Just one tiny criticism.  You titled the thread A2 to A1 lower conversion, yet have actually made up a very nice M16, not M16A1, dup.

Apart from that. well done

Quoted: Does anyone know why Colt made a retro slab side lower and used it on a modern rifle and called it an A2 match grade sporter? That's the other minor draw back it does say sporter on the left side of the mag well.

Why?  Because they had a bunch of the early forgings at the plant, they couldn't use them on service rifles, and they could unload them on the civie market.

Colt has always done this. Just one of those things you have to love them for. NOT!

Quoted: Just one tiny criticism.  You titled the thread A2 to A1 lower conversion, yet have actually made up a very nice M16, not M16A1, dup. Apart from that. well done

Not really. M16s were slabside lowers, this is more of an XM16e1 lower.
The complete rifle is basically a Colt model 604.

Quoted: Quoted: Just one tiny criticism.  You titled the thread A2 to A1 lower conversion, yet have actually made up a very nice M16, not M16A1, dup. Apart from that. well done Not really. M16s were slabside lowers, this is more of an XM16e1 lower. The complete rifle is basically a Colt model 604.

Actually it’s late 602 clone, with a 602 upper. (or at least that was my intent)

My understanding is that later 602’s had the partial mag fence A1 lower, takedown/pivot pins with the divot, selector with hole, magazine release with the circular patterns, and the directional markings on the receiver are recessed.  One thing that is not correct is the bolt catch/release, as I have not found any of the old retro style.  Does anyone know where these can be found?

The model 603/M16A1 had the buttstock with internal storage, fullfence A1 lower, later style take down/pivot pins, later style selector and later style boltcatch.  The rear sight had raised directional markings and the barrel has the A1 birdcage type flashhider.

I’m currently working on a 601 clone.  This would be a true slab side, non captive pivot pin, old magazine release with horizontal pattern, this would also have the flat end bolt catch, old green furniture, old style charging handle, no directional markings on the upper receiver rear sight, duck bill flash hider, etc.

Any thoughts or input is welcome, as I would like to clone these as true as possible.

I kind of figured it was something along those lines. Does this mean I actually have an original M16 slab side that was made back in the day (that wasn't ser numbered), had been sitting on the shelf until colt got into a financial bind around 1989 and slapped a bunch of rifles together to recoup some capitol?

Quoted: Quoted: Does anyone know why Colt made a retro slab side lower and used it on a modern rifle and called it an A2 match grade sporter? That's the other minor draw back it does say sporter on the left side of the mag well.   Why?  Because they had a bunch of the early forgings at the plant, they couldn't use them on service rifles, and they could unload them on the civie market. Colt has always done this. Just one of those things you have to love them for. NOT!

This is a good thread so I wanted to bring it back to life.  I really like the conversion, it came out well.

Is there currently any companies making a SP1 type lower ?

That would be cool if they were reasonbly priced.

Quoted: This is a good thread so I wanted to bring it back to life.  I really like the conversion, it came out well. Is there currently any companies making a SP1 type lower ? That would be cool if they were reasonbly priced.

No modern company is making any A1 spec lowers (slabside, partial fence, or full fence M16A1) Everyone just makes the A2 spec lowers. If you want a slabside (SP1 type), you'll need to either dish out $400+ for a real Colt SP1 lower or break out the dremmel/files/sand paper.

Quoted: Quoted: This is a good thread so I wanted to bring it back to life.  I really like the conversion, it came out well. Is there currently any companies making a SP1 type lower ? That would be cool if they were reasonbly priced. No modern company is making any A1 spec lowers (slabside, partial fence, or full fence M16A1) Everyone just makes the A2 spec lowers. If you want a slabside (SP1 type), you'll need to either dish out $400+ for a real Colt SP1 lower or break out the dremmel/files/sand paper.

Or wait for someone to get their ATF paperwork approved and start the conversions from A2 to A1. That's the jist of this thread.

Quoted: Quoted: This is a good thread so I wanted to bring it back to life.  I really like the conversion, it came out well. Is there currently any companies making a SP1 type lower ? That would be cool if they were reasonbly priced. No modern company is making any A1 spec lowers (slabside, partial fence, or full fence M16A1) Everyone just makes the A2 spec lowers. If you want a slabside (SP1 type), you'll need to either dish out $400+ for a real Colt SP1 lower or break out the dremmel/files/sand paper.

I have 1 real Colt SP1 now (1960's vintage), but I'm leaving it in the original configuration.  I would like to build some other configurations, just not with my current SP1 as the foundation.