Scenario: Putting together my first build. I started about 8 months ago and was missing a part so I ordered the part and it came in but I had kind of lost interest by that time so this sat until I was in my work space the other day during the hurricane and I decided to give it another go. I greased the mounting point on the upper to install the barrel. I put barrel in and using the barrel wrench I started to tighten the barrel. I then loosed it and started to tighten again and I hear a cracking sound. Apparently my delta ring cracked. So now I am back in the same predicament as I was in earlier. So my question is, am I doing it right? The wrench I am using isn’t tight fitting on the barrel nut and slips a little. What can I do to keep this from happening with the next delta ring?
Thanks.

What wrench are you using? There really should be no stress on the delta ring at all unless something is wrong.

It was the Brownells armorers wrench

https://www.brownells.com/gunsmith-tools-supplies/rifle-tools/wrenches/ar-15-armorer-s-wrench-prod80294.aspx

There should be zero pressure on a delta ring when torquing one, other than pushing it towards the rear slightly so the teeth can engage on the barrel nut.

Was it a plastic delta ring?  I can’t see an aluminum one cracking when installing a barrel.

I've seen the finish get damaged and some pretty bad dings and chips on delta rings before from crap barrel wrenches slipping off the barrel nut, but I've never seen one with a crack in it.

What side were you using?

I think we have a winner...

(The Armorer’s Wrench has two sides, one is for traditional barrel nuts and the other is for free-float tubes and rails.)

The side with all the teeth not the nubs for free float barrel nuts

Do you mind posting pictures?

Of which? The wrench or the delta ring?

yep,

had the good old USGI tool slip once,  (totally my fault) and the nub took a chunk out of the delta ring,
seen them dented as well,

I suppose it could happen with any barrel wrench if you aren't paying full attention.

You said that this is your first barrel installation? There is a learning curve to installing standard barrel nuts with delta/slip rings (believe it or not), it's not always as easy as Legos.

I had my issues with installing standard barrel nuts when I first started out too. The best move I ever made was ditching those all in one type tools, such as the DPMS/Smith Enterprise style wrenches. They have a very shallow engagement of the barrel nut teeth and make it very easy to slip off and cause damage to the barrel nut and delta ring. I ended up switching to the 3 pin GI barrel nut wrench and found that it was much easier to use, but the fact that it only has 3 pins puts a lot of stress on only three of the teeth on the barrel nut, and the teeth will start to bend when you get up into the mid to higher torque range.

I got to a point where I gave up working on the AR15 until I could find a better barrel wrench. I wanted something that would be similar to the GI wrench but had more pins, which resulted in me starting this still ongoing thread, started long long ago. > Barrel wrench thread.

That thread led to a few different prototype wrenches, which resulted in two of them (one from Spike's Tactical and one from BRD Engineering) becoming available for a little while.

Long story short, 2UniqueLLC eventually came out with a couple similar wrenches to what I wanted and I'm much happier. > Link. > Link.

After that I focused on barreling jigs. > Barreling jig thread.