870 receiver shell size compatibility identification

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River runner

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I have a Wingmaster 870 with an aftermarket short barrel marked 2 3/4" and 3"... but how can I be sure the receiver and internals are 3" compatible?
Is it just a matter of loading and cycling 3" without discharging to prove it is?

Thanks for entertaining newbie questions.
 
Your barrel is marked 3" so shoot a 3" in it and if it ejects without problems it is a 3" receiver. If it gets hung up and doesn't eject then you have a 2 3/4" version. Most older, but not all, 3" guns are marked "Magnum" on the receiver.
 
Thank you for your reply. The receiver isn't marked Magnum, and through some google research, apparently the serial number will have in it or end with a "M". My serial number doesn't have an "M" in it either.
By your reply one can assume a 2 3/4" receiver can handle pressure a 3" will create, but will not eject the spent shell without binding?
 
River runner said:
Thank you for your reply. The receiver isn't marked Magnum, and through some google research, apparently the serial number will have in it or end with a "M". My serial number doesn't have an "M" in it either.
By your reply one can assume a 2 3/4" receiver can handle pressure a 3" will create, but will not eject the spent shell without binding?
Click to expand...

All the receivers in the 2 3/4 and 3" are the same just the ejector set up different.If yours won't eject a 3" $60-75.oo at a gunsmith will have it corrected with the new 3" ejector installed.
 
3macs1 said:
All the receivers in the 2 3/4 and 3" are the same just the ejector set up different.If yours won't eject a 3" $60-75.oo at a gunsmith will have it corrected with the new 3" ejector installed.
Click to expand...

You will need to install new ejector and springs as 3macs1 said but the receiver might need refinish as the ejector and the ejector spring is held by two rivets.

If you look at your receiver with the action is open ( make sure the gun is unloaded ) if the step where is ejector and spring is at or near the end of the opening then your receiver is capable to ejector 3" without issue like the pic below:
IMG_0510_zps86071ab1.jpg



But if the step of the ejector and spring is about 1/4" from the rear most of the opening then your's a 2 3/4" inch like this:

IMG_0511_zps15a33377.jpg


Don't ask me how I know this because I was in person with Casey ( Tac Ord) and he taught me how to tell at his shop :)
 
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River runner said:
Thank you for your reply. The receiver isn't marked Magnum, and through some google research, apparently the serial number will have in it or end with a "M". My serial number doesn't have an "M" in it either.
By your reply one can assume a 2 3/4" receiver can handle pressure a 3" will create, but will not eject the spent shell without binding?
Click to expand...

It is the chamber of the barrel and bolt that contain the pressure. There's very little to no extra stress on the reciever when you fire 3" shells. As 3macs1 said, the only difference between the 2 3/4" and 3" receiver is the ejector and ejector spring. When I convert older guns to 3" I simply grind the ejector notch back and replace the spring and front rivet. It saves me a $17 compared to replacing the 4 parts (2 rivets , ejector & ejector spring)...I may be cheap...but that $17 gets me an extra 75 rounds of 12 gauge factory ammo! Haha!
 
Spcamno and everyone else...... thank you very much. Those pictures are great. Looks like I have a 2 3/4". I was planning on refinishing this one in Arma/Dura coat, so I guess off to the gunsmith it goes to be scratched up and converted to 3".
Any recommends for a one stop gunsmith who does paint jobs too?
 
I remember saw someone was able to replace to ejector spring to a 3 inch one without replace the rivets and refinish the receiver.

All he did was grind or dremel the rivet head slightly enough to pry the ejector spring off and use a dremel and carefully cut the step to extend another1/4 inch or so on the ejector and put the new ejector spring back and peen the original rivets and hold it down.

If you google 870 ejector shotgunworld you should be able to find some more info.

The spring is a few dollars item and since you already prepared to pay someone to have it refinish you have nothing to loose for trying it out.
 
Spcamno said:
I remember saw someone was able to replace to ejector spring to a 3 inch one without replace the rivets and refinish the receiver.

All he did was grind or dremel the rivet head slightly enough to pry the ejector spring off and use a dremel and carefully cut the step to extend another1/4 inch or so on the ejector and put the new ejector spring back and peen the original rivets and hold it down.

If you google 870 ejector shotgunworld you should be able to find some more info.

The spring is a few dollars item and since you already prepared to pay someone to have it refinish you have nothing to loose for trying it out.
Click to expand...

You have to be careful when peening the rivet portion that retains the ejector spring...especially the newer thinner version of said spring as they will crack at the hole if you go to hard at it!!!
 
well... took the "new to me" short barrel 870 out today for a test run.... cycled through five 3" slugs,numerous other loads and ejected them all with authority. Looks like I get to save some money...
Thanks again everyone for your replies.
Image1-1.jpg
 
I think our friend Spcamno spelled it out quite nicely with photos and all, but here's something additional that may be of value to you and others. Provided that a conversion hasn't already been performed. Keep in mind that non expended 3" shells will cycle through a 2-3/4" receiver just fine and expended shells may, or may not eject "reliably", but will most times.

The barrel and receiver design combination determines what can be shot from your 870 gauge.

All barrels are clearly marked with the chamber information.
Receivers are marked with letters at the end of the serial number that determine ejection size as follows:

Serial Number Suffix Gauge Ejection

V -- 12 -- 2 3/4" Only
M -- 12 -- 2 3/4" or 3" Only
A -- 12 -- 2 3/4", 3" or 3 1/2"
W -- 16 -- 2 3/4" Only
K, X -- 20 -- 2 3/4" Only
U, N -- 20 -- 2 3/4" or 3" Only
J -- 28 -- 2 3/4" Only
H -- .410 -- 2 1/2" or 3"
Click to expand...

Also, if anyone is inclined to replacing the extractor spring to a 3" one, you can do so without replacing the ejector rivets by purchasing an ejector spring rivet cutter. It allows you to cleanly cut the rivets and reuse them for the new installation.

The original rivets should not be disturbed from the receiver and a different tool is used to correctly re-stake the rivet in place. You only need to cut the front rivet to replace the ejector spring. The ejector itself needs not be removed or unstaked if you're going to file the ejector 1/4" back.
 
if you are only shooting slugs. why not just shoot 2 3/4" they kick a lot less, are cheaper and still shoot the same...
 
Agree with your chart easy except the V -- 12 -- 2 3/4" Only
As you know.

All the V means on that one is it left the factory with a 2 3/4" barrel on the end but it may still be a 3" set up.
Somewhere in the range of serial numbers which nobody knows remington used all 3" set ups for both 2 3/4" and 3"
Also they stopped making the 2 3/4" ejector so if you had a gunsmith replace yours a 3" was fitted.
There was talk about the 2 3/4 " having a smaller opening or port but In the 100's I have touched have never seen it.
If you have a 3" barrel there will be no harm to try it despite it maybe a V serial number many times it will be fine. I have a couple of 2 3/4 marked V guns with 3" ejectors and many more have the same.
 
3macs1 ... I agree completely with the V nomenclature. REM must have had a whole lot of V marked receivers at the time they decided to discontinued the 2-3/4" ejectors and used up the V marked receivers instead of scrapping them. Much like Colt's transition years and AR15s.

I don't recall ever seeing smaller ejection ports on 870s either. Maybe the confusion comes from the model 31s. They have a shorter ejection port and were the basis of the 870 design early '50s.
 
River runner said:
..being this will be a hiking, backwoods, and camp safety gun.... I want to have the hardest hitting round possible.

All other fun shooting will be 2 3/4".
Click to expand...


Glad to hear you are having fun.

I understand what you mean is always better you have and don't need it rather than you need it when you don't have it.

As easy suggested you might or might not ejector expanded 3" reliably, if you run into issue ejecting 3" shell pay a smith to get it done or get one of these rivet cutter as easy recommend

http://www.brownells.com/gunsmith-tools-supplies/shotgun-tools/shotgun-specialty-tools/remington-870-ejector-spring-rivet-cutter-prod368.aspx?ttver=2

And once you had the job done you can always list it on EE and recover most of your investment.

PS: I noticed you have the sling on the right side, did you do that on purpose because I remember you were looking to mount on the left, no?
 
Spcamno said:
PS: I noticed you have the sling on the right side, did you do that on purpose because I remember you were looking to mount on the left, no?
Click to expand...

I did mount to the left... but shooting right and mounting the sling to the left side of the SGA stock caused the stock to be forced into my bicep and not my shoulder. So mounting it on the right side seems to be best. The only downfall is the forward portion of the sling comes under the for end when in firing position, but its not that big of a deal.
The gun hangs nice and flat diagonally against my back when the sling is on the same side, forward and rear. Very comfortable for bush carry I hope.
 
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