Nuprol Pioneer Defender Upgrades

[Spartan09]

as the title suggests, im looking to upgrade my nuprol pioneer defender to inprove FPS and range.

 

Before anyone says to just buy a new gun, i will not have the money to buy a new gun for a while due to various critical non-airsoft expenses over the next few months, and i plan on upgrading the gun slowly over the next few months to spread the cost...

 

I would appreciate any pointers regarding spring ratings, gearbox upgrades, hop up rubbers etc...

 

I have also read about r hop mods etc, however i dont plan on attempting such a mod until i have more confidence, and i have the rest of the gun tuned.

 

If it helps, i currently use .25g bbs, and plan to try .32g in the future

[strykerles]

I have a nuprol delta sopmod I brought boneyard

 

changed the inner barrel to a zci 6.02, prowin rotary hop, prommy purple bucking and nub, asg 20k motor and also a 105 spring

 

shoots about 340 on an 0.2 with a rps of about 18 with a 7.4 lipo

going to gut the gearbox soon though as I feel it needs more oomph and fit a fet

 

it's been relegated to my secondary though as I now have a G&G rk-74e which I teched and love more :D

[Adolf Hamster]

going by your profile you have a few spare gats lying around, so if you're feeling brave enough to crack open the box there's a fair few options.

 

in ascending order of difficulty you'll want to:

run good quality heavier ammo (i like ~.3g for assault guns)

change hop rubber if it can't lift said heavy ammo (ml macaron+omega nub is pretty good although can have feeding issues in some guns, pdi W-hop works quite nicely too and is a bit more universal)

then air seal air seal air seal.

 

for the air seal there's a few tips in here for the places you want to be looking out for:

 

once you've got some good confidence that your air seal is good then you can think about changing springs if it's under the site limit by a big enough margin.

 

 

[Spartan09]

Thank you for your suggestions @strykerles and @Adolf Hamster. I will give the options you have listed.

 

and thank you for the gearbox guide adolf, a very interesting read, though i admit the gearbox will be the last item i tinker with.....   just in case.

 

Chronoed the gun yesterday on .25s and it was shooting about 280fps =(

 

If i remove the main spring, should there be some kind of identifying mark to say what spring i have?  Or does anyone know what spring is in the gun as stock?  (Dont really want to waste time and money buying and replacing the spring, only to find out i have swapped it for the exact same rating... lol)

[Adolf Hamster]

27 minutes ago, Spartan09 said:

If i remove the main spring, should there be some kind of identifying mark to say what spring i have?  Or does anyone know what spring is in the gun as stock?  (Dont really want to waste time and money buying and replacing the spring, only to find out i have swapped it for the exact same rating... lol)

 

i wish springs had identifying marks, got a whole box of them and no idea what they all are lol.

 

normally i keep a stock of known ratings (easy enough given i'm only dealing with a target of 1j).

 

problem is it's possible for even brand new springs to be mis-marked, which is why ensuring the air seal is good before you start (because bad air seal can hide the true spring energy) and having a chrono on hand is very important.

[Lozart]

280 fps on a 0.25 is around 313 fps in real money so are you after better range or accuracy? A spring is an easy bit to change but if your issue is airseal then it's just putting a Band-Aid over an axe wound.

[Spartan09]

@Lozart im after the best range and accuracy i can get.   

next week on my days off work i will give the gun a going over to make sure i have a decent air seal before i start changing parts...

just ordered a prometheus purple, 105 spring and spring guide and a sorbothane pad for the piston when i eventually get around to setting up the gearbox and angle of engagement....   going to leave the hop unit itself alone for now, maybe change it next month when i have some more money and have tested all the other mods.

also seen this, and was wondering if it would be worth doing?  https://airlab.parts/collections/products/products/airlab-air-hop-installation-kit

also, when i chrono the gun, as i only have .25g bbs, what FPS reading should i be looking at to be equivalent of 350FPS on a .2 (to make sure im not running too hot)

taking my time though as its my first time doing any kind of teching...  and apologies if im asking simple questions, i dont want to end up messing up my main gun

[Stratton Oakmont]

Here you go, save the link

https://www.airsoftmaster.com/fps-chart-for-airsoft-guns/

 

[Lozart]

5 hours ago, Spartan09 said:

@Lozart im after the best range and accuracy i can get.   

next week on my days off work i will give the gun a going over to make sure i have a decent air seal before i start changing parts...

just ordered a prometheus purple, 105 spring and spring guide and a sorbothane pad for the piston when i eventually get around to setting up the gearbox and angle of engagement....   going to leave the hop unit itself alone for now, maybe change it next month when i have some more money and have tested all the other mods.

also seen this, and was wondering if it would be worth doing?  https://airlab.parts/collections/products/products/airlab-air-hop-installation-kit

also, when i chrono the gun, as i only have .25g bbs, what FPS reading should i be looking at to be equivalent of 350FPS on a .2 (to make sure im not running too hot)

taking my time though as its my first time doing any kind of teching...  and apologies if im asking simple questions, i dont want to end up messing up my main gun

 

So from someone who has pulled many a gearbox apart and spent many years in the engineering/commissioning world here's a quick bit of advice. Change one thing at a time. Yes, it's a ballache doing something then checking it and then taking it all apart to change the next bit but if you do more than one thing at a time you'll not know which bit either made the improvement or screwed the whole thing up. If you do the gearbox work first and get close to your intended FPS the subsequent work you do on the hop will more than likely put you over the top which means you'll have to go back and change the spring again so do the hop and airseal stuff first (especially if you intend to upgrade the inner barrel).

 

As far as the AirHop goes, it's a fancy kit to do R-Hop with. R-Hop is really only worth it on high FPS, longer range guns like DMRs and BASRs and for a 350FPS AEG you'd be better off buying a Maple Leaf rubber and nub. It'll give you 90% of the same effect for about 10% of the effort.

 

If you're going for the sorbothane pad, get the one from AirLab as it come bonded to a harder plastic pad. Sorbothane is not very tough so while it does work for cushioning and making the thing a bit quieter a naked sorbothane pad will quite quickly fall apart. If you have the Airlab one don't be surprised if it's WAY too chunky, I've had to cut mine down every time, just use a sharp knife and take your time to get it level. Alternatively use shims behind the piston head as that will not reduce your swept cylinder volume so much which will stop you losing as much power as you do with a sorbo pad.

 

Hop unit wise, if you're getting good, consistent FPS and decent groupings with the OEM one then yes, leave it be. Consistency is the key to range and accuracy though so if you're in any way unhappy with it or intend to replace it anyway, do it first along with the hop rubber. A better hop unit will hold its adjustment better and most likely improve your airseal so again, it'll affect your FPS so if you do it after the AoE/spring etc you'll have to go back and do it all over again.

 

Generally I'd suggest you go airseal > gears (clean, shim, relube with better grease) > AoE > spring. That way you're less likely to overshoot your target FPS and spend less time re-doing things.

[Iceni]

There's not a lot you can do with it.

Barrel should be reasonable 6.03, If it's aluminium then I would swap if for a steel ZCI. If it's brass leave it be.
 

https://www.ak2m4.co.uk/internal-parts/inner-barrels?manufacturer_filter=15

Hop unit should be as decent as any other plastic M4 hop, if you are wanting to play about buy another decent plastic hop unit with a barrel and leave the stock one alone. That way if your mods don't work as expected you have the untouched original ready to just drop back in. The rotary ZCI I've linked to is a decent unit, you sometimes have to slightly modify the back edge of the dial with a file to make it fit and turn nice when installed.
 

https://www.ak2m4.co.uk/internal-parts/hop-up-chambers/zci-prowin-style-hopup-chamber-plastic-m4

 

And a new rubber for it.

I'd normally recommand the prommy purple - but at £10 it's a bit expensive to learn to build a hop with.

https://www.ak2m4.co.uk/internal-parts/hop-up-buckings-nubs/laylax-prometheus-bucking-purple
 

A cheaper alternative for playing about with is the guarder 50deg - at £4 it's cheap enough to play about with and install wrongly. It's also cheap enough to have a go at a flat hop with from new.

https://www.ak2m4.co.uk/internal-parts/hop-up-buckings-nubs/guarder-hop-up-bucking-50-degrees

 

For the mainspring, If you have access to a chrono then get an M110 and have a go at cutting it down to 350fps. If you don't have access to a chrono at home then get a safe M100 spring like the ZCI.

 

https://www.ak2m4.co.uk/internal-parts/springs/zci-aeg-spring-m100

 

 

Long term upgrades should include:

A decent cheap mostfet - Xcoretech XET304u or Acetech Acemos are good starter mosfets that work well and give a decent install project with the soldering iron.
Better wire.
Deans.

If you want to move onto a high ROF 7.4v build:

13:1 gears
Decent motor - SHS HT, ZCI 16TPA, ASG 30K
Bushings
Shimming
2 tooth SS
And it'll probably be due a piston ring as well at that point.



The trouble with all that is the cost. By the time you have done the basic stuff, then done the mosfet you are already at about £60 invested but no value added to the gun. Then doing the ROF build adds even more £70+ and at that point the upgrades have exceeded the base value of the gun, and again there is no real added value there. You could save another £100 and not spend that money and get a really nice mid tier gun and have the stock nuprol as your backup and loaner to friends.

[Rogerborg]

On 15/08/2020 at 01:29, Iceni said:

If it's aluminium

 

"Tin foil".

 

 

[Spartan09]

Ok guys...   started tinkering with the gun today.

 

Started out on chrono, and had some pretty inconsistent results.  Have now streched and lubed the piston o ring and PTFE taped the cylinder head.

 

Re chronoed the gun with some .2g bbs i got from my brother, and im shooting around 243 fps.

 

I went to swap the spring for an ASG M105 and matching spring guide, but the new spring is a couple of inches longer than the stock spring (see pic below)

 

I need a little advice on how to proceed as i dont want to force the spring and break something....   have i bought the wrong length spring?

 

 

And @Iceni  not touching the barrel yet, cant afford to swap the hop unit for a rotary one at the moment,  and i got a prometheus purple with the spring, so will probably fit that once i sort out the spring issue...   and im not looking to make it a high RoF gun.

 

I was also under the impression the gun has a mosfet built in to the microswitch trigger unit, as its listed as lipo ready and i run it on 1450mAh 7.4v lipos

[Speedbird_666]

23 minutes ago, Spartan09 said:

I was also under the impression the gun has a mosfet built in to the microswitch trigger unit, as its listed as lipo ready and i run it on 1450mAh 7.4v lipos

 

Umm...no. There ain't no MOSFET in there. 'LiPo ready' is just marketing spin.

[Rogerborg]

54 minutes ago, Spartan09 said:

Have now streched and lubed the piston o ring

 

Nice, although you may want to replace it if it's not flawless.  19mm x 2.5mm, pack of 5 or 10 from eBay, £2 or so, most of the cost is postage.

 

 

Quote

and PTFE taped the cylinder head.

 

 

Well, if it works, it works.

 

Quote

Re chronoed the gun with some .2g bbs i got from my brother, and im shooting around 243 fps.

 

Oof, but maybe it doesn't work, that's low.  How's the air seal, including the nozzle?  Do you have good compression?  Test like this:

 

 

 

 

Quote

 

I went to swap the spring for an ASG M105 and matching spring guide, but the new spring is a couple of inches longer than the stock spring (see pic below)

 

That "stock" spring looks like someone has chopped it down, which might explain the low energy (or it might be air-seal, always sort that first).  Is the gun new to you?  If so, are you sure that it was actually new?  You wouldn't be the first person to be sold a returned gun as "new" stock.

 

A full length spring should be under compression even with the piston right forward.  Now, I don't personally like that very much and feel that it's putting unnecessary strain on the box, but it's the way everyone does it.

 

 

Quote

I was also under the impression the gun has a mosfet built in to the microswitch trigger unit, as its listed as lipo ready and i run it on 1450mAh 7.4v lipos

 

Nah, "lipo ready" is just marketwank.  I would want a mosfet to protect a microswitch, but I don't see any sign that it has one. Nothing to worry about, really, just stick with those batteries and you should be fine.

 

[Spartan09]

@Rogerborg

Piston O ring is in good condition, so i just streched it to get a better seal. But i will look at buying a pack of spares.

 

The cylinder head is plastic and has a moulding ridge on top. I sanded that down, and although it has an o ring, ir was still leaking at the ridge (confirmed with a soapy water test) so i added the ptfe to help it seal.

 

I tested the piston as shown in the video and i have excellent air seal.

 

The stock spring doesnt show any signs of being cut, as both end coils are identical to the end coils of the new spring.  And i am certain the gun was new to me, as i saw the shop staff take it out of a sealed box delivered to them from nuprol.

 

I had no plans to change batteries as i have had no issues.

 

Biggest question i had was wether it would be safe to cram the longer spring into the gearbox.

[Iceni]

34 minutes ago, Spartan09 said:

Piston O ring is in good condition, so i just streched it to get a better seal. But i will look at buying a pack of spares.

I normally buy 50 at a time. It's not really any more expensive than buying 2 (£3.61), 5 (£3.99), 10 (£4.14) or 50 (£5.71). It's £2 more for 48 more rings. I normally go to somewhere like simply bearings and pick 70 shore nitrile.

I then sell them to my shooting buddies at £1 for 5 if they want them. Means they cost nothing if a couple of mates grab a set.

ASG springs are fine and it looks to have the correct number of coils for that design 28ish. The shorter spring you have is more like a ZCI spring with fewer coils in a more stout wire. You can always install the spring then turn the gearbox over using a screwdriver in the bevel gear taking it back an anti reversal click a time until it either jams or shoots. Just be warned it needs quite a bit of effort to turn a gearbox in this way. If it shoots then you have a winner, If it jams then you have a problem. And the gearbox isn't wrecked in the process.

[Spartan09]

Ok, i will give it a go tomorrow.  Hopefully the spring will do the trick and wont cause the gearbox to struggle to turn over.

[Spartan09]

Well, i fitted the 105 spring, but had to use the original spring guide as the ASG one is slightly too big to fit in the box without filing it down.

 

Turned the gearbox over by hand and it doesnt lock up,  but i have noticed that the spring has deflected downward slightly (see pics)

 

Do i need to modify the spring  or is this normal with ASG springs?  Or is the spring ok as the piston will realign it?

 

Apologies if im asking silly questions, but this is my first time teching, and its on my main gun, so i dont want to wreck the gearbox.

 

I also anticipate the need to fit the airlab sorbothane pad due to the increased stress caused by the strong spring, and will look into doing that after this issue is dealt with at the same time as (trying to) fix the AoE

 

 

 

[Adolf Hamster]

Thats the spring guide not sitting right, you want to fix that.

[Spartan09]

22 minutes ago, Adolf Hamster said:

Thats the spring guide not sitting right, you want to fix that.

How can i do that?

Looking at the gearbox there is only a couple of cutouts for the bayonet "wings" of the spring guide to sit in,  and it sits in the grooves, but there is nothing to stop it from pivoting, nor is any way i can pack it out...

 

[Adolf Hamster]

once you've got it poked into the right position it should naturally sit right.

 

bearing in mind the spring guide is how the stock bolts on so once you have the stock bolted it won't move.

[Spartan09]

5 minutes ago, Adolf Hamster said:

the spring guide is how the stock bolts on so once you have the stock bolted it won't move.

 

I literally just realised this as you replied...   im an idiot.

 

I will try building the gun up and give it a test

[Iceni]

4 hours ago, Spartan09 said:

I also anticipate the need to fit the airlab sorbothane pad due to the increased stress caused by the strong spring

Sorbo isn't used to counter spring force. It's used to lower piston slap and correct AOE if needed. Personally I prefer the silent head system as it corrects AOE and adds some damping. The element silent head set is usually about £10, and replaces the cylinder and piston head. You can also build a set using AK2M4 for about the same money with the rocket airsoft stuff. It's up to you the path you take with that, If you do any modifications at all. The AOE correction isn't as big an issue as you would think, It helps, but it's not a difference you could tell by picking up a gun and shooting it, and you probably wouldn't know if you used the gun for a year without the modifications. It's more a peace of mind thing IMO.

Gearboxes are generally fine up to USA spec. So 400+ fps. The UK market runs underpowered and doesn't really need the same level of modifications.

The spring force counter is to radius the front of the gearbox where the cut out for the cylinder is. This removal of the sharp corners stops a stress fracture happening right on that corner that over time can cause the front of the gearbox to fall off. It's not an essential modification IMO unless you know the gun you have has had issues with gearbox quality, or you are planning on running a 400fps+ DMR.

It's also a modification you can not do without having the cylinder out of the gun, so it'll have to wait until you are ready to crack open the gearbox.

[Rogerborg]

2 hours ago, Spartan09 said:

I literally just realised this as you replied...   im an idiot.

 

No, you're not.  None of this is obvious until you've done it both wrong and then right.  There are no real standards, everything is approximate, and the slightest changes can make big differences.

 

Case in point, I just managed to get a quite unintended 375fps out of an M100 spring and a 229mm barrel, just by getting the air seal spot on entirely by accident.

 

How's yours looking now?

[Spartan09]

4 hours ago, Rogerborg said:

How's yours looking now?

 

Well, i am unable to test it tonight, a tiny spring on the side of the gearbox just went spinging off into the carpet after i accidentally caught it ...   4 hours of searching and i still cant find it. Nor could i find a suitable replacement anywhere in my house.

 

i will have to pay my brother a visit tomorrow and try to scrounge a spare from him....

(i know he still has all the gearbox parts from when he gutted his M4 to make an HPA build, i just have to pray hes in a charitable mood)