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Posted: 5/8/2007 5:31:04 AM EDT
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Okay, I have a Romy G build and the barrel is trashed (trust me on this one). As it was a all matching set I think I'm right for assuming what ever I do, the headspace needs to be redone with the new barrel. There are dozens of sites showing how to check headspace but nothing on the correction. I've searched for the following answers but cannot find them. I'm planning on either a new US manufactured barrel or a unissued replacement from Copes and well as go and no-go gauges. Informative links would be appreciated. Any barrel I get has the cutout for the barrel pin and I will be re-indexing onto this cutout with my existing trunion, right? Sounds like a stupid question but what other choice do I have? I understand how to headspace but what are my chances that a new barrel will headspace just fine? I'll assume that insuffcient headspace can be adjusted by removing minute amounts of material from the back of the locking lugs but how would I fix excessive space? Thanks to all in advance. ETA - If anyone wants to recommend a source for barrels, feel free. |
| If you can get a barrel without the cut out for the pin thats the way to go.If not,then set the headspace right by moving the barrel back and forth in the trunnion.When its right,drill the existing pin hole for a larger diameter pin and press it in.You might get lucky and it will line up OK without drilling it out. |
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You need to get headspace gauges. At least get the no-go gauge and use a live round for a go gauge. You press the barrel on and use teh bolt and bolt carrier to see if you can chamber the live round. Make sure that you take the firing pin out of the bolt. I would also take the extractor off that way you don't end up with any false readings. You then gently slide the bolt/bolt carrer into the trunnion with the live round in there. If it chambers and the lugs lock up, you nkow that you have enough headspace. Then you put the NO-GO gauge and gently slide the bolt carrier assembly forward. It should NOT lockup. If it does, then you have too much headspace (BAD). If it does lockup, then you need to press the barrel further into the trunnion (closing the distance between the locked bolt face and the barrel chamber). Then check again with the live/go round and the no-go. Once you get it to the point that the bolt locks up on the live round/go gauge and does not lockup with he no-go gauge, then your headspace is set. AT that point you look though the barrel pin hole. Use this picture for reference: http://www.q45.org/bo/gun/hedspaceing.gif If the hole is lined up perfectly with the barrel pin notch, then you just put the pin in its place and call it good. If the barrel is a tad bit forward (you see the green portion of the barrel pin notch showing) then you can just drill it out with the same size bore/drill bit as the barrel pin hole already has. Since the firing pressure is pushing the barrel forward, you are safe to do that. However if the barrel is a tad bit rearward (you see the orange portion of the barrel pin notch showing) then you must drill the whole hole oversized so that you seen a smooth concentric hole though the barrel pin hole. Then you would use the proper sized new barrel pin to put in place of the now undersized factory barrel pin. |
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