ejector lever on MP5 not allowing charging

[ambis]

hello,

Just received a BMP barreled upper, rcm bolt carrier, and a roberts sef semi trigger assembly (links below). I cannot charge the weapon because the ejector (or possibly the ejector lever), when fully mounted to the receiver, is not allowing the bolt to clear it.

Any suggestions?

Thx!

http://www.hkparts.net/shop/pc/MP5-94-Bolt-Group-US-German-HK-90p2201.htm

http://www.robertrtg.com/hk94semiautofcg.html

[mrlonewolf]

hello,

Just received a BMP barreled upper, rcm bolt carrier, and a roberts sef semi trigger assembly (links below). I cannot charge the weapon because the ejector lever, when fully mounted to the receiver, is not allowing the bolt to clear it.

Any suggestions?

Thx!

http://www.hkparts.net/shop/pc/MP5-94-Bolt-Group-US-German-HK-90p2201.htm

http://www.robertrtg.com/hk94semiautofcg.html

Are you just hand held the parts all together?.

Is the stuff welded already?.

[ambis]

Yes, it's a barreled upper. when the gun is completely assembled I cannot charge it if the trigger housing is completely in line with the rear take down hole. However, if I give it some slack, it charges. I've attached a photo with the bolt carrier riding the ejector, outside of the gun. Should I shave the ejector lever a bit? Best I can tell that's where it's hitting because it's scuffing there.

[ambis]

Yes, it's a barreled upper, already welded, with the cocking tube, etc. I've attached a photo with the bolt carrier riding the ejector, outside of the gun. Should I shave the ejector lever a bit?

[saki302]

If something is out of spec, you may have to file down part of the ejector.

Sounds like someone who knows HKs well needs to take a look in person.

[mrlonewolf]

Nice HK stuff, most likely unissued..!!!

Don't sweat it man.

You are just not there yet.

When the times comes, please post again so we can debug it.

That being said, build it.....

[bollero]

[cpl_dan]

1) you bought from bmp, not known for quality and can be out of specs ie. weld spots or placement of trunnions or cocking tube ect..

2) your building a frankengun from parts various venders and trying to slap it together, esp on hks don't like that much.

3) Pm rocoborro, he built many from flats and knows it pretty well.

[ambis]

I know about BMP, but it's my best option. The gun cycles fine when the ejector lever is removed, and headspace accurate, so I'm pretty sure it's the ejector lever. To be sure, I'm returning the trigger pack and getting a pack from hkparts with a german lever. Peeps are telling me it should work. As far as trunnion and cocking tube, that's to be seen....Thx. I'll PM rocoborro. I'm aware I might need to spend a bit more to tune it up

[kingjoey]

I would wager that your triggerpack has a .308 ejector in it

[DEF23]

Since, I have some background in building HK's........

No, that isn't a .308 ejector in there. And those are some pretty new parts. They are gonna be somewhat tight until they break in. Unless you radius the edges off a little bit.

You do realize that in HK 9x weapon system that the ejector is supposed to actually ride in a slot in the bottom of the bolt and YES --- it is supposed to be virtually in full contact of the bolts bottom slot during function.

In fact, I tell people to fit it EXACTLY as you have it now !!! I wouldn't send anything back to anyone. What you have is proper and then you would start using a hand file or diamond hone to remove any excess material between the two.

And here I am talking .010"-to-.025" (sheets of paper) of gap. Basically, if you can see daylight between the two at all during hand cycling/fitting --- you are going to have intermittent ejection issues. The .308 and .223 versions don't experience this as much as they have a longer reciprocation time, longer cartridges and much differently designed ejectors.

The FCG tabs on the bottom of the receiver are what actually control the fixed height of your lower in relationship to your upper. If the receiver has already had it's tabs ground down to fit (yours has) then there isn't much you can do. (Although I have re-welded them for people who ground the off altogether, not knowing what they were doing......LOL !!!)

I'd have to agree with my fellow Cal Gunners --- I wouldn't do anything to it yet until you get everything else finished on the gun and you are going for your final dry fit & assembly.

HK receiver flats have a nasty habit of changing internal shape each time that you weld on them without have a shaping mandrel and the proper heat sinks in there.

Your receiver sound good BTW. Too squished up top is better than hanging too far down on an HK. Mostly this stems from people not using the proper sized jig and mandrel to from their flats.

BMP is the ONLY company here in the US who uses actual German made HK jigs and mandrels for forming their receivers. Their shoddy assembly was fully dependent on WHO at BMP was doing the assembling of the weapon. At the height of their production BMP/SW had at least three different people doing their welding, three other people doing their assembling and only one person to do the quality control, customer service and repairs........LMAO !!!

If you need any help with your HK, I am always available, just shoot me a PM --- I have built a few dozen so far (almost every model of the 9X series, left handed guns and even some non-standard calibers, ect.)

Hope this helps you out some, sir.

[cosmos0665]

hello,

Just received a BMP barreled upper, rcm bolt carrier, and a roberts sef semi trigger assembly (links below). I cannot charge the weapon because the ejector (or possibly the ejector lever), when fully mounted to the receiver, is not allowing the bolt to clear it.

Any suggestions?

Thx!

http://www.hkparts.net/shop/pc/MP5-94-Bolt-Group-US-German-HK-90p2201.htm

http://www.robertrtg.com/hk94semiautofcg.html

I have encountered this problem before with my clone mp5. The shelf is probably out of spec., welded high. What I did is I puchased a new German made trigger housing only from HKParts and I did my own adjustments in the hole where the shelf goes into. It's not that hard. I used a dremel to do it.
Hope this helps.

[ambis]

All,

thx for the help! I've attached more pictures. I returned the trigger box, kept the housing and bolt, and I'm waiting on a new pack + german lever. I'm hesitant to shave the shelf down, but then again I don't know if I should shave the lever. It's hard to see how the bolt rides the ejector in the weapon. Any suggestions, or things to check, when the new trigger pack arrives?

Oh, and gotta love that BMP paint job! I'm sand blasting and repainting with cerakote after the fitting is done!!!!!!

[saki302]

Looking at the pics and the lower fit, the shelf appears to be fine.

Wait until the new trigger pack comes in, and have an expert check things out before doing damage that requires TIG welding to repair

-Dav

[DEF23]

ambis,

Your weld-shelf placement looks just fine, sir. Because you have a paddle release system in your weapon, it then sets the placement of your weld-shelf differently than those who have just the push button release.

It also means that you shouldn't try to mess with it too much. So, you either need to swap out your lower (not the FCG box), modify it as explained above by cosmos0665 or trim the lever when it gets here, as I suggested.

"It's hard to see how the bolt rides the ejector in the weapon. Any suggestions, or things to check, when the new trigger pack arrives?"

When you want to see the direct interaction between the ejector lever and the BCG slot for it, all you need to do is --- install your BCG minus the recoil spring, insert your lower (w/trigger pack installed), flip it over, use a flashlight and then look through your mag-well while cycling it. You can also look through the ejection port towards the rear as you cycle it by not putting anything on the back end and inserting a flashlight into the gun.

Just remember you'd rather have your ejector scraping and have to give it a trim, then have too much more gap the .075" (1/16" of an inch) and have all of your empties getting kicked back inside your gun (this is what MP5's do when the ejector is either too short or adjusted incorrectly).

If you have ever built or had to deal with an AK ejector --- the concepts are very much the same with the part geometry being the only major difference.