Initial Impressions of the TM SOPMOD M4 AEG

[Hopewell]

This makes me super excited!

 

I don't know the price and I am loathed to Google it..

[Zereck]

A little birde just told me the BTC Next GEN Spectre unit is dropping.. Getting mine this sunday!!!

Good to hear as I started using 11.1v lipos. It works well(20 rps with a heavier recoil weight, it almost feels like a weaker gbb) but I will feel safer with a mosfet installed.

(btw is there a place where you can preorder one?)

Edited March 8, 2014 by Zereck

[Aod]

Edited to add - I guess short stroking the piston by removing one of the teeth from the front would test the hypothesis that it's this which is causing an issue. Of course, the lower fps might then negate putting an uprated spring in it in the first place, but at least it'd confirm the theory.

1 tooth off the piston should equate to about 10FPS, but I'd be concerned about lessening recoil force as the recoil weight is only actuated by the last 1/3rd of the piston movement iirc.

 

Hatchet, if you are worried about it coming back two much you can fit a spacer or two between the piston head and piston. The piston will move the same distance but the piston head won't reach the same point. If your theory's correct then that will rule it out.

 

More likely there's some issue with the pistol grip causing poor Engadgement with the bevel gear and there for making it more work to turn over than it should be. Hence it no having the guys to carry on over the hill, since as you say you can turn it manually.

 

Refit the original pistol grip, add 1mm or 2mm of spacers and test again, double check shimming to. What bushings are they ? I may have a shim sheet already written down for that part config.

Spacers are a good idea, should also be used to correct the AoE.

Do you find that the consistency of these Marui casings is good enough for shim configurations to be transferable from gearbox to gearbox like that? In my experience there's enough fluctuations with casings, bushings and gear sizes that it's easier to just shim from zero every time.

 

 

I think the spacers will be the next port of call, but I've lost the will to tackle it tonight. I did chuck some in initially, but of course that threw the AoE off... It's all good fun.

This seems odd to me, again it could be the SHS piston but usually these Marui recoil setups need a fair amount of AoE correction, the 416 that I just did, that spawned my Baton adapter modification thread needed about five whole millimeters of spacing for correct AoE

 

Can you take a photo showing the engagement of the sector gear to the pickup tooth on the piston?

Edited March 8, 2014 by Aod

[Hatchet]

A new day, and all that...

 

So, to try and answer some of the questions.

 

It's a CQB-R with the original quick change system (gold contacts, eagle6 lipo). The shimming was tested with the gearbox fully tightened and no piston, etc so I was able to spin it (hornbill gears) from the top. Seems to spin fine, only the weight of the gears acting as resistance, if you see what I mean. Shimming was done from the pinion/bevel first, then the sector gear. The sector gear clears the piston rack ok, so it's not catching on that. I couldn't tell you off the top of my head what the shims are set at.

 

Aod - You're right on the AoE correction, I neglected to mention I'd sorbo'd the back of the cylinder head. I don't *think* this should be having any effect relating to the current problem though - it doesn't alter the position of anything when the working parts are to the rear, if you see what I mean. I can pull this and try spacers behind the piston head instead.

 

The pain with all this is having to remove the stock tube every time.

[Aod]

A new day, and all that...

 

So, to try and answer some of the questions.

 

It's a CQB-R with the original quick change system (gold contacts, eagle6 lipo). The shimming was tested with the gearbox fully tightened and no piston, etc so I was able to spin it (hornbill gears) from the top. Seems to spin fine, only the weight of the gears acting as resistance, if you see what I mean. Shimming was done from the pinion/bevel first, then the sector gear. The sector gear clears the piston rack ok, so it's not catching on that. I couldn't tell you off the top of my head what the shims are set at.

 

Aod - You're right on the AoE correction, I neglected to mention I'd sorbo'd the back of the cylinder head. I don't *think* this should be having any effect relating to the current problem though - it doesn't alter the position of anything when the working parts are to the rear, if you see what I mean. I can pull this and try spacers behind the piston head instead.

 

The pain with all this is having to remove the stock tube every time.

Aaah yes, the Sorbo'd do the trick. I definitely understand your pain about having to remove the stock tube each time, major PITA! How do you guys deal with the wiring and castle/lock nut? I've taken to unscrewing the lock nut very gently over the wiring, it leaves indents in the insulation but doesn't cut it fully, but I'm starting to think that desoldering the slider-contact might be a better method.

 

When I was working on a particularly problematic SOPMOD (Kanzen 6mm bearings ¬_¬) I used to just screw the stock tube in place without the back-plate and castle/lock-nut for testing, saved loads of time and hassle.

 

Are you running the stock EG1000? From your photos I'm pretty sure you're right about the pistonhead catching but it helps to eliminate any other possibilities.

[Hatchet]

Yes, stock EG1000. Although I have just ordered a SHS hi-torque as another last ditch attempt to fix it. I know this is brute forcing it, but... Anyway, will have to reshim, again, when that turns up.

 

I've been just screwing the stock on and not bothering with anything else too. When I'm "testing" I just leave the wiring loose. Actually I've unscrewed the contact plates so I can more easily connect different batteries to it to test. Have an 11.1 on the way to see what odds that makes too.

 

TBH, if I hadn't sunk so much into it already I'd have quit a while ago. It's great when it's working, but...

[Richard Y]

Kanzen 6mm are utter rubbish .. Remove them from any gun you find. Japan promy bearings are the only bearing that's never failed. Kanzen even emailed me to tell me they arnt fit for purpose. The more people start passing it round the better.

 

I always unsoldier the wires, undo the castle nut and slide the wires through it's the only way to prevent rubbing the Teflon coating off during a problematic Sopmod and I've had them

 

The shs pistons a pain in the *albatross*, it needs loads of aoe adjustment and also if you do the second tooth mod ie best practice from version 2 gearboxes it tends to break the back off the shs piston in a short period of time.

 

I'm still confused how it could be catching the casing wouldn't have worn and unless the cylinders short there shouldn't be a gap.

 

Yeah I find the gearbox casings really consistent , the benefit of refusing to work on other guns anymore, alas though it's not for every gun tech that has to work on many guns it's still best from scratch I'm just anal about documenting stuff, I hate when people talk about the magic inside .. It's not magic it's engineering and someone had to put them together to a set standard on a production line. So the last time I took a brand new Sopmod apart I measured and wrote down the shims. Measured the original tm bushings. Theoretically to churn them out 1000 at a time they would have a preset shim for each gearbox and no daubt qc testing.

 

I use the sheet as a guide simply to speed things up a bit the issue is screw tightness , you can add or remove 0.3 mm by screwing it tighter. Hence why in testing I over tighten and ultimately end up with a little play.

 

Maybe tm production line uses torque wrench or something for consistency.

[Richard Y]

Yeah when testing a Sopmod I leave the wires loose and poke the ends into a battery... Tamiyas works great for that. I just screw the stock tube back on for testing. It has to work fine before introducing stock and recoil weight. The stock can introduce extra issues if there's a poor connection. It's best not to test with it ever on Sopmod / cqb / hk416

[PureSilver]

A little birde just told me the BTC Next GEN Spectre unit is dropping.. Getting mine this sunday!!!

 

Where from?!

[Richard Y]

From btc no Daubt, I reckon half his stock never makes it to the website.

[sacairsoftsn00py]

That shs piston looks a lot like the king arms piston for the next gen m4 series. I've had one in mine. Lasted maybe 15k rounds with springs ranging from 380 to 450 fps. The rear plastic piece that braced the steel rack snapped on me. Other than that...no issues. I did remove the 2nd to the last tooth as I have an ARS sorbo installed on my SOCOM/ MK18 build.

 

I'm on my second KA piston.

 

FYI....

 

Guarder Infinite Torque Motors are pretty good for a snappier trigger response with either a 7.4v sub 1200mah lipo or an 8.4v 1300mah nimh sopmod battery. Night and day difference if you're running rear wired next gen m4's stock. The motor will drop right in with the pinion gear meshing well with the stock tm gear set.

 

If you install an SHS steel gear set for the next gen series, you'll want to use the stock eg1000 motor's pinion gear for the guarder motor. Then the gun sounds smooth.

 

Stock guarder pinion gear doesn't mesh that well with the shs gear set (have not tried this with a different grip however)

 

Best thing I like about the infinite motor is efficiency. From putting bbs in the air, it seems to be more efficient than my Tienly 35000 (the motor that supposedly cycles up to a 190 spring).

 

With a limited battery capacity, I think this is the way to go...unless ROF is important to you.

 

This motor doesn't improve ROF with the said battery. This helps with ammo management on full auto....specially if you have the mags set for 30rds.

 

I have a TM EG3000 High Cycle motor inbound. Compared to the EG1000, these supposedly crank out up to 3 RPS faster. I'm not sure how much better they are for trigger response. When I test it, I'll be sure to report back.

 

 

--------

 

 

Richard...have you installed a Prometheus Bearing Spring Guide with just the stock spring? If so, What kind of power increase did you get after the upgrade?

 

From messing with cut down springs, I get up to a 30 fps boost with them. Of course, the increase will vary depending on the brand, and number of coils/length of the spring used.

 

I'm just wondering about the stock springs power output with just the bearing spring guide upgrade.

 

Thanks!

 

 

Sent from my iPad using Tapatalk

[Hatchet]

Finally, some progress.

 

I made a spacer to sit behind the piston head from a 5p piece with a hole drilled in the middle. It's pretty much exactly the right size. It needs to just cover the piston rack gear but not stick out far enough to foul.

 

However, this wasn't the main change. What actually seems to have helped a lot is putting the original Marui bushings back in. For whatever reason, I think these are fractionally thinner than the others I've tried (or perhaps it's just how they sit in my gearbox). Anyway, the other bushings were sitting slightly more proud on the outside of the gearbox and I believe them rubbing/being under compression had essentially the same effect as overshimming the gears. Except that it's not noticeable when you do the standard shimming test of spinning the gears...

 

With the old bushings in I'm getting far livelier response and rate of fire. It's not perfect and has jammed a couple of times on non-completed cycles, but it's looking an awful lot better so far. I suspect/hope with the addition of the hi-torque motor (and eventually, the Spectre...) this should work as expected.

 

I still have tidying up/relubing/rewiring and so on to do, and putting the stock tube back on properly. I'm hoping this might improve matters further.

 

Because it'd be really nice to actually be able to go shooting with it again!

[SixtyNiner]

Good to hear you might have found a solution to your problem Hatchet.

Working on AEGs can be so frustrating. Which brings me to…

 

I recently rewired my gun from the front (aka SOCOM) to the rear. Everything went well, no big problems, but I did notice I wasn't getting the FPS I was expecting and there was quite a bit of fluctuation in the readings. With an M100 spring from Eagle6 I was just nudging 300fps but some shots were as low as 280fps. Thanks to the legendary TM hop the gun was still shooting well so I haven't given it much thought.

 

But today I noticed the air nozzle doesn't seem to be far enough forward. Comparing my gun to the photos on the second page of this thread and those on TKOverkill (link also at the beginning of this thread) my Prommy air nozzle looks as if it's about 5mm or so further back. And when I test fitted the hop unit the BB feeding tube isn't completely sealed off by the air nozzle. I'm thinking that maybe some of the pressure from the piston is escaping down through the feed tube.

This photo was taken after firing on semi, so the piston should be all the way forward.

 

 

I thought I'd get your thoughts before cracking open the gearbox again. Or am I barking up the wrong tree and I just happen to looking at a gearbox in a different stage of the cycle?

 

FYI: Just about everything internally is Prommy, including the piston, cylinder, cylinder head and air nozzle. Piston head is TM with a sorbo pad to adjust the AOE. Hop unit is TM, inner barrel a Prommy 300mm.

Aside from the slightly low and inconsistent FPS everything has worked perfectly for the 1000+ rounds I've shot since the rewiring.

 

Thanks in advance for the help.

Jason

 

 

PS. My rewiring involved sneaking a lipo and mosfet into a Magpul UBR stock. I'll post pics as soon as I have time.

Edited March 8, 2014 by SixtyNiner

[sacairsoftsn00py]

Piston doesn't always go all the way forward after completing a cycle on semi auto.

 

Try yanking out the pistol grip and releasing the anti reversal latch. If you're checking for nozzle to hop/barrel assembly seal, place it against the gearbox and blow through the barrel...see how much air leaks

 

 

Sent from my iPad using Tapatalk

Edited March 8, 2014 by sacairsoftsn00py

[Hatchet]

Good to hear you might have found a solution to your problem Hatchet.

Working on AEGs can be so frustrating. Which brings me to…

 

I recently rewired my gun from the front (aka SOCOM) to the rear. Everything went well, no big problems, but I did notice I wasn't getting the FPS I was expecting and there was quite a bit of fluctuation in the readings. With an M100 spring from Eagle6 I was just nudging 300fps but some shots were as low as 280fps. Thanks to the legendary TM hop the gun was still shooting well so I haven't given it much thought.

 

I have this too, which is why I went down the whole spring thing in the first place. I did it the other day and was only pulling about 320ish on a e6 M110... Checked the usual suspects (compression, etc) last time but seem ok. Will have to take another look...

[Richard Y]

That shs piston looks a lot like the king arms piston for the next gen m4 series. I've had one in mine. Lasted maybe 15k rounds with springs ranging from 380 to 450 fps. The rear plastic piece that braced the steel rack snapped on me. Other than that...no issues. I did remove the 2nd to the last tooth as I have an ARS sorbo installed on my SOCOM/ MK18 build.

 

I'm on my second KA piston.

 

FYI....

 

Guarder Infinite Torque Motors are pretty good for a snappier trigger response with either a 7.4v sub 1200mah lipo or an 8.4v 1300mah nimh sopmod battery. Night and day difference if you're running rear wired next gen m4's stock. The motor will drop right in with the pinion gear meshing well with the stock tm gear set.

 

If you install an SHS steel gear set for the next gen series, you'll want to use the stock eg1000 motor's pinion gear for the guarder motor. Then the gun sounds smooth.

 

Stock guarder pinion gear doesn't mesh that well with the shs gear set (have not tried this with a different grip however)

 

Best thing I like about the infinite motor is efficiency. From putting bbs in the air, it seems to be more efficient than my Tienly 35000 (the motor that supposedly cycles up to a 190 spring).

 

With a limited battery capacity, I think this is the way to go...unless ROF is important to you.

 

This motor doesn't improve ROF with the said battery. This helps with ammo management on full auto....specially if you have the mags set for 30rds.

 

I have a TM EG3000 High Cycle motor inbound. Compared to the EG1000, these supposedly crank out up to 3 RPS faster. I'm not sure how much better they are for trigger response. When I test it, I'll be sure to report back.

 

 

--------

 

 

Richard...have you installed a Prometheus Bearing Spring Guide with just the stock spring? If so, What kind of power increase did you get after the upgrade?

 

From messing with cut down springs, I get up to a 30 fps boost with them. Of course, the increase will vary depending on the brand, and number of coils/length of the spring used.

 

I'm just wondering about the stock springs power output with just the bearing spring guide upgrade.

 

Thanks!

 

 

Sent from my iPad using Tapatalk

 

Theres lots of owners on the recoil appreciation facebook group that have installed spring guide and barrel, on stock spring and gotten up to 320 fps from what ever the gun was stock usually between 290 sopmod and 300 scar.  

 

its usually about 5 - 10 with spring guide as a rule. 

 

5 - 20fps with barrel depending on bore, but with the new barrel types some being 6.20 mm in diameter we will see a decline in fps.

 

as a general rule you can install all internal gearbox upgrades to an AEG and see a 3 - 6% increase in overall FPS.  doesn't sound much but a 5% increase on a standard spring is a solid 14 fps before adding a barrel or stronger spring so thats free fps with little or no decrease in battery or ROF.  and its a percentage so it will naturally increase when adding a power spring though now you battery and rof decrease.  And it doesn't take into consideration the efficiency advantage of adding upgrades like vented piston head, teflon cylinders, high torque ratio gear set, high torque motor, even the anodizing on a cylinder head technically can increase efficiency marginally.  Alot of players are Not bothering with upgrades nowadays the trend being to do spring guide and barrel and live with just 320 fps becuase they dont want to cuase reliability problems by "messing" with the marui setup, that just says to me they need to use a decent gun tech or learn how to shim. But personally ive seen the benefit from cumulative marginal gains, and they all add up and its not just about the fps gain, that said im a strong believer of getting as close to a site fps limits as possible.  If someone asks me if an extra 10 fps makes a difference in range, i simply say well you wouldn't want it to be 10fps less would you!  a drop from 280 to 270, would see the tm recoil being massively out classed, so an increase from 340 - 350 would be equally important even if its less apparent.

[Richard Y]

Finally, some progress.

 

I made a spacer to sit behind the piston head from a 5p piece with a hole drilled in the middle. It's pretty much exactly the right size. It needs to just cover the piston rack gear but not stick out far enough to foul.

 

However, this wasn't the main change. What actually seems to have helped a lot is putting the original Marui bushings back in. For whatever reason, I think these are fractionally thinner than the others I've tried (or perhaps it's just how they sit in my gearbox). Anyway, the other bushings were sitting slightly more proud on the outside of the gearbox and I believe them rubbing/being under compression had essentially the same effect as overshimming the gears. Except that it's not noticeable when you do the standard shimming test of spinning the gears...

 

With the old bushings in I'm getting far livelier response and rate of fire. It's not perfect and has jammed a couple of times on non-completed cycles, but it's looking an awful lot better so far. I suspect/hope with the addition of the hi-torque motor (and eventually, the Spectre...) this should work as expected.

 

I still have tidying up/relubing/rewiring and so on to do, and putting the stock tube back on properly. I'm hoping this might improve matters further.

 

Because it'd be really nice to actually be able to go shooting with it again!

 

Yup, as i say the issue sounded shimming related, unfortunatly over the years ive had to evole shimming methods, and often it can involve "telling" the customer no to certain guns and or parts.  Simply becuase of the potential for compatibility issues verses time to get a good shim.  All bushings are different sizes in height, both overall height and height of the "lip" which protrudes.  you want to feel a "pop" of press fit as the bushing pushes home all the way in.  Theoretically at this point there should be no fouling of the external bushings, especially if its prometheus as they are tried and tested faultless.  The lip a advantages and disadvantages, it can reduce overall shims needed.  The no lip bushings or flush fit and often take 20 odd shims if using 0.1mm shims only.  Thats a lot of gap to fill, and the lip version can take less but has reduced area for shimming instantly your starting point of shimming gears is 1mm higher than with no lip flush fit.  

 

Typically because of the sector gear you will want to shim it as low as possible to avoid the half teeth piston rubbing but could then see the AXLE of the gears protruding to much so you will want to find a balance.  I once had an SRC m4 which i had to dremel the gears axle as it was the only way it wouldn't push on the selector plate with the correct shimming.  

 

Because of the issues ive had with sopmod specifically ie this whole tighten gb case and suddenly my perfect shim is to tight, i always air on the side of caution 0.1mm - 0.2mm less than is needed.  At worst your adding 0.1mm - 0.2mm of play.. which is bugger all.  And you potentially you now have removed that tiny chance of over shimming.  Which is so common as we try and perfect our own shimming methods, in our minds its perfect but so many times specifically with sopmod as its has ZERO leeway for over shim with the quick change battery system its caught me out.

 

also another thing which is why i use my own shims is that the wider shims in the wrong place can also cause issues with the casing closed, so i only use small type shims.

 

Original TM shimming with tm gears and tm bushings

 

sector gear - top - 0.50mm - bottom - 0.15

spur gear - top - 0.15mm - bottom - 0.15

bevel gear - top - 0.50mm - bottom - 0.15

 

Gap between top of bevel gear and gb casing is 0.9mm - 1mm for perfect bevel gear to motor pinion height as per tm.  Measured with feelerguage.

 

notice how less is needed on the spur, its the easiest to over shim.

 

Lip height of standard tm bushings is 0.85mm 

 

sector gear height of standard gears

 

sector gear 12.38mm

spur gear - 12.92mm

bevel gear - 12.86mm

 

sector gear + bushing lip + tm shim = 16.81 mm rounded up

spur gear + bushing lip + tm shim = 17.00 mm rounded up

bevel gear + bushing lip + tm shim = 17.29 mm Rounded up

 

thats your "tm magic" 

 

If somebody wants to return it to normal thats what you would do, obviously the moment you change a part you now change things, ie bushings or gears or shims.   You could measure your new parts, assuming the rounded up tm shim is either perfect or a little on the loose side you could work out the change of adding the new parts.  Youll still need to do testing with case tightened as much as you can.  

[Richard Y]

Good to hear you might have found a solution to your problem Hatchet.

Working on AEGs can be so frustrating. Which brings me to…

 

I recently rewired my gun from the front (aka SOCOM) to the rear. Everything went well, no big problems, but I did notice I wasn't getting the FPS I was expecting and there was quite a bit of fluctuation in the readings. With an M100 spring from Eagle6 I was just nudging 300fps but some shots were as low as 280fps. Thanks to the legendary TM hop the gun was still shooting well so I haven't given it much thought.

 

But today I noticed the air nozzle doesn't seem to be far enough forward. Comparing my gun to the photos on the second page of this thread and those on TKOverkill (link also at the beginning of this thread) my Prommy air nozzle looks as if it's about 5mm or so further back. And when I test fitted the hop unit the BB feeding tube isn't completely sealed off by the air nozzle. I'm thinking that maybe some of the pressure from the piston is escaping down through the feed tube.

This photo was taken after firing on semi, so the piston should be all the way forward.

 

IMG_2862.jpg

 

I thought I'd get your thoughts before cracking open the gearbox again. Or am I barking up the wrong tree and I just happen to looking at a gearbox in a different stage of the cycle?

 

FYI: Just about everything internally is Prommy, including the piston, cylinder, cylinder head and air nozzle. Piston head is TM with a sorbo pad to adjust the AOE. Hop unit is TM, inner barrel a Prommy 300mm.

Aside from the slightly low and inconsistent FPS everything has worked perfectly for the 1000+ rounds I've shot since the rewiring.

 

Thanks in advance for the help.

Jason

 

 

PS. My rewiring involved sneaking a lipo and mosfet into a Magpul UBR stock. I'll post pics as soon as I have time.

Thats all normal, the issue is your piston head, its tm and non vented which means your o ring will not widen when the piston is released.  Its soley reliant on the o ring being wide enough in the first place.

 

3 options..

 

Promy piston head for next gen series.

 

Take the TM piston head o ring off and place it around the brass cylinder.  now using a light underneath, gentle heat the o ring for a few mins, and leave for 1 hour.  The o ring will now hold a slightly larger size and the heat makes it maintain  this longer.  you WILL see a bump in fps and consitency.

 

thirdly looking at the front of the tm piston head is 4 small moulding holes, usinga  very small drill fit, drill through these moulding holes, you will see the inside of the piston head where the oring sits, is like a u shape, youve now in theory drilled perfectly into the bottom of this U 4 times.  as the piston head is released now air will pass through the holes in the the bottom of the U under the o ring, lifting the o ring outwards which forms a harder seal against the inside of the cylinder, basic principle of vented piston head.  it also increases ROf as it allows you to have a smaller o ring which isn't reliant on touching the cylinder in the compression stroke, not too small though.  Which is why the expanding o ring trick is handy but not usually needed on AFTERMARKET piston head o rings.

[Hatchet]

Lot of useful info there Richard. My shimming is quite different to that though. Using the standard systema shims,

 

bevel gear 0.3 top, 0.2 bottom

spur gear 0.2 top, 0.3 bottom

sector gear 0.3 top 0.2 bottom.

 

Which seems to run smoothly. I don't think I felt any clicking per se from the marui bushings, but I did give them a little tap with an appropriately sized punch pin just to make sure they were seated. 

 

I think I'll wait on the motor before I meddle with it again as it's going to need the bevel gear reshimming at that point (and I'm going to rewire again as the existing is getting a bit dog eared). An easy way of direct wiring it also occurred to me, which I may or may not try out for testing purposes.

[Zereck]

So anyone know how can I get the next-gen BTC mosfet? I read on airsoftmechanics that they got their shipment on March 7th(altough prototype) but I haven't seen anything on their site and I didn't get any replies when I wrote them there. I guess Im bit impatient.

[arne71]

Well, you`ve been waiting for about three years.  You are allowed to be impatient.

[mrezzy]

Where from?!

 

He's back in NYC, will be picking it up from him sometime this week. he said the manual isn't even written, so I'll just do it based on the V2 spectre install! I got my gearbox out and ready for this baby!

[Hatchet]

Hi torque motor has been installed and is making a significant difference. Trigger response and RoF have gone through the roof - I'm not going to test it with the 11.1 because I think it would explode. This is direct wired for ease of testing, so there may be a drop when I switch back to the quick change system. The only thing outstanding is I think I'll need to change the cylinder to a full type to make up for the volume loss from the AoE sorbo correction. More exact calculations to be taken when I have it apart.

 

As an added bonus, I no longer have to search for my car keys. I just wave the gun in the general area I think they might be and they fly towards the pistol grip...

[JCheeseright]

which motor did you go for?  I'm tempted to go the whole hog on my 416 and get the trigger response as fast as I possibly can. 

[Hatchet]

Just the SHS hi-torque. £35. Money well spent.