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Posted: 2/17/2026 5:24:44 PM EDT
[Last Edit: Jambalaya][Edited]
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I want to replace the original barrel in my VZ61 kit with a longer, threaded version designed to clear the stock for suppressor use. I went and bought a 12 ton shop press during the weekend 15% sale at Harbor Freight. I know that the trunion must be supported from the inside to prevent crushing the receiver when pressing out the barrel. I intend to use a round section of pipe around the chamber end of the barrel to support the trunion. However, I am stuck on the part where I need to drive out the cross pin. It looks like this pin is flared on both ends and it isnt readily apparent which direction to drive it out, and I dont know if I shoul be using something like a stiff center drill to remove the flare, or which side of the receiver to do that on.  And further, will I need to buy a new pin if this one needs to have the flare removed? I have some 3mm stainless steel rod stock that could be used to make a new pin, unless there is some technical reason I cant use it, or it requires a tool I dont have. Also I have piles of PETG and a 3D printer if that would be helpful for printing any necessary fixtures. Any guidance would be appreciated.  |
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I’ve swapped barrels back and forth on mine. Barrel pin can either come out with an appropriate sized punch or be pressed out very carefully with the press. There’s a chance it can be reused. Some 3mm stock, like you have, can be cut and domed if you want to start fresh. I used a section of heavy walled pipe to support the rear side of the trunnion when pressing out. I’ve used both thick leather or a hockey puck to protect the crown on the ram side. Just make sure your pipe is seated well when you start pressing or it’ll want to shift the upper to the side. Go slow with little pumps on the press. They come out relatively easy. For installing the new barrel I’ve just used the bolt as a slide hammer to get it driven home, then drill the barrel pin notch and carefully put the pin in. |
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Originally Posted By zaitsev44: I've swapped barrels back and forth on mine. Barrel pin can either come out with an appropriate sized punch or be pressed out very carefully with the press. There's a chance it can be reused. Some 3mm stock, like you have, can be cut and domed if you want to start fresh. I used a section of heavy walled pipe to support the rear side of the trunnion when pressing out. I've used both thick leather or a hockey puck to protect the crown on the ram side. Just make sure your pipe is seated well when you start pressing or it'll want to shift the upper to the side. Go slow with little pumps on the press. They come out relatively easy. For installing the new barrel I've just used the bolt as a slide hammer to get it driven home, then drill the barrel pin notch and carefully put the pin in. Okay thank you for the guidance. Did your barrel pins look flared like the pictures I posted above? Searching says it should be pressed out from left to right. |
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How does this new pressed in barrel headspace? I've had a VZ52 barrelling project on hold because I am uncertain how the headspace will grow after I fit the barrel and start shooting it. I'd have to cut the barrel for the 6mm (?) barrel pin and install the pin. Is there a rule of thumb about short chambering and allowing the barrel to settle in before finish reaming? Or how is this done with a rifle round? |
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Originally Posted By Elwood_Blues: How does this new pressed in barrel headspace? I've had a VZ52 barrelling project on hold because I am uncertain how the headspace will grow after I fit the barrel and start shooting it. I'd have to cut the barrel for the 6mm (?) barrel pin and install the pin. Is there a rule of thumb about short chambering and allowing the barrel to settle in before finish reaming? Or how is this done with a rifle round? Its a blowback gun. So headspace isnt super critical. Itd have to be WAAAYYYY off to cause an issue. And its just best a functional issue at that point. |
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