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2/2/2009 8:49:55 PM EDT
As far as I've been able to find out, it seems that the .154 size LPK is the standard mil spec size for most lowers except for some colts that use the .170 size. Specialized armament lists 2 different LPKs at .155 and .170 size, but none in .154.  I've seen KNS pins offered in both .154 and .155 so there seems to be a difference between the two. So my question is, is there a difference in pin size between the colt .155 LPK and all the other LPKs in .154?  I have a non colt lower I want to build with colt parts, if I can, but i'm afraid the larger (.155) pins will overstress the holes in the lower. Also, what parts do the sizes refer to?  I'm thinking about using KNS non rotational pins. If the pins that come in the KNS kit are the only pins that make the difference between the sizes, I guess it wouldn't really matter.  If I were to have a colt .170 LPK and I bought the KNS pins in .154, would i have all the parts to build on a mil spec lower?  Thanks guys.
2/2/2009 9:18:32 PM EDT
[#1]
NO. The pins dont just fit the receiver they also fit the hammer, trigger and disconnector.
2/3/2009 3:52:00 AM EDT
[#2]
Have not had a problem either way. RRA's 2-stage trigger comes with the "bigger" ( .155 ) pins, but in my 3 builds so far ( Mega lowers ) they both ( .154&.155 ) work fine with no appreciable difference in fit.
2/3/2009 5:38:11 AM EDT
[#3]
I believe that the actual size is something like .1547899274897589427589475258978954 and some people choose to round up when describing them. Either way, a "larger" pin in a "smaller" hole will simply be a little harder to install.

You can't mix and match FCG pin sizes.

Don't bother with KNS pins. Oh, and their .1555 pins are for worn receivers, not new receivers.
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