Tikka bolt stop pin break diagnosis

[ehayes]

I recently had a tikka bolt release pin break during a normal bolt cycle. I cycle my bolt as I imagine most do, quickly and aggressively to be ready for a follow up. This is my first and only tikka and have never noticed this pin before it broke. My action was professionally bedded in an aftermarket stock. The stock has a shelf for the bottom of this pin to rest on, which it was resting on after it was broken. The top part of the broken pin was missing, I found the black finger mechanism and spring on the ground.
After receiving my new pin and installing it, I noticed something seemed odd to me. When installed this pin goes through a hole, then through the finger mechanism and into a small hole in the action above the mechanism. It sticks out the bottom as much as seen here when properly installed.


My pin was sticking out about 1/4-3/8" lower than seen here because the shelf in my stock sits that much below the pin when the pin is properly installed, meaning it drops to rest on the shelf. This appears to me to result in the pin dropping out of the top hole and resting still within the finger mechanism. I confirmed this by the new pin (properly installed) dropping the same amount when installed after manipulating the bolt release mechanism a couple of times. In the pic below it drops to about the bottom red line. When the pin falls out of the top hole, it puts a force on the pin it was not designed for, resulting in what I think caused the breakage.
I
After recognizing this, I put some bedding compound on the shelf up to the height of the properly installed pin. You can see in the picture, the bottom of the bedding compound (lower red line) is the top of the normal shelf. The pin now sits just a hair above the bedding compound. I added just under 3/8" of compound.


I have very little experience with this kind of stuff. Does what I am saying make sense? Does this fix seem appropriate? Thanks for any feedback.

 

[The Guide]

Never had that issue with any Tikka action. The spring behind the bolt stop/bolt release that holds the bolt stop in the closed/unreleased position holds the pin in place firmly. I've never seen the issue you are seeing. That looks like an upgraded bolt stop? Maybe there is something out of spec with that bolt stop?

Jay

 

[kswaterfowl]

I've seen those fall out of multiple tikkas while doing barrel swaps. That is one of my only complaints with Tikka actions.

 

[ehayes]

Never had that issue with any Tikka action. The spring behind the bolt stop/bolt release that holds the bolt stop in the closed/unreleased position holds the pin in place firmly. I've never seen the issue you are seeing. That looks like an upgraded bolt stop? Maybe there is something out of spec with that bolt stop?

Jay

That is a picture I used off the internet just to show the pin.

 

[ehayes]

I've seen those fall out of multiple tikkas while doing barrel swaps. That is one of my only complaints with Tikka actions.

Am I correct that it is only held in place by a shelf on the tikka stock? It falls out with gravity otherwise.

 

[Lawnboi]

Did the factory pin break and is it a t3 or t3x?

The factory t3x bolt stop hole is oblong to allow the stop to slide and contact the action before placing the load on the pin. Sometimes with aftermarket bolt stops, or older t3 actions, most of the load is on the pin.

But yes the spring in the bolt stop along with the stock should retain the pin. If your pin snapped make sure there isn’t a piece stuck in there. I have a barreled action sitting on the shelf now with the bolt stop in, no stock, and it isn’t going anywhere. So it shouldn’t just fall out

I wouldn’t consider this a common problem with tikkas, atleast not mine. I purposely buy factory stops with the oblong hole.

 

[kswaterfowl]

Am I correct that it is only held in place by a shelf on the tikka stock? It falls out with gravity otherwise.

That and the tension from the bolt stop. If you have your barreled action out of the stock and push your bolt release, that pin can fall out. Make sure you have that pin all the way in before placing it in a stock. I always turn my barreled action upside down, and put the stock on. Then get your action screws started. Whenever I remove a barrel or put a new one on, I put a piece of tape over the hole to prevent it from falling out.

 

[ehayes]

Did the factory pin break and is it a t3 or t3x?

The factory t3x bolt stop hole is oblong to allow the stop to slide and contact the action before placing the load on the pin. Sometimes with aftermarket bolt stops, or older t3 actions, most of the load is on the pin.

But yes the spring in the bolt stop along with the stock should retain the pin. If your pin snapped make sure there isn’t a piece stuck in there. I have a barreled action sitting on the shelf now with the bolt stop in, no stock, and it isn’t going anywhere. So it shouldn’t just fall out

I wouldn’t consider this a common problem with tikkas, atleast not mine. I purposely buy factory stops with the oblong hole.

T3x. Your stock has a shelf of some sort that holds the pin? Is it odd that the shelf on my stock sits so far below the pin? Or is that normal?

 

[ehayes]

That and the tension from the bolt stop. If you have your barreled action out of the stock and push your bolt release, that pin can fall out. Make sure you have that pin all the way in before placing it in a stock. I always turn my barreled action upside down, and put the stock on. Then get your action screws started. Whenever I remove a barrel or put a new one on, I put a piece of tape over the hole to prevent it from falling out.

My pin stays in place until I start manipulating the bolt stop, the it drops as I described, to the level of the shelf on the stock.

 

[Lawnboi]

T3x. Your stock has a shelf of some sort that holds the pin? Is it odd that the shelf on my stock sits so far below the pin? Or is that normal?

The shelf holds the pin when in the stock. But it should stay under only spring pressure when not manipulating it.

I wonder if there was something up with your inlet, in that the pin began to slide out and broke?

What stock is it and when bedded did they make the necessary opening for the pin?

 

[kswaterfowl]

The shelf holds the pin when in the stock. But it should stay under only spring pressure when not manipulating it.

I wonder if there was something up with your inlet, in that the pin began to slide out and broke?

What stock is it and when bedded did they make the necessary opening for the pin?

That would be my guess as well. I remember a few years back people having issues with that pin breaking during matches, and I would bet that's the reason.

 

[kswaterfowl]

My pin stays in place until I start manipulating the bolt stop, the it drops as I described, to the level of the shelf on the stock.

I would have done the same as you did by building up that shelf with a bedding compound, so that pin can't drop out of there.

 

[Antares]

Maybe stretch your spring out a little. I've never had one fall out.

 

[ehayes]

I would have done the same as you did by building up that shelf with a bedding compound, so that pin can't drop out of there.

This was my thinking. Going forward, if my decision to raise the shelf was correct, I will be looking to make sure any new stock I get for a tikka, the shelf snugs up to the pin appropriately. Not something I would have thought to look before

 

[ehayes]

The shelf holds the pin when in the stock. But it should stay under only spring pressure when not manipulating it.

I wonder if there was something up with your inlet, in that the pin began to slide out and broke?

What stock is it and when bedded did they make the necessary opening for the pin?

Basically, what I think happened is the shelf sits too low.
On your stocks, I’m assuming the shelf for the pin is high enough to retain the pin in its normal seated position, is that correct?

 

[The Guide]

Basically, what I think happened is the shelf sits too low.
On your stocks, I’m assuming the shelf for the pin is high enough to retain the pin in its normal seated position, is that correct?

Is your pin seating fully into the top hole in the action?

Jay

 

[ehayes]

Is your pin seating fully into the top hole in the action?

Jay

I installed it that way. Now that I raised the shelf it stays put. Prior to that modification it would drop down so that it was no longer in the top hole. That’s where I think it’s integrity was compromised running the bolt against an unseated pin. The pin was still long enough to keep the bolt release mechanism in place.

 

[The Guide]

I installed it that way. Now that I raised the shelf it stays put. Prior to that modification it would drop down so that it was no longer in the top hole. That’s where I think it’s integrity was compromised running the bolt against an unseated pin. The pin was still long enough to keep the bolt release mechanism in place.

Is there a chance that the pin was undersized or the hole is now "egged" from hard use? I've just never seen it in any of the 8 Tikka actions I own in both stainless and blued. Where did you get the replacement pin?

Jay

 

[Lawnboi]

Basically, what I think happened is the shelf sits too low.
On your stocks, I’m assuming the shelf for the pin is high enough to retain the pin in its normal seated position, is that correct?

Yes

 

[kswaterfowl]

I've seen enough of them fall out that I put tape over it when pulling or putting on new barrels.