I have a Rem 870 Magnum that I  have recently been issued to carry on duty. There are not any special marking other that the 870 Magnum markings, so I do not know what specific model it is, if any.

I have my RRA M4 that I carry oin duty, but I also want to carry this 870. However, it has seen better days and I want to do some mods.

It came with wood stock, which I plan on replacing with some Rem black synthetic stocks.

Does anyone or has anyone used the GG&G front and/or rear sling plates? If so, how did they work?

What capacity magazine extensions can I get? 2, 3, 4 rounds?

Thanks for any and all info.

the only help i can offer is if you mention the length of the barrel then you can determine the correct mag ext.

synthetic stocks are a great upgrade.  Rmington factory original is good and so is Choate and Speedfeed

Quoted: the only help i can offer is if you mention the length of the barrel then you can determine the correct mag ext. synthetic stocks are a great upgrade.  Rmington factory original is good and so is Choate and Speedfeed

Can I accurately and properly measure the barrel without disassembling the shotgun?

If so, how exactly is a shotgun barrel measured?

Also, what are my options for carrying extra shells?

I am currenty using a black slip on (elastic style) sheel carrier that slips over the rear buttstock.

I believe TacStar makes the SideSaddle. How solid is this mount? Does it hold up and can it take abuse?

To measure the barrel:
UNLOAD the gun and close the bolt ALL THE WAY SHUT.
Put a cleaning rod or a dowel rod down the barrel until it touches the face of the bolt.
Mark the rod even with the muzzle.
Remove and measure the rod with a tape measure.

An 18" barrel will take a 2 shot extension, a 20" will take a 3 shot.
USE A BARREL CLAMP.  If the extension you buy doesn't come with one, buy one.

The left side of the receiver should say 870 Police Magnum, 870 Wingmaster Magnum, or 870 Express Magnum.

If it doesn't, it's probably an older Wingmaster/Police gun.
If you were issued the gun, it's almost certainly a 870P Police gun.

Police guns have a shorter fore arm with grooves cut in it.  Commercial sporting fore ends are longer and are checkered.
You need to make SURE you buy a Police fore arm if you plan on using a side saddle, since the longer sporting fore arms will NOT work with a side saddle.

Some people like side saddles, some don't.
The "Watch outs" are, not to tighten the side saddle mounting screws too tight.  This can actually compress the receiver walls and cause jams.
Also, the side saddle WILL interfere with your vision by blocking you view to that side.

Other options are to buy a Speedfeed stock that carries 4 extra rounds in internal "magazines".
You simple use a finger to flip extra rounds out.

I use a GGandG single point mount.  It mounts between the stock and the receiver.  You have to remove the stock slide it on the back of the receiver then put your stock back on.  It only goes one way.  They are a little expensive, but I believe they are the best design (Sorry to all you Mesa Tactical Fans).  I don't use 3-point slings because I am left handed.  

As far as stocks, I recommend the Speed Feed IV-S LE.  It is a shorter stock and works well with body armor.  It, however, does not have the carriers inside the stock.  Also, when you buy the stock, the short LE forend comes with it.  The best place I found to buy the stock is at Brownells.  

For my speed reloads, I have a TacStar mounted to my 870P-Max.  It is reliable, although I recommend periodically checking the small allen screws that mount the carrier to the metal plate.  I lost one about a year ago.  Having said that, I'm going to get a Mesa Tactical side saddle and try it out.  Being left handed, the mount does not effect my vision even though I mount the shells brass up.

For the mag extensions, go to...
www.remingtonle.com/axx/gunparts.htm

I'm not sure on the cost, but have one on both of my 870's.  They came with the gun.

Good luck with the new gun.

 

Quoted: An 18" barrel will take a 2 shot extension, a 20" will take a 3 shot. USE A BARREL CLAMP.  If the extension you buy doesn't come with one, buy one. The left side of the receiver should say 870 Police Magnum, 870 Wingmaster Magnum, or 870 Express Magnum. If it doesn't, it's probably an older Wingmaster/Police gun. If you were issued the gun, it's almost certainly a 870P Police gun. Police guns have a shorter fore arm with grooves cut in it.  Commercial sporting fore ends are longer and are checkered. You need to make SURE you buy a Police fore arm if you plan on using a side saddle, since the longer sporting fore arms will NOT work with a side saddle.

Ok. I just measured and I have a 20" barrel.

So, I can get a magazine extension for 3 shells, right?

The receiver is marked "870 MAGNUM", nothing else.

I just bought and installed a TacStar Side Saddle .

My shotgun's stock wood (pump) forearm is about 7 3/8" long and has grooves cut into it, nothing is checkered. When the pump is all the way back (open), there is about 1/2" clearance to the SideSaddle.

My question then is: What synthetic stocks will fit with this setup?  I assume I have to buy synthetic police stocks and these replacement synthetic stocks will be the same length as my current stock wood forearm, correct?

Also, and tips or tricks on taking the stock magazine cap off?