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8/21/2008 7:48:06 AM EDT
I know the Hammer pin size/trigger/hammer are larger size in their lowers.

What other parts if any are different??
8/21/2008 8:17:21 AM EDT
[#1]
Not all Colt lowers have 0.170" fire control pins.

Some Colt lowers take a 0.315" pivot pin, this is considered "big hole".
8/21/2008 1:33:44 PM EDT
[#2]
Colt has made models with .154" and .170" fire control pins.

They have also made receivers with .315" and .250" pivot pins.
8/25/2008 10:24:30 AM EDT
[#3]
Roger... i understand that my question was if I have a colt with the the "Big Hole" parts... What parts differ from the say RRA/DPMS small hole lowers.
8/25/2008 10:34:03 AM EDT
[#4]
Check out this thread that compared the differences between different brands of lowers.


AR Lower Receiver FAQ (56k beware) MMS, CMT, LAR, LMT compared... tacked thread link
8/25/2008 10:44:02 AM EDT
[#5]

Quoted:
Check out this thread that compared the differences between different brands of lowers.


AR Lower Receiver FAQ (56k beware) MMS, CMT, LAR, LMT compared... tacked thread link


I am aware of the differences in lowers, and thank you for pointing out a thread that talks about the milling of lowers and the cute white lettering.  I can't find one post in that thread that addresses the PARTS that are different in big hole/small hole lowers.

I am talking about PARTS is in internal PARTS i am aware of the size of the hole, and difference in the lowers themselves.  My question is about the PARTS.
8/25/2008 10:57:17 AM EDT
[#6]
The first two replies explained this. Colt fire control pins, triggers, and hammers come in two sizes, 0.155" and 0.170". There are also two pivot pin sizes, 0.250" and 0.315". The rest of the lower parts are all identical.
8/25/2008 11:24:54 AM EDT
[#7]
If you have the old A1 SP1 lower then its standard .154 size but the front could be the larger .315 or smaller .250 size but the FCG is standard size.Late model Colts with the A2 reciever that has the fence around the mag catch have the .170 larger FCG parts and pins and the 2 screw front is usually the larger .315 size.Late model Colts with A2 type lowers that have the spring loaded push pin as well as current civilian and LEO Colts have the normal .250 front pin but the still larger .170 FCG parts but at least dont have the steel lowere receiver block.Every other part is compatible older or newer.
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