Mossberg 51M(b) help. Bolt handle won’t stay in

[Saltwater60]

I helped a friend clean the dirtiest gun I’ve ever seen in my life and it came out great. Went to put it back together and everything went great except the bolt handle won’t get caught by the firing pin. I tried it without installing the bolt and it will stay in but just barely. I can also get it to stay in and locked but when I cock it the handle comes out. I found a link to this thread where it’s discussed and I followed the procedure but it won’t stay in. I have to say it was the easiest bolt to remove ever so it may have came to me this way. Any thoughts or help would be appreciated.
I’m 99.99% sure the gun is back the way it came. A YouTube video or even a better parts diagram would help.

Old Mossberg 51m help...

Hi folks: I've been tasked with cleaning up my mother-in-law's Mossberg 51m .22 rifle... (semi-auto) I got it apart, cleaned it, and everything back together just fine. The only left-over parts I have are the 2 screws that hold the barreled action to the stock and the two screws that hold the...

www.indianagunowners.com

 

[Saltwater60]

I found this picture of the firing pin and it is upside down compared to how it was installed when I received the gun and to how I installed it. I’m positive I installed it the way it came but do you think it’s oriented properly in this picture?

 

[Saltwater60]

I also found this. The firing pin is opposite above and this is the way it came.

 

[Acer-m14]

is this the 51m -b ??
like photo below ?? just bolt action ??

my 152 .. to remove the bolt unscrew the breach screw and hold on for the spring lol ..






or like a 142 bolt version ??






i would have to have it my hands to play with it so see whats up ..

every time i clean the 152 its takes a brick or 2 of shooting to get it dirty and running fine again .. lol ..

just how that old gun is ..

 

[Saltwater60]

The bolts look like those but I saw a video for the 151 and the bolt/firing pin assembly is much different. For the 51 the finding pin just sits on top of the bolt in a channel. I can get it to stay in when the bolt is forward but then if I cock the gun it doesn’t stay in anymore. He did say the gun had all sorts of firing issues prior to me doing anything with it. Were the issues because it’s filthy or something else. The firing pin is about $20 on line so I may order one for him. I don’t know.

 

[FP1201]

Let me throw a caution to you that you might not know: Only use "Standard Velocity" ammunition in these (and other) vintage .22's especially semi-automatic ones; they weren't designed or sprung for "High-Speed" ammo and WILL break Firing Pins, have failures to extract.
For Mossberg Parts, I've had success with these folks: Havlin Sales & Service - Mossberg Gun Parts

 

[S&W Fan]

I haven’t taken the bolt out of my mossy 51m in quite some time so I won’t be much help but , I would highly recommend going on over to rimfire central site and posing your question in the Mossberg section . Those guys over there are Old Mossberg gurus.

P.S. These old timers are much more accurate if they aren’t squeaky clean and as @FP1201 suggested Using only standard velocity ammo in these old timers is highly recommended.

 

[FP1201]

I haven’t taken the bolt out of my mossy 151 in quite some time so I won’t be much help but , I would highly recommend going on over to rimfire central site and posing your question in the Mossberg section . Those guys over there are Old Mossberg gurus.

P.S. These old timers are much more accurate if they aren’t squeaky clean and as @FP1201 suggested Using only standard velocity ammo in these old timers is highly recommended.

For a while I was "collecting" Mossbergs, had better than 20 of them, but anymore all I have is my Great Grandfathers 151K and three 44US Trainers...there might be an action or even compete gun or two in the corner that have been forgotten, but yea those old Rifle DO shoot very well!

 

[S&W Fan]

For a while I was "collecting" Mossbergs, had better than 20 of them, but anymore all I have is my Great Grandfathers 151K and three 44US Trainers...there might be an action or even compete gun or two in the corner that have been forgotten, but yea those old Rifle DO shoot very well!

I’ve got about 6 or so that I can think of off the top of my head. They’re Great old rifles.

 

[Saltwater60]

This rifle is pretty beat. The stock is in good shape but many all the metal was so dirty I had to use a pick and a screw driver in some areas to get the gunn out. The tube was crunchy when it moved. Some rust on the barrel and the sights on it are pretty rough. The front sight is fairly roached. I’ll take a look at rimfire central and this question seems to be asked a lot because I see a lot of folks losing the same question on line. Not many follow up recommendations other than the instructions I have. I’ll mess with it this week. Thanks guys and yes the low velocity ammo makes sense but I would not have know that so that’s great.

 

[tony]

Look at the bolt face to see where the firing pin will strike the rim. That should tell much about the proper orientation for it..

 

[nortatoga]

For all ? Rimfire- Rimfire Central Firearm Forum my go to site..

 

[Saltwater60]

Look at the bolt face to see where the firing pin will strike the rim. That should tell much about the proper orientation for it..

I’m sure the firing pin is back in properly. There’s really only one way it can go back in from what I saw. Also I found a schematic for it finally. Also your theory lines up with where I’m at with the installation that I have now.

 

[sschrad]

 

[Saltwater60]

View attachment 221220

I saw this and tried it. I have to get it larger and print it. I’m having trouble reading it on my phone. I’m either missing something stupid or the firing pin is warn. It was so easy to remove the bolt handle when I did it but I was trying to so I don’t know if it just fell out prior to me taking it out. It hasn’t been shot in 20 years and the friend who got it from his dad hasn’t shot it since he was a teenager so who knows.

 

[sschrad]

I get it with the phone! That's why I have a 24 inch screen on my desktop I can't do anything on my phone, for the same reason. If you have a desktop or a laptop, just go to the three dots in the upper right of your screen and after you click on those, just look for ZOOM and click the + symbol until you can see it well enough. Hope it works out.

 

[sschrad]

It's hard to get a clear picture of the instructions when it's a copy of a copy of a copy, of something that was published in the 1940's . That rifle is approximately 85 years old.

 

[Acer-m14]

let see if this helps any .. i doubled the image size ..

 

[Acer-m14]

If that 51M(b) in the photo/manual above is what you have @Saltwater60

it looks like the same take down instructions as my Moss 152 semi

i have just removed the bolt and sprayed it down and scrubbed with a tooth brush ..

i have never striped the bolt down to parts and removed the firing pin ..

did that once with my Mosin and took 2 hours to get it back together LOL ..

to me it looks the same set up as my 152 ..

 

[Saltwater60]

If that 51M(b) in the photo/manual above is what you have @Saltwater60

it looks like the same take down instructions as my Moss 152 semi

i have just removed the bolt and sprayed it down and scrubbed with a tooth brush ..

i have never striped the bolt down to parts and removed the firing pin ..

did that once with my Mosin and took 2 hours to get it back together LOL ..

to me it looks the same set up as my 152 ..

Your bolt and firing pin is different. My firing pin just falls right out of the bolt. Your firing pin has to be put back in or removed with a retaining pin and mine just rests right on the top. I’m assuming it was an inferior design on the one I’m dealing with and that’s why yours has the improvement. I had no reason to remove my firing pin but it just fell out. The bolts look identical but the firing pin is different. I found a video for the 151 model and was excited but when I got to the bolt reassembly all excitement disappeared because it was not the same.

 

[sschrad]

www.rimfirecentral.com/threads/mossberg-51m-a-cocking-handle-retention-problem.1239093/

I know that this is for a 51M(a) but it should be the same. Hope it helps

 

[Acer-m14]

Your bolt and firing pin is different. My firing pin just falls right out of the bolt. Your firing pin has to be put back in or removed with a retaining pin and mine just rests right on the top. I’m assuming it was an inferior design on the one I’m dealing with and that’s why yours has the improvement. I had no reason to remove my firing pin but it just fell out. The bolts look identical but the firing pin is different. I found a video for the 151 model and was excited but when I got to the bolt reassembly all excitement disappeared because it was not the same.

sounds the same as when i was watching videos on the take down on a 500 moss ... my 500 moss is stamped 500AT ..

every video i watch the slide just slide right off ..

not on mine ... it has a fat flat spring welded to the mag tube that keep the slide from coming off ..

on mine i have to unscrew the mag tube and remove it then presto the slid come off the gun ..

 

[Saltwater60]

sounds the same as when i was watching videos on the take down on a 500 moss ... my 500 moss is stamped 500AT ..

every video i watch the slide just slide right off ..

not on mine ... it has a fat flat spring welded to the mag tube that keep the slide from coming off ..

on mine i have to unscrew the mag tube and remove it then presto the slid come off the gun ..

Holy crap I have the 500 AT as well. I’ve never disassembled it.

 

[Saltwater60]

www.rimfirecentral.com/threads/mossberg-51m-a-cocking-handle-retention-problem.1239093/

I know that this is for a 51M(a) but it should be the same. Hope it helps

So I think that put it together for me and with one other post I read as well. The other post wasn’t clear and I was like how the hell could you do that. I think what I need to do and what I have been doing wrong is that spring assembly from the rear needs to go in first and then the firing pin with the handle. It will be hard to do but that ring on the back holds the firing pin in place by that little tab coming down from the firing pin. That’s also what moves the firing pin forward and rearward while cocking the gun. That makes a ton of sense now. That rod holding the handle in place makes great sense because when looking at the firing pin I could not see a way for it to retain the handle unless it was put in upside down and I know that wasn’t right. I’ll check it out outside of the gun to get the feel for it then reassemble it. Thanks so much!!

 

[sschrad]

You're very welcome

 

[Acer-m14]

Holy crap I have the 500 AT as well. I’ve never disassembled it.

well now you know ... every thing else is just about the same in the vids for the normal 500's i watched ..

removing the cap and mag spring will not let the slide come off .. need to un screw the tube ..

in case you want to strip it down and make it pretty again ..


i tore mind down .. dad gave it to me .. mule kicker .. plastic butt plate .. its gave a few scope eyes in its days .. i actually hated that gun

then i got into guns and reloading ..

lets see if i can tame this mule kicker

tore it all down

sanded it down .. refinished the wood , cut the butt down to add a 1 inch limb saver pad to it ..

to keep the length of pull ..

its a totally different shooter .. i even use to shoot skeet with it .. 24/25 is my best so far with that old pump ..

 

[Saltwater60]

well now you know ... every thing else is just about the same in the vids for the normal 500's i watched ..

removing the cap and mag spring will not let the slide come off .. need to un screw the tube ..

in case you want to strip it down and make it pretty again ..


i tore mind down .. dad gave it to me .. mule kicker .. plastic butt plate .. its gave a few scope eyes in its days .. i actually hated that gun

then i got into guns and reloading ..

lets see if i can tame this mule kicker

tore it all down

sanded it down .. refinished the wood , cut the butt down to add a 1 inch limb saver pad to it ..

to keep the length of pull ..

its a totally different shooter .. i even use to shoot skeet with it .. 24/25 is my best so far with that old pump ..

I think I knew that the tube needed to be unscrewed but I haven’t taken it apart in years. The gun is too big for me and it’s heavy. Since I bought my Benelli 20 gauge shotgun I haven’t used that gun in a long time. My dad bought it for me when I was 15-16 and maybe I’ll give it back to him to keep at his camp for a pest gun.

 

[Acer-m14]

I think I knew that the tube needed to be unscrewed but I haven’t taken it apart in years. The gun is too big for me and it’s heavy. Since I bought my Benelli 20 gauge shotgun I haven’t used that gun in a long time. My dad bought it for me when I was 15-16 and maybe I’ll give it back to him to keep at his camp for a pest gun.

i just keep the short open cyl bore barrel on it . the long full choke barrel is up in the shops rafters .