870 Mag Tube Installation

Chris · November 20, 1998, 01:56 AM

I just purchased an 870 Express Magnum w/parkerized finish and fiberglass stocks. Also, got a TacStar mag extension (which came w/spring)when I bought the gun. Instructions state that the two small detents inside the tube must be filed down to function. Well, I ground them down w/the handy Dremel. The factory follower still seems to hang up sometimes near the front of the tube when the mag is full and causing a failure to feed. I ground the detents off and I don`t dare take any more metal off from inside the tube. I plan on getting a new high vis follower - are these any smaller in diameter. Anybody have similar problem - any suggestions would be greatly appreciated.

Mac Scott · November 20, 1998, 04:21 AM

I would guess that you've still got some "unremoved" metal within the end of the mag tube that is restricting movement of inserted rounds. The most normal problem here, when removing those damnable indentations that Remington insisted on adding, is failure to completely (and uniformly) remove all evidence of restriction.

More people get in trouble with Dremel tools and guns than any other combination of working tools I can think of. What you need to do is assure concentricity of the inside of the mag tube, something difficult, but not impossible, to do with a hand-held grinder. An adjustable reamer, set for the proper I.D. of the tube, would set up and maintain concentricity. Lacking such a device, a simple brake hone might also be used for the purpose, albeit with a major judiciousness in its application: Wouldn't take much with a hone to screw up and go through the thin walls of the tube.

Bottom line is that this really is something that can be done by the average home 'smith with the average shop tools, but it takes going low and slow for a while, trying and fitting until your shells are free within the tube. You can actually do it properly with your Dremel, just so long as you manually feel for high spots, relieve those as encountered, and proceed slowly and carefully. Best of luck.

----Mac

motorep · November 20, 1998, 05:04 PM

I recently went through the same process on an 1100 - used a Dremel, fit the follower, grind, fit the follower, etc. Finally got it to work. The next week, I mentioned this whole process to my gunsmith- he said all you need to do is drill the detents out with a 1/4" drill and smooth up the burrs with the Dremel. He loves guys with Dremel tools.

Chris · November 20, 1998, 05:26 PM

Thanks guys. I think I`ll use a combination of your suggestions - drill out the detents and use the brake hone to smoth out the inside. Mac, I used the brake hone earlier with fine stones-just used it on slow and only a little but worked nice. Yeah, believe me I GO SLOW WITH DREMELS - couldn`t take it if I screwed up a gun!

Chris · November 21, 1998, 05:13 PM

As I said earlier, I took both of your suggestions - I drilled out the indentations w/ 1/4" drill then used the brake hone with fine (400 grit stones) on the inside of the tube. Smooooth! The spring was still binding when using the factory follower w/ 6 rounds in the tube and I couldn`t find an extended follower locally - but I did have a metal follower from an old shotgun that fit fine - used that for now and works w/100% reliability. I`m still going to order a Scattergun Technologies extended mag tube with kit(spring and high viz follower). To replace the TacStar one.

Thanks again guys - this is a great place; need advice, just ask and ye shall receive; get info or just be social.

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November 20, 1998, 01:56 AM	#1
Chris Junior Member Join Date: November 20, 1998 Posts: 5	I just purchased an 870 Express Magnum w/parkerized finish and fiberglass stocks. Also, got a TacStar mag extension (which came w/spring)when I bought the gun. Instructions state that the two small detents inside the tube must be filed down to function. Well, I ground them down w/the handy Dremel. The factory follower still seems to hang up sometimes near the front of the tube when the mag is full and causing a failure to feed. I ground the detents off and I don`t dare take any more metal off from inside the tube. I plan on getting a new high vis follower - are these any smaller in diameter. Anybody have similar problem - any suggestions would be greatly appreciated.

November 20, 1998, 04:21 AM	#2
Mac Scott Member Join Date: October 6, 1998 Location: Cotati, CA USA Posts: 37	I would guess that you've still got some "unremoved" metal within the end of the mag tube that is restricting movement of inserted rounds. The most normal problem here, when removing those damnable indentations that Remington insisted on adding, is failure to completely (and uniformly) remove all evidence of restriction. More people get in trouble with Dremel tools and guns than any other combination of working tools I can think of. What you need to do is assure concentricity of the inside of the mag tube, something difficult, but not impossible, to do with a hand-held grinder. An adjustable reamer, set for the proper I.D. of the tube, would set up and maintain concentricity. Lacking such a device, a simple brake hone might also be used for the purpose, albeit with a major judiciousness in its application: Wouldn't take much with a hone to screw up and go through the thin walls of the tube. Bottom line is that this really is something that can be done by the average home 'smith with the average shop tools, but it takes going low and slow for a while, trying and fitting until your shells are free within the tube. You can actually do it properly with your Dremel, just so long as you manually feel for high spots, relieve those as encountered, and proceed slowly and carefully. Best of luck. ----Mac

November 20, 1998, 05:04 PM	#3
motorep Senior Member Join Date: October 29, 1998 Location: mid-coast Maine Posts: 546	I recently went through the same process on an 1100 - used a Dremel, fit the follower, grind, fit the follower, etc. Finally got it to work. The next week, I mentioned this whole process to my gunsmith- he said all you need to do is drill the detents out with a 1/4" drill and smooth up the burrs with the Dremel. He loves guys with Dremel tools.

November 20, 1998, 05:26 PM	#4
Chris Junior Member Join Date: November 20, 1998 Posts: 5	Thanks guys. I think I`ll use a combination of your suggestions - drill out the detents and use the brake hone to smoth out the inside. Mac, I used the brake hone earlier with fine stones-just used it on slow and only a little but worked nice. Yeah, believe me I GO SLOW WITH DREMELS - couldn`t take it if I screwed up a gun!

November 21, 1998, 05:13 PM	#5
Chris Junior Member Join Date: November 20, 1998 Posts: 5	As I said earlier, I took both of your suggestions - I drilled out the indentations w/ 1/4" drill then used the brake hone with fine (400 grit stones) on the inside of the tube. Smooooth! The spring was still binding when using the factory follower w/ 6 rounds in the tube and I couldn`t find an extended follower locally - but I did have a metal follower from an old shotgun that fit fine - used that for now and works w/100% reliability. I`m still going to order a Scattergun Technologies extended mag tube with kit(spring and high viz follower). To replace the TacStar one. Thanks again guys - this is a great place; need advice, just ask and ye shall receive; get info or just be social.