So I traded my M4 upper away so that I could play with an Oly 9mm upper. I complete the trade, and I'm happy, but I dont really know what I got...   I've basically confirmed that it IS an oly upper, and that it was made around 95, so that would make it a "Transition Upper." I dont know anything else..

My questions are:

1. Have you ever seen a "Straight sided delta ring?" (whats the story?)
2.  Whats the issue with the Nubby Gas Tube??? (I know 9mm doesnt need it, so WTF?)

I'm probably going to replace the A1 with an A3 soon, and maybe the CAR handgaurds with some M4 or FIRSH gaurds....





-Jason

Maybe the nubby gas tube is to keep that peice in the front from moving?????  The part where the handguards go on the front..... (it's late...brain fried)....

Quoted: Maybe the nubby gas tube is to keep that peice in the front from moving?????  The part where the handguards go on the front..... (it's late...brain fried)....

That's what I thought too.

Quoted: 1. Have you ever seen a "Straight sided delta ring?" (whats the story?)

It's just an older style delta ring, from the A1 I believe.  There are a bunch of them in this thread.

www.ar15.com/forums/topic.html?b=3&f=118&t=213973

Quoted: Maybe the nubby gas tube is to keep that peice in the front from moving?

Bingo, that's exactly what it's for.  Rock River uses a roll pin in that loaction on their 9mm barrels. It keeps the HG cap from moving and adds a little strength to help keep the HG's from twisting while under stress.