What are the options for a +5 extension tube?

[AustenW]

I'm from the UK where the minimum legal barrel length is 24"

I'm looking for a tube extension around 12" to match the barrel

What are the options?

I'd like a steel tube with an option for a bayonet mount in the future?

I see the Remington would work great but does it only go upto +3?


I guess for +5 its the tacstar or ???

I've got a Nordic follower and wolf spring already

[Synchronizor]

If you want to be able to mount a bayonet, you're probably not going to find any extension kits on the market that will work. The only extensions I'm aware of that accept bayonets are from Remington and S&J Hardware, and those extensions don't get larger than +3.

If you're the handy type, you could always build a custom extension tube yourself. You can buy unfinished magazine tubes from Remington, which are essentially 12-inch tubes with threads cut into one end.

870 mag tube (bright).JPG (69.1 KiB) Viewed 4977 times

You can also order coupling nuts and extension tubes individually, instead of buying a whole kit.


If you cut the magazine tube down a little, cut off the end of the extension tube that's sized to accept a bayonet mounting ring, and then attach the two together, you'll have a custom-length extension tube that works just like the factory Remington extensions. Refinish it, and install it using your spring, the coupling nut, and a magazine clamp (or just pick up a bayonet lug and use that).

[AustenW]

I'm pretty handy on the tools so the custom tube option sounds good

I'm getting the entire thing cerakoted anyway, my godson is an approved applicator here in the uk.

Where do I buy the kit from?

Is the end cap available separately too? I guess this is braised in with silver solder?

[JBall]

There is no end cap on the extension tubes. It's threaded on one end and solid on the other. I'm assuming that's where the being handy part comes in. LoL. Good luck! We would love to see photos of the process and finished product!

[Synchronizor]

The end on the factory tubes is a separate piece that appears to be brazed in place. I don't believe Remington offers that part separately, because it's really not something anyone would need as a repair part. Buying a replacement tube is a lot easier and cheaper than repairing a broken one. If you have access to a lathe though, you could always have something custom-made pretty easily. If a magazine tube by itself is long enough, and you didn't have to pay someone shop rates for the custom part (or run into any legal problems making gun parts), this might be a better choice than trying to attach two tubes with a clean butt-joint.

If you weren't having a bayonet-compatible cap custom-made, you would need an unfinished magazine tube, a magazine extension tube (for the bayonet end), and a coupling nut. The latter two parts come in different finishes. I don't know what would be easiest to work with and have refinished, you may want to check with your godson. These can be ordered directly from Remington in the US, but you may have to go through someone else in the UK.

You mentioned you already had a spring, so the only other item you'd want to have is a clamp. There are a bunch of options there, but if you want to get the bayonet lug right away, I linked to the S&J accessory in my last post. Apart from custom-made parts and old USMC clamps that are essentially collector's items not, that's the only 870 bayonet lug on the market.

[AustenW]

Thanks for the info

I'm looking at using a choate or a tacstar +5 extension as there easy to get hold of over here

I'll machine the end off and make up an end piece for the bayonet and silver solder it on

Once its Cerakoted it will look factory

This is the second 870 I've done

The first 870 has LPA sights magpul furniture and finished in Graphite black Cerakote

I silver soldered the front sight on, had the barrel ported, chambered for 3" shells and backbored, then Cerakoted

Its come out mint, just in the process of building up the alloy trigger housing as I had it coated too

I've also just finished a Saiga 12 build too with all the bells and whistles, just had it coated so building that up as well

[Synchronizor]

If you're going to make an end piece yourself, and you already have a spring, it would probably be a good idea to check and see if you can order an unfinished magazine tube and a coupling nut. I don't know what prices and availability are like over in your area, but in the US, those parts are just $10 and $15, which is a lot less than buying a complete extension kit.

Those are the only two additional parts you'll need (aside from whatever clamp you want to use), and the plain magazine tube will be easier to work with than a cut-off aftermarket extension. The magazine tube will be the exact same size as factory Remington extensions, so it should work with any bayonet lugs meant for them. The 12" tube will also be a close match with the muzzle of a 24" barrel. You can solder/epoxy/screw/whatever your custom end cap on the tube as-is if you don't mind it sticking past the muzzle a half-inch or so; or you can cut it back a little so that it sits flush.

End Cap Small.PNG (138.13 KiB) Viewed 4915 times

Not saying your idea is wrong, or that it won't work; just offering my thoughts as an engineer and 870 nerd.