. I am sure it will be quite fine! Thanks
 
good walnut or synthetic stocks will minimize the need for barrel recoil lugs on rifles up to and including 375 h&h.
the problem with these lugs is that to do what they need to do, they should contact the stock on their rear face, with clearance on the sides and bottom.
this means that when (not if) the forend moves, the point of impact also moves.
it also means that resting the forend on something hard will move the point of impact away from the rest.
which brings us to tolerance stacking.
these point of impact moves can be of the magnitude of 1 moa
go back to 200 yds and that could make the shot 2" high.
then add 1 moa shooter error, another 2" high = 4" high.
then if the shot is high in the group of a 1 moa rifle, another 1" high and we are up to a total of 5" high on a reasonably good shot.
float the barrel and this goes back to 3" high, far more acceptable.
on a dangerous game rifle this is a non issue, due to shorter distances.
it does however suggest that a rifle a little more powerful is better than one of border line power.
the trend to cut costs on modern rifles with bolt on or dovetailed recoil lugs is worrying when considering tolerance stacking, grouping consistently, and holding zero.
bruce.
 
I believe that the design on CZ 550 with 2 recoil lugs is newish. Before they had some problems with heavy calibres (+ 375) splitting stocks. So they added the front lug which someone pictured above. I have sat and thought long and hard why they added the front lug.(shown in the pictures above) What I think is that the front lug is in solid wood. Recoil then spreads out through 2-3 inches of solid wood before the magazine box. The second lug is just in front of the mag box and so more likely to split this area. My 458 had a plastic strip on the wood in this back lug space. I have epoxy bedded both these lugs (not full bedding, just the lugs) I do think the front lug carries most of the recoil because it has solid wood to bear the load. Can you not simply cut or route out some new slots for the front insert ? Surely a gunsmith wont charge too much ? You can also epoxy this front steel insert in if the routing is a bit rough.
 
Never heard of CZs splitting stocks but I'm sure someone has one. Barrel recoil lugs were found on ZKK 602's even way back when, so not that new. Rifles shot well even with barrel touching wood. Some shot even better free-floated. I say glass bed the action, free float the barrel, ditch the lug. I did on a .375H&H ZKK 602 and it shot very well that way. No split stocks. I still have the barrel lug in my 9.3x62 but that's because I'm lazy and the rifle seems to shoot well anyway.
 
With the CZs I remove the sliding T barrel retainer, then machine and fit a second recoil lug on the knox form
Easy as
 
With good quality dense air dried wood (which is inlet correctly!), the need for under barrel lugs and cross bolts up to around 404J is nil. Often the under barrel lug is used to hold the heavy barrel into place and to create an adjustable tension point for pressure points in the tip of the stock. If the rifle is free floated via bedding, this point is void.

cross bolts can be seen on even medium Parker Hale rifles in .243, it was used as a way to mitigate bedding and precise inletting whilst avoiding stock splits from cheap wood.

cross bolts in calibres deserving of them, for the right reasons, is usually to avoid ugly glass bedding, avoid stock splits in the mag weld area, in the area between the mag and trigger guard, and to avoid splitting of the sidewalls along the receiver to stop the recoil creating a ‘bulge’ type effect. This is one of the reasons the earlier type B Mauser’s had enlarged sidewalls of course.

a well fitted 9.3 in decent walnut does not require cross bolts.
If free floated, then neither the barrel
Recoil lug (usually also matched with a pressure point).
 
I have owned 3 CZ's in 9.3x62 and all had the barrel lug and all shot well and gave no problems. I havent yet bedded the current one, but have been working on the barrel channel whose relation to the barrel was somewhat indifferent shall we say.
Best group so far with this rifle is 4 in sub MOA at 100 and if it continues that way I will probably leave it alone.
I always thought the second lug was a positive feature, thought everyone did..
 
The second lugs for cz 550 stock
This what it looks like. Got it machined for my extra back up stocks in case.
Krish
16532599625437726531107861906935.jpg
16532600328581955860480568709986.jpg
 
Bedding provides no additional strength to the stock

Action screw pillars provide no additional strength to the stock

Cross bolts ( not hidden ) when fitted correctly apply a crushing effect L to R and stop the stock expanding during firing

CZ 550s have a small piece of black rubber between the action recoil lug and the recoil lug recess rear face, this rubber needs to be removed

Second recoil lug aids in transmitting the recoil motion of the metal work through the stock

Relieving the tang to tang recess is essential

All my large cartridge, Big Bores over say 375cal in wood stocks have second recoil lugs fitted

No one ever bitched about a second recoil lug, but by crikey there's some tears when the second lug is not fitted and the stock fails
 
Cz call them " F " blocks.
Krish
These F Blocks are rubbish and are thrown over the shoulder to be replaced with a solid lug and bedding
F Block allow too much movement of metal work in the stock
 
Bedding provides no additional strength to the stock

Action screw pillars provide no additional strength to the stock

Cross bolts ( not hidden ) when fitted correctly apply a crushing effect L to R and stop the stock expanding during firing

CZ 550s have a small piece of black rubber between the action recoil lug and the recoil lug recess rear face, this rubber needs to be removed

Second recoil lug aids in transmitting the recoil motion of the metal work through the stock

Relieving the tang to tang recess is essential

All my large cartridge, Big Bores over say 375cal in wood stocks have second recoil lugs fitted

No one ever bitched about a second recoil lug, but by crikey there's some tears when the second lug is not fitted and the stock fails
I would quibble with a couple of points.

I believe that a good glass bedding job does strengthen the stock in critical areas, the main recoil lug in particular. Have seen more than a few rifles with this whole area either cracked down the middle, up, down and sideways, or sheared completely off.
A bedding job here makes it good for years to come and improves accuracy proving to me at least that it does strengthen the stock. My 1983 vintage Whitworth .375 left the factory with good epoxy at both the main lug and its forward extra lug. Have put many, many rounds thru it with nary an issue.
To the contrary a year or so ago I picked up a first year 1974 Whitworth in .458 with no bedding and no forward extra lug at all. Guess what? Stock was all blown out in the main recoil lug area. I bet it failed in less than 10 rounds! I have since repaired it myself though a sore shoulder has kept me from shooting it again since the repairs.
Had it been bedded like my .375 its likely it would have been OK.

The piece of rubber you refer to is actually a hard plastic I think similar to the stuff they use for the magazine follower which I replace with steel parts.
As to removing it and chucking it, then what? That space that the plastic piece occupied must now be filled with something else, lest the action puts all of its rearward forces on the forward lug, not a good situation, or it blows that out and continues to move back into the tang, which as you said must be relieved anyway as most are fitted too close to the horseshoe which eventually leads to a cracked tang area.
So if that piece is removed, then glass bedding is the natural replacement for it, which again, will add to accuracy and strengthen it.
Just my observations.
 
The forward F block is steel bedded along with the forward barrel screw so there is no movement or slack. When i get a chance i will post a picture. So is the action lug is steel bedded as well. I have had no prblems. It is important the tang is relieved. Good idea to piller block and cross bolts. All my 550's are double cross bolted. Some are also piller blocked.
Krish
 
I would quibble with a couple of points.

I believe that a good glass bedding job does strengthen the stock in critical areas, the main recoil lug in particular. Have seen more than a few rifles with this whole area either cracked down the middle, up, down and sideways, or sheared completely off.
A bedding job here makes it good for years to come and improves accuracy proving to me at least that it does strengthen the stock. My 1983 vintage Whitworth .375 left the factory with good epoxy at both the main lug and its forward extra lug. Have put many, many rounds thru it with nary an issue.
To the contrary a year or so ago I picked up a first year 1974 Whitworth in .458 with no bedding and no forward extra lug at all. Guess what? Stock was all blown out in the main recoil lug area. I bet it failed in less than 10 rounds! I have since repaired it myself though a sore shoulder has kept me from shooting it again since the repairs.
Had it been bedded like my .375 its likely it would have been OK.

The piece of rubber you refer to is actually a hard plastic I think similar to the stuff they use for the magazine follower which I replace with steel parts.
As to removing it and chucking it, then what? That space that the plastic piece occupied must now be filled with something else, lest the action puts all of its rearward forces on the forward lug, not a good situation, or it blows that out and continues to move back into the tang, which as you said must be relieved anyway as most are fitted too close to the horseshoe which eventually leads to a cracked tang area.
So if that piece is removed, then glass bedding is the natural replacement for it, which again, will add to accuracy and strengthen it.
Just my observations.
In what way does bedding the recoil lug and know form add to the stock strength ??

Yes bedding compound replaces the rubber piece that is removed
 
So I had a specific conversation about this with the owner of Triple River Gunsmithing. MY 550 in 9.3 came from the factory with the Kevlar B&C stock and NO barrel mounted recoil lug. Apparently they aren’t necessary on a 9.3. So if I want to get that factory walnut stock, I’ll have to go with fake cross bolts I guess.

Harlan is great guy. He did some excellent work on my CZ 550 in 500 Jeffery. I've heard he's retired. I wish him the best.
 
IMO glasss bedding and recoil lugs go together on a using rifle thats going to the edge of the world where gunsmith are not handy....Needed or not recoil lugs can't hurt thing...
 

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