TM VSR / JG Bar10 and other clones 

The Most Common rifle and the one that achieves constant performance is the TM VSR.  Here we are upgrading a TM VSR GSPEC but the exact same principle is applied with all VSR’s only the barrel length is changed. 

The Stock internals use a 45 Degree trigger and piston system which is renowned for being weak and un reliable.  Also the 45 degree plastic piston and spring guide are not very good at withstanding the high FPS out puts that we wish to achieve.  We Always choose to use 90 degree zero triggers and CNC Piston and cylinder sets with all our builds and these offer far better consistency against the dreaded slam fire issues.


Firstly, we need to build the new cylinder up with its new internal components.


For this you will need to use some none oil based Silicone grease.


Grease the head of the spring and the bearings on the spring guide.  If your spring has tighter coils at one end, then this is the end you need to slide the spring guide into.

Once the spring and spring guide has been greased you can slide them into the cylinder spring guide first.

Now we take the piston and grease the O Ring and two white Teflon rings.

Insert the piston over the spring and into the cylinder.

At this stage we always Use Teflon/PTFE tape on the threads of the cylinder head to ensure the best air seal possible.  You will need to wrap around 2-3 complete wraps of tape around the cylinder head threads.

Screw the cylinder head into the cylinder and set aside, for this you will have to apply downwards pressure to the piston to compress the spring as it is tightened.  We find using a pair of long nosed pliers helps when tightening the head and then give the head a final nip up with some adjustable pliers.

Screw the cylinder head into the cylinder and set aside, for this you will have to apply downwards pressure to the piston to compress the spring as it is tightened.  We find using a pair of long nosed pliers helps when tightening the head and then give the head a final nip up with some adjustable pliers.


it's time to strip the rifle.



Remove the two Allen head screws from the Body using a 2.5mm Allen key. 

Lift the Body from the barrel and receiver, it is advisable to lift from the barrel end and then slide towards the cocking lever as you lift. Once removed you can now set the body to one side.

Now remove the trigger guide screw and remove the trigger guide.

Once the trigger guide has been removed we can remove the spring guide stopper and the two screws that hold the trigger set in place. Once these have been removed we can now disconnect the trigger mechanism from the upper receiver.

Now simply slide the bolt back as you would when cocking and the bolt will slide free of the receiver.


Now its time to remove the cocking handle from the standard cylinder this is quite easy to do but just be sure to hold the two parts of the cocking handle together so you don’t loose the locating nub and spring.

It is advised to install the Cocking handle straight on to the new cylinder at this stage, this will save you losing any small components. Rub a thin film of oil free silicone grease over the whole of the cylinder and Insert the new cylinder in the upper receiver and align ready to fit the new 90 degree zero trigger.

The new Zero trigger is quite a bit different from the standard trigger when it comes to fitting them to the upper receiver.  All brands seem to differ slightly but they all generally use the same system.  The one we are using require you to remove the four hex key screws at the back of the trigger which will allow you to remove the brass plate.

You will also need to remove the safety lever and the spring guide stopper please note the one we are using has a hex screw that needs to be removed first.

Once the rear brass plate has been removed it’s now time to install the new 90 degree zero trigger.  Start by screwing the rear brass plate to the rifle using the screw provided and then locate the trigger block over the brass plate, align and fix the front mounting screw install the four rear hex screws before fully tightening the front screw. Last But not least reinstall the safety lever and spring guide stopper (don’t forget to fit the spring guide stopper retaining screw).

That is all the power work done you now have a rifle that is shooting 500FPS consistently and reliably but what about accuracy?  We find now the standard hop arm is no longer adequate to keep the BB stable in flight.

Installing a new CNC aluminium Hop arm and 6.03 stainless steel tight bore barrel will resolve this.


Now unscrew the outer barrel from the upper receiver and set the upper receiver to one side.

Two unscrew the outer barrel we first need to unscrew two-barrel retaining screws which are located in the bottom of the upper receiver and the last screw in the scope rail.

Remove the hop block by taking out the 2 retaining screws, this block is designed to hold the body to the outer barrel and also to hold the hop chamber and inner barrel in place.

Once the hop block is removed the whole inner barrel and hop unit will slide out of the outer barrel.

Once removed we need to strip the hop unit down for 3 reasons,

One-Remove the inner barrel and replace with a new shiny tight bore

Two-Complete the air seal Mod to the hop rubber

Three-Install the new hop lever.

What no new hop rubber I hear you ask?  We will inspect the rubber but we like the original TM stock rubbers Although I hear Bodgeups Mentioning a new Rubber so we will have to see what this one is like when he reveals his source. 

Remove the three black Philips head screws from the hop adjuster slide bar  And then remove this side of the bar.

Next remove the two silver coloured screws from the hop chamber.

Next comes the tricky part.  We want to install the new hop lever but we also want to eliminate any axis wobble and any lever wobble.  We do this by shimming in two different places.  Firstly, removing axis wobble.  We find the easiest way to do this is by using normal AEG Gear shims.  Make sure there is no wobble but the arm is still free to move up and down.

Secondly we want to eliminate any movement form the hop adjuster.  We do this by using heat shrink on the plastic hop selector bar, it usually is fine with just one piece of 3mm heat shrink but you can layer up to the desired level, again you want to have a snug fit but without restriction of movement.

And then trim any excess

Now Moving over to the inner barrel we can keep the standard bucking or opt for an upgrade. And the same with the barrel spacer, the TM comes with a standard black plastic spacer glued to the barrel or you could make your own or buy upgrade replacements.  Firstly, remover the hop rubber and barrel spacer from the original barrel the spacer may need a tap with a small hammer just to free the glue. 

Now fit the barrel spacer and hop Rubber to the new tight bore barrel.  Once this step is complete we like to wrap two or three wraps of PTFE tape around the end of the bucking and barrel to ensure a good air seal.


Ok So you are now ready to reverse the above steps and rebuild the hop unit.  Install the barrel with the slot in the bucking at the top, this will align with the slot in the hop half of the hop unit when you screw it together.

Once the hop is built it is a good idea to look down the barrel and check the hop and bucking is operating correctly.

Lets now put it all back together.  Slide the inner barrel in the outer.  Align screw holes and fit the hop adjustment lever.  Once this is fitted refit the hop block.

Tighten the barrel locating screws

Re fit the trigger guide and install the body.  Be sure you  slide the fin on the back of the trigger guide in the body first before tightening the screws

That’s it!

You should now have a working upgraded TM VSR ...I guess its time to take it to the range and chronograph.

Over 10 shots we ensure a fluctuation of 17FPS this is largely done with the new spring and New hop unit 485-502 FPS within a short space of time this will settle just below 500FPS on 0.20 gram BBs

  • Facebook - Black Circle
  • Instagram - Black Circle