This weekend, I ran the WTF Biathlon Sprint; it's a varied terrain run over 3 miles with shooting stages interspersed. I was an early runner so the temp was somewhat cool out, but not cold. Say ~65 degrees.

As I got to the 1st rifle stage, I went to chamber my rifle. Inserted the mag (downloaded to 28 rounds) and dropped the bolt using the BAD lever. I felt it not drive home, and went straight to a tap-rack. Started my day with a double feed.

Pulled the mag out, cleared the rounds, seated the mag and used the charging handle to drop the bolt. I'm not sure how many more times it didn't go into battery but it was several. Finally was able to use my finger to force the bolt into battery (No-FA on the upper), and from then on I had no problems for the rest of the match. Easily cost me a minute, if not more. I did charge the rifle at every stage (you had to run unloaded) with the charging handle from then on.

Rifle Setup:
Noveske 16" barrel
Rainier No Forward Assist Upper
High quality NP3 coated BCG
MicroMOA Gasblock

Other misc:
Bad Lever
VLTOR A5 stock, spring and buffer

Ammo:
55 gr Wolf Gold Brass Case

This rifle is a known entity. I've had it built for over a year and ran it in a few matches and other events with no issues. Mags I used are my standard windowed PMAGS that I keep aside for matches; never had a problem. I put ~90 rounds through it the day before, mostly suppressed. It hadn't been cleaned in ~500 rounds.

I've never had this issue before and am wondering what potential causes there are.

At this point, I'm thinking it was simply dry and somewhat dirty but want to rule out other options. What should I consider?

I'm also weighing the cost/benefit of rebuilding the upper using a FA upper.

Dirt, sticks, lack of lube or ammo.

This is a previously well functioning rifle, right?  Not one put together the night before your event?
I'm kinda with the overly scoped one on this.
In addition to the above, I have heard of BAD levers malfunctioning, although how that would prevent going into battery I can't think of.  BAD malf reports are failures to lock back or prematurely dropping the bolt.
I think you just inadvertently made a case for a forward assist.

I think that's the take-away here.

have you used frog lube?

Because frog lube did that exact thing to my AR

if you are not using frog lube, what are you using and is the BCG wet.

Never used Frog Lube.

I'm using remoil or something similar. I typically run my rifles fairly dry.

I agree with most of you that I think that was the problem, especially with a "cold" rifle.

I'm going to change my rifle lubrication practices and probably eventually rebuild this (and one other) upper and replace the upper with one with a forward assist.



As to the BAD lever, I don't think it had anything to do with it and, if anything, assisted me in clearing the malfunction.

It's a machine, it is not meant to run dry. It is metal against metal.

It needs to run wet. Put a coating of oil on it and it will likely work fine.

Rem Oil burns off way too fast in AR type rifles.  Works OK in bolt-actions and lever-actions, but not so much in AR's.  

Ya have been thinking about going to a true synthetic motor oil.

They run best on the wet side.

I've been shooting AR's for 10+ years now; never had a lubrication problem.

However, I think the suppressor stuff is the new fly in my ointment.

Very likely.  
If you don't like the smell of burnt motor oil, I'd suggest Slip 2000 EWL.  It makes cleanup of the BCG much easier, too.  

If it didn't give you problems for the rest of the match then there was probably something in the way of he locking lugs, this weekend I had some Independence m193 ball blow a primer straight onto a locking lug. My fudd friend that was shooting at the time had no clue how to troubleshoot a malfunction and went straight to the forward assist and jammed on it 7 or 8 times despite the fact that the bolt was almost halfway back.

Charging handle vs. Cheek rest?

CH was latched? I'm maybe not following what you're getting at.

OK.  You are the one who said you run them fairly dry.
Let us know if you figure out the root cause.

I wasn't saying that he was wrong. I was saying that it likely IS a lubrication issue, but that how I've run my rifles in the past doesn't necessarily work well when you put suppressors in the mix.

Got it.  
I run CLP because it is so consistent and works, and comes in nice little bottles and spray cans and I can dose the BCG down at intervals. I can even pull the
BCG and hose it down with CLP and it's good to go. You clearly don't need that for biathlon but need something with good stickiness and lubricity.
Some 3 gun folks run a mix of synthetic oil and ATF and some just a synthetic like mobil1, but they are pouring rounds down range.
Slip 2000 has an educated and active following.
I am interested in what you eventually settle in on and how it works out for you.
Keep shooting!