Hello. For those that have done this before, I want to have a 404 Jeffery caliber barrel put on my 458 WM Brno 602. My question is how important is the third screw thru the forearm into the barrel? Thank you. Gary

None whatsoever. Every maker who used that 19th century feature, and they all did, has long since abandoned them. The theory was to anchor the barrel firmly to the wood stock, which as we now know, is a bad idea.

depends -- are you going to load to 60K or classic loads?

Classic 404 loads.

What difference does the pressure make?

quote:

Originally posted by dpcd:
What difference does the pressure make?

uhm, the difference between a shattered stock and a sound one? at classic load levels, "who cares" about a third bit . for pushing it into 416 remington specs, (or rum) it can certainly break stocks without a third lug -- btdt

Let us not confuse that screw, with the separate recoil lug against which the rear sight boss rests. So, yes you need the barrel recoil lug, of course, But the screw? Ok the reason it is there is to hold the barrel down, but without the lug, which is a separate piece, the screw is useless; it's lug is quite small.
I much prefer the Model 70 type recoil lugs which are attached to the barrels.
You are a ZKK expert; you know what is under the barrel.
I just want to make sure that the OP knows that just using that screw won't help him.

Ok then. If I am understanding things here, I need to order the new barrel set up like the original barrel, not just a turned barrel. Sorry but I have never set up a project like this before. Thanks. Gary

Also, can the barrel maker do just the 3d lug and not the island for the rear sight? Just the bottom and not the top?

First, understand that to make an integral lug, either top or bottom will cost at least twice the price of the barrel; you have to start with an oversize blank and turn and mill out for the lugs. Not an efficient way to do it and only for the high end, well heeled clients. Definitely the most expensive way to do it.
And not necessary. The usual way is to use a standard barrel, and either solder on, or dovetail in, a barrel recoil lug. Look at a winchester model 70 and see how they are done. Very large, separate lug, soldered into a slot in the bottom of the barrel.
Can a barrel maker just make a lower lug? Most barrel makers won't do that; custom smiths do that. Very rarely as, as I said, it is very time consuming for no gain.
The original BRNO lug is just a little piece of steel set into the stock and the rear sight base has a lower flat on it. Again, pretty, but very expensive to make. Unless you have $1200 to spend on a barrel, don't do it that way.
So for the OP; pick the barrel you want; (I use only Douglas, easy to get and as accurate as any, more accurate than most, well proven). Make a recoil lug like the Model 70, and solder it into a milled slot under the barrel. I can send you a picture of what you need if you PM me your email address.

Or use a solder on rear sight band that has an integral recoil lug on the bottom; Recknagel. Those look cool.

is truth == i am more concerned about 3rd lug than the screw .. though zkk ans cz aren't exactly n00bs or low volume producers of big bores ... all of my heavies have a 3rd lug, most of them have a screw,but not all