View Full Version : Removing magazine dimples from 870

November 15, 2001, 07:10 PM
Hey guys,

Just got my new barrel and mag extension for the 870. Before I do it, what has your experience been removing the dimples in the magazine?

Did you drill it?
Did you Dremmel it?
Did you take it to a gunsmith? How much did it cost?
I hear we can buy the tool a smith uses; where can I get it?


November 16, 2001, 09:13 AM
I tried all sort of clever ways but I eventually ended up stuffing a rag down the mag tube and using a Dremel to carefully grind off the bumps. I use a half-round file and then some sandpaper to smooth things up. I pulled out the rag and the debris came with it.
Then I stuffed another rag in there and taped off the outside and applied a bit of semi-flat (satin?) black to the inside and outside.
It came out great and cost pretty much nothing.
Good luck,

November 18, 2001, 04:51 PM
I dremmeled/filed on one, and drilled out on another. Both methods worked fine for me. The drilling went a little faster.

November 19, 2001, 07:25 PM
I used a tapered punch to try to iron out the dimples a little. Used oil and drove the punch in with a hammer. (not too hard) Then I used an adjustable hand reamer to cut out the rest of the dimple.

November 20, 2001, 02:24 AM
Thanks for all the ideas. I'm gonna do it this holiday weekend - I'll let you know what I do and how it goes.


November 23, 2001, 06:37 AM
40Glocker - Tried to PM you, but it's disabled. Here was the message I tried to send:

Hey man, sounds like we're doing the same thing this holiday weekend. I just bought another 870 from a friend and I'm trying like hell to put a mag extension on it.

I drilled mine and cleaned it up with a chainsaw file. Worked fine, considering the barrel band covers the mess.

Now I seem to be having trouble with the plastic follower sticking in there somewhere after the first 5 shells.

Have you done yours yet? Does your follower hang?

November 23, 2001, 09:33 PM
Well, I did another one today. This time I used a Craftsman 17mm socket that I tapped into the mag tube. Then I used a small but heavy brass hammer to flatten the dimples. The socket went loose as soon as the dimples were undone. I touched it up with the dremel and then some sandpaper wrapped around my finger. Worked fine.
I do not have my new hi-vis follower yet so I put the factory black, stubby follower in and a spring I had laying around from Wilson.
A side note is that although my extension is a factory +3 and the spring is for their (Wilson's) +2 extension, it is really really long IMHO and works great for the +3.
The amount of dremel work was way less this way but you really need to make sure that the socket (or pipe or whatever) is a good fit so you do not pound the mag tube out of round.

November 26, 2001, 09:51 PM
Ok, this is what I did.

Went to my parent's house for Thanksgiving. Late Thursday morning, drank one Corona beer. Then went into Dad's garage. I found a piece of round steel that fit just right (kinda tight) into the magazine. Ground the leading end into a slight taper. Oiled it up, lightly hammered into the magazine. Removed and repeated a few times. This pushed the dimples about 1/2 to 3/4 of the way out.

Then I got out the dremel bits and looked at it, decided it would be a bit tedious. I ended up using a automotive brake cylinder hone, and a power hand drill. Oiled hone and mag tube, and let it rip! This made the inside of the mag nice!

When I put the barrel back on, it was a bit tight. I realized that when I pounded the steel tube in, it actually pushed part of the dimple too far out. I fixed this by taking some emery cloth to it. Took about one minute.

Went back inside the house, feasted on Mom's cooking!

I am happy with how the magazine turned out. I would do it the same way in the future.


November 27, 2001, 12:25 AM
I just performed this mod the other day to my 870 riot-bbl gun. I took a small (?/? inch) drill bit and drilled a pilot hole. I then took a larger (?+?/?+? inch) drill bit and drilled out the hole a bit, pretty much removing the dimple. I took a dremmel and very fine grit sandpaper to the resulting holes and smoothed it out.

Was reasonably fast (30 minutes, all told) and easy. The mag extension (Scattergun Tech) functions flawlessly thus far.


PS I wish I could say the same for the shooter. I also added a speedfeed III stock with pistol grip. Using a PG on a shotgun, even with a full stock, is like learning a whole new weapon. *sigh*

November 27, 2001, 12:46 AM
"Search" is still turned off. I just dremeled mine and it works great. The real problem is to decide how light I can go on the mag spring and still get reliable feeding. I am used to shooting an old Win '97 in SASS and it has the lightest spring that I ever saw and works all the time. The 2 870's that I have set up as tactical guns seemed to have 50# springs in the magazine and were a bear to use on the clock. I put the stock springs back in (one is a +2 on an 18", the other a +3 on a 20") and then clipped off a little more a couple of times. They are still heavier than my '97, but better. I may take a little more off one until it doesn't work good and then relace it with a little longer spring. I thought that the carrier didn't line up correctly so that it caused the ammo to hang up when loading. Of course there is no way to know how light is too light until you get there.

September 11, 2002, 09:45 PM
I took the dimples out of my 870 with a round file. I used a fine grit sandpaper to smooth out the final product, but noticed a slight sticking at the 5th shell or so. I sanded the inside of the tube some more and I also sanded the orange follower slighly all the way around in the direction that the follower moves within the tube. Be sure to clean all debris out of the tube and to wipe off the small amount of follower material. Try this trick to get it to work better.

I can fit 7 (2 3/4) in the tube and they feed reliably. Smooth as p**p through a goose!

September 12, 2002, 07:50 AM
I dremeled, polished, and blued. Also put in a Choate follower. Works great.