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Posted: 1/8/2014 9:38:32 AM EDT
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I bought a pro upper from PSA. I then found Geissele rail and his tool kit on sale so I bought it.
Went to take the upper apart and the barrel turned in the upper receiver. I was using the Geissele reaction rod. The barrel is suppose to be made by FN. It looks to me that the pin in the barrel was not installed properly and was not sticking out far enough to engage the upper receiver. So now the barrel spins when the barrel nut is attempted to be tightened. How do I fix the barrel? I could only get my potato to focus so much on the bottom 2 pics but you can see it was not engaging the upper slot very well. 
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You may need to to drill it out, once the bit bites, pull on the bit and remove the pin. Roll pins have been known to do the job... |
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Quoted:
You may need to to drill it out, once the bit bites, pull on the bit and remove the pin. http://www.midwestgunworks.com/page/mgwi/prod/F1003204 Roll pins have been known to do the job... Would not recommend using a roll pin as a replacement. Use the correct part.....a solid steel pin. |
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Quoted:
How does a steel pin get stripped off flush from a thin piece of aluminum! Without screwing up the aluminum at least a little bit?? AL it looks like a pretty good groove in the upper from the pin. how the pin got that damaged by a much softer metal is beyond me. |
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I’m a home machinist, so first of all I don’t think I would have allowed that to happen, but that’s me, I have a good eye for mechanical issues that non metal workers don’t have.
Now if someone brought me this problem, I would remove the pin, and there are many ways to do this, as it’s just a steel pin, similar to a key way used in allot of other type of equipment, it’s most likely nothing real special, just a steel pin that fits the hole in the barrel adapter, with an interference fit, it’s probably pressed into the hole. I’d remove it and make a new pin, with either some drill rod stock, and some grinding and shaping, then press the new pin into the barrel adapter. I’d say go find a local machinist somewhere that don’t mind working on firearm parts. Some will tell you to take a walk. But most would be happy to tackle this small problem. Or send it to the pro’s that everyone has recommended. As far as the damage done inside the upper mounting tube, don’t worry about that, if you fit a new pin and install the barrel, nobody will ever see this gouge in the lip of the barrel tube. I doubt it will be any issue for your recreation fun gun. And use a action block to keep things from turning that are not supposed to be turning, as you found out the hard way. Some machinists would weld another piece of metal to this damaged pin, the heat will do two things, when metal gets welding hot, it expands, then when it cools, it’s now a bit smaller in diameter, then the machinist has something to grab onto, with the right type of tool, such as a good pair of vice grips and a lever block, and some protection cover for the barrel, and then just pry that bugger out of the hole after it’s cooled off. Some will just drill it out with a smaller drill bit, and then use a screw remover type bit, and twist it out. Some may just drill the whole pin diameter and then make a new properly fitting pin. And you may even have to heat the barrel adapter slightly to expand that. allowing the pin to be removed with the welded pin attachment and vise grips. Let us know how it turns out. Good luck. |
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Receiver block/clamp would not have prevented this.
Steel does not get sheared by aluminum as shown here. This is some bullshit on the assembler. Damaged or short index pin upon barrel install, and most likely a barrel but that was galled upon install. Key question. Are those cheap ass PSA parts REALLY worth fukin with? Not in my eyes. |
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Had this happen using a barrel vise. Rainier ultramatch barrel in a seekins billet upper with seekins barrel nut. Doing the second tighten and loosen while installing barrel the whole receiver spun with the nut. MADE ME SICK. Didn't damage the receiver at all. Used a drill press to get the pin out. Once the drill went into the pin a little the pin stuck to the drill and it lifted right out.
To make a new pin i cut a little off the bottom of a 1/8" drill bit. tapered the end of the pin a hair and put it in the freezer for 20 minutes to shrink it then pressed it into the hole with a vise. Worked great. Had never used a torque wrench to install a barrel nut but broke one out after this aggravation. After using the torque wrench I'm positive there was never over 35 ft lb on the barrel nut first time around. Seems crazy but it apparently happens. Almost positive the original pin had a flaw in it. Everything went together like it should the second time around. Told an armorer buddy about my experience and he said i was nuts and I'm sure others think this too. For the steel pin to shear off flush with the barrel extension and no damage be done to the aluminum receiver is nuts and lucky. |
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