Model 81 Bolt malfunction

Information on Malfunctions and Care of your Model 8 & 81
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Lebengeek
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Joined: Thu Sep 08, 2016 7:41 pm

Model 81 Bolt malfunction

Post by Lebengeek »

Hi Forum,
Any advice to why my bolt in my model 81 is rotating prior to entering barrel? I can only shoot once maybe twice before this malfunction occurs. The gun is new to me and seems to function correctly when running the bolt back and forth manually. Ammo was 35 rem200gr Rem core lokt sp The round in the breach is live so the fired case was ejected.

Thanks,

Alan
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81police
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Location: TEXAS

Re: Model 81 Bolt malfunction

Post by 81police »

Alan, have you tried to use a flathead screw driver and push forward and up on the right bolt lug? Picture is hard to tell but it looks like the bolt lugs are misaligned. Before entering the chamber they should be in the 12 o clock and 6 o clock positions. If there's not damaged components inside the bolt carrier (cams pins, etc) this should line it out. Let us know.
Cam Woodall
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Sebastian21
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Re: Model 81 Bolt malfunction

Post by Sebastian21 »

I would not fire this gun until it was inspected. Was it recently taken apart? The cam pins could be missing or broken and should be inspected. There is a guide in the receiver to prevent this from occurring if the bolt is correctly assembled. This will happen if the barrel is not on. It often occurs if the gun is taken down. The solution is to insert the barrel and pry the bolt head foreword and vertical using a screwdriver. Once you do this with the barrel on it should stay that way until the barrel assembly is again removed. If it does not, remove the bolt and make sure it is assembled correctly, nothing is broken and the cam pins are working.
Lebengeek
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Joined: Thu Sep 08, 2016 7:41 pm

Re: Model 81 Bolt malfunction

Post by Lebengeek »

Sebastian21 wrote:I would not fire this gun until it was inspected. Was it recently taken apart? The cam pins could be missing or broken and should be inspected. There is a guide in the receiver to prevent this from occurring if the bolt is correctly assembled. This will happen if the barrel is not on. It often occurs if the gun is taken down. The solution is to insert the barrel and pry the bolt head foreword and vertical using a screwdriver. Once you do this with the barrel on it should stay that way until the barrel assembly is again removed. If it does not, remove the bolt and make sure it is assembled correctly, nothing is broken and the cam pins are working.
Thanks for the info Sebastion21. Before firing the rifle I had a gunsmith inspect the rifle but I don't know how detailed of an inspection he did. Manually working the action everything seems to operate and cam once the lugs go into the barrel. If I try I cant get the lugs to rotate if the bolt is held back and slowly allowed to move into battery. once in the correct position inside the barrel the lugs rotate as they should. Interesting about the take down alignment issues. I'm try to picture where you pry on the bolt when it is in the barrel once the rifle has been locked back together. This may be the issue. It would be nice if it was an easy fix. I plan to take things apart over the weekend. Thanks so much for the help!
Lebengeek
Posts: 11
Joined: Thu Sep 08, 2016 7:41 pm

Re: Model 81 Bolt malfunction

Post by Lebengeek »

81police wrote:Alan, have you tried to use a flathead screw driver and push forward and up on the right bolt lug? Picture is hard to tell but it looks like the bolt lugs are misaligned. Before entering the chamber they should be in the 12 o clock and 6 o clock positions. If there's not damaged components inside the bolt carrier (cams pins, etc) this should line it out. Let us know.
Once I pull the bolt back the bolt realigns without issue. For some reason it was hanging up when trying to go into battery after the first shot. I'm going to try S21's advice about aligning the bolt and barrel. If that doesn't work I'll have to investigate the bolt pieces as well. Thanks again for the help.

Alan
Sebastian21
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Re: Model 81 Bolt malfunction

Post by Sebastian21 »

If the barrel assembly is on the gun and the lugs have snapped 90 degrees out of alinement then to close the bolt you release the bolt, allow it to go foreword to about 3/4 inch short of the barrel face. Hold the bolt, put a screwdriver behind the lug, push foreward pulling the bolt face out of the bolt carrier. Then snap the lug upward and the bolt face will lock foreward out of the bolt carrier. Let go of the bolt and it will lock into the barrel. The bolt lugs should not rotate out of alinement as long as the barrel assembly is in place. This is best done with the rifle in a vise. If it rotates again when the bolt is retracted and the barrel assembly is in place then something is not assembled correctly.
Lebengeek
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Re: Model 81 Bolt malfunction

Post by Lebengeek »

Well I tried working on the barrel and bolt alignment today The gun seems to work flawlessly when you run the action by hand the lugs stay at 12 and 6 until inside of the barrel then rotate to lock up the action. You pull back on the charging handle and bolt unlocks and sets lugs at 12 and 6 for the ejection cycle. Bolt locks back on last round and the bolt release works as it should. Put a few rounds in the mag, shoot one round. that round ejects and as the bolt comes forward it picks up the next round but at some point the lugs are not at a full 12 and 6 they are more like 3 and 9 and the bolt stops its forward momentum when it contacts the back of the barrel. I contacted my FFL and he is going to have his gunsmith check things out. I'll keep you guys posted. Thanks again for the help !





Alan
Lebengeek
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Re: Model 81 Bolt malfunction

Post by Lebengeek »

Sebastian21 wrote:If the barrel assembly is on the gun and the lugs have snapped 90 degrees out of alinement then to close the bolt you release the bolt, allow it to go foreword to about 3/4 inch short of the barrel face. Hold the bolt, put a screwdriver behind the lug, push foreward pulling the bolt face out of the bolt carrier. Then snap the lug upward and the bolt face will lock foreward out of the bolt carrier. Let go of the bolt and it will lock into the barrel. The bolt lugs should not rotate out of alinement as long as the barrel assembly is in place. This is best done with the rifle in a vise. If it rotates again when the bolt is retracted and the barrel assembly is in place then something is not assembled correctly.
Hi Sebastian21,
When the lugs do rotate and hang up all I've had to do is pull the charging handle back and the lugs pop back into 12 and 6. Not sure if that is the correct way or a sign that parts are either broken or put together wrong. Rifle is back at the gunsmith for inspection.

Thanks,

Alan
Sebastian21
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Joined: Fri Aug 28, 2015 1:06 pm

Re: Model 81 Bolt malfunction

Post by Sebastian21 »

When the rifle fires the lugs are horizontal and locked to the barrel. The barrel recoil and the bolt lugs rotate to vertical position and unlock from the barrel. The lugs remain vertical as the bolt recoils to pick up a new cartridge. The lugs should not rotate horizontal during this operation. I can Not think what would cause this to happen. If your gunsmith finds what is causing this post it on this fourm. My thought it is a timing issue. Some how the bolt thinks it is in battery locked to the barrel before it is, and is rotating into the Locked position before it enters the barrel. This could be caused by the wrong barrel recoil springs. If the springs were compressed, or too lite, or somebody installed the wrong spring or the springs are not positioned correctly. This most certainly would change the timing. The obvious thing would be to try another barrel assembly but your gunsmith probably does not have another barrel assembly laying around. Perhaps somebody near you could meet and switch barrel assembly. Unfortunately yous is a 35 so only another 35 will work as the bolts are different. Headspace is automatic set and is never a concern. Try ALL tests with factory rounds, NEVER test guns with reloads. Keep us informed. If the barrel switch does not show anything try another carrier /bolt assembly . Bolts with carriers are cheap just make sure it is a 35. There are plenty on Ebay for about 80.00. Some sellers on Ebay are dis-honest and say one bolt fits all. You have to measure the bolt face to establish the caliber, do not go by the stamping on the extractor as they all say 35. I would not file anything on your bolt unless there is a obvious error.
Lebengeek
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Re: Model 81 Bolt malfunction

Post by Lebengeek »

Thanks for all the info Sebastion21!
As I was trouble shooting today I was pushing on the end of the barrel and wondered the exact same thing. That some how the timing was off and the bolt was unlocking under recoil but at the wrong time causing the lugs to be rotated out of sequence. I will pass on info when I get it. I will also share advice if gunsmith needs. The rifle seems to be in nice shape so I hope I don't need to hunt for parts, but if that's what it takes then so be it.

Thanks Again!

Alan
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Phyrbird
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Re: Model 81 Bolt malfunction

Post by Phyrbird »

LG,
I've been thinking :o about your fault, it could be something to do with the bolt lock in the carrier. Study this link at the very last of the second page for additional understanding of how this stuff works.

https://www.flickr.com/photos/buster_ch ... 0342/page2

It could be something as simple as the bolt lock spring in backwards. Also verify the bolt lock bar is in the receiver, it's a permanent riveted installation, but as a riveted part it could work loose.
Phyrbird
SOKY
Sebastian21
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Joined: Fri Aug 28, 2015 1:06 pm

Re: Model 81 Bolt malfunction

Post by Sebastian21 »

These are the best pictures I have seen on a model 8. These pictures show every aspect of the bolt. I am saving this page. Zphyrbir has a good idea. I have never see the rivets loose but I have seen the part worn.
Sebastian21
Posts: 84
Joined: Fri Aug 28, 2015 1:06 pm

Re: Model 81 Bolt malfunction

Post by Sebastian21 »

Have your gunsmith look at the bolt latch. I studied one of my bolts to see how it worked. When the bolt is in battery the bolt latch is depressed and the bolt is free to rotate out of battery. When the bolt carrier starts back after firing the bolt latch slides back beyond the block riveted to the inside of the receiver and can swing down and lock the bolt in the vertical position. As long as the latch is nose down the bolt can not rotate to the horizontal position. Yours is rotating with the carrier in the unlocked position. That bolt latch is there to prevent this. The bolt latch can only be installed in one position. The only reason it would not work is: the tip is broken off; the spring is missing, broken or installed upside down; the block on the receiver is damaged or missing. Hope this helps.
Lebengeek
Posts: 11
Joined: Thu Sep 08, 2016 7:41 pm

Re: Model 81 Bolt malfunction

Post by Lebengeek »

Thanks again Guys!
I will pass on the info to the gunsmith. I hope to get some answers soon.
Great community of people here!

Thanks again for all your time and help. I look forward to the even bigger smile I'll have on my face when I have a fully functional Model 81 :)

Alan
Lebengeek
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Re: Model 81 Bolt malfunction

Post by Lebengeek »

Sorry for the long delay on an update to the Model 81. To be honest it has been to several so called smiths until finally I found a true gunsmith who didn't just lube and clean the gun and call it good. The true smith worked on the gun for some time to get it working correctly. It was about a two month wait at the last smith before finally getting it back. Three issues came up that had to be fixed. The main issue was the bolt not locking vertical under recoil then rotating prior to lock up during feeding and jamming the gun. Smith figured the barrel was out of spec from use so added metal and machined barrel chamber for tighter tolerance when the bolt lugs are in the vertical position. He also replaced extractor spring with a heavier one. The second issue was the extractor fell out of the bolt. He reinstalled and reshaped the angle of the extractor which had opened up a bit from use. The last issue was that the gun would not feed the last round ,the bolt would hang up. This was an issue with the bolt hold open spring like some folks had mentioned. Now to Head to the range to have some fun. Again Sorry for the update delay. This has been a long process. Thanks again for the advice and info!
jim c 351
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Location: ohio

Re: Model 81 Bolt malfunction

Post by jim c 351 »

As John Henwood said in his book on the 8/81, "where do you find a gunsmith that knows a thing about a model 8."
I wish you luck but I have my doubts as to whether the last gunsmith solved your problem.
Jim C
Lebengeek
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Joined: Thu Sep 08, 2016 7:41 pm

Re: Model 81 Bolt malfunction

Post by Lebengeek »

Thanks Jim :) Well if the work doesn't fix the issues it will go back till it does. :)
jim c 351
Posts: 41
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Location: ohio

Re: Model 81 Bolt malfunction

Post by jim c 351 »

leben,
I know how you feel, but be cautious trying to force someone to do something that he is incapable of doing.
Even the small percentage of gunsmiths that actually went to a trade school probably learned about blueing, 1911s and AR15s. Probably didn't have a model 8 within 200 miles of the school.
I had a problem like yours a few years ago, but at my age I have trouble remembering how I solved the problem.
I vaguely remember some sort of spring pressure that prevented the bolt from rotating prematurely.
Best of luck.
Jim C
Lebengeek
Posts: 11
Joined: Thu Sep 08, 2016 7:41 pm

Re: Model 81 Bolt malfunction

Post by Lebengeek »

Well you were correct Jim.
The bolt stays locked vertically now on feeding and extraction but I had failures to extract, double feeds and failure to load. Runs actually worse than before. The action is not smooth so the saga continues. The shots I did manage to get out all were touching so I hope I can get it running reliably.
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