[gearbox]

I've heard that they can be grinded out and they can be pounded out. What methods are available, and what methods are practical?

[Old Fuff]

It depends on how deep these “dimples" are. But a gunsmith supply firm at : www.brownnels.com sells the equipment and offers free technical help. They’re a good outfit. Check them out.

[Schiessuebung]

I second the recommendation; but the website link is www.brownells.com

[444]

Just drill a hole where the dimples are.

[Bix]

I am about as common a man as you will find, and I did it successfully with a dremel bit chucked into a variable speed drill. After grinding the bulk of the nubs down, I went over them with increasingly fine sandpaper. I would sand a little, test with a follower, and repeat until the follower moved freely. I then polished with fine steel wool, and dabbed blue touch-up on the exposed metal. Probably a four hour project - good quality time with the 870!

[Blueduck]

I understand the "dimples" make installing mag extensions more difficult, but do they serve a purpose on stock gun???

[Bix]

Yikes. Sorry about the double post, I'm still getting the hang of this.

Blueduck, the dimples do serve a purpose: they keep the mag spring retainer from rotating in the mag tube. This, in turn, keeps your magazine cap from unscrewing (the "teeth" in the retainer hold the cap in place).

In my experience, a cap will unscrew a bit on a gun with the dimples milled out - my barrel gets a little loose about halfway through a round of trap.

I haven't really figured out a good solution to this problem yet. Right now, I am keeping my eye out for a cheap used wingmaster barrel, which uses a detent ball to hold the cap in place.

[Blueduck]

Thanks Bix!

[Kharn]

Does anyone know the procedure for installing a detent ball into an Express barrel? I bet Brownells would have the parts required, but I have no clue how to go about installing them.

Kharn

[Guyon]

Bix, have you tried channel locks and a rag? After getting the mag cap hand tight, use the channel locks to turn it an additional 1/8 to 1/4 turn. Just don't over do it. Use the rag to keep the channel locks from biting into your mag cap and marring the finish.

It'll stay put. The only downside is that you need the channel locks to remove the cap for cleaning. You have to carry a set around with you.

gearbox: I used the same method as Bix. Dremel and some patience. A drill bit works just fine too though and is a lot quicker. The barrel ring covers the holes.

[Wyobuckaroo]

Howdy
After the dimples are gone, you can take the very end of the stock mag spring and bend the last 1/8" strait out to the side. Drill a slotted hole in the side of the plastic stock plastic spring/mag cap retainer and let the 1/8" long leg stick into one of the holes where the dimple used to be.

Kind of a trial and error and time consuming thing to get right. But it does work and will retain the spring, spring cap, and magazine cap with out using a pliers to get it tight.

Having a detent ball installed will cost anywhere from 25 to 50 $$$ depending where you are at. It requires a special size and hardened staking tool. And a replacement mag cap.
Good luck
Wyo

[seeker_two]

Blueduck, the dimples do serve a purpose: they keep the mag spring retainer from rotating in the mag tube. This, in turn, keeps your magazine cap from unscrewing (the "teeth" in the retainer hold the cap in place)....

I haven't really figured out a good solution to this problem yet.

Would Loctite work? :confused:

[Guyon]

Would Loctite work?

Only if you don't plan to clean your gun.

[Blueduck]

Being for all pratical purposes a shotgun "newbie" I'm a bit confused...

Is this a problem only if you try to go back to the original configiration or is it a continueing issue with the new mag extension in place???

[Guyon]

Absent a detent ball, a hand tightened mag cap or a mag extension can get a little looser. IIRC though, my 20"Remington IC barrel with rifle sights had a detent for some reason. As a result, the mag extension on my HD gun stays put.

[dfariswheel]

BlueDuck:

If you remove the dimples you can't really go back to the original Express magazine assembly.

You CAN replace the Express parts, but without the dimples to lock the plastic plug in place, as soon as you unscrew the magazine cap, the mag spring and plastic plug will shoot out the end.

If you want to go back to the non-magazine extension configuration, you can either do as above, and really tighten the mag cap down, OR install a spring and plunger into the hole in the barrel support ring.

To do this, you basically insert a spring and plunger into the hole, then crimp the hole so the parts are retained.
If you go this route, you will need a Wingmaster/Police magazine cap, since the Express cap is designed to work only with the plastic Express mag plug, and a cup-type mag spring retainer from the Wingmaster/Police.

So, for simplicity, plan on sticking with either the standard 4 shot mag, or an extension mag.

This is one of the penalties when you buy an Express instead of a Wingmaster/Police gun.

If you go with an extension, make sure to use one that has a support clamp, or bracket that attaches to the barrel and magazine tube. This serves two purposes.
One, it supports the magazine and prevents it from being bent or knocked off the thin magazine tube threads.

And two, it prevents the mag extension from unscrewing. So with the mag extension and a support clamp, no other retention device is needed.

[Blueduck]

Got it, thanks!

[Devonai]

I used a semi-circular file on mine. Took 15 minutes.

I never had a problem with the mag extension tube loosening. That was probably because I was using one of those brackets as dfariswheel mentions. I only used it for the sling attachment point, but if it was preventing the extension from loosening I guess I'll never know. I did find that I had to place some electrical tape under the brackets to keep them from slipping during firing.

I never returned the 870 to the 4+1 configuration before I sold it, so I'll never know whether or not there would have been problems sans dimples.