Home Forums Hunting & Shooting Hunting Rifles Misfiring Mossberg bolt action.

Question, My SIL has a Mossberg bolt action rifle that when used in cold weather and carried for a period of time will misfire. It happened last year while we were deer hunting in -6 weather and it happened again this year while hunting elk in -10 degree weather. you pull the trigger and it misfires, but if you cycle the bolt and pull the trigger again it will fire. Warm weather is not a problem, fires everytime and brand of ammo makes no difference either. I told him that the bolt must have some grease or contamination in it. I just brought the rifle home this weekend and just disassembled the bolt and gave it a good look expecting to find the problem. Bolt is clean and no signs of grease or anything else that would effect cold weather operation. My SIL has figured out that if you leave the chamber empty and leave the mag out so the gun is empty, you dry fire it about every 15 minutes it will work when you need it. Not being proficient with Mossbergs I thought I would turn to you guys for suggestions. The one thing I did not check for was a light primer strike on the misfires, because when it happens he usually just pulls the bolt back and lets that round fly and chambers another round and it works. The suspect round usually flys into the next county. Thanks for any help you can give my in solving this issue.

Clean the inside of the bolt, the firing pin and firing pin spring with a solvent to completely remove any existing lubricant. My guess is that a silicone based lube is the problem.
On my bolt rifles, I use Tri-Flow spray lube that is rated for extreme cold. I spray the individual bolt components and let dry overnight. I then reassemble the bolt. No problems in below zero weather.
I also do NOT take a cold rifle into a warm cabin if I intend to hunt with it the next day. Condensation can & will cause misfired. I leave the rifle in my truck or unheated out building.
Don't take a warm rifle out into frigid weather and expect it to function. I put my UNCASED rifle with the bolt open in an unheated out building overnight before using it.

To strip a Mossberg bolt (I am assuming it's one of the new ones) Take the bolt in your left hand, lugs pointing down. Hold it like an ice-pick. Let the bolt handle rest against your thumb.

Now, take the bolt shroud in your right hand holding on like it was a very short handle on an ice pick. Twist it clockwise. In about 1/3 of a turn it will pop up and you can pull the firing pin, spring and bolt shroud out.

A cross pin, about 1-1/4" back from the bolt face then is pushed out to either side. When that's done the bolt head comes out.

Clean it all up in white gas or acetone to get all lube off it. If there is grease, get it off.

I make a lube with 1 part automatic transmission fluid and 10 parts Mobile 1 full synthetic 5W30. Works very well in every condition I have tried in in, down to -35 F. That's what I would coat the gu8ts with but other lubes may be as good. Just make sure they are thin and non-gelling down to some VERY cold temps.

A good test is to put some on a thin piece of steel and then press that steel to some dry ice. If after a full minute of that it's still thin and runny you have a winner for a winter lube.

To reassemble put the bolt head on. it only goes in one way, so there is no worry about doing it wrong. Put the cross pin back in making sure the hole is aligned with the bolt body. Now hold the bolt as you did to start.

Look at the rear of the bolt and you will see a square cut. Look at the bolt shroud and you'll see a corresponding lug. Put the firing pin back into the bolt so the lug goes into the cut.

Now press down hard on the shroud so the spring compresses and turn it counter clockwise until the nose of the cocking piece drops into the shallow recess that is made for it. Done!
Put the bolt back into the rifle.

Thanks guys, I already have it apart and have cleaned what little oil on it off. I have wiped it down with an oily cloth and it is in the freezer right now. Going to see if the problem is still there or went away. If it went away then I am going to put bolt and rifle in freezer and let it sit over night and try it again.

Do NOT lube the bolt with anything other than dry spray! Even if it remains loose at deep cold temps that just means it will pick up dirt and dust!

Use a dry spray... Dri-Slide is my preference... You may want to replace the firing pin spring with a slightly heavier version.

Thanks Sitka deer. Thought of that today and I believe that is the road I will go. Looking for a heavier spring.

Dri-slide as SD says if you must lube it.

I use Eezox or Corrosion X - which clean, and when properly applied, dry to the touch, then don't attract gunk, thicken, or gum, resist rust and corrosion, and provides lubrication.

Either is all you need in the way of cleaning, rust protection, and lubrication.

I still have some of the other things around, but can't recall using anything else in at least 15 years.

Is this an ATR? My father in law had the same problem. I found that when he was carrying the rifle he would bump the bolt up slightly and it would misfire. Make sure the bolt is all the way down and it will fire. I was able to duplicate it at the range after I figured it out.