A friend bought a Colt military marked M4 14.5 inch barrel used off GB. The barrel has the standard F-Marked front sight and barrel nut but no spring loaded slip ring/Delta ring. The front sight staking pins do not look like they were ever removed. Colt phosphates/parkerizes over them. Yes there is the round Handguard cap just behind the front sight.
He wishes to add a flash hider/muzzle brake permanently attached to bring the length to over 16 inches and add the 2 piece hand guards. To make the upper look like an M4 with a 16 inch barrel.
But how?? No delta ring? Front sight assembly was never removed so how were original hand guards retained with no delta ring to hold them on? Heck, how ( and why? ) was the Delta ring even removed? Please advise.

Failing to get it off, they cut it off?

Get a delta ring assembly and install it.

Maybe cut off, or sold for a free float setup?

Are you saying there's no barrel nut either? If the barrel nut is present, it's easy to add the rest and like $20

PGT, That's the strange thing. The barrel nut is on the barrel ( can't come off without removing front sight) but no Delta ring. The Delta ring had to be cut off. But why? The hand guards would come off easily by pulling the Delta ring to the rear.

Most barrels come this way.

The delta ring installs from the barrel extension end of the barrel. Does not require removal of the front sight base/assembly.

Delta ring first, then spring and retaining snap ring.

This ^^^^^^

Delta ring installs from the Chamber end so you're fine.

quote:

Originally posted by SIGWALLY:
PGT, That's the strange thing. The barrel nut is on the barrel ( can't come off without removing front sight) but no Delta ring. The Delta ring had to be cut off. But why? The hand guards would come off easily by pulling the Delta ring to the rear.

No, it didn't. Remove the snap ring and delta ring comes off to the rear. I just put one on a 6720 barrel that I bought that was missing, like you...at auction and was surprised that it was missing.

Of the dozen or so new replacement Colt M4A1 barrels I’ve handled over the years, all were received as you describe. As others have posted, the delta ring assembly installs from the chamber side of the barrel extension.

Also, Colt doesn’t parkerize over the taper pins. They are parkerized prior to assembly. The only way to tell if they have been removed/reinstalled is to look for signs of amateur removal/reinstallation, ie buggered pin heads and marring of the gasblock adjacent the pin holes.

THANKS EVERYBODY! I could swear the Delta ring went on from the front. Clearly I was mistaken. I have done several builds but all required removing everything to free float the barrel. I have never actually had to do it the other way around. I really appreciate all the help, Thanks for taking the time to help me out.

Sigwally, don’t feel too bad. I know how this works because several years ago someone had to explain it to me. I just knew the front sight base had to come off to install the delta ring A good friend was kind enough to show me

Thanks Sauer Kraut for making me feel slightly less idiotic. Every little bit helps...

You might have been thinking of the front handguard retainer. The FSB does have to be removed to install or remove that piece. You also need to remove the FSB to remove the barrel nut itself.