bb's dropping at about 80 feet.

[inch high pi]

hi all.

just after some dvice here.

i just picked up a second hand ca mp5a2. i think its quite an old one with the hop up lever at the top of the foregrip.

the problem im having is that the range is very low and the bb's are dropping to the floor at abot 70-80 feet.

ive had the gun completly apart cleaned out the gearbox shimmed and greased it, there seems to be no problem with the piston that i can see and there seems to be no loss of preassure from the gearbox.

the only thing i can think is that the hop rubber and nub might need replacing. i have taken the hop uinti apart and refitted it but the rubber seemed a bit crappy and i assume a new nub is never going ot hurt. oh also when i adjust the hop the bb's miss feed

my main question is does the rubber and nub sound like the problem?

any help or advice would be great

cheers

rich.

[The General]

Re: bb's dropping at about 80 feet.

Yes this is exactly what you would expect from the rubber and nub needing replacing.

[laurence]

Re: bb's dropping at about 80 feet.

I had a similar problem with my JG mp5 mate. Basically, The design is a bit of a cr@#py one and so when you fire it, the hop-up selector will come out of position due to vibrations and such. When you put too much hop-on, it presses down too much on the bb and thus causes misfeeds. I did two things which are as follows:
-Take the hop-up out and replace the bucking (not rubber) with the end of a BIC biro tube (just cut a little off), this will mean that you will get more hop at a lower setting as it wont flex land bend like normal rubber buckings and will also increase consistency due to there being less play than normal buckings. Then put your gun back together.
-Secondly, load your mag up with the weight of bb that you use the most, adjust and hold it in place with your hand. Fire off a few shots and carry on adjusting and holding in place till you get to your desired hop-up setting. WHen the setting has been reached. Get some electrical tape, take off the hanguard, and wrap the tape around the gun so it holds the hop-up adjuster in place. This will mean that your hop will not move at all, and you will get consistent hop-up without it being shaken out of place.

hope this helps

*IF you want you can replace the rubber to a new one as the one in it may be old, but its not necessary

[inch high pi]

Re: bb's dropping at about 80 feet.

cheers guys.

ill pick up a new rubber and nub (ill try the bic trick too).

i also took it apart again after posting and used a tiny srping washer on the screw that holds the hop lever and tightend it till it had a good resistance that solved the problem of the hop moving about on its own.

i also whipped the barrel back out gave it a good cleaning with silicone (forgot to do it the first time) stuck it all back together and it seems a lot better

the hop is def working as i can get the bb's to fly up at about 90-100 meters by adding too much and level off if i get it just right.
only thing is because id just siliconed the barrel the bunchings were all over the place.

i do think a new rubber would do the world of good tho.

[inch high pi]

Re: bb's dropping at about 80 feet.

ah also one more thing

like a lemon i cant remember how i put the cylinder back together but

there is a square cut out on the side which i thought a bit odd but i was wondering!

when putting the cylinder back together i assume the cut out would be towards the back of the gearbox (otherwise it would cause a loss of compresion) am i right??

[sparrowhawk]

Re: bb's dropping at about 80 feet.

yes towards the spring

[inch high pi]

Re: bb's dropping at about 80 feet.

cheers i took it apart last night just to double check and add a bit more grease as i think i was a bit tight and the cut out is towards the back of the gearbox.

one more thing doe anyne know what the use of the cut out is for? to lower fps or something?