I have a 9mm upper and need to collect the rest of the parts to complete the rifle.

I know I need another hammer, mag block, mags and buffer.  What else do I need?

Do I need a different buffer spring or stock spacer?

Cool.  I appreciate it.  Just need to find or buy a hammer and I am ready for the range.

Hammer -


Buffer -


* If you have a rifle stock, leave it alone, rifle buffer is 5.2oz ---- If you have a CAR stock, install a CAR style buffer with a weight over 5.0oz,  the "9mm" buffer be a start @ 5.4oz, but if you plan to run suppressor, step up to the 7oz CAR style buffer if you have the CAR stock/tube.....

I run 9mm and 223/556 with the above system,  though my buffer has a brass dowel inside to bring the weight to 7.04 oz.


Never ever put CAR parts in a rifle tube...

Some carbine springs are too tight for the 9mm buffer.  If your carbine spring slips easily over the 9mm buffer, you're OK.  If the spring has to be 'threaded' onto the buffer, another buffer spring would be a good idea.  The tight spring could cause short stroking.

DPMS carbine springs work with the 9mm buffer (there are others, but I don't know which ones).  Two springs that came with stocks I bought (one from M1S, the other an unknown manufacture stock found at a gunshow) don't work with the 9mm buffer.

I am going to use a car stock and tube.  I would like to get a shorter barrel after my form 1 comes back but what I have now will do.

Thanks for the information.