870 +1 mag extension questions

Tom E Gun

Tom E Gun

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I posted this on the S&J forum, but have gotten no responses:...

I recently purchased and S&J +1 nickel mag extension for my marine 870 tac14. The included spring is too long and I am wondering what the correct length should be. Also wondering if the mag tube dimples need to be removed for a plus 1 extension and if so what is the best method. I have goggled these questions and get a variety of conflicting info. I think I trust the CGN community more than random internet info.
Thanks
CGN
 
I would cut the spring longer than the stock one by a foot or so for starters and then trim it till it fits 5 shells plus a bit, their full length spring is the same length as the stock Rem +2 or 3 mag tube spring replacement and double the length of a standard mag tube spring.

The quick way to remove the dimples is to drill them out, I have swaged them out with a deep well socket. Lube it well with grease and when the socket is past the dimples tap them lightly with a mallet, remove the socket periodically so you don’t get it jammed in the tube. Brownells makes a swaging tool but I didn’t feel like buy and waiting for it, plus I can’t see myself removing multiples. I rounded over the leading edge of the socket to make it easier to start it in the tube.

oI9PoYz.jpg

sJkidjH.jpg
 
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Tom E Gun said:
I posted this on the S&J forum, but have gotten no responses:...

I recently purchased and S&J +1 nickel mag extension for my marine 870 tac14. The included spring is too long and I am wondering what the correct length should be. Also wondering if the mag tube dimples need to be removed for a plus 1 extension and if so what is the best method. I have goggled these questions and get a variety of conflicting info. I think I trust the CGN community more than random internet info.
Thanks
CGN
Click to expand...

For the +1, a 22" spring works well. It is the spring that comes in the 870 Police from the factory without a mag extension.

Casey
 
Butcherbill said:
I would cut the spring longer than the stock one by a foot or so for starters and then trim it till it fits 5 shells plus a bit, their full length spring is the same length as the stock Rem +2 or 3 mag tube spring replacement and double the length of a standard mag tube spring.

The quick way to remove the dimples is to drill them out, I have swaged them out with a deep well socket. Lube it well with grease and when the socket is past the dimples tap them lightly with a mallet, remove the socket periodically so you don’t get it jammed in the tube. Brownells makes a swaging tool but I didn’t feel like buy and waiting for it, plus I can’t see myself removing multiples. I rounded over the leading edge of the socket to make it easier to start it in the tube.

oI9PoYz.jpg

sJkidjH.jpg
Click to expand...

Butcherbill, do you know if this method will work with a Marine?
I still have to get rid of the dimples of my Tac-14 Marine .... but somehow I am afraid the nickel plating will flake off ...

Has anybody used this method (socket) on a nickel plated Marine?
 
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People have to be careful using the socket method. There have been a number of people who have seized up the socket and completely pooched the mag tube. The mag tube can bend or collapse like an accordion Getting the socket out, particularily if you are using a ratchet extension can be an issue. That is why the Brownells is long and tapered, it gives support to the inside and does it gradually (but it isn't worth the money). The socket works good, as long as you are careful. Use lots of grease or even a slightly smaller socket to get started
 
I did 3 passes with mine in 1 mm increments , lots of grease. And zero issues. I cant even understand how someone would screw that up.
 
0faustus0 said:
Butcherbill, do you know if this method will work with a Marine?
I still have to get rid of the dimples of my Tac-14 Marine .... but somehow I am afraid the nickel plating will flake off ...

Has anybody used this method (socket) on a nickel plated Marine?
Click to expand...

I can’t answer that one, I don’t own a Marine magnum.

dogzilla said:
People have to be careful using the socket method. There have been a number of people who have seized up the socket and completely pooched the mag tube. The mag tube can bend or collapse like an accordion Getting the socket out, particularily if you are using a ratchet extension can be an issue. That is why the Brownells is long and tapered, it gives support to the inside and does it gradually (but it isn't worth the money). The socket works good, as long as you are careful. Use lots of grease or even a slightly smaller socket to get started
Click to expand...

Yeah I’ve seen pic of people that royally screw it up, which is hard to wrap my head around lol. It’s a pretty simple operation, lots of grease and slowly tap it in. The key to not getting it stuck is to tap the dents from the outside while the socket supports the wall of the mag tube, it just like using a hammer and dolly on a dented car fender. Tap it in a bit and remove it, repeat till it’s all the way through. If you just hammer it in all ham fisted you’ll either get it stuck or bend the mag tube, some people have no finesse.
 
Success!

I started with a 16mm socket (the 17mm was a tight fit) and tapped it into the tube very carefully using lots of lube. It got slightly stuck a few times but could easily be removed with a ratchet rotating counterclockwise. Once the 16mm socket was in past the dimples I used a wide brass punch to flatten the dimples as much as possible using the 16mm socket as an "anvil". Then I repeated the whole process with the 17mm socket. When I was done the dimples were still very slightly protruding into the mag tube. The cheap orange plastic follower that came with the mag extension was still hanging up on the dimples, but I changed to a Type 1 S&J green follower and it works perfectly. I can't see any damage to the finish on the outside of the tube. Hard to tell on the inside, but no noticeable damage. The type 1 follower is significantly longer than the little orange cup follower that came with the extension, so I can only just fit 5 rounds of 2 3/4". 5 rounds of 3" would not fit.

I'm much happier with this method than drilling 2 holes in the mag tube.

I cut the spring to 22.5" prior to installation. After installing it several times I checked the spring length and it was sitting right at 22".

Thanks again to everyone for their helpful guidance!

IMG-0756.jpg


The only other mods so far are an S&J jumbo safety and an aluminum hand stop at the front of the Magpul forend. I hope to shoot it for the first time tomorrow. Not sure how I am going to like the birdshead grip, it may be getting a full stock soon.
 
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Tom E Gun said:
Success!

I started with a 16mm socket (the 17mm was a tight fit) and tapped it into the tube very carefully using lots of lube. It got slightly stuck a few times but could easily be removed with a ratchet rotating counterclockwise. Once the 16mm socket was in past the dimples I used a wide brass punch to flatten the dimples as much as possible using the 16mm socket as an "anvil". Then I repeated the whole process with the 17mm socket. When I was done the dimples were still very slightly protruding into the mag tube. The cheap orange plastic follower that came with the mag extension was still hanging up on the dimples, but I changed to a Type 1 S&J green follower and it works perfectly. I can't see any damage to the finish on the outside of the tube. Hard to tell on the inside, but no noticeable damage. The type 1 follower is significantly longer than the little orange cup follower that came with the extension, so I can only just fit 5 rounds of 2 3/4". 5 rounds of 3" would not fit.

I'm much happier with this method than drilling 2 holes in the mag tube.

I cut the spring to 22.5" prior to installation. After installing it several times I checked the spring length and it was sitting right at 22".

Thanks again to everyone for their helpful guidance!

IMG-0756.jpg


The only other mods so far are an S&J jumbo safety and an aluminum hand stop at the front of the Magpul forend. I hope to shoot it for the first time tomorrow. Not sure how I am going to like the birdseed grip, it may be getting a full stock soon.
Click to expand...

Good job, it’s an easy job if you aren’t a gorilla with the tools lol. Maybe someone else with a +1 will comment on if they can fit five 3” shells, sometimes it depends on the brand of shells. Some shells vary in crimped length or maybe the spring needs to be trimmed in it more. I’m pretty positive I can fit a full six of 3” with my +2 extension with some space to spare.

If you don’t like the birds head grip and you want to sell it give me a dm, I’ve been looking for one and everyone in Canada is sold out.
 
Butcherbill said:
If you don’t like the birds head grip and you want to sell it give me a dm, I’ve been looking for one and everyone in Canada is sold out.
Click to expand...

No problem. I have been wanting to try one and I love how compact the shotgun is, but I am skeptical. I bought the shotgun from CGN member Brobee and he has some good videos on shooting techniques, we will see. I may also try some low recoil loads.
 
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