Range Time and the Misfire Rounds Bin

MacD

Finally found time to get out for some recoil therapy today. When I first arrive at the range my habit is to check the brass buckets for cases I reload or intend to reload in the future. I also look in the plastic wide mouth bottles hung near the firing points to receive misfires. Besides the usual 22 lr duds there is usually a few centrefire rounds. Today there were a couple of 30-06 and about 20 5.56 NATO ones. Upon inspection, it appeared that all had soft firing pin hits as primer dimples were small and shallow. When I tried the 5.56 in my rifle they all went bang. Another shooter got the 30-06 to do the same. During a target hanging break we discussed what makes a rifles firing pin fail to hit hard or deep enough for reliable primer detonation. There were many suggested causes but no clear favourate. So I put the same question to the "Nuts". So open up a cool one from Vince's fridge and share your thoughts and insights.

DallanC · Site Admin Joined: Jan 18, 2005 Posts: 3571 Location: Utah

When I've run across it its been from dirty firing pins that have too much friction when released. My Remington M700ML is famous for blow-back getting into the bolt and weakening the spring or otherwise fouling the firing pin within the bolt. I'm pretty careful to make sure I fully disassemble the bolt on cleanings and lube it heavily before reassembling.

Some lubes will get too thick in super cold weather so if that is a possibility, I usually disassemble, wipe dry and try an reapply an extremely light coating of oil.

So, my answer would be fouling inside the bolt / on the firing pin first and foremost, followed by weak firing springs. 3rd I guess would be to mike the firing pin itself to see if its worn down or broken.

-DallanC

Gil Martin

It depends. I had a problem with a Remington Model 581 .22 l.r. bolt action experiencing frequent misfires. My local gunsmith looked the rifle over and replaced the firing pin spring. Problem solved. Misfires can be caused by many reasons and I agree with DallanC that cleaning the bolt and firing pin can help remedy the problem. So it depends. All the best...
Gil

Suzanne

Guns and ammo are all like individuals and have their quirks. When ever it happens to me it's so rare that I just figure it's the ammo itself. With me it's mostly happened with very cheap ammo. My 40 cal. Glock did not like cheap ammo. Put some reloads in or better quality ammo and never had a problem. My AR-15 in 7.62x39 didn't like steel cased ammo (possibly harder primer) so I changed out the firing pin and got better ignition. Only reloads for that rifle tho as the steel cases tended to stick in the chamber after a few firings.

Suz

Bushmaster

When cleaning the firing pin and housing never use grease or heavily oiled as this will help in collecting powder residue and other debris causing the pin to hang up. Clean the firing pin housing and oil with a thinly saturated oily rag or Q-tip. Wipe the firing pin with the same rag. Never over oil the pin or it's housing.

DallanC · Site Admin Joined: Jan 18, 2005 Posts: 3571 Location: Utah

Good advice.

I oil my 700ML firing pin / spring a little heavier than normal as I want to protect it from that corrosive black powder, vs trying to really "lube" it. The gun really only goes a shot or two between cleaning during hunting season, maybe 10 or so if its been out target shooting. But either way its fully disassembled and cleaned after shooting as finished. If I'm hunting in cold weather, I'll use Bore Butter over oil.

-DallanC

Elvis

my .223 bolt action would misfire badly about 6 mths after I got it, usually cheap ammo
mate taught me to let firing spring pressure off when storing and Ive never had an issue since...with added bonus the bolt wont go back into rifle until its been turned back again.

slimjim

seems like you all covered it. I had to clean the bolt firing pin in my 50-year old Mossberg bolt action. Also had to replace spring and firing pin in 1869 Rem Rolling Block to get it to ignite. Well, guess we didn't cover the primary reason - neglect.

MacD · Last edited by MacD on Fri Sep 11, 2015 7:59 am; edited 1 time in total

You guys probably hit the nail as I suspect very few people actually disassemble their bolts. In some cases this is not helped by some bolt designs. The other cause we duscussed was excessive headspace which would allow the pin to push the case forward and therefore cushion the blow of the pin. There wasn't unamity on this as some felt the extractor should hold the case tight enough to the bolt face. Again design counts a lot here.

These little discussions at the range are great fun. We had a real good one the same day over a case seperation in a venerable Lee Enfield Mrk III. The case seperated about 1/4" under the shoulder. These were handloads in cases that had been fired "several" times. He was full length resizing, not annealing or trimming. While some automatically blamed the cases others, myself included, told him to also get his rifle checked out. I suspect a long chamber may be a coupled with thr FL sizing is leading to excessive stretch of thr case. Add hardened necks from the sizing and seperation was the result. BTW there was no gas escape that he could notice. The case must have sealed well below the seperation.

slimjim

MacD wrote:

The case seperated about 1/4" under the shoulder. These were handloads in cases that had been fired "several" times. He was full length resizing, not annealing or trimming. While some automatically blamed the cases others, myself included, told him to get also get his headspace checked.

I had excessive headspace in my .45-70 (0.028") which caused a case separation. that is a straight wall cartridge, however. Most of the case separations I've seen in AR platforms have been just below the shoulder. Full-length resize in a bolt gun - I hope he was only setting the shoulder back 0.001".

MacD

I edited my post. While I originally said headspace I actually corrected myself to say rifle. Excessive headspace on a Lee Enfield is usually a bolt head issue or wear of the locking lugs. The. 303 being a rimmed cartridge obviously doesn't headspace on the shoulder although some would argue this is just as critical a measurement. His rifle was a original Mrk III making it at least 100 years old. Sometimes I feel as old as that rifle and SWMBO says I definately have a headspace problem. Lol

Vince

I agree wholeheartedly with both Dallan and Elvis. Only problems I've had with light strikes came from sludge in the firing pin carriage and on another rifle, a weak spring. Cleaning and a replacement spring in both cases corrected the issue.

I've only ever seen excessive headspace cause a misfire a couple of times, but that was quickly corrected. I remember on the .30 cal and the .50 BMG Machine guns, you had to set the headspace every time you replaced the barrel or it simply wouldn't fire. The CES for every gun contained a GO/NO GO gauge.

The AR platform would no doubt suffer from the same problems as the old venerable M16 which was terrible for bolt fouling, not just in general, but specifically in the firing pin channel and under the extractor.

I used to get regular misfires on my O/U 12g shottie until I realised the problem was a loose Nut...the one behind the butt. I wasn't releasing the trigger fully between shots. This can also happen with some pistols.

Another cause of I have identified for light strikes or misfires, but only on reloads, is a primer not fully seated. The initial strike would 'seat' the primer fully, but not hit it hard enough it cause ignition. The round generally fired withlout problem on a second strike.

Elvis

also seen it with single shots if not closed firm enough...Bakail of bro in laws needed tweek from gunsmith to fix this and Ive read the Bergeras will do the same if not firmly closed...you get click but no boom.

gelandangan

Reading about the remington above reminds me, years ago I got a 788 that also have weak firing spring.
I wonder if this is a problem with remingtons?

PaulS

I own three Remingtons and have never had a weak strike. I have seen semi-autos give light strikes when there was too much taper on crimp or when the chamber wore enough to allow the round to go too deep into the chamber. I have also seen a 9mm shoot 380 - single fire. They would fire but not cycle the action.