Monday, October 4, 2010

FLASC Magic: "Milsimming" the BT TM7

The Hechler & Koch MP7 is a relatively new weapon on the scene, that's quickly making a name for itself in the world of Personal Defence Weapons (PDWs) for military and police.

With its compact form factor, light weight, and tacticool appearance, the MP7 is a favourite of special ops troops and Cobra operatives alike.

In 2008, BT Paintball brought to the scene their paintball "replica" of this weapon, dubbed the TM7. It also bears the compact form factor, light weight, and MOST of the tacticool appearance of its genuine counterpart, which has made it a hit with many Milsim paintball players.

I'm one of those players, and I faithfully use my TM7 as my primary marker. But one thing that never sat right with me was that extra length of barrel sticking out from the front of the shroud. BT included a 9-inch barrel with the marker, which is generally a length that offers a good balance of air efficiency, shot consistency, and accuracy. But instead of recessing the barrel further back into the marker to keep that MP7 look, it was designed to stick out, giving it a grease-gun front end look reminiscent of the M3 submachinegun.

So with FLASC offering a wide range of barrel lengths and tips at their store, I set out to find a combo that would bless my TM7 with that MP7 barrel look.

Dave from FLASC was extremely helpful with my questions, and suggested I go for the 5-inch unported barrel to keep a barrel tip tight to the marker. As for the tip, I chose the FLASC "Bullpen" style to attach on the end, because I found it most closely resembled the flash suppressor most commonly found on the end of the MP7's barrel.

Now before anyone starts complaining about a 5-inch barrel being too short, keep in mind that the TPX pistol has a 6.25-inch barrel out of the box, and it's pretty accurate even with that length. With the tip attached, the setup I bought makes for a barrel approximately 6.5-inches long. And if you're worried about the shorter barrel affecting range, don't be; because of field velocity limits, a paintball exiting a 5-inch barrel at 280 feet per second will travel just as far as a paintball exiting a 14-inch barrel at 280fps. The main difference affecting the shorter barrel is with its air efficiency, which I'll discuss later.

Armed with my new FLASC parts, I screwed the bullpen tip onto the end of the barrel, then screwed the barrel into the shroud of my TM7. Here's the end result:

I'll admit the look still isn't perfect, as the barrel is made for .68cal (17.5mm) paintballs, while the real MP7's tip is meant for much slimmer 4.6mm rounds. Still (in my humble opinion at least), this relatively simple and inexpensive mod goes a long way towards improving the look of a stock TM7. Throw a TM Series Rip Clip on there to get rid of the hopper, and you're golden.

The shorter barrel also gives a suppressor-style look to an APEX tip, keeping it in tight and close to the front end of the marker. The TM7 below is equipped with FLASC's APEX-ready adapter:

FLASC also offers a suppressor tip that resembles more closely the real-life "silencer" designed for the MP7. However, unlike the APEX the FLASC suppressor is cosmetic only, and doesn't offer the performance/range benefit of the APEX.

Some Difficulties

Having just brought this out to the field today, the main question I got from most players asking about my TM7 was, "Does the shorter barrel mean it doesn't shoot as far as regular guns?". Although I mentioned it in passing above, I'll take a short tangent to elaborate on why people have this misconception.

The confusion over barrel length vs. range has to do with the physics of real firearms, not paintball guns. With real firearms, the longer the barrel, the further a given cartridge will fly before being brought to the ground by gravity. This has to do with the shape of modern munitions, and the fact that modern firearms barrels are "rifled". If you look on the inside of a firearms barrel, you'll lines that twist lengthwise on the barrel's surface. These lines put friction on the round/bullet and cause it to spin in flight, keeping it airborne longer than if it had been fired out of a smooth barrel. Generally the longer the barrel, the more chance the rifling will have to spin the bullet, and the greater the range will be. Pistols also have rifled barrels, although with the limited length of the pistol barrel, there isn't much room for the bullet to twist. Hence the main reason why a 9mm bullet fired from a Glock 17 pistol has a much shorter range than that same 9mm bullet fired from an MP5 submachinegun.

However, with a paintball field velocity limit of 280fps, a paintball leaves a gun with a 16-inch barrel at the same speed as it leaves a gun with a 5-inch barrel. Two identical .68cal paintballs travelling at the same speed will succumb to air resistance and gravity the same way, and thus have the same range. When you understand this, you'll realize what a waste of money it is to invest in a 21-inch "sniper" barrel, and how impractical a 4ft-long gun is on the field.

So what's the downside to a 5-inch barrel? Well, the shorter barrel leaves less room and time for the air to gather behind that paintball and accelerate it to that 280fps exit speed, so it's less efficient with air. You'll have to increase your velocity on your marker a bit if you're switching from a longer barrel to a shorter one. In my case, I had my TM7 dialed in at 270-280fps, but after switching to the 5-inch barrel, my shots were going over the chrono at 265-275fps. It wasn't a huge difference, and I didn't have to increase the velocity/air output that much, but I did get less shots out of my usual tank.

Another issue I had with the short barrel was that it was hard to remove it from the marker. Because the short barrel is recessed inside the shroud of the TM7, you can't squeeze the barrel in-hand and unscrew it like you would on any other paintball gun. You have to pinch the lip of the barrel between your fingers and try to twist it out instead. If you screw it in tightly, you won't be able to remove it that way, and you'll have to take the TM7 apart to get the barrel out. A possible fix for this is to put some loc-tite on the Bullpen barrel tip and then screwing it onto the end of the barrel permanently. This way you could just grab onto the Bullpen tip when you unscrew the barrel. However, because this permanently attaches the tip, you wouldn't be able to swap it out for another tip like the APEX if you went with this "solution".

Overall Thoughts

Despite these two issues, I still love this modification to the TM7. Not only does it bring the look more in line with that of a real steel MP7, it also makes this already compact marker a full 3 inches shorter, making it even better for CQB in tight spots.

FLASC has become THE one-stop shop for barrel modifications on Milsim markers, and once again I've not been disappointed with their product. From barrel kits and accessories to obscure mods for specific markers, you'll probably find something on their site that fits that project you had in mind. Be sure to check them out!

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