View Full Version : MR2 LP Project

02-07-2007, 11:14 AM
INTRODUCTION: With all the problems with the MR2 spanning from a flawed operating pressure, I took initiative to find a way to lower that without removing many of the stock features. Essentially, there are three parts to reduce ball chops in the MR2 system: the bolt, the feed system/detents, and the airflow, corrected by changing to a LP system. The latter is what I focused on.

SPECS: One of the primary flaws with the stock operating system is a valve spring too strong. This can be corrected by getting a spring kit (which would be necessary anyways for the bolt to work correctly). You could always clip the spring, but it is attached at a weird angle and is slightly harder to alter than the striker spring. A significantly weaker spring will allow the airflow to pass through at a lower pressure, which will enable the LP system to work.

REGULATOR: The LP system itself is comprised merely of a regulator. There are tons out there, but many are for HPA systems only, clogging and eventually disabling themselves with liquid CO2. There are two primary regulators out there that help considerably, the Bob Long Torpedo and Palmer's Pursuit Shops Stabilizer. Since you want to minimize stock changes, I recommend the stabilizer, which functions better as an inline regulator than the Torpedo. Cost runs about $70-80, same with the inline Torpedo.

Whenever you install the reg via the standard ASA output on it (just stick it onto your bottomline and put a quick disconnect on it), it will regulate the pressure anywhere from 0-900 psi. Standard operating pressure is around 850 psi, and with a clipped striker spring or reduced tension striker spring, you can easily set it to around 450 without it burping. Personally, I managed to get it to 325, but the thing chronoed at 170 fps, so I suggest a range of 425-475 psi.

BOLT: Now, the bolt. There are many many arguments for bolt replacement. Quite a few people here have opted to get the Alamo City bolt & striker, and then found that they are quite temperamental. The AC bolt doesn't quite fit the bore on the inside of the chamber, not even with the o-rings. With the higher frictional force against the chamber, it is going to take a larger force and pressure to force it back after the ball is expelled. I therefore suggest you do NOT get the AC bolt, but keep the stock ACS delrin bolt. Have a machinist use a lathe to install o-rings on the bolt. Two should be fine. Put one before the valve opening and one after it to stop airflow on both sides and prevent premature discharge.

LOADER: The feed system, contrary to what many think, need not be especially complicated. The Halo B V35 is exceptionally fast and sexy, but it has eyes and can be quite temperamental. In addition, if you don't have a T-board, taking advantage of the 35 BPS is laughable. The stock board is capable of delivering 18 BPS on full auto, and up to 25 BPS on semi, but you have to walk it VERY fast to accomplish that. DraXxus Pulse is also beautiful, with a nice sound operated system, but with a tag of $190, it can hurt you before you're able to use it. I personally recommend the Reloader B or Reloader B2 (with increased board speed); sound activated like the Pulse, but less susceptible to damage and with a lower price tag. Stock speed limit is 22 BPS, but with a bit of soldering to allow for a larger current, you can easily achieve 25-27 BPS

Don't bother with a Q-loader. They're nice and they give your gun some versatility, but trust me, they are not practical at all. And they are temperamental.

Obviously, that's a lot of crap to swallow, and I know I could probably improve the operating pressure, but it's nearly impossible to find some aftermarket regs that fit inside the housing for the foregrip. Only bottom-input ones would fit, and those can't regulate worth poo.

02-07-2007, 02:11 PM
Where to get lighter valve spring MR2 valve springs is longer than normal spyder ones. Also the AC Bolt is just fine with me...tho the striker is too big.

02-07-2007, 06:15 PM
The delrin jacket inside the striker lightens it but it also cripples it.

I wonder, you have an Apex. Does it actually work? If so, HOW???

02-07-2007, 06:52 PM
Keep in mind what you are doing is solely lowering the pressure only. You simply changed some springs and a bolt. This is drastically affecting the efficiency of the marker. It might be Lower Pressure, but it needs more air to propell the ball. I'd suggest going the more conventional way.

Specs of Conventional:
New VA (Not avaliable for MR2)
New Valve/Valve Pin (maybe modded)
AKA Bolt, Spunkl, ect. (O-ring bolt to decrease Blowback !!!)
Lighter Striker (Modded or aftermarket. Aftermarket does not make much a difference)
Reg (Palmers, Torp for co2, CP, Sidewinder, ect for HPA)
Barrel (Paint to Bore Match)
Spring kit