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Old 10-13-2020, 07:46 AM
LESchwartz

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Marlin 81 Bolt Retention Problem



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I changed the rings on my 50-year old Model 81, so it was back to the range to re-sight it in. A couple of times while I was there, the bolt came all the way out while I was cycling it. It looks like the sear is the only thing keeping the bolt from being able to be removed. However, I'm a right handed shooter, so it isn't like my finger was still on the trigger when I was cycling the bolt. (Of course when the bolt came out the remainder of the cartridges in the tube dumped inside the stock -- very irritating.) The rifle was just cleaned and lubed, so I don think the trigger is sticking in the rear position.

Any one have any ideas?

Thanks in advance,

Larry
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  #2  
Old 10-13-2020, 09:32 AM
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Sounds like the sear is worn. Fairly common after a lifetime of shooting.

https://www.gunpartscorp.com/products/403300A at $12.70 a good place to begin!
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  #3  
Old 10-13-2020, 07:46 PM
LESchwartz

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I finally got a chance to pull it apart tonight . . . here's my analysis:

Theory of operation: The sear not only interacts with the firing pin, but interacts with the bolt. Pull the trigger and the sear is released, striking the firing pin -- continue to pull the trigger and the sear is lifted up, releasing the bolt.

Diagnosis: First I found quite a bit of really sticky gunk on pivots for both the trigger and the sear. This couldn't help the free movement of these components, so I cleaned them. Second, while the sear was in pristine condition, the trigger had some amount of roughness on the trigger surface that lifts the sear. I imagine the drag couldn't be good, so I polished that particular surface. (Note that I did not touch the engagement surface.) And finally, the springs: The sear spring looked like it had compressed over the years and was allowing the sear to partially release the bolt -- a good tug was all it took to remove the bolt. The trigger spring looked bent and one end looked mangled. I expect the springs are the main problem. I ordered up some new ones from Numrich.

Larry

Last edited by LESchwartz; 05-02-2021 at 05:06 PM.
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Old 10-13-2020, 08:06 PM
pipestone
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You know Larry that if you don't want to stay stock there is a trigger stickey at the top of this page that could help you find your way for a very nice shootable trigger

You can always change back if you don't like it




pipestone
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Old 10-22-2020, 07:13 PM
LESchwartz

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The parts came today. I installed the sear spring. It held the sear more securely into the bolt and I was unable to yank the bolt out. Problem solved.

The trigger spring on the other hand was a different story: I spring Numrich sent was way too long and about a dozen times too stiff. I double checked their web site and the spring they sent look similar to the one I received. I also noted that the trigger springs for all the variants of Model 81 shown on their web site listed the same p/n for the spring. Upsetting -- as I'm pretty sure this is *not* the trigger spring for this rifle.

I finally dug through my parts bin and found some springs I ordered a decade ago for a previous project (not even sure which one anymore). The spring was longer than the one I was replacing, but otherwise looked similar and seemed to have the same "springiness" (https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1). After reassembling the rifle, I measured the trigger weight with my Wheeler gauge at right around 2.5 lbs. A touch too light for my liking . . .

My intent was to gift this rifle to my granddaughters for use in hunting and plinking. I worry that a this trigger might be inappropriately light for my granddaughters' first rifle.

Any thoughts?

Larry

Last edited by LESchwartz; 10-22-2020 at 07:16 PM.
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  #6  
Old 10-22-2020, 09:34 PM
pipestone
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Sounds pretty sweet to me

Personally I don't see a problem, if she's old enough to hunt, she's old enough to handle a nice trigger


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