View Full Version : 16 to 12 conversion 870.

July 11, 2011, 03:41 AM
I have an 870 in 16 gauge. I am thinking the reciever is the same size as the 12 gauge. Could any body tell me why I could not throw in a 12 gauge bolt and put on a 12 gauge barrel, giving me a missing gauge without purchasing a new gun. I saw a barrel on here that was 1970's priced.

July 11, 2011, 05:18 AM
Contact "briley manufacturing" in houston, texas---they are a shotgun specialists & should be able to quickly & expertly answer your questions, regarding the gauge change you wish to do.


July 12, 2011, 11:35 PM
Magazine tube diameter for the 16 may be smaller. The carrier may be different.

July 13, 2011, 03:52 AM
Scorch, i also was wondering about the mag tube ID. I will get out the calipers.

July 13, 2011, 10:05 AM
Try sticking a 12GA shell in the tube. I bet it won't fit. The receiver may be the same but after you buy all the new parts you might as well just get a new 870.

Mike Irwin
July 13, 2011, 10:37 AM
Magazine tube, carrier, lifter, shell guides, barrel....

By the time you get all that replaced by buying it a la carte, it would probably be cheaper to buy another 870.

Or sell the 16 gauge and guy a 12 gauge.

Oh, another thought...

If the mag. tube is (I'm sure it is) a different diameter, you're going to have to drill the receiver to accept a new magazine tube in 12 gauge.

At that point, you no longer have a 16 gauge. You've rededicated it.

July 13, 2011, 12:01 PM
The mag tube is .901" ID, which is adequate for 12 gauge .881 at rim.
The problem was the ring at the receiver end of the mag tube was only .836, and the ejection port was .846". I am no longer thinking the conversion as a quick swap out of parts. Thanks to all who participated.