Recently acquired two HK clones and had a chance to shoot them today. One is a Special Weapons SP10 the other a Special Weapons SW5 MP5K.
Well the Sp10 ran great through several mags but the MP5K was a different story. It started out fine but towards the end of the first mag it
would get an empty casing stuck between the cocking tube and the bolt and as I went on it would go as far as to not even eject the empty
casing. It was almost like the ammo did not have enough oomph to get the bolt back far enough. Funny thing is this ammo worked fine in the SP10?
Any advice you guys could give me on what to do to remedy this?

Sounds like a weak extractor spring and/or worn extractor. Replace at least the extractor spring with a genuine German HK gold mp5 extractor spring and thoroughly clean the extractor and extractor pocket before reassembly.

First add "clone" to your title because those are not HK's and that's why you're troubleshooting them.

As Josh stated the extractor spring is now toast and I've seen improvement in function in my Coharies by replacing the ejector lever with a German piece.

Thanks  for the help I will try those things and as far as the whole HK/Clone thing
is any other AR that is not a armalite a clone? No they are all AR's! The whole
snobbery of the HK brand is what kept me away for so along and I am sure I am
not alone.

ETA: The more I think about it I really think the ammo was not being ejected and was staying on the extractor as
it rode forward and tried to strip another round from the magazine. When I would pull the charging handle out it
Would spit out an empty and a hot round.

Found this thread on HKpro and in it the guy is having the exact same problems I am
unfortunately he never posts what the resolution was but the problems are identical!
Link to HKpro thread

you never said what type of ammo you are using. also, the sw5 is a clone, the sp10 is, well, an sp10. Theyt are not HK's because they are not made by HK. My UMP clone is just that, a clone.

At any rate, let us know the ammo type and what kind of mags you used. I would also recommend posting in that thread (if you haven't already) and asking what the resolution was.

Well known issue with Todd Bailey products. Replace extractor spring (I use a rifle extractor spring, the gray one), extractor, and ejector lever with genuine HK parts. Problem solved.

Just cleaned the two and while I had them apart I took a pic the SEF lower that was on the MP5K has a different looking ejector than the lower that was on the SP10.
The ammo was DRT ten-ring that I picked up from academy sports and after reading the reviews online it seems that it is garbage ammo. What threw me off was that
the SP10 ran fine on the DRT ammo but after taking it apart to clean it I noticed the extractor has a gray spring and is so loose I could push it out with my finger and also
everything just felt very "loose" where the MP5K has a gold extractor spring that is supposed to be geniune HK according to the guy I got it from and the bolt was really
tight when I put it back together. Here is a pic showing the two different ejectors.

pfffft... I bet you think your car isnt an automobile clone either....

No snobbery on my end I own Coharie's, Vector's, MKE's and HK's and enjoy them all. However the guns with problems are U.S. made and your title is misleading plain and simple. I offered some advice based on my experience in the past concerning U.S. guns and you'd most likely get more hits & help if the title reflected the guns true origin. 'Nuff said on that issue now on to more troubleshooting..............

The ejector on the K looks unlike anything I've seen, looks like it's in the white (unfinished) but that could be the lighting, but even the profile looks odd. Also check the bolt face diameter IIRC my Coharie 9mm bolt was out of spec - it was a few thousandths too large and the case was not a snug fit. I installed a spare German BCG and things improved dramatically.

Good luck with them cuz they're a blast once sorted out.

Fixed the title and the ejector on the K is silver but there is no rust on it anywhere as far as
the bolt face on the K a 9mm case fits snug but on the SP-10 it is really loose. Weird thing
though is as loose and sloppy as the SP-10 bolt felt when cleaning it ran great!

You could try swapping the bolts & ejectors around between them since the only real difference should be the carriers themselves.

Swapping bolts would require checking the headspace correct?

I don't think it's a big deal to shoot 'em without checking provided the force required to cock the gun feels normal. You could check the bolt gap (head space) it's easy to do but doubt I'd bother in this case.

I bought an SP89 clone that has been giving me the same problems. In the course of attempting to throw enough parts at it to fix it I've replaced the locking piece with a 100° item,the ejector lever,extractor and replaced the extractor spring with a rifle version.
The improvement has been rather than jamming a case above the bolt every 5 rounds to approximately 1 in 20 now stovepipe in the port so it's moved from being a big Lorcin to a big Grendel.

 I'm wondering if the damn thing just hasn't been broken in yet as I've only managed about 150 rounds out of it due to recalcitrance. Just FWIW,using proper MP5 magazines.



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maybe it's just me, but the angle of the mag as its inserted into the receiver does not match the angle of the receiver. is everything in spec? is the mag seated and locked in properly. My MP5 straight mags dont seat like that, unless ofcourse the picture is just an illusion.

This is excellent advice IMHO.  I have several Coharie Arms and Special Weapons guns and barreled receivers.  A couple of them , the extractor worked okay but the TB extractor springs just didn't give the tension the extractor needed.  I would highly suggest, when ordering the parts, I would by several rifle extractor springs.  All it takes is one misfeed/bad mag, the shell gets cocked under the extractor, as the bolt group comes forward, the extractor spring gets hyper extended, and it is toast.  Once the spring is bent, you can bend it back, but within a few rounds of use, the spring will loosen and there will be more feed problems.

As far as the language is concerned, this is a different firearm platform that has different terms.  There is no "upper" and "lower".  There is a barreled receiver, and trigger group.  HK came up with the nomenclature for the firearm they designed, so that one person talking to the other, when they were not in the same room or reading from text, could follow how to take things apart and put them together properly.  Yes it would be easier if all types of firearms used the same nomenclature for parts.  By the same token, it would be handy if everyone on the planet spoke the same language.  But we don't.  So when in Rome...  I would highly recommend you look over the MP5 Armorer's Manual http://www.scribd.com/doc/31788988/Hk-Mp5-Armorers-Manual so you can use the terms that are associated with the specific parts, so we are using the same part names to cut down confusion.

Can the front of grip housing housing move up and down on the "K" gun, or is it tight against the shelf?  Again, TB guns are know for having shelf height issues.  I have a bunch of clones and most all of them are built using TB receivers.  I've had a bunch of grip housings "clipped" 0.010" too low.  I hand fit each grip housing to each receiver so the grip housings are tight on the receiver shelf.  If the "K" grip housing is clipped to high, the trigger pack won't be held tight against the tabs on the bottom of the frame.  If the trigger pack is not up tight against the receiver, that will make the ejector low in the ejector groove of the bolt.  So the shell will tend to be push up rather than out the ejection port.  You have two 9mm guns.  One of them runs.  I would try swapping trigger packs and bolts from the one that runs to the one that doesn't.  Also could be an issue with the grip housing?

As far as checking bolt gap, a $5.00 set of feeler gauges can be purchased at most any automotive store.  Proper bolt gap should be between 0.010" and 0.018".  A set of feeler gauges for a little greater than and less than those measurements would be best.  There are specs and a basic how to on page 29.  I hope you get both guns running soon.  Please keep us updated.

Scott

my fixes for Coharie and tod guns (roughly in order):
HK mags
Good strong ammo (no Remington green box)
Extractor spring
Oversized bolt
Ejector
Shelf height

Start with ammo. Pick up some fed maroon box from Walmart. I have no idea abt DRT ammo but Some guns need hotter ammo to function. If that doesn't fix it, swap the two ejectors.