[soundguy]

been researching getting an upper.. and I see a few pales mentioning 'small front pin' Looking at my milspec lower it appears ( have not measured ) that the pis are the same size.. I take it there are some models with a smaller front pin i should be avoiding?

again.. ar newb here..

thanks for any help.

 

[Guest]

Colt makes a large pin lower I believe. I think Colt stopped making that for civilian models.

So I believe if you have any thing other than a Colt lower you should be good.

 

[soundguy]

after much research.. I guess it was the older colts that had that one larger pin.. and everything else nowadays is small pin front and rear.. ie same size.

cool.. make sit a tad easier.

shocked me when i saw some guys saying small front pin ( and yes.. it was a colt upper.. )

 

[Bindernut]

Yup the early civilian Colt ARs were the large pin variety.

I believe this was originally done on the thinking that folks couldn't mix-n-match "borrowed" mil-spec full auto M16 parts onto a civilian model. Not positive on that though.
I don't remember when Colt went away from the large pin setup. Maybe around the time of the '94 bill or maybe before ???

Pretty much all of the current "generic" ARs out there that I've looked at seem to follow the mil-spec sheet pretty close and use the same pin size as the military variants.

 

[soundguy]

cool, thanks