Convert a Colt 6920 to 9MM ?s

[CHASER]

I have a Colt LE 6920

I would like to convert it to 9mm for use at the range buy keep it 556 for SHTF

Can I just bay anouther upper and some sort of mag adapter? What do I need?

I saw a completed gunbroker ad that made it seam that with a 9mm upper and a mag adapter you can go back and forth in minutes

 

[Qbeam]

An upper and mag adapter would solve your problems. Unfortunately, everything seems to be in high demand.

Good Luck,

Qbeam

 

[canuck]

as q said - except, you'll need a 9mm hammer if your new upper does not come with a ramped bolt.

 

[Qbeam]

Learned something new.

 

[canuck]

Learned something new.

yes. grasshopper.

 

[K-Romulus]

Here is some good background: http://www.ar15.com/forums/topic.html?b=3&f=15&t=108261

Basically you will need an upper and a magazine well adapter and some sort of 9mm magazines (at least).
You have two options:

1) Olympic Arms' style 9mm upper and magwell block
- uses Sten(?) magazines, and can be slapped on top of pretty much any 5.56 lower without any other mods.

2) Colt/RRA style 9mm upper and magwell block
- uses a Colt-style 9mm upper, and any of several types of magwell adaptors to use UZI, Sten, or Colt 9mm mags.

- these types of uppers will not work off-the-shelf with 5.56 hammers that are "notched" i.e., do not have a perfectly flat hammer face. (The FAQ should have more info). What happens is that the 9mm bolt carrier snags and locks up with the notch on the hammer. DMPS hammers are the only ones that are not "notched" and can be used as-is. Otherwise, you will need to switch the 5.56 hammer with a 9mm hammer (makes it hard to switch calibers at the range), BUT

- you can make these uppers work by getting the 9mm bolt "ramped" so that the carrier doesn't snag on the notched hammer face. "Ramping" is explained in the FAQ and more in depth here:http://www.ar15.com/forums/topic.html?b=3&f=15&t=385344

I run a RRA 9mm upper with ramped bolt, using a DPMS hammer, Hahn Precision bottom-loading mag block, and the C-products 9mm mags. I can switch calibers in less than 5 minutes.