Converting an older 870 to home defense platform

[rcollier]

I have an older 870 that was my FiL’s old bird gun. It has a 30” barrel and the stock is in rough shape but I was thinking it would be a good home defense weapon. My main concern is getting the barrel shortened. We don’t have a gun smith in our community. Any thoughts on what I would need to convert this?
Thanks

 

[L-2]

It's been over an hour and nobody else has yet posted a response, so I'll give some of my thoughts.
I've not shortened or cut a shotgun barrel previously. If I were to do so, I'd want the end finished or rounded relatively smoothly, then blued or painted somehow to reduce rusting. I'd also be concerned with drilling and tapping a hole in just the right place to install a bead. I also realize not everybody cares about how the barrel looks after it's been sawed shorter.

I'm fairly handy and do own a manual hacksaw, reciprocating saw, aka a Milwaukee "Sawzall", and other power saws (jigsaw and compact circular saw). Also, a drill press, spare beads with taps, tap handles, cutting oil, etc., but I realize not everyone is handy working with tools and guns.

The legal length without it being an "SBS" (aka short barreled shotgun) is 18" measured from the bolt-face with bolt closed/forward. Often, the barrel is at 18.5" to be extra safe, but some folks desire a 20" or 22" barrel for longer home-defense/tactical purposes.

I actually really like my 14" barreled SBS, but, to be legal, it'll take submitting a form to the ATF with a $200 payment; fingerprint cards; a photo; and a few months' wait for approval. I almost forgot the engraving of the receiver with one's name, city, and state in accordance with more ATF laws.

The easiest way would to buy a replacement barrel, making sure to get one of the right gauge, length, and barrel lug placement. For example, I understand most 870 barrels being sold have a relatively standard lug placement for 4-round magazine tubes but there were some 870s with either shorter or longer mag tubes.

Also, with a replacement barrel. The barrel may say OK for 2 3/4", 3", or 3 1/2" ammo, but make sure to use ammo no longer length than made for the subject 870's receiver and barrel for safety and functionality.

A shorter replacement barrel can cost another $200, and a replacement stock might cost $120. Some folks would rather just buy a new or used shotgun already in the desired barrel length or configuration. Good luck on the project.

 

[rcollier]

L-2

That is exactly the kind of advice I was looking for!!
Using my FiL’s old gun was kind of a sentimental reason. I like the idea of a replacement barrel though.
I appreciate you taking the time to respond.

 

[44 AMP]

Absolutely get as replacement barrel instead of cutting the original. Lots of 870 out there, and barrels for even the older ones are still around. Might take a bit of looking, and will cost what it costs, but that way you preserve the "bird gun" utility.

20" riot or slug barrels will serve just fine for home defense.

I have no idea what a smith would charge these days, but chopping the long barrel isn't just sawing it off shorter, if it's going to be done right. Cutting the tube, cleaning up the muzzle, remounting the bead, and if there's a rib involved, remounting that, as well. Also, a chopped barrel will have no choke, which may, or may not matter to you.

The barrel is not legally a firearm, it is just a part, and can legally be mailed/shipped directly to you. If you do decide to have the original chopped, any decent smith, anywhere in the country can do it, and you can just send them the barrel, the entire gun doesn't need to be shipped, so you avoid that cost and hassle.

Good Luck with your project!

 

[rcollier]

44 Amp
I like the Slug Barrel suggestion! I can use it for double duty during deer season here in southern Mn.

 

[rc]

There are a lot of 870 barrels out there.

I think this is what you want because it's a cheap extra HD barrel. I know it's made in China but has a screw in choke. Is your receiver set up for 2 and 3/4 or 3 inch? That will determine what you can shoot more than the chamber markings on the new barrel.

https://www.cdnnsports.com/remington-870-12ga-18-5in-barrel-target-sports-tarr18.html

https://www.ebay.com/itm/2958237027...9qP6Y1RRnpkyRjtz7O7nRKuBeVcF|tkp:BFBMgK7C5pFj

https://www.ebay.com/itm/3950640367...qiyaE6srMzeV34mCug0Nv3zQ==|tkp:Bk9SR4SuwuaRYw

https://www.ebay.com/itm/3847521268...sjxNatlcktUJzLRmxwRLpvk9pL|tkp:Bk9SR4KuwuaRYw
You can sand the original stock if it's not all beat to crap and steam out the dents, then stain with some birchwood walnut finish and with gloves rub on mixed devcon two part epoxy to seal the wood and let it dry till it cures hard. It will look very traditional and protect the wood when you are done. I fixed a cracked winchester 22 stock in the 90s with devcon and it's still looks good.

 

[jmr40]

I'd have no use for a 30" barrel. I've cut several myself, it ain't rocket science. You need a sharp hacksaw blade and will need to cut it on one of the ribs. On the ones I've cut I could either cut it at 21" or 19" and still be legal. The next post would have meant a 17" barrel.

I cut the 1st one at 21" so if I messed up, I had one more chance at 19". It ended up perfect and I actually like 21" better.

Shotgun barrel steel is relatively soft and a sharp blade goes through it like a hot knife through butter. I then used a small square and a flat file to true up the end of the barrel and remove any burrs.

There are several options to replace the sights that clamp onto the vent rib. Total cost can be around $20 if you do it yourself. More if you want fancy sights.

https://www.midwayusa.com/s?searchTerm=shotgun sights

I picked up a Winchester 1300 pump a couple of years ago cheap because it had a damaged barrel near the muzzle. I had a gunsmith cut the bad part off at 24" and he threaded the barrel to accept chole tubes. Since I already had a buttload of Remington tubes I had it cut for them instead of Winchester tubes. That cost me $150 and doesn't look any better than the ones I've cut myself. Of course the ones I cut are cylinder bore with no choke.

If nothing else I'd have to cut the 30 barrel down to 26 or 28" and have it threaded for choke tubes.

 

[rcollier]

My barrel is not ribbed so attaching the site might be an issue?
I think I may try to cut it myself and see how it goes, if it looks like crap I can always go to a replacement.
The receiver needs to be re-blued as well. I am planning on cold blueing.
Any recommendations for. Good cold blue product?

 

[rc]

How about a bead blasted surface to get rid of any rust followed by a heat cured black poly finish?

 

[Bill DeShivs]

Please don't cold blue the gun.
Cold blue is for touch ups. It doesn't cover evenly, it stinks, looks terrible and doesn't prevent rust.

You would be better off spray painting the gun. It won't look any worse and it will at least protect it.

 

[rcollier]

Painting is intriguing
Any special prep? Planning acetone clean amp prep with 0000 steel wool
Rustoleum black matte?

 

[rc]

This might help you decide what finish to use.

https://thewildhunter.com/duracoat-vs-cerakote-vs-gunkote/

 

[FITASC]

Buy a imported new barrel or find a pawn shop that might have older take-offs and go at it. DON'T cut the barrel - if you do decide to sell the gun, having both barrels opens up the potential buyer's market a LOT.

 

[bamaranger]

870

I would not recommend you lop the barrel, for both value and whatever civil reasons might crop up later. I have not priced 870 barrels in a long while , but at one time a 18.5" HD barrel was available from Mossberg (for the 870) for about $100, probably more these days. Ebay has a beater right now for $45 can't say if it's lopped or not.

Depending on what you want to spend, there are a lot of options for tricking out an 870. At some point one could easily reach the price of dependable dedicated HD shotgun like the Mossberg Maverick. Wood stock is entirely functional. A mag tube extension is desirable but not a necessity, so too on board ammo stowage. A cheap elastic butt cuff is one way to solve that. I anchor mine with a sling swivel stud, when the elastic goes wonky, I buy another one for a few bucks at Wally World. A swivel stud equipped mag cap up front allows for easy attachment of a sling. There may be occasion to sling your shotgun to use hands for something else. The biggest issue with a pump shotgun is attaching a light. Mounts are available to take dedicated weapon lights, but will add more cost. No lights on my shotguns, as my carbine has one.

 

[Webleymkv]

I'd also recommend against cutting down the existing barrel. While shortening a shotgun barrel might not be the most difficult bit of home gunsmithing, it isn't all that difficult to royally botch it either. If you really want to use your 870 as a home defense gun, I'd recommend either buying an existing 18-20" barrel or buying an additional used field barrel to shorten (that way if you mess it up, you haven't botched the original barrel).

Honestly, the days of turning a bird gun into an economical home defense gun are largely over as the cheap, used pawn shop specials are largely a thing of the past. For the cost of a replacement 870 barrel, you can almost buy an inexpensive dedicated HD shotgun like a Maverick 88 Security or Winchester SXP Defender.

Also, consider that any gun actually used in self-defense is likely to disappear into an evidence locker for months, years, or forever. That fact alone would give me pause on the idea of using a family heirloom as a home defense gun.

 

[labnoti]

Brownells sells a barrel facer for this purpose. Generally, the expected practice is to cut it off with a hacksaw and then use the barrel facer to square the end. Personally, I think I would use a Rigid tubing cutter which is sure to cut it square but leave it rolled inward creating a bore constriction. This could be removed with the barrel facer, but the roll would have to be minor enough that the pilot bushing would fit.

https://www.brownells.com/tools-cleaning/gun-tools/shotgun-tools/shotgun-barrel-facer/

Note that you also need the appropriate size Cylmer bushing. This is a bronze bushing that fits inside the bore and acts as a pilot for the facing tool. They're $15, bringing the total tooling cost to $100 plus shipping and tax. Note that Brownells sells 18.5" Remington 870 barrels for $189 and they can be had for less elsewhere.

Brownells sells Alumahyde which is a gun-solvent resistant spray coating. It's as easy to apply as spray paint but chemical resistant like cerakote. It doesn't have the durability of cerakote, but it's easy to touch-up or repair.

https://www.brownells.com/tools-cleaning/paint-metal-prep/paint-finishing/aluma-hyde-ii/

 

[Bill DeShivs]

Never use a tubing cutter on a shotgun barrel.
Barrels should be cut with a hacksaw, straightened and cleaned up with a file, and burrs inside the barrel removed with a sharp pocket knife.

 

[stinkeypete]

I will eventually help you but first I have to warn:

1. Without seeing a photo, you might regret hacking up your father-in-law's old bird gun some day. I retired and hunt pheasants about 3 times a week. I love it.
2. "Old" can be "vintage" or "beat up." I suspect it's in decent shape.
3. It's an 870, not an 870 Wingmaster, correct? Because Wingmasters are DELUXE and must never be butchered.
4. You know that "home defense" is just silly, right? The shotgun works fine as it is.

5. You looked on EBAY and see that for $90, shipping included, you can get a brand new 18.5" barrel with bead sight attached and choke tube, yes?
Then you can keep your original barrel if anyone in the family ever wished to go bird hunting. This is the way.

But given all that, if you're bound and determined to hack up a perfectly good shotgun.. you will need:
A sturdy work bench, hack saw, masking tape, set of metal files

1. Measure the length of the barrel from the start of the chamber. Don't mess this up, if you cut the barrel too short you'll be in posession of a firearm that you do not have the specialist tax stamp for and it's a serious felony. If you don't understand, see step #5 above.

2. Find the rib post farther out from your safe minimum barrel length. Wrap masking tape about the barrel to protect the barrel but also give a parralel, flush cutting line. Go at it with a sharp new hacksaw blade, showing your craftsmanship.

3. Use your metal files to square the end. With a good eye, practice and skill, you should be able to get your dimensions withing a thousandth of an inch. If you've never worked with metal before, see #5 above.

4. Remove the masking tape. The barrel has been cut and finished. Deburr the inside edge.

5. Mix up half a cup of salt water. Or get fancy with half a cup of hydrogen peroxide, a couple tablespoons of vinnegar and a teaspoon of salt. We're going to RUST BLUE your cut.

6. Dab rusting solution onto the end of the barrel. Yes, we WANT it to rust! Trust me. Put the barrel in a warm, damp place. Rust the tip of that barrel. Just do it.

7. Set an old pot of water to boil. Let the tip of the barrel rest in boiling water for 30 minutes. This process steals an oxygen molicule and converts the red rust to super hard magnetite.

8. Polish the end gently with 000 steel wool. Remember to soak the steel wool in acetone a few times, steel wool has oil on it. We want rust! No oil!

9. Try to rust the end of the barrel again. If it will rust, good. Boil and polish again.

10. Repeat this process until any steel that could rust, HAS rusted and been converted to magnetite. It might take 3-10 passes, depending on your experience. There are very few metal finishes more durable. Or you can use Rusoleum.

11. You want a front sight? For what? See step 5 above. Or.. you have a drill press with proper vise and taps, right? Probably not, or you'd be done!

I have a fondness for older shotguns. While and 870 isn't one of the sweethearts (Wingmaster, Model 37, Model 12) it's a decent shotgun. Please don't hack it up.

If you must, get a Mossberg Maverick 88 for $236.00... all set up for "home defense" and you can get flashlights and heat shields and hair driers and waffle irons to stick onto it. Or see #5, above

 

[labnoti]

Never use a tubing cutter on a shotgun barrel.
Barrels should be cut with a hacksaw, straightened and cleaned up with a file, and burrs inside the barrel removed with a sharp pocket knife.

Why not? I'm not arguing, but want to know why I wouldn't use a much cleaner cutting method that would produce a perfectly square cut. I realize the cutter will roll the barrel in, but how much depends on the pressure used. No matter how it's cut, it will have to be faced. It seems like removing a minor roll would be easier than removing the results of a hacksaw.

But: I've never done it. So I'm open to correction with an explanation.

 

[FITASC]

How would you use your method on a barrel with a rib?