Barrel Threaded - Problem With Re-assembly

cjw3cma · January 21, 2008, 02:53 PM

Sent my 18-1/2" 870 barrel to Mike O. to be threaded (he did a great job and fast too) and now for some reason I am having problems re-assembling (Model 870™ Express® Synthetic 7-Round).

The magazine extension seems to bottom out before the barrel is tight to the receiver; there is at least a 1/4" space left. I don't know what is up as it came apart normally but I can't seem to get it back together again (and I have taken it apart before without a problem).

Are there any words of wisdom before I humbly take it to my gunsmith for (proper) re-assembly? Here's some pics to better describe my "situation" -

1. The barrel is seated properly as seen here:

2. When seated properly, the exposed threads measure: .359

3. The thread depth on the (factory) extension - .325

So when I install the spring and attach the magazine extension, I'm left with a gap (.359 - .325 = .034).

[color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color]? What am I missing here? This has got me stumped.

[Posted on more than one site to maximize possible replies]

rem870hunter · January 21, 2008, 04:11 PM

with the mag extension screwed on. is there more than just a gap problem? like does the barrel seem to have a lot of wiggle? my express magnum without the extension has a little play even with the cap tight. even with the gap there is the barrel tight as it was before the threading job being done? by threading the barrel do you mean it was backbored/threaded to take choke tubes?

cjw3cma · January 21, 2008, 04:19 PM

with the mag extension screwed on. is there more than just a gap problem?
No other problems - just the gap - which keeps the barrel from being tight to the receiver.

like does the barrel seem to have a lot of wiggle? my express magnum without the extension has a little play even with the cap tight.

Not any side to side , but it moves more than I ever remember it doing; it seemed to be a tight fit.

even with the gap there is the barrel tight as it was before the threading job being done? by threading the barrel do you mean it was backbored/threaded to take choke tubes?

The barrel was threaded for REM chokes. There was not the "looseness" that therre is now - but I can't think of anything done to the barrel that would cause this - as the end that fits into the received is just as it was before being worked on.

It seems to me that now there is a gap that needs a washer added between the magazine extension and the gun - but why was it not needed before???????

I took the barrel off, got it back and now the gun does not FIT together like it should.

rem870hunter · January 21, 2008, 04:40 PM

how about the forend? is it tight to rack the slide back and forth? or normal? have you tried with the slide all the way back , or in mid position? the forend on my express was tight with a brand new slug barrel with the synthetic aftermarket speedfeed type. with the wood model it was fine. i filed a little bit of the plastic off the inner part of the forend. it moves better now. do you have to force the barrel into the receiver or does it fall right in?

cjw3cma · January 21, 2008, 06:36 PM

how about the forend? is it tight to rack the slide back and forth? or normal?

Normal / smooth action.

have you tried with the slide all the way back , or in mid position?

Every position possible.

do you have to force the barrel into the receiver or does it fall right in?

With the slide partially open, the barrel slides into position very smoothly. But it looks like the barrel is going into the receiver a bit more (deeper) than it used to. I read in the Remington Owner's Manual - "WARNING! DO NOT pump the action or pull the trigger repeatedly with the barrel removed" - AFTER I had pumped the action a few times to make sure nothing was out of place / binding

. Could that have done anything?

The barrel seems to "sit" further into the receiver (as shown on this representation) -

almost like the Ejector Spring (in color) has moved position - but I don't know if that is possible.

What'd you think?

paul salchow · January 21, 2008, 06:47 PM

If that is a remington 7 shot extension, unscrew the cap from the tube untill the cap tightens down on the mag tube support.
Tighten the tube all the way and than back it out 1/4 turn and install your extension clamp.

cjw3cma · January 21, 2008, 08:15 PM

I had assumed that the magazine extension was a one piece design - which caused me to proceed down the WRONG path - and now I feel

(yeah) embarrassed.

Thank you, Paul, for getting me onto the proper path of Remington 870 maintenance. I just wish that the manual was not soooooooooooo generic and it covered magazine extensions (so I could have figured it out myself).

But that's what forums are all about - LEARNING.

Thanks again; the 870 is back together (properly).

paul salchow · January 21, 2008, 08:32 PM

I get these in alot from law enforcement departments with the same problems and some you would'ent believe.
These are shotguns that have been in use for 50 plus years and after all that time the professional users can't get it correct, you have nothing to be embarrassed about, remington should change the design.
It's far to easy to tighten it down to the point where the spring binds.

January 21, 2008, 02:53 PM	#1
cjw3cma Senior Member Join Date: July 9, 2007 Location: Chiloquin, OR Posts: 217	Barrel Threaded - Problem With Re-assembly Sent my 18-1/2" 870 barrel to Mike O. to be threaded (he did a great job and fast too) and now for some reason I am having problems re-assembling (Model 870™ Express® Synthetic 7-Round). The magazine extension seems to bottom out before the barrel is tight to the receiver; there is at least a 1/4" space left. I don't know what is up as it came apart normally but I can't seem to get it back together again (and I have taken it apart before without a problem). Are there any words of wisdom before I humbly take it to my gunsmith for (proper) re-assembly? Here's some pics to better describe my "situation" - 1. The barrel is seated properly as seen here: 2. When seated properly, the exposed threads measure: .359 3. The thread depth on the (factory) extension - .325 So when I install the spring and attach the magazine extension, I'm left with a gap (.359 - .325 = .034). [color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color]? What am I missing here? This has got me stumped. [Posted on more than one site to maximize possible replies]

January 21, 2008, 06:47 PM	#6
paul salchow Member Join Date: July 2, 2004 Posts: 64	remington If that is a remington 7 shot extension, unscrew the cap from the tube untill the cap tightens down on the mag tube support. Tighten the tube all the way and than back it out 1/4 turn and install your extension clamp. __________________ simmons gun repair/law enforcement

January 21, 2008, 08:32 PM	#8
paul salchow Member Join Date: July 2, 2004 Posts: 64	I get these in alot from law enforcement departments with the same problems and some you would'ent believe. These are shotguns that have been in use for 50 plus years and after all that time the professional users can't get it correct, you have nothing to be embarrassed about, remington should change the design. It's far to easy to tighten it down to the point where the spring binds. __________________ simmons gun repair/law enforcement Last edited by paul salchow; January 21, 2008 at 08:57 PM. Reason: tired fingers

January 21, 2008, 04:11 PM	#2
rem870hunter Senior Member Join Date: October 12, 2007 Location: N.J. and trying to decide what state to move to. Posts: 973	with the mag extension screwed on. is there more than just a gap problem? like does the barrel seem to have a lot of wiggle? my express magnum without the extension has a little play even with the cap tight. even with the gap there is the barrel tight as it was before the threading job being done? by threading the barrel do you mean it was backbored/threaded to take choke tubes?

January 21, 2008, 04:19 PM	#3
cjw3cma Senior Member Join Date: July 9, 2007 Location: Chiloquin, OR Posts: 217	with the mag extension screwed on. is there more than just a gap problem? No other problems - just the gap - which keeps the barrel from being tight to the receiver. like does the barrel seem to have a lot of wiggle? my express magnum without the extension has a little play even with the cap tight. Not any side to side , but it moves more than I ever remember it doing; it seemed to be a tight fit. even with the gap there is the barrel tight as it was before the threading job being done? by threading the barrel do you mean it was backbored/threaded to take choke tubes? The barrel was threaded for REM chokes. There was not the "looseness" that therre is now - but I can't think of anything done to the barrel that would cause this - as the end that fits into the received is just as it was before being worked on. It seems to me that now there is a gap that needs a washer added between the magazine extension and the gun - but why was it not needed before??????? I took the barrel off, got it back and now the gun does not FIT together like it should.

January 21, 2008, 04:40 PM	#4
rem870hunter Senior Member Join Date: October 12, 2007 Location: N.J. and trying to decide what state to move to. Posts: 973	how about the forend? is it tight to rack the slide back and forth? or normal? have you tried with the slide all the way back , or in mid position? the forend on my express was tight with a brand new slug barrel with the synthetic aftermarket speedfeed type. with the wood model it was fine. i filed a little bit of the plastic off the inner part of the forend. it moves better now. do you have to force the barrel into the receiver or does it fall right in?

January 21, 2008, 06:36 PM	#5
cjw3cma Senior Member Join Date: July 9, 2007 Location: Chiloquin, OR Posts: 217	how about the forend? is it tight to rack the slide back and forth? or normal? Normal / smooth action. have you tried with the slide all the way back , or in mid position? Every position possible. do you have to force the barrel into the receiver or does it fall right in? With the slide partially open, the barrel slides into position very smoothly. But it looks like the barrel is going into the receiver a bit more (deeper) than it used to. I read in the Remington Owner's Manual - "WARNING! DO NOT pump the action or pull the trigger repeatedly with the barrel removed" - AFTER I had pumped the action a few times to make sure nothing was out of place / binding . Could that have done anything? The barrel seems to "sit" further into the receiver (as shown on this representation) - almost like the Ejector Spring (in color) has moved position - but I don't know if that is possible. What'd you think?

January 21, 2008, 08:15 PM	#7
cjw3cma Senior Member Join Date: July 9, 2007 Location: Chiloquin, OR Posts: 217	I had assumed that the magazine extension was a one piece design - which caused me to proceed down the WRONG path - and now I feel (yeah) embarrassed. Thank you, Paul, for getting me onto the proper path of Remington 870 maintenance. I just wish that the manual was not soooooooooooo generic and it covered magazine extensions (so I could have figured it out myself). But that's what forums are all about - LEARNING. Thanks again; the 870 is back together (properly).