Classic Army M15 Hop-Up "Backing Off" fix

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Classic Army M15 Hop-Up "Backing Off" fix

Postby prometheus » Mon Mar 26, 2007 8:11 pm

As I stated in my CQB review, the Classic Army M15's have a problem with the hop-up backing off over time. It is more common issue with upgraded guns, but even a stock m4 will do it over time. so here is a quick fix guide for the problem. Once fixed, it will not move on its own.

1st-you want to locate the pin that holds the upper receiver onto the lower. described as the front pin in the image below. remove the screw holding the pin together with a size 2.5 Allen wrench, and push it out the other side.
Image

2nd-With the mag removed, hold the stock/tube with your right hand and the front assembly with your left. with your left thumb push on the mag well so to bring the upper receiver forward. this is a little tricky because if you are not careful you can overextend the spring connected to the charging handle. Even being fully aware of this I still did it the 1st 2 times so don't beat yourself up, a replacement is cheap, or just use a rubber band. you have to slowly pull the two apart until you can bring the charging handle over the nub on top of the GearBox. now pull the upper off of the lower, taking note as to where the mock bolt is sitting under the ejection port cover, possibly still being held into place by its magnet. don't loose the bolt catch either, it may just fall out with the upper and lower separated.
Image

3rd-remove the hop-up and inner barrel by simply pulling it out the back of the upper receiver. now take a small phillips head driver and remove the screw holding the adjustment wheel down.(shim in image)
Image

4th-place what ever size GearBox shim works (.05 most of the time) under the screw and replace it into the hop-up unit. Image

you have fixed your hop-up unit, now just reverse the steps to get it all back together. You will see that there are two slots down in the front assembly that the hop-up will slide down into.




The problems not getting the politicians out of war, its getting the war out of the politicians.
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