Confused on shotgun barrels

[Tangthebay]

So I am new to shotgun owning. I have a 28 inch barrel for the Remington 870 express. I would like to get a 18.5 inch barrel. The only problem is that they all say 3” not 2 3/4. The picture that I posted is the barrel that came with my shotgun. It says ‘12 g. 2 3/4” and 3”’. The guy at bass pro said it was only 2 3/4. So if I buy a 18.5 barrel that says 3” will I be able to use it? Also I posted a picture of the barrels I am planning on buying. Which one would be best for the shotgun I have? It will be use for home defense. Also each description says I can use both 2 3/4 and 3” shells if I have a magnum receiver. I don’t know if I have that. I posted a picture of the shotgun I have so you can tell me if I have a magnum receiver. (Sorry if these questions may seem stupid I just want to be safe )

[Scorpion8]

Also each description says I can use both 2 3/4 and 3” shells if I have a magnum receiver. I don’t know if I have that.

The barrel limits the shell size you can use, as well as (some) receivers. The 870 receiver has to say "Magnum" to use 3-1/2" magnum shells, but the barrel has to be stamped for that also. If you have a barrel that says 2-3/4 or 3" shells, then you can use either. Almost every modern shotgun barrel is rated for both but some older barrels are 2-3/4 only. The ejection port limits your typical 870 from using 3-1/2" magnum shells...they may eject, they may not. Since 870 barrels get swapped around like Legos-for-Big-Boys, you have to examine both barrel and receiver.

[Chef Duane]

A bit off topic, but... Did you pay $329 for an 870 Express with the 28" barrel? A recent sale at Academy had them for $259. (Yes, I bought one.)

[Germansheperd]

That is the barrel you want. All Expresses were 2-3/4 and 3”.