For all you 'smiths out there. Removing a barrel?

P

Pond James Pond

New member
As some know, having read my lamentations about some chipped rifling in my new VZ58, I am exploring all options for getting the gun that I want from this tidy set up.

One such possibility is perhaps replacing the barrel or repairing it. I need to examine the rules on this too. It may be easier for the barrel to be removed (for legislative simplicity).

So, in preparation, I want to have some idea of what is needed to remove the barrel, whether it becomes necessary or not.

So. What needs to be done (in general terms) to remove the barrel from a VZ58?
 
I have to ask, how does the rifle shoot? I read your other post and IIRC you never stated how the rifle shot. As far as crowns go take a look at the Colt Python muzzle of the barrel is a straight cut. No crown at all.
 
You need specialized tooling and a hydraulic press- not worth your expense for a one-time replacement; find a local gunsmith that specializes in these and/or AK's.
 
Action wrench. This fits onto the receiver and clamps down tightly on it.
Barrel blocks. Cut for the outer diameter of the barrel.
Barrel vise.

Action is removed from the stock.
Action wrench is slipped onto the action near the barrel.
Barrel blocks are inserted into the barrel vise and the barrel vise is tightened down. May want to put a bit of graphite on the barrel.
Rotate counterclockwise to remove the action from the barrel.
 
I have to ask, how does the rifle shoot?
Click to expand...

No idea, as yet. Hope to find out but as yet not had the time. Basically, if a chance comes to get it sorted I'll take it whether I've shot it or not, TBH.

There is no way that a sorted barrel will be worse than that muzzle as it is.
It may cost a bit more, but it is peace of mind for me and that is worth quite a bit!
 
First,I don't know anything about your rifle.MOST centerfire rifles have threaded barrels that screw in. 4V50 Gary is PROBABLY correct.He may know,for sure.

But there are other systems.Our AR-15 type rifles are an example.

You might search for a reference book with details or a military armorers manual.

In theory,perhaps the CZ is made to such exacting standards the barrels are truly interchangeable and drop in.
But,as far as I now,nearly all rifles require a headspace check after installing a barrel.You have a chrome bore.That means you aren't likely to fix a headspace problem easily.

This is a situation where I would want to know exactly what I was doing before I started.

Update: The barrelDOES NOT unscrew.It is pressed.

https://youtu.be/HOPtRYvqsHw

https://youtu.be/6AjYE6cll3g

Revisiting the idea of a counterbore,It looks like another option would be to put the rear of the receiver into a 4 jaw chuck on a lathe and the barrel in a steady rest. With patience and a dial indicator or two,the barrel and receiver can be adjusted with the 4 jaw chuck to run true to the bore,at least as true as the OD of the barrel is to the bore.

That done,you could use a carbide boring bar or Uncle Nick's toolpost grinder idea.
While a Dremel lacks the spindle bearings you need,you could probably get by using a Fordom grinder ball bearing handpiece to jury rig a "good enough" toolpost grinder.Just use a light touch!
 
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Rest assured. This is not me attempting a barrel change.

I just want some idea of the work involved in case I need to pay someone. Gives me some idea if they know what they are doing and if their quote is reasonable.

For example, that point about headspacing is very useful to know. I'll know to ask if it has been done.
 
Action wrench. This fits onto the receiver and clamps down tightly on it.
Barrel blocks. Cut for the outer diameter of the barrel.
Barrel vise.

Action is removed from the stock.
Action wrench is slipped onto the action near the barrel.
Barrel blocks are inserted into the barrel vise and the barrel vise is tightened down. May want to put a bit of graphite on the barrel.
Rotate counterclockwise to remove the action from the barrel.
Click to expand...

Not a bolt gun, guys - similar design to an AK.

Different animal, altogether. Headspace is set by pressing the barrel in place with a hydraulic press. Install bolt/locking lug, press barrel into receiver (the hydraulic press), drill/pin in place.
In this case of a re-barreling, the damaged barrel would be pressed out first by reversing the procedure.
 
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I have seen there is a pin traversing the receiver right in the area of the chamber. It may be that this helps not only retain but also align the barrel...
 
weaponsguild.com is a great resource to see how home builders tackle processes like this. It may not be on professional equipment or quality, but you'll get to understand how they are commonly put together.

My understanding of the VZ58 is that it's similar to an AK or a HK91/CETME/G3 in how the barrel is installed. The barrel is not threaded, but has been turned to an interference fit with the trunnion. The barrel must be aligned in the trunnion (so you don't get a crooked front sight or gas tube) and then the installations are pressed on with a hydraulic press (populating the barrel). I'm going to assume your barrel has already been chambered, drilled for a gas port, and all of the attachments pressed on - otherwise you will add a fair bit of work.

The barrel is pressed into the trunnion until headspace is set correctly. Once this is set and the barrel is confirmed to be aligned, the barrel is likely drilled/milled and then reamed to match a hole in the trunnion. A tight fitting pin will be driven through to hold the barrel at the correct spacing and orientation (no wandering headspace).

So, removal might go something like this:
Complete disassembly of your firearm

Removal of the barrel retaining pin/trunnion through pin - this step hopefully will require only a press and not some drilling or other coaxing of the pin.

Pressing the barrel out through the rear of the receiver (likely requires some kind of specialized jig since I doubt the ram will reach the rear of the barrel)

Population of the new barrel/drilling of the gas port/reaming the chamber if this has not already been done (hopefully it has)

Pressing the new barrel into the trunnion until it sets correct headspace (using a hydraulic press and alignment/pressing jigs)

Drill out the barrel for the retaining pin using the the existing hole as a guide. This will probably be done with a high speed steel or carbide endmill (the flat surface will be less likely to walk off the rounded barrel) and the reamed to size. Then the new pin will be pressed in, probably also requiring the use of a press.

Assuming proper headspace, gas hole alignment etc, from this point all that should be left is to re-assemble the gun. Hopefully the barrel you are working from is already finished and doesn't need blued or parkerized.

In other words -- it is a hassle and not too many gunsmiths do the type of work. It's very different than re-barreling most sporting rifles using a lathe/mill and most gunsmiths just don't have the experience or equipment to do it. You want to make sure your gunsmith understands military arms and their assembly enough to do this type of work.

To me, it makes more sense to shoot it and see how it groups and try addressing the crown before rebarreling everything. These guns weren't meant to replace the barrels easily as some other designs are. My German manual for G3 armoring and repair rates the barrel replacement (a very similar process) to the highest level repair requiring central replacement. You are essentially rebuilding a significant part of the gun when doing so.

Hope this helped some.
 
It does help a lot.

Indeed, I agree that this guy would need to know what he is doing...

This would be done via the shop anyway, but if I can, I'd like to meet him...

Otherwise, counterboring does seem like the simpler option: less to go wrong!!
 
James,

If you were to tackle the counter-boring in a home shop, would you have to report the repair to authorities there? Just curious. Some places have some regulations I don't understand, including many of them here.
 
I have heard of some crazy laws, but never heard that one. You are not even changing caliber, just running an oversize (.40" or so) drill 1/2 inch or so into the muzzle to clean up the point at which the bullet exits from contact with the rifling. This was often done to restore accuracy in barrels that were worn at the muzzle from use of a cleaning cord (pull-through) or a cleaning rod. It was seldom done in US service as a wealthy country could afford to replace worn barrels.

More to the point, I think the barrel installation would probably not be in that order. The barrel would be made short chambered. It would be installed and aligned in a jig, then the alignment hole drilled through the receiver and the barrel; with a replacement barrel, the hole in the receiver would stay; the hole in the barrel would be drilled using the receiver holes as a guide. Then the chamber would be final reamed to set headspace.

Jim
 
If you were to tackle the counter-boring in a home shop, would you have to report the repair to authorities there?
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The law here is basically all about keeping a track of guns.

So if I hand it over to a 'smith, I'll get a receipt that I could show to the police if the need arose, accounting for why a gun in my name is not in my possession, given that I am legally responsible for it...

Doing stuff at home is fine, as long as you don't change a gun beyond legal dimensions/parameters, such as shortening a long-gun excessively. Then again that would be forbidden in a shop too, but you see what I mean.
 
I gotta say, the OPs multiple threads have questions where the answers don't matter until he shoots the thing to see if any work needs to be done at all. Without knowing if the damage is .003 in depth or .100 it's not easy to advise on the best solution for a problem that may not exist.

Jeff

Sent from my XT1254 using Tapatalk
 
The multiple threads are there to focus the discussion. Otherwise questions that may arise from learning something new get lost in the rest of a thread on a different aspect of the same problem.

The problem does exist. That being that I'm not happy with the rifle as it is. I also can't believe that, however it shoots now, it won't shoot better once this is addressed.

I have seen the factory targets that came with this gun and a couple of others and the group on mine is more spread out and lateral to the POA. Others were tighter and in the vertical plane of the POA. Not a good sign for me.
 
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