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Posted: 6/29/2004 9:33:48 AM EDT
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How snug should these pins fit in the lower? I have a Colt lower rec(large pin) and just picked up a parts kit for it. The pins fit in an appear not to have any excess space but even a gentle jiggle of the receiver causes the pins to fall out(no other parts of course). I've put a few lowers together with other parts and they seem to fit more snugly. I do not want to use parts that might cause excessive wear to the rec holes. Thanks. |
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The pins should be able to be inserted with firm finger pressure, or light taps from a rubber mallet. If they drop out when wiggled, either the pins are undersized, or the holes are oversized. The trigger pin should not jiggle free at all, since the leg of the hammer spring should rest in the pin's groove and hold it in place. If you have the capability, measure the holes (they should be 0.156" +/- 0.0015). I don't have the spec for the pin diameters, but I expect they should be somewhere around 0.155" +/- 0.0010. It is possible that your lower has holes on the large side of the spec (0.1575) while the pins are on the small side of the spec (0.1549). Something on this order (a 0.0026" difference) could cause problems you mentioned. Is this a new lower and new pins? |
| The spring pressure holds them in,if you can push in say the hammer pin in assembly through to the other side without the help of a mallet then the hammers J pin is weak.Before assembly the pins should go through the holes freely.The hammer pin should rotate when the hammer is moving like was mentioned the hammer spring tails over the trigger pin and the spring pressure hold it all in.The day you can push out a pin the springs and or hammer needs replacing.The holes should not wear out unless you are banging around a pin punch not knowing what you are doing.The israelis have M16s that have been in service 30 years being rebuilt time and time again and still kicking.If you replace lower parts only when they need to be you will minimize wear on the holes. |
| The pins pass right through the holes it dosent hurt the holes to see how the pins pass through.Like I said its the spring pressure and the hammer spring tail on the trigger pin groove that holds it all in,they should rotate freely in their holes.I know the hammer rotates on the over sized snug fitting match grade pins. |
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