King Arms body+wobbly Font end? Possible strange threading?
 

Well, I have been working on and off on a scratch built AR for a while now, however, I am having serious issues getting my rail system to work right. It is a Huang DD MK18 rail system, on a King Arms stag-arms metal body.

No matter how much i tighten the delta ring, the RAS doesn't seem as solid as it should be, neither does the outer barrel.

I noticed this image on the KA website.

http://www.kingarms.com/productimages/ka-m4-20-S04.jpg

See where it says "Perfect fit with M4 RIS"?

Does this mean I can't use airsoft front ends?

Will the G&P versions work? I know they use different threading too.

Thanks a lot,

Ben

Not the answer you were looking for but mid-low quality front end plus good quality body maybe the issue. The "Perfect fit with M4 RIS" probly means with their own made RIS.

okay, thanks.

So just pick up a higher end front end?

Any brand in particular?

I guess King Arms would be an obvious first choice

If you want to ensure the best fit.. Definitely get King Arms. Matching brands is always a good idea, even with externals. They make their own products mesh perfectly together.

Well before you go and invest more money lets examine your situation some more.

When you initially stated that it did not feel as "solid" as it should be can you perhaps expand on that? Do things wobble? Do things flex ( oh god please don't tell me things are bending randomly) Does the rail not line up with the receiver? Please clarify your situation,

I think you should buy a gas block while your at it. Maybe even a gas tube.

hint hint

Well, first off.. did you try adjusting the spacers?

You should have gotten a set of small metal discs with your front end, which are used as spacers between the barrel and receiver. This allows you to space the front end properly (most people just throw on their RAS, but properly done the rail intervals should be continuously spaced between the receiver and front end).

Drake makes an excellent point that I should have brought up initially. I apologies Im kind of off today. Check those spacers. There should be absolutely no play for the outer barrel to move forward and should not wobble from side to side. You may have to play around a bit before you may find something kosher.

Both the rail system and the outer barrel are fairly solid when first installed. No wobbles unless i really try to bend them, however, after a day of playing, not specifically baning the front end around, but just standard wear & tear, both the outer and RIS are a little loose. Sorry if this is vague, its a little hard to explain.

This is especially worrying as the movement in my outer is causing my hop-up unit to move slightly, giving me feeding issues, and airseal issues

Yea, i know, Ill pick up both with my new RAS system.

Forgive my ignorance, this is my first AR platform, does the faux gas block/gas tube actually add any stability?


Nope, these were not included in the package.

You may need some of those, your RAS/RIS should have come with them, although I'm not surprised that you didn't receive any of them. These spacers should help out a fair amount.

A bit, it's basically like a bar connecting the front of the barrel to the receiver, parallel to the barrel. But I don't think it would be sufficient to remedy your current problem.

I really think you need those spacers/shims in space. I've never been able to tighten down a barrel nut enough (even with a real steel armorer's wrench) to get a solid fit without those spacers installed (I'd describe the feeling as "the nut is as tight as it'll go, but the barrel is still loose").

Thats bang on where I am right now.

Any idea where i could acquire some?

My rail system didn't include any.

yup, Drake's got that one right, you are lacking the shims that goes in between the Delta Ring and the outer barrel.

I have a few extra but I may need them. So I measured it for you, see if you can find any online or in any hardware store

3cm diameter. The ring is 2mm wide. These shims I got with the King Arms Troy MRF rails.
http://img442.imageshack.us/img442/8929/shimring.jpg

Awesome!

Thanks so much, thats perfect.

How exactly do I install them?

Is it like gearbox shimming? Add one at a time until it works? or just throw 4 or 5 on there?

I believe I may have some shims from a front end kit I got a while ago, pm me if your interested

yup that's how you do it. add by small portions and the usual "trial and failure" method. For me, I only needed 2 shims, but everyone's is different, just like gearboxes.

Alrighty, Brodie_BHD as been kind enough to send me a few extra's he had. Ill report once they arrive and have a chance to try em out.

so basically this wobble problem is remedied by pressing the barrel down by way of the fake gas tube?

the gas tube only stabalizes the barrel, the shims as pictured are used to cause preasure which makes a tighter fit, which reduces or eliminated wobble