Troubleshoot my rifle misfiring?

[DawnPatrol]

Hi folks.

I have a Ruger M77 in 270 (1975 vintage). I inherited it a couple years ago. It sometimes misfires.

First time it happened, my FIL was shooting at an elk and it failed to fire like 5-6 times in a row before finally going off. I took it to the range afterwards and it shot w/o issue, so I chalked the previous problems up to maybe ice in the trigger/action (we had crawled through the snow a fair ways to get into position for the shot).

I was having work done on my primary deer/elk rifle this fall, so I took this one outta the safe for a little time at the range before taking it in the field this season. First time I pull the trigger, nothing happens. Sooo…back into the safe it goes till I figure this out.

This has occurred using different kinds of ammo. After the misfire, the primer is dimpled.

Any idea what could be causing this?

 

[realunlucky]

Clean the firing pin and spring

Sent from my SM-S926U using Tapatalk

 

[willtim]

As above. Pretty simple.

 

[E.Shell]

+3
Ever pierce a primer?

 

[MallardSX2]

M77 Rugers have been known to have weakened firing springs if left cocked over time.

We had the same exact issue with my wife’s rifle and I really did a ton of research and talked to a lot of people about it. We actually ended up buying a special tool to be able to take the bolt apart to be able to replace it with a 25 pound wolf spring.

FYI- Her rifle went “click” on the biggest buck she has ever seen.

If it were me, I would have taken a chop saw to the gun. But I’m wired different.

 

[bigunit]

I had one in 7mm rem mag. It did that once in a while. I ended up putting a new firing pin in it as the old one wasn't protruding from the bolt face enough. Never trusted it again though and traded it off.

 

[DawnPatrol]

+3
Ever pierce a primer?

No

 

[DawnPatrol]

Thanks everyone! I’ll do that and see what happens.

 

[EdP]

A guy I was partnered with on a guided hunt had a similar problem with his rifle. He had come to Wy for the hunt from Florida and had never had a failure to fire in Florida. The time his rifle did fire he had not been long out of the guide's truck. When it didn't fire was after he had been out in the cold for quite a while. My take was that he had oil in the firing pin hole and it would thicken in the cold. So, back to what realunlucky said, clean the firing pin and spring. Don't oil it after cleaning. Test it in the cold.

As far as the spring getting weak if left compressed for long periods, I have read that it is cycles that weakens springs, not being compressed for long periods. That was in regard to leaving magazines loaded and not firing pin springs, but it is still coil spring physics.

 

[BCsteve]

I have an early Ruger MKII (the transition years when they had the claw extractor but was still a push feed) that I bought used as a donor for a .35 Whelen project. When I got it back from the smith I was having missfires. Thought it might be a chambering issue or the supposed issue of the limited shoulder on the .35 Whelen cartridge. After ruling those things out the next step was to buy a a new firing pin spring. When the new spring came in I took the old spring out and I was shocked a the length difference. Don't know if Ruger had issues with springs for a while but I've never had a missfire since. Worth a try for the cost of a new spring.

 

[MallardSX2]

Wolff Extra Power Firing Pin Spring Ruger 77, 77 Mark II 24 lb

These extra-power striker springs make the striker move faster and hit harder to reduce misfires and lock time. To the shooter, the faster the firing...

www.bing.com

 

[TaperPin]

Hi folks.

I have a Ruger M77 in 270 (1975 vintage). I inherited it a couple years ago. It sometimes misfires.

First time it happened, my FIL was shooting at an elk and it failed to fire like 5-6 times in a row before finally going off. I took it to the range afterwards and it shot w/o issue, so I chalked the previous problems up to maybe ice in the trigger/action (we had crawled through the snow a fair ways to get into position for the shot).

I was having work done on my primary deer/elk rifle this fall, so I took this one outta the safe for a little time at the range before taking it in the field this season. First time I pull the trigger, nothing happens. Sooo…back into the safe it goes till I figure this out.

This has occurred using different kinds of ammo. After the misfire, the primer is dimpled.

Any idea what could be causing this?

The firing pin has to extend out of the bolt face enough (at least around .050”), hit with enough force from the spring (old springs do get slightly weaker), and the firing pin has to be free to move within the bolt body with minimal friction (clean and lightly oiled).

 

[RockAndSage]

Crap lubes getting cold or old is the biggest source of misfires in most people's hunting rifles. Always start your troubleshooting with a good cleaning.