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Posted: 12/24/2008 12:44:06 PM EDT
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Hey guys,
Well a buddy of mine took the plunge and got a MP5SD w/ a SEAR pack. He is having some problems with it so far. First when you turn it upside down it sounds like a million particles are falling like a bunch of sand in the barrel. Is that normal? Second, when the sear pack is put on it wont fire FA. It fires off one round then jams. It either stovepipes or double feeds. But it does fire fine with the semi pack. The SEAR pack was bought from a different person, the weapon was purchased as a semi then the SEAR pack was bought. It seems easy enough to slide right on after you take off the semi pack but I realize we could be doing some wrong. Any help is greatly appreciated. Thanks. |
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Dumb question, but does it have a full auto bolt?
This is exactly what he did: 1) Bought a semi SD 2) Bought a SEAR pack 3) Took off the semi pack, put on the FA pack and FA didnt work So if you go that route should you be getting a FA bolt automatically because the weapon was semi? Or do most weapons work if you just switch the pack? Im new to HK's so how would he know if he had a FA bolt? |
| The ejector or ejector spring might be bad. Switch the ejector & spring with the one that works. See what happens. Every so often you have to tap the bottom of the suppressor on a wood plank to loosen up the carbon and shake it out. Perfectly normal. I cleaned the outside of the barrel and the barrel ports every few hundred rounds. It's a neat gun but a lot of maintenance and work to clean before I sold it. It also gets hot fast. I much prefer a separate suppressor now. |
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There are just too many possibilities here. The fact that it's not a mated gun is an issue, meaning it was assembled by your friend rather than a full conversion done by a known entity.
Verify the FA bolt first. If it's an SA bolt, then get the FA bolt and install. If this doesn't "move" the problem let alone fix it, then I would send the gun off to a qualified C2 for review. If it's not the bolt, then there are too many possibles and it'll likely be beyond your friend's ability to diagnose and fix. |
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Quoted:
Sorry for the late reply, but it is an FA bolt. The problem is still happening though. We don't know what to do next, we would hate to send it away again.. Yes, it obviously has a FA carrier. It wouldn't fire at all if it didn't have one, as the trip lever would not be engaged and therefor the hammer would never be released. As someone said before, try switching out the ejector with the one that works from the other trigger pack. Lots of good info in the sticky threads above. The ejector levers changed over the years and can greatly impact the ejection. On the first shot that fires, note what angle and distance that it ejects the case. It should come out at about 2:00 o'clock and shoot out about 6-10 feet. Anything less is a weak ejection. Secondly, make sure the trigger pack has a 9mm hammer spring. Sometimes you get them and they had a rifle spring installed. That can rob the carrier of a little power and keep it from cycling back far enough for a good ejection. Check the following thread for spring ID and replacement: http://hkpro.com/forum/showthread.php?t=65232 The SD model is designed to "bleed off" extra energy of a regular super-sonic 9mm round, making it sub-sonic. You might need to keep everything you can get for the ejection process so making sure all the springs are correct might help. |
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This was the one in it.
This is the one in there now. We just changed it, the charging handle is harder to get back now, rougher.. edit: just tried it and it still doesn work. This is what the weapon does when we fire it (last weekend), then when we pull back the charging handle a good round comes out along with the "stovepiped" casing. 
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Lots of good suggestions have already been mentioned, here are some of them again and a couple new ones.
I'd double check the ejector lever and ejector spring, make sure that they pivot back and forth freely without binding. While the pack is separated from the gun, check the hammer spring make sure it's a 9mm spring, not a .223 or .308 spring - I use the older style chrome looking 9mm spring in my SD and not the newer / stiffer, silver "F" spring. Believe it or not the stiffer springs offer more resistance to the rearward movement of the bolt carrier. You should definitely be using an SD locking piece, as mentioned above the angles are different than a standard MP5 locking piece. Make sure that the trigger pack internals aren't pivoting inside your SEF housing - I've also seen before where semi auto internals were inside an SEF housing that had been "clipped" incorrectly (i.e. clipped and pinned). The internals should be sitting firmly on the shelf if they were converted from a full auto pack, best way to check this is to remove the internals from the SEF housing and slide them up against the receiver / shelf, I cut mine to have no more than .005 play (about the thickness of a piece of paper) between the shelf and the notch in the bottom of the pack. About 13 or 14 years ago Ralph at RDTS built an SD for me - couldn't get the damn thing to shoot more than a round or two without stove piping - I changed out everything / trigger packs / springs / bolt carriers / etc. etc. and it still wouldn't work. After two boxes of ammo the gun "magically" fixed itself and ran perfectly. What I eventually figured out was that the gas ports needed to clog up a little bit before the gun had enough back pressure to eject the brass. I must have put a thousand rounds through it before it's first cleaning (yeah, I know). To test my theory about the clogged gas ports I cleaned them - sure enough, the gun quit running and didn't run right again until another box or two of ammo. I hope all that made sense. Here's a picture of one that I clipped the other day: http://hkspecialist.net/ http://i701.photobucket.com/albums/ww19/Oberndorf/SHOP020309004.jpg |
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