M4 Upgrade Question for a novice

[airplaneman]

Well I was looking at the G&P boxes as well as a J.G. one. I was leaning towards the JG once since it already had upgraded bearings, then I was going to add a metal spring guide and cylinder head, to start. If I went with the G&P one I'd end up swapping out more parts. Basically I want 430+, preferably 450+ fps. I currently have a high speed motor, and a decent battery pack (the specs elude me at the moment), so all I really need is a decent mechbox I think.

Thoughts?

[Maethori]

Here's a few comments:

Of those two choices G&P is definitely higher quality. JG isn't too bad but there's more of a hit-and-miss chance of getting decent quality. But (as far as I've seen) good JG quality will never match up to G&P quality. Stock G&P shouldn't need more parts changed out than JG. The bearing/bushings that come with it should be fine. Of course without knowing the specific gearboxes you're looking at I can't make perfect comparisons.

At a lot of fields over 400fps is not allowed unless it's a BA rifle. If that's not a problem for you then all you really need to upgrade is an m120 spring. I would think stock G&P should be able to handle that, though really I'm just going by their pre-built guns (which are upgraded for importation to 430fps) and not separate gearboxes. That said, upgrades won't hurt as long as you make sure the quality is uniform and don't create fail-points that are more expensive to fix. One small downside to G&P is that their motor connections are proprietary and would need to be changed out unless you have a G&P motor. As for upgrading to a metal cylinder head, did you mean piston head? (I'm also guessing here that metal referred to both spring guide and piston head.) Either way, that is usually unnecessary. Sure it's more durable, but it does create more work and stress for the whole system.

Hopefully that helps (and didn't give false info). I'm definitely not the most experienced in building guns here, but I try.


EDIT: Ah, on my phone I didn't see the links to the gearboxes....my bad.
So to add to my comments.... Both of those gearboxes seem to have bearings, and neither of them says "upgraded bearings" like you indicated. (Did you find other info on these elsewhere as well?) The G&P gearbox seems to have the regular motor connections, so replacing that is a non-issue. Just looking at what the two say, I would still recommend the G&P. It may or may not be able to shoot 400-420, but I believe it would be a better base to work off of. It's also a bit cheaper... I just built a gun using a G&P gearbox from a pre-built gun. All I did was give it an S120 spring and a motor to match and it consistently fires between 417-422fps, but usually between 419-421fps. I'm just using an old, stock CA hop-up and inner barrel and it shoots amazingly well.

[L473ncy]

Just putting it out there you're probably not going to be able to pull the spring if you've got an M130 and a high speed motor with standard gears.

At minimum you should probably have a standard speed motor and standard gears if not a high torque motor or high torque gears. Motor is easy to do since it's a relatively simple "drop in" whereas gears are a bit more involved but if you're in the gearbox anyways might as well do those while you're doing the spring and spring guide.

[m102404]

Take a good look at the G&P M120 Complete mechboxes as a starting point. Very good bang for buck. Same with the King Arms complete mechboxes.

On both, I would swap the piston body...if not the piston body and piston head. The normal reshimming and air-leak checks would be done as well.

For 420-ish...a M120 spring would do...for 450-ish you're into the M130/140 springs. I'd be looking at a torque gear set (which some of the complete mechboxes have already) and a G&P M140 motor.

[spike9]

Not to be a critic, but I though you said the gun was in pretty good shape and shooting 430-450 fps. Between buying a new gearbox and internals, a new upper, a new front end and a crane stock wouldn't you be better off just buying a new gun? I mean the only thing left that's going to be orginal is the lower receiver, barrel and pistol grip. Just my 2 cents worth.

[Maethori]

Originally Posted by spike9

Not to be a critic, but I though you said the gun was in pretty good shape and shooting 430-450 fps. Between buying a new gearbox and internals, a new upper, a new front end and a crane stock wouldn't you be better off just buying a new gun? I mean the only thing left that's going to be orginal is the lower receiver, barrel and pistol grip. Just my 2 cents worth.

Not a bad point.

Essentially what you are looking for is a stock G&P gun. You can get one that is almost exactly what you are looking for in all areas.

[MaciekA]

The least expensive G&P gun you can find from a retailer is the Canadian Carbine (C8). Other than that, there are occasionally good deals in the AV for sale section. Note that a used one might actually be a better deal due to the fact that it might have had upgraded gears/piston, which are the parts people usually replace in a G&P as a first order of business

[airplaneman]

Originally Posted by Maethori

Here's a few comments:

Of those two choices G&P is definitely higher quality. JG isn't too bad but there's more of a hit-and-miss chance of getting decent quality. But (as far as I've seen) good JG quality will never match up to G&P quality. Stock G&P shouldn't need more parts changed out than JG. The bearing/bushings that come with it should be fine. Of course without knowing the specific gearboxes you're looking at I can't make perfect comparisons.

At a lot of fields over 400fps is not allowed unless it's a BA rifle. If that's not a problem for you then all you really need to upgrade is an m120 spring. I would think stock G&P should be able to handle that, though really I'm just going by their pre-built guns (which are upgraded for importation to 430fps) and not separate gearboxes. That said, upgrades won't hurt as long as you make sure the quality is uniform and don't create fail-points that are more expensive to fix. One small downside to G&P is that their motor connections are proprietary and would need to be changed out unless you have a G&P motor. As for upgrading to a metal cylinder head, did you mean piston head? (I'm also guessing here that metal referred to both spring guide and piston head.) Either way, that is usually unnecessary. Sure it's more durable, but it does create more work and stress for the whole system.

Hopefully that helps (and didn't give false info). I'm definitely not the most experienced in building guns here, but I try.


EDIT: Ah, on my phone I didn't see the links to the gearboxes....my bad.
So to add to my comments.... Both of those gearboxes seem to have bearings, and neither of them says "upgraded bearings" like you indicated. (Did you find other info on these elsewhere as well?) The G&P gearbox seems to have the regular motor connections, so replacing that is a non-issue. Just looking at what the two say, I would still recommend the G&P. It may or may not be able to shoot 400-420, but I believe it would be a better base to work off of. It's also a bit cheaper... I just built a gun using a G&P gearbox from a pre-built gun. All I did was give it an S120 spring and a motor to match and it consistently fires between 417-422fps, but usually between 419-421fps. I'm just using an old, stock CA hop-up and inner barrel and it shoots amazingly well.

I misread the upgraded bearings, I meant to say spring I think. What would I have to add to allow myself a M120/130 spring, aside from the spring itself? Gears? And I did mean metal cylinder head, I had a plastic one before and the tip broke, so I was hoping buying this would prevent that. And yeah, I did mean metal spring guide as well. I read that it would reduce friction in the gearbox, and thus increasing fps. I also worry that adding a more powerful spring would add stress to the spring guide. Perhaps I will buy that G&P, but I was skeptical because of that 90% power in the description. I don't necessarily know what it means, but I saw others at 150% power... any input on that?

Originally Posted by L473ncy

Just putting it out there you're probably not going to be able to pull the spring if you've got an M130 and a high speed motor with standard gears.

At minimum you should probably have a standard speed motor and standard gears if not a high torque motor or high torque gears. Motor is easy to do since it's a relatively simple "drop in" whereas gears are a bit more involved but if you're in the gearbox anyways might as well do those while you're doing the spring and spring guide.

Sorry, I thought it was high speed, it's actually a high-torque motor. You think the high-torque motor would work with an M120 or M130 spring without changing the gears?

Originally Posted by m102404

Take a good look at the G&P M120 Complete mechboxes as a starting point. Very good bang for buck. Same with the King Arms complete mechboxes.

On both, I would swap the piston body...if not the piston body and piston head. The normal reshimming and air-leak checks would be done as well.

For 420-ish...a M120 spring would do...for 450-ish you're into the M130/140 springs. I'd be looking at a torque gear set (which some of the complete mechboxes have already) and a G&P M140 motor.

Do you have any links to these parts? I can't seem to find them at the stores I've been shopping at. I linked the G&P box which I was leaning towards, and figure I could just upgrade the spring to M120. If 450 meant changing out the motor and gears, then I'd just settle with 420.

Originally Posted by spike9

Not to be a critic, but I though you said the gun was in pretty good shape and shooting 430-450 fps. Between buying a new gearbox and internals, a new upper, a new front end and a crane stock wouldn't you be better off just buying a new gun? I mean the only thing left that's going to be orginal is the lower receiver, barrel and pistol grip. Just my 2 cents worth.

Its in good shape, and it was shooting at that, but I've lost my gearbox, so now that is all I really need to change. The other parts were just personal taste. I've found a way to mount rails to the outside of my hand guard which mean I can keep the batteries in the front. That would save me from buying new rails, stock and batteries, meaning all I would need is a new upper. And besides, to change out everything I've mentioned looks like it'll cost around $2-300, whereas buying a whole new gun would run me almost $700. If I could sell my current gun with a new gearbox for $4-$500, then sure, I would do it, but I don't know where to get my gun appraised.

Originally Posted by Maethori

Not a bad point.

Essentially what you are looking for is a stock G&P gun. You can get one that is almost exactly what you are looking for in all areas.

Yeah, that is basically what I'm after, but I don't want to drop $700 on a new gun...

Originally Posted by MaciekA

The least expensive G&P gun you can find from a retailer is the Canadian Carbine (C8). Other than that, there are occasionally good deals in the AV for sale section. Note that a used one might actually be a better deal due to the fact that it might have had upgraded gears/piston, which are the parts people usually replace in a G&P as a first order of business

Not looking for least expensive, I want something decent. I just don't want to buy a whole new gun if I don't have to. I emailed a couple people about getting AV'd, so hopefully that happens in a few days and I can cruise the classifieds.

Thanks for the suggestions guys! Sorry for the huge post :P

[MaciekA]

Not looking for least expensive, I want something decent. I just don't want to buy a whole new gun if I don't have to. I emailed a couple people about getting AV'd, so hopefully that happens in a few days and I can cruise the classifieds.

Thanks for the suggestions guys! Sorry for the huge post :P

All the G&Ps you will find retail in Canada are going to have exactly the same build quality and nearly identical gearboxes across the board. The differences are in the particular replica you want. That's where the prices start to shoot up quickly just to get something more "rare" looking. If you were looking to base a custom rifle off of anything G&P, the C8 was my recommendation because it gets you a G&P CNC'd receiver and gearbox even if you replace everything else, and getting a receiver is going to be the hardest thing to find.

[airplaneman]

Originally Posted by MaciekA

All the G&Ps you will find retail in Canada are going to have exactly the same build quality and nearly identical gearboxes across the board. The differences are in the particular replica you want. That's where the prices start to shoot up quickly just to get something more "rare" looking. If you were looking to base a custom rifle off of anything G&P, the C8 was my recommendation because it gets you a G&P CNC'd receiver and gearbox even if you replace everything else, and getting a receiver is going to be the hardest thing to find.

Oooh, ok. I see what you mean now.

[m102404]

Go to airsoftparts.ca....go to AEG Internals...Gearboxes.

Jugglez (owner/operator) will help you out with whatever you need. He also gets a good preview of what coming down the pipe...so can give you a heads up to try something different.

He's got a good relationship with a number of Gun Docs...so there's continual feedback on what's working, what's not, what to focus in on.