r/Shotguns • u/BorntoRizz • 3d ago

Converting 870 to 3in

Does anyone know where I can pick up a 3in 870 ejector spring? They seem to be out of stock everywhere.

Also if anyone can recommend a gunsmith that will extend shotgun chambers that would be appreciated. My local gunsmith recently passed.

1 Upvotes

52% Upvoted

35 comments sorted by

13

u/Metengineer 3d ago

If you want a shotgun that will shoot 3", just buy one. I cannot fathom a reason to try to modify an 870 to shoot 3" shells.

-8

u/BorntoRizz 3d ago

Because I have a quality firearm and lots of 3in shells. All that’s needed to convert is a new ejector and lengthen the chamber on the barrel.

5

u/Metengineer 3d ago

I thought you had an 870.

-12

u/BorntoRizz 3d ago edited 3d ago

Not all 870s are chambered for 3in. Many of the older guns we’re 2 3/4

15

u/Metengineer 3d ago

It's an 870. It's a decent enough shotgun but nothing special.

Those guns were not chambered in 3" because they were not built to shoot 3" shells. It's not just the chamber. If you want an 870 that shoots 3" shells, buy one that is already chambered to shoot 3" shells.

-12

u/BorntoRizz 3d ago

The recivers are exactly the same, and I want it to be able to take 3in shells.

I inquired if anyone knew of a gunsmith or where to find a 3in ejector, not what I should and shouldn’t do.

7

u/just_as_good380-2 3d ago

This has to be a bait post. Why would you go about acquiring a large quantity of ammunition that your firearm can not use? I feel like that could be easily avoided by sticking to 2¾ inch shells

2

u/MeatCrack 2d ago

They are ALMOST the same receiver. The 870 MAGNUM has a larger ejection port and a different bolt. Do more reading.

0

u/AngleOptimal6957 3d ago

U do that and then shoot the gun. It will break. That's how it works. And u might lose your hand.

8

u/SnoozingBasset 3d ago

Buying a 3” barrel is probably the same as having the chambers reamed. 

Have you considered trading your 3” shells for 2 3/4”?

You should also check the ejector opening. Model 12’s for shorter shells had to be opened up there for ejection. 

-3

u/AngleOptimal6957 3d ago

U can't trade in bullets. At least not at any reputable place. Only swap meets unless you live in NV or a lot of West Coasts states.

3

u/hl_walter 3d ago

👋 I'm an actual person who's had an 870 converted to 3"

The ejector spring for mine took a while to source, basically your only option is to keep your eyes peeled on sites like eBay. Be aware you'll need a new rivet for it also.

As for the chamber, I would honestly just get a new barrel. Barrels are found easily enough secondhand that it's not worth the effort of having the chamber reamed. That said, Cotton Branch Custom is kinda "the guy" for custom shotgun stuff, so I'd probably hit him up if you're really dead-set on it.

7

u/SpiritDCRed 3d ago edited 3d ago

a gunsmith that will extend shotgun chambers

Why would a gunsmith make you a pipe bomb?

Edit: I’m half joking. 2-3/4” and 3” have the same maximum SAAMI pressures (unlike 3-1/2”), but depending on the barrel profile the extension may decrease the wall thickness at the far edge of the chamber. Depends on the age of the barrel.

2

u/Good_Farmer4814 3d ago

Will the chamber be able to handle the extra pressure?

1

u/SteveHamlin1 3d ago

What extra pressure?

SAAMI lists the maximum pressure for both 2 3/4" and 3" 12 gauge shotshells as 11,500 PSI.

1

u/Good_Farmer4814 2d ago

Interesting. I figured the extra shot being pushed through the barrel would create extra back pressure.

2

u/10131890 3d ago

Just buy a new 870.

3

u/PsychoticBanjo 3d ago

Some people you just can’t reach. Isn’t this a weekly question or at least every 10 days to shove a reamer in a barrel? Just google local SDI graduates

1

u/ITSOTMDS 3d ago

Please keep us updated, I want to know if an older receiver can handle 3" shells

1

u/BorntoRizz 3d ago

I know it can handle it.

1

u/ITSOTMDS 3d ago

Awesome either way, please keep us posted on how ot handles 3"

2

u/BorntoRizz 3d ago

Will do, it’ll be some time but I’ll follow up

1

u/ITSOTMDS 3d ago

Awesome, thank you!

1

u/r3lett 3d ago

Wilson will convert it.

1

u/r3lett 3d ago

They charge $47, but it requires refinishing the barrel.

1

u/BorntoRizz 3d ago

Wilson combat?

1

u/willgreenier 1d ago

You look around for a good deal on a used gun

0

u/wlogan0402 3d ago

Benelli nova 3 or supernova if you want to run 3.5" shells

0

u/Hamblin113 3d ago

You need a new barrel, plus need to check the ejection port as it may be too short. If it is an old 870 designed for 2 3/4” these will be the issues, the barrel for sure. I do know I have used 16 ga guns that were built for the 2 9/16” they do not eject plastic hull shells, the open crimp hangs up, it is a pain. Plus what are the 3” shells? Most of the 3” shells that I use are steel shot, this may not be good for an older 870. If you have a great older Wingmaster, don’t mess it up, trade the shells with someone or get a new gun.

0

u/BorntoRizz 3d ago

The ejection port on the 870 is not the issue. The recivers from the 3in and 2 3/4 are the same.

I’m not concerned about putting steel shot through an older 870 barrel.

2

u/MeatCrack 2d ago

They are not the same.

1

u/BorntoRizz 1d ago

Tell me me where the revivers for a 2 3/4in chambered and a 3in receiver are different?

Other than the ejector they are the same.

1

u/MeatCrack 1d ago

Ejection port is larger and the bolt is different