About 100 rounds of LC and 200 rounds of wolf.

Notable occurances:
-FTF once with wolf, near the end of the magazine.  round nosedived.
-FTE once with wolf (stovepipe)
-Occasional failure to lock the bolt back after the last round.  Same mag that had the FTF

Diagnosis:
After checking BHO it was found not to be binding.  Magpul follower not binding

Treatment:
-Wolff XP magazine springs
-Wolff XP extractor spring
-Crane O-ring

Other than the two jams it was uneventful...aside from being a lot of fun.  I'm confident that the springs and the o-ring will fix the two minor problems and make the rifle 100% reliable.  It's damn accurate and very stable in rapid fire.

Does this rifle have an aftermarket per say gas block or a front sight?

My latest build does the same thing when I have a M&A Gas block on but when I have the front sight on it works perfect.  I figure something like the gas holes arent lining up or something.  I have only had this problem once before and that was since I was burnin 35gr bullets out of my varmiter.  It would  cycle good but would not hold open on last round.  

Some ammo that is weak wont hold the last round open and occasionaly FTE's (short stroking)  I have seen Wolf do this on new guns, until they were broken in a bit.

No cause for alarm.  Now, if it does it on M193... I might have some concern.

Barrel and gas block are factory armalite.

I'm 100% sure it's the magazine.  I can pull back the bolt completely and it won't catch.  It will catch if i pop out the mag and put it back in.  I think that test rules out short stroking.  It just needs some monster springs.

I'd look at your bolt catch.  It's very common for the bolt catch to bind on the roll pin, for the bolt catcht o be rough and bind in the lower, and/or for the lower to be rough and grab on the bolt catch.  I rub the lower area and sides of the bolt catch with fine sandpaper, and always ensure the bolt catch moves freely on the roll pin.  

You dont want to have to have super-springs in all your mags.... you want your gun to work with just about ANY mag.

as stated above, i checked the bolt catch for binding.  It's nice and smooth.  And judging by the FTF from the same mag.  I think the springs in these D&H's may just be abnormally weak.  Perhaps it's the spring on the bolt catch just needing to be broken in.  Either way, i can't go wrong with heavy springs in my primary mags.

Make sure that the carrier key is secure. My uncle had an Armalite that was doing the same thing. Loose carrier key was the culprit. James,

Treatment:

Don't shoot wolf!

Quoted: TreatmentCure: Don't shoot wolf!