A&K M4 Problem.

[TAN]

Hello,

I am a new member of this forum. I do not find a thread for introducing oneself, otherwise I would have introduced myself properly first before start asking questions. Hope you don't mind.

I recently purchased an A&K M4 R.I.S. gun from an online store (http://www.koongmintoy.co.kr/shop/shopdetail.html?brandcode=049000000055&search=&sort=order) residing in Korea. The gun is KPS certified thus its fire power must fall under the safety limit.

On the sellers website, I found a statement saying that "the hop-up rubber has been removed". I, then, order the hop-up rubber and installed it, and find that the muzzle speed has increased considerably.

Since the playing limit is under 300 fps, I would love to hear a few tips on how to get the gun down to 300 fps. Albeit, having no chronometer with me now, I am not even sure if it is even over 300 fps. Perhaps anyone have experience with this gun?

Thank you in advance. Hope to join you all soon in the next game.

[krobinson103]

Bring it to a game and we can measure it. As a test get a coke can and shoot it (empty is better of course). If goes through one side and doesn't do much to the other you are safe :)

If its not a spring change is easy enough to do.

[ackme]

No hopup rubber? That would render the gun pretty useless. The backspin from the rubber keeps the bb going straight. You need to buy an M85~M90 spring. That would fix it up. THIS SITE (http://www.mechbox.com/) has details on how to change it. Most stores will sell them. I found that the Korean brands are stronger then they should be, prometheus and system springs are best.

[Righteous]

It sounds to me like they took the hopup rubber off to break the air seal and lower the velocity. What is KPS certification?

[TAN]

@Krobinson103: Thanks for the coke-can test tips. I will try that an report it back. I hope I do not have to downgrade it as I like the gun the way it is now.

@Righteous: yes, exactly that. The hop-up rubber was removed to "power brake" the gun. KPS certification is to certify that the items has passed a certain test that make it safe for consumer use. I am not so sure about this though.

@Chris: As of now, I am not yet sure if the gun is over the limit. May be I can bring it to our next game and have it chrono-ed. Thank you for the great info.

One more thing, anyone know what is this black small plastic for?
http://i102.photobucket.com/albums/m100/suryanto_tan/m4ris.png

[Righteous]

It looks like the front sight adjustment tool. Either that or a tool to adjust the hopup. That little dial under the dust cover on the upper receiver can be a pain to turn. If it is a new A&K then it probably shoots in the 370-410 fps range once you put the hopup rubber back in based upon the guns they sell in the US. They are probably exactly the same. You'll have to change the spring to get back below 300.

[TAN]

I tried it on the front sight, and it fits perfectly. So that must be it.

Thank you.

[warblade]

hi TAN... fellow A&K owner (A&K M933 full metal) here. you are correct, that black little plastic is for adjusting the front site. based on the picture that you posted it looks like a 1st generation plastic version of the m4 RIS, if thats the case then then your fps should be stock at 320fps. Latest release of full metal A&K peaks at 440fps out of the box.

[TAN]

Hello Warblade,

Mine is also a full metal one, but I have no idea what its series is.

I have tested its power on a coke can, and it did not even penetrate one side. I hope that means it is somewhere under 300 fps. :) But I will have it tested in the next game.

Does your gun also have problems like it shoot out two bb's instead of one when used in semi mode?

How about the magazine, is it work perfectly fine for you? After fully wind the magazine, I only get to fire a few shots before it jammed. And I will have to tap it to make it work back normally. I am considering to get new magazines, but wonder if I should get normal type or high capacity ones.

[warblade]

i heard that first generation A&K have no logo markings on the gun. i have no problem with 'double feeds' and my magazine works fine. however, i found out that my 300 round hi-cap mag is not enough during game time and its awkward to change magazine while in the middle of a fight. i bought a 850 round motorized double-mag with dummy bullets and it fits fine with the gun. i'll be posting pics of my baby soon. hope you enjoy your gun as much as i do with mine. :)

[TAN]

I know I will. I think the gun just need a small fix here and there. Other than the problems I mentioned, it is beautiful piece. I love it. :)