Length of upgraded spring?

[Janz99]

I was wondering if someone had an upgraded spring kicking around, if they could measure the length of it for me?

Im having an issues with my gun pulling back an s110 or s120 in my dpms m4, and im wondering if the spring is just to long with the bearing piston head and bearing spring guide in order to compress it far enough.

Thanks
Ryan

[surebet]

What battery do you have?

[Amos]

Problems that may be causing this:
Too weak of a motor
Too small of a battery
Very bad shimming
incorrectly labeled spring

I'd recommend something to the tune of an 8.4 3600 MAH large battery, or a 8.4 1500MAH mini battery (Choose the large over the mini if possible)

What brand M120 are you trying to pull?

Did you to the upgrade work yourself or did you have a guntech in Winnipeg look at it?

If you need any help, I'm located in Winnipeg and I've got a good reputation for building solid preforming guns

(If you want references PM MrPrimeTime, Stutlc, Bootyourface, TGAAllday, Maverick0, Zekk05, GiddenVonJigger {I think that's how he spells it..})

[Janz99]

Im using an 8.4v 1100mah battery that came with the gun. I did all the upgrading work myself, but im very confident in my mechanical abilities.

Ive double checked the shim job twice now to make sure it wasnt to tight when the case is bolted up. I can sping the gears freely with my fingers (1-2 revolutions with a decent spin).

Ive tried both my modify S110(420fps) spring and an S120 spring(450fps) without any luck. Ive put the stock spring back in and it works fine. At this point i think the stock motor just doesnt have the grunt to pull back a stiffer spring.

Amos- Shoot me a PM with your pricing and when your normaly available to look at guns. I might have you take a look at it if you dont mind.

THanks
Ryan

[m102404]

If you're worried about the spring being too long or binding....try this.

with the spring guide, spring and piston out of the rifle, place the spring guide point up on a table. Place the spring over it and then the piston. While guiding it with your off hand...push the piston down slowly and steadily. Try it with a "soft" stock spring first...to get the feel of it. (Don't lean your face over top of it in case you slip...d'uh. but i mention it for good reason)

The open end of the piston should end up flush with the table (the tabs of the spring guide might be in the way...but you get what I mean). Just shy of that is where it'll be when it's fully retracted (i.e. the most the spring will be compressed in normal usage). The inside of the piston shouldn't be binding on the spring as it compresses...it'll rub, but it shouldn't bind. Watch the end of the spring against the spring guide (especially if there's a thrust plate for a bearing setup). Make sure the very end of the spring isn't spreading out...if it is, it'll stop the piston from retracting enough. Never had that issue with Modify springs...not all bearing spring guides are exactly the same.

But if you have multiple good springs that it won't pull...I suspect the motor, or wiring. Try adjusting the motor a bit or swapping it out. Fully charged batteries of course.

[Janz99]

I'll try compressing the spring like mentioned. Ive tried multiple springs and 3 different batteries without an luck.

[Amos]

Originally Posted by Janz99

Im using an 8.4v 1100mah battery that came with the gun. I did all the upgrading work myself, but im very confident in my mechanical abilities.

Ive double checked the shim job twice now to make sure it wasnt to tight when the case is bolted up. I can sping the gears freely with my fingers (1-2 revolutions with a decent spin).

Ive tried both my modify S110(420fps) spring and an S120 spring(450fps) without any luck. Ive put the stock spring back in and it works fine. At this point i think the stock motor just doesnt have the grunt to pull back a stiffer spring.

Amos- Shoot me a PM with your pricing and when your normaly available to look at guns. I might have you take a look at it if you dont mind.

THanks
Ryan

I'm free all week, if you want me to give it a quick once over I wont charge you anything, but I'm normally $5/15m ($20/H) (first hour is $20 regardless of time)

Your gear ratio may be wrong for what you're trying to do, you can remedy that with new gears... or a better motor / bigger battery.

I have to ask though... Did you upgrade the mechbox shell? I can't see the V2 shell lasting that long with a 420+ FPS spring

[Janz99]

No i didnt, its a factory shell that has "SG" marked on it. Right out of the box the gun was shooting 370-380 fps with .2's. I didnt think an additional 40fps would cause that much of an issue.

Thanks for the heads up amo's. Im going to try a different motor i think, and if that doesnt work then ill give you a shout!

Thanks
Ryan

[Crunchmeister]

Yes, an additional 40 fps will blow that mechbox apart. Actually, it's on a short-timer schedule with anything above 350 fps (including the stock spring). Anything over 350 fps with a V2, you want a reinforced shell.

[CPT Spork]

hmm.. my DPSM M4 stripped out its gear box with the stock spring..

[SHÖCK]

length is variable. It depends on the stiffness of the coils under compression. Airsoft surgeon springs are 60% of the length of regular springs because they are already compressed and super stiff to avoid post-compression issues.

A mad bull, prometheus, guarder, etc. 110 or 120 spring would be the same length as a stock spring. Just with stiffer coils. Length of spring is NOT your problem.

Having done this many times, the answer is that your battery is too weak. With torque up or helical gears and a stronger motor, your battery might be able to pull it a few times, but as I just worked on an AUG last night that went from stock 280 FPS spring to a 420 FPS spring...even 9.6v minis were not powerful enough due to weak discharge rate and I slapped on a 20C lipo (both 7.4v and 11.1v lipos both rated at 20C) which did the job with no problems with stock metal gears and stock TM motor.

[Styrak]

Originally Posted by Janz99

Im using an 8.4v 1100mah battery...

Ive tried both my modify S110(420fps) spring and an S120 spring(450fps) without any luck.

Not big enough of a battery for that heavy of a spring.

[BeAcH]

You should be running torque up gears for that sp120 spring and a large battery something like 9.6v 3600 mah and a hefty motor such as a EG1000 or something else that has good torque.....systema magnum or G&P 120 or 140, then you will be set.

Why not just keep your Dpms m4 stock, perfect for cqb games and invest in a good quality m4 such as a G@P, TM, CA.....

best of luck

[Janz99]

Well, the modify springs are about 3/8-1/2" longer then the stock springs. Ive also tried two different batteries, and niether of them would turn over the spring as well. Ive also tried going back to the stock spring guide to see if that extra bit shorter would allow it to turn over and it didnt.

I really think its the motor at this point?

The reason i have even been trying to upgrade the gun, was to try and make it a bit more accurate. The added fps was just a bonus. I tried to use the gun with the stock spring now, but because i had to trim off the hook on the end, and cant use the factory aluminum spacer that attaches to the piston head, the gun seems like its LOBBING in the BB's. They dont shoot a straight tradgectory (sp) anymore. It was actually better when it was stock then it is now with the bearnig piston head, bearing spring guide and nozzle.

Ryan

[surebet]

I'm still calling battery. What are the sprcs and brands of all of them?