G&P Firing issues

[Devinian]

ok so iv tryed everything, and now i give up..

so my G&P m4a1 full metal with metal hop up, replaced tapet, new sytema air nozle, and metal G&P gears. also, one of those metal front ends.

it fires ok in single... way too weak for a 190 spring

on full auto it seems to fire once fine and then it either miss fires or fires a lob shot (which goes about 10 ft).:rrr:

i freakin love this gun and cant seem to detach myself from it so im determined to fix it. anyhelp would be good and realize that iv tryed just about everything so keep the ideas comming

M4A1 45 glock small.jpg[IMG]
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[mcguyver]

Turn your hop-up all the way off. Spray a shot of silicone oil down the barrel and swab it out until the patch of paper towel comes out clean and clear.

Then reset your hop-up with several test shots using semi-auto. See what happens.

If problem persists, re-install stock G&P nozzle but remove the airseal o-ring. You will lose a few fps, but the G&P nozzles does make a pretty good seal with the hop-up.

If problem still persists, take the gun to a priest and have it excorsised.

[Devinian]

ok tried the cleaning method and nada, old stainless nozzle is back on, checked cylinder compression (excellent), noticed outerbarrel was slightly twisted (fixed). Tryed TM mags G&P mag and Star Mag

On semi it fires about every second shot, penetrates one side of pop can. on full auto it fires about every 3 or 4 th shot. the Gun Fires Extreemly fast and might be the issue. About as fast or faster then a Star L85A2.

I must say that this gun did in fact work with its current setup when i bought it.

Thanks for all your help.

Lorant

[Devinian]

Bump

[CDN_Stalker]

190 spring, ouch! I have a 170 spring for my M24, it shoots 550fps. Even though the G&P is reinforced, it still has the same flaws as the other V2 mechboxes, will break sometime.

Sounds like yo uhave an airleak somwhere, possibly in your hop up area. Might have installed incorrectly.

Also heard that Star mags dont' feed right in G&P Armalites. Doesn't explain the issues you are having with other brand mags, but lube your mags inside. put oil in the top, load a bunch of BBs to spread the oil throughout, then unload inot a bowl, then reload the same ones. Do that for all mags. Some mags tend to jam up slightly and will misfire, then after a couple shots they load and fire, then jam up a bit as well.

[Devinian]

sorry not 100% about the spring power. I do belive its stock so its probably less. About the hop up, I have two metal one piece hop ups i have tryed them both. dosn't seem to make a difference. I have tryed brand new tm mags in the gun and still miss fed but i will try to clean and lub one up and see if it makes a difference.

How would i go by slowing down the nozzle? It might be moving too fast to allow bbs to enter the chamber.

[CDN_Stalker]

Only way to slow down the nozzle is to use a lower voltage battery, but your rate of fire will suffer. Still, the nozzle's forward speed is dictated by the tappet spring.

If your hop up units are Guarder, I've had and have been told they are crap and cause all kinds of problems.

[Flatlander]

I just fixed a buddies m4 with what sounds to be the same problem:

- Semi: every second shot fires a bb (sometimes worked fine)
- Auto: very spiratically shot a bb - every 5th bb or so.

Now his gun was really weird, some times the feeding issues would be there and some times it would go away for some reason (more often then not it was there). What I found was that the nozzle was a bit too long. I turned the gun upside down and looked into the hopup unit and saw that the nozzle would stick out ever so slightly, usually stopping the BB's from loading. I sanded down the nozzle tip a tiny bit and that has seemed to solve his feeding problems.

[The Saint]

If one needs to "slow down the nozzle", install a sector chip. It'll not only pull back the nozzle earlier, but also delay the release of the nozzle, effectively slowing it down.

[Sha Do]

Originally Posted by CDN_Stalker

190 spring, ouch! I have a 170 spring for my M24, it shoots 550fps.....

Hmmm.....a 190% or SP190 AEG spring should get him 400 fps with 0.20s....and an M170 would get you over 550 fps. I know how much you hate PDI springs STALKER, and I don't know your Laylax (?) springs that well......LOL

Either way, our problamatic friend here does indeed have a hop up seal issue, and STALKER has a very well tuned M24.
Make sure you are not over tightening the stock bolt that runs into the back of the mech box. If you over tighten it you'll pull your mech box back enough that you could/will end up with mag release problems, as well as a poor hop up seal and feeding issues.

SHA DO

[Devinian]

thank you all! Ill be trying all these possible solutions tonight... leaving the sanding one till last.

one more question for now. what is a sector chip?

Lorant

[m102404]

A sector chip is a little metal disc that installs on top of your sector gear. Some are round, others are "blob" shaped. It essentially makes the nub on your sector gear, the nub/pin that pulls the tappet plate and nozzle back, a different diameter and thus holds the nozzle open longer. From my understanding, it's for high ROF guns that need a bit more time for bbs to feed.

I've run into the "nozzle slightly protruding into the feed tube" as well. On one occasion, disassembling and reassembling seemed re-align things (it may have been a different amount of tension on the rear stock screw in the second assembly, as Sha Do described). On another occasion, I ended up swapping nozzles. Another time I put a thin, rubber o-ring in-between the hopup and the mechbox to push the hopup forward a hair (I thought it might cause an air-leak, but it didn't?!?). I also reset a barrel a hair more forward with a shim or two (thought that I'd get an air leak there as well, but didn't) to "clear the feed way". Clone bodies mixed with a variety of mechboxes and hopups can really suck sometimes...

If you're getting intermittent feeding, it might be prudent to check that your mags are releasing bbs properly/consistently when inserted and locked in the mag well. Insert mag, shoot a couple of shots single fire. Tug down on the mag, while it's still locked in, and try some more shots. If you get any "blanks", hold the mag up (and/or tip the base of the mag away from you). If you hear the "zipppp" of bbs being released, the feed tube of the hopup may not be pushing the magazine's bb retention "hook/nub" far enough out of the way to allow the bbs to feed. Seems to be a common issue with KA mags recently. There are several things to look at to fix this...but that's another story...

Best of luck getting this fixed!

[CDN_Stalker]

Originally Posted by Sha Do

Hmmm.....a 190% or SP190 AEG spring should get him 400 fps with 0.20s....and an M170 would get you over 550 fps. I know how much you hate PDI springs STALKER, and I don't know your Laylax (?) springs that well......LOL

Either way, our problamatic friend here does indeed have a hop up seal issue, and STALKER has a very well tuned M24.
Make sure you are not over tightening the stock bolt that runs into the back of the mech box. If you over tighten it you'll pull your mech box back enough that you could/will end up with mag release problems, as well as a poor hop up seal and feeding issues.

SHA DO

Even more tuned now (since I down graded it with parts I had lying around to 440fps for the Muskoka game, it went fubar on me when chronying, got 217 and 271pfs out of it, Barf said "That's not right!" "Ya, no shit", next couple days I got it all running strong, turned out the cylinder/pistonhead were suddenly no longer giving any compression), it's damned sweet. Have only tried my 170 once to chrony and got 540-500fps, but mostly I use my 150 spring and have it at 490fps now.

Good info regarding the not tightening the stock screw too much though, common sense and one I never considered. Rather fine line there if yo uask me though, not enough the stock wobbles, too much and the mechbox *might* pull away. Glad you posted it, wish there was an ideal torque setting to go by. I tend to give a good 'snug' on all screws and bolts I install (including those on the aircraft I work on), get it so it doesn't turn anymore, then one little partial turn (a tweak) past that. Tight enough to not come off by itself, not tight enough to strip/break the screw/bolt yet can be removed without power tools.

[Devinian]

ok update time.

I noticed that the nozzle was infact visible when the gun should be loading, when i pulled on the hopup unit it was able to move back and forth so I put a O ring on the black one pice hopup, where it connects to the mechbox. this stoped the movement and the nozzle wasnt visible anymore.

the gun accually worked for almost one mag. It didnt have enough power to break through one side of a pop can. and eventually just started getting jammed. Im assuming that it dosnt have enough power to push the bbs through the hopup unit because i could push them through with a pen.

I removed the oring and tryed firing it and, yup it didnt work, just jams up. so i put a o ring on the other side of the hop up unit. ( slid it on the barrel) this also tightened it up against the gearbox. but it didnt seem to improve the situation.

Im totally lost now. Any Repairmen in calgary? I think i need a professionaly to take a look at it.

[CDN_Stalker]

I don't suppose the front spring on your hop up unit is missing/damaged/too short, eh? It pushes the hop up unit back to mate up with the mechbox. If the spring is there, take it off and pull it to stretch it a bit, then put all back together and try again.