870 Magazine Dimple Removal Fail Help

[freshjojos]

So this is going to be my first post here and probably the most painful.

I have a new 870 and ordered a new magazine extension for it. In the process of preparing for the extension I used the "socket" method to remove the dimples in the tube. Well, I used one of my flared deep impact sockets and should have measured it more closely (I'm sure I will be reminded of this ad nausea) but it pushed out the dimples but also increased the diameter of the tube ever so slightly, enough so that the cap cannot thread on and the barrel ring can't go over the tube ( so probably a bit more than slight ).

How do I reduce the diameter so that 1. I can fit the cap back on and 2. as importantly I can fit the barrel ring over the tube so I have something to shoot out of SMH...

I've tried to used a pair of channel locks a rag and a smaller socket but it just bends and bends right back since it's just a slight increase. Don't tell me I've just destroyed my new gun, as a new tube braze in would cost as much as I paid for this base 870 but i'm open to try other things. I have oxy/acetylene but am afraid of heating and disturbing the silver solder at the other end... sigh. Help!

[Germansheperd]

Not an attack on OP but why, why, why do people keep doing this?
Drill bit and Dremel folks.- Remington TELLS you to drill out the dimples.
I’ve cant believe there are so may people that think and act like 50’s and 60’s hacks.
Old 870’s came from the factory with what.........holes drilled in the magazine tube.
The magazine tube is brazed in from the factory, no good can come from smashing a socket down the tube. I know some inbred is going to say “I did it” yeah well someone is going to win the lottery this week too.

[Scorpion8]

Well, back to actually helping a user....

How do I reduce the diameter so that 1. I can fit the cap back on and 2. as importantly I can fit the barrel ring over the tube so I have something to shoot out of SMH...

There are only so many ways to 'shrink" metal once it's been stretched. Most mechanical means will require some application of heat, so go very slowly. Sliding anything down the magazine tube to shrink it will probably mess up the exterior finish also. But since we're probably past that, you should find a collar as close to the original spec tube size as you need, heat the magazine tube and drift the collar down the tube length slowly while applying heat. Frankly I'd just get a new tube.

[Banshee]

Not an attack on OP but why, why, why do people keep doing this?
Drill bit and Dremel folks.- Remington TELLS you to drill out the dimples.
I’ve cant believe there are so may people that think and act like 50’s and 60’s hacks.
Old 870’s came from the factory with what.........holes drilled in the magazine tube.
The magazine tube is brazed in from the factory, no good can come from smashing a socket down the tube. I know some inbred is going to say “I did it” yeah well someone is going to win the lottery this week too.

If you use the proper tool it works great, if you don’t it can wrong very quickly. A socket is NOT the proper tool.

[Chef Duane]

... Frankly I'd just get a new tube.

^^^^ This.

[JimS]

I'm rescuing a 870 Express Magnum 12 ga. the mag tube was buggered. I have straightened and got dimples and dents out BUT the threads were "compressed' at the end, during the original damage. I'm sure a die would clean them up, the tube straightening and punch and hammer work have it all straight. Another fix would be to mill or file the 1 and 1/2 threads off that are buggered. Because I can not find a 1" 12 pitch single lead , flat thread die! Where would one purchase one of those?

[Scorpion8]

Because I can not find a 1" 12 pitch single lead , flat thread die! Where would one purchase one of those?

https://www.mcmaster.com/dies/thread-size~1-12-1/

? Would that work?

[Banshee]

Because I can not find a 1" 12 pitch single lead , flat thread die! Where would one purchase one of those?

https://www.mcmaster.com/dies/thread-size~1-12-1/

? Would that work?

No, magazine tube threads are square threads not 60deg v threads. As where to find a die, i have never seen a die for square threads.

It is possible to repair square threads with a set of (swiss) needle files. If it is just the first thread i would simply cut it off if you can not repair it

[JimS]

Thanks. that leaves 3-4 threads for cap to attach, enough?

[Banshee]

Well, we put sling plates under the cap all the time with no problems and that shortens the tread length. I would try repairing them with a couple of needle files first and remove the bad thread as a last ditch effort.I have repaired some pretty rough threads with files. You can get a set of files from Harbor Freight for less than $10. They only have last long enough to fix your mess. Any pictures of the damage?