CDM BMT clamp

[EdwardE]

I picked up one of these clamps after reading one of the flashlight blogs http://www.rem870.com/2012/01/23/stream ... 70-review/. I disliked the stock barrel/magazine clamp and was looking for something a little better, both in terms of versatility and design. While the stock clamp does its job, it is limited in expanding functionality; a sling attachment is about it. The stock clamp is also prone to damaging the finish where it contacts the barrel and magazine.
The BMT is a vast improvement. The package came with an allan wrench, 4 peel-and-stick pads, the 2 pc. aluminum clamp and installation instructions. The clamp is a 2 piece design held in place with a single allan head machine screw. The advertised weight of the clamp is 1 ounce compared to the stock clamp weight of 1.3 ounces. I couldn't tell any difference and I imagine with the additional weight of rail, flashlight or other accessory, that .3 difference is a moot point. The finish on the clamp is very well done and blends in well with the finish of the Express.
The pads that came with the clamp are intended to serve two purposes: give the clamp some additional grip and prevent any direct metal-to metal contact between the clamp and the magazine and barrel. Nice. The pads are pre-cut and replacements are available from CDM on their website.
Once installed, the profile is fairly narrow but it does appear that the design has changed when looking at the one in the link. In terms of functionality, there is a receiver for a QD sling (one side) and taps for rails on both sides. Since the clamp is reversible you could mount the sling left or right though it is only possible to mount one rail if you do install a QD sling.
I purchased the BMT from Harris Tactical out in Arizona and it arrived in 3 days to the east coast. Pretty fast shipping.
Some pics:

[dtjacob]

Does this require an adapter to use a QD swivel??????

Thanks.

[Vitaly]

Looks very good, I really like CDM Gear clamps, recommended!

Here is mine:

[Ace of Spades]

[quote="EdwardE"]I picked up one of these clamps after reading one of the flashlight blogs http://www.rem870.com/2012/01/23/stream ... 70-review/. I disliked the stock barrel/magazine clamp and was looking for something a little better, both in terms of versatility and design. While the stock clamp does its job, it is limited in expanding functionality; a sling attachment is about it. The stock clamp is also prone to damaging the finish where it contacts the barrel and magazine.
The BMT is a vast improvement. The package came with an allan wrench, 4 peel-and-stick pads, the 2 pc. aluminum clamp and installation instructions. The clamp is a 2 piece design held in place with a single allan head machine screw. The advertised weight of the clamp is 1 ounce compared to the stock clamp weight of 1.3 ounces. I couldn't tell any difference and I imagine with the additional weight of rail, flashlight or other accessory, that .3 difference is a moot point. The finish on the clamp is very well done and blends in well with the finish of the Express.
The pads that came with the clamp are intended to serve two purposes: give the clamp some additional grip and prevent any direct metal-to metal contact between the clamp and the magazine and barrel. Nice. The pads are pre-cut and replacements are available from CDM on their website.
Once installed, the profile is fairly narrow but it does appear that the design has changed when looking at the one in the link. In terms of functionality, there is a receiver for a QD sling (one side) and taps for rails on both sides. Since the clamp is reversible you could mount the sling left or right though it is only possible to mount one rail if you do install a QD sling.
I purchased the BMT from Harris Tactical out in Arizona and it arrived in 3 days to the east coast. Pretty fast shipping.


Yes the stock clamp scratches the hell out of both barrell and mag extension and works itself loose in no time. I changed mine to a Magpul clamp which also has peel and stick pads to prevent scratching. Holds rock solid but your clamp does look very cool. Since you have the same 870 as myself and the same mag extension does your gun hold 6 or 7 shells in the mag. Remington advertises the 870 Express Tactical as a 7+1 gun but I've only ever been able to fit 6 shells in the mag using the shortest shells I could find.

[EdwardE]

Ace of Spades, I can only get 6 into the tube (2.75" shells). I changed the follower to a Vang Comp almost as soon as I got the 870 but, I don't think that impacted the capacity. Looking at Remington's website, they state 7 rounds (another way of saying 6+1).

Vitaly, your set-up looks good. I'm still in decision-making mode with what flashlight to get. Did you have any issues with fitment to the Nordic magazine? I only ask because CDM's FAQ's (on their website) left some doubt about their clamps fitment to aftermarket tubes.

[Synchronizor]

Yes the stock clamp scratches the hell out of both barrell and mag extension and works itself loose in no time.

The factory extension bracket can be rough on the finish, but it shouldn't be coming loose on you if you installed it correctly. It was designed to be simple and solid for working military/LE guns.

Since you have the same 870 as myself and the same mag extension does your gun hold 6 or 7 shells in the mag. Remington advertises the 870 Express Tactical as a 7+1 gun but I've only ever been able to fit 6 shells in the mag using the shortest shells I could find.

With the Remington extensions, the 870 will have a capacity of 6+1 with a +2 extension (the ones that line up with an 18.5" barrel), and 7+1 with a +3 (meant for 20" barrels, though they'll extend past the muzzle of those by about half an inch), when using 2.75" shells. You may not be able to fit a full 6 or 7 of some 3" shells in these magazines, but keep in mind that these were designed for maximum durability and reliability with the 2.75" shells used by military and police, and accordingly, they have follower stops built in to keep the spring from compressing too far and becoming damaged or binding (something I've personally experienced - and it wasn't pretty). That said, you should have the full rated capacity with any SAAMI-compliant 2.75" shells, unless you're running a really long aftermarket magazine follower or an overly wide or long aftermarket magazine spring.

There is a version of the Express that comes with a +3 extension, so you may have confused that with the more common 18.5" Expresses that have +2 extensions. Or, you may have misunderstood and thought that 870s advertised as having "7-round" capacities had 7-round magazines, instead of 6-round magazines and room for the seventh in the chamber.

[Ace of Spades]

Hey Guys,
Thanks for setting me straight. I chose the Express Tactical over the Magpul Tactical because I thought it held an extra shell and also I wanted to install the FDE Magpul furniture. However since I have bought it I realise thanks to your explanation that the mag extension offers the benefit of not overcompressing the mag spring and also the barrell is easily interchangeable as opposed to the Mag Tac. BTW I also use the Vang Comp follower which is the same thickness as the standard plastic follower. I do however really think Remington have skimped on the barrell/mag clamp and should have installed a tritium front sight as standard. Nevertheless I am happy that my mag will be more reliable even if it is a 6+1. If I can't sort out a problem with 7 double 0 shells a Blackhawk 55 shell bandolier and a S&W M&P 17+1 9MM I should have dialled 911!!!!! LOL

[Synchronizor]

I do however really think Remington have skimped on the barrell/mag clamp...

The original military design used a much larger bracket that integrated a bayonet lug, sling attachment, and the front sight. A simple but solid setup for 1960's military issue, where everyone got the same thing.

The smaller clamps used today on military, LE, and civilian tactical models (and yes, the Express bracket is the same as the LE/military part) are based on that same design and follow the same function-over-looks philosophy; but they take up less space, are quicker and easier to take on and off, cost less, and allow the front sight to be installed on the barrel, so the guns are more configurable.

True, neither are real nice to the finish, but that's not a major priority for a working military/LE gun that's just going to get beat on anyway.

...and should have installed a tritium front sight as standard.

You're not going to see tritium sights coming standard on a basic, value-oriented Express. You'll have to spring for a Police 870 if you want those features. However, an 870 is an 870; anything you see on a Police model can be put on Express if you're willing to spring for it, and a front bead or blade sight is easy to change.

If I can't sort out a problem with 7 double 0 shells a Blackhawk 55 shell bandolier and a S&W M&P 17+1 9MM I should have dialled 911!!!!! LOL

To be fair, if you have the chance you should be dialing 911 no matter how much ammo you have.

[Ace of Spades]

Synch,
Didn't realise Rem had been making the same mag extension for 50 years. What better recommendation could you have than that. Great info!

[Synchronizor]

What better recommendation could you have than that.

My thoughts exactly.

Also, for the record, I went through and rewrote my previous posts extensively. I found them to be poorly-written upon later review. I didn't reverse my position on anything, but I added some detail and clarified things.