Failed primer in cold temp
 

Larue OBR
Federal 168 otm and 175 bthp
20 to 34 degrees F

I got clicks from 5 different rounds and tried three times with each. Saw prominent dimple in each.
Only change in the rifle was
I switched from oil to grease. The bolt movement did feel more sluggish, but surely it does not affect the inertia of the firing pin or the geissele national match?
I think I read somewhere federal uses hard primer?
Is it because I left the rifle and ammo in car for days with temp down to the teens?

Long story short, i put the rifle to the side under the sun while playing with AK, which of course went bang each time. About an hour later the OBR went bang all the way. So is it the ammo? The rifle?

That episode of unrealiabiliyy really bugs me

What oil and what grease, and when did you switch? After the failure to ignite? Did you ever get an ignition after making the switch?

I wouldn't think it was cold enough to effect the primer and would think it was a cleaning/lubrication issue, but I could be wrong. Plus, you got a dimple, so I don't know.

Federal's aftermarket primers are considered some of, if not the easiest, to ignite.

It's probably because you left the rifle in the car for days (BAD idea BTW). I doubt it has anything to do with the primers. Most likely the firing pin lacked the energy required to detonate the primer. Strip the grease (make sure you include the firing pin channel in the bolt) and replace with a quality low-viscosity oil. I usually do this mid-NOV and return to greases mid-MAY. I've been using Slip 2000 EWL or Lucas Extreme Duty Gun Oil (because I keep receiving free samples that are convenient for the range bag) but almost anything will work. (Literally almost anything - "secret formulas" include 50/50 Mobile 1 Synthetic and a high detergent ATF - amazingly inexpensive if you don't mind ending up with a 10 year supply of the stuff.)

It was this red grease with vtac logo on it from general Jackson....

Amateur hour here but what had happened was I used that grease for my national match M9 all the way to earning the P100 and was impressed. Did not come off after hundreds of rounds and I even perceived less recoil as the slide seemed to move smoother/slower. So I thought I can replicate the magic with the OBR.... yeah, I know.

I have not been able to replicate the malfunction since though. Of course it’s also warmer now.

On the bright side, the multiple failed primers gave me solid one man ball n dummy + npoa sanity check and solid follow through exercise. By the time the rifle was warmer I was good to go. I’ll take sub 0.5 MOA out of gas gun and commercial ammo every day and twice on Sunday :cool:

This is in freezing temp and months of no practice.