I have read here and there about some type of hanh mag block.  I  have a ASA 9mm upper that I could never get to reliably work on full auto so I put it up and never touched it again.  I like the idea of the 9mm upper but without reliability I hate it.  Would this mag block fit my conversion kit and would it solve  my problems?  Thanks for any help.

Short answer, YES.

May I ask what mags you were using?  With the Colt system, the majority of the issues of 'reliability' is w/ the magazines.  Pro mag is making a 'plastic' mag and people have reported good luck with it (well, the 2nd version of the mags).  CDNN Investments has some and I think a few others.  I'd suggest getting two mags to try before replacing the block.....

If you're dead set on getting a Hahn block, you can get one from Brownells: Link here

I am using uzi mags of which  2 out of 5 seem to work a little better than the others.  I also have several other after market mags and a Real Colt mag which is only 20 rds and will not work at all!.  I love the 9mm when it works but it is just to frustrating when it jams every 10 rounds.  Thanks for your help.

So, what is it doing when it's not working?

I have an ASA 9mm set up (ASA block) that worked fine in one Cav 15 lower I had, but I switched it toanother....  Been having issues since then.  I'm not quite sure if it's mag related or the ammo as of now.....  I put it away to play w/ a Cav 15 MKII and Oly 45 upper....

Good Point, Actually I did have a little better results with different ammo.  I tried several different brands and loads of ammo with all the different mags I have and it never proved reliable so I just threw it in the closet and went for a 300 whisper upper which I have been impressed with, but I run into a problem with it after a couple of hundred rounds I get so much Dirt and of debri blown back into the chamber from the suppressor that it loses its reliability.  I have been considering trying to convert it to one of those piston uppers if it would solve the problem.
 I really like to shoot my M16 suppressed but overall that 9mm upper has been a big pain.  Do you know of anyone that you can send it off to to have it  made reliable.  Or should I just scrap it and buy a reputable brand (when I bought it I didn't know which one to get and had not found this site for advice).  Thanks for your advice.

To answer your first question it jams ever possible way imaginable from failure to strip the next round to the round jaming into the feed ramp and even sometimes it doesn't extract the spent shell all the way out and it jams on the next round trying to load.  I am using and AAC rate reducing buffer and My bolt is not ramped.  Thanks

If you are having feed problems with your set-up, you may have a magazine related issue, an ammo compatibility issue, or a possible mag block/feed ramp issue.  I personally like the Hahn blocks and think they are quality products.  I use Uzi mags that I modified myself and the original top load Hahn block I use seems to be very tolerant of some slight variance in the location of the notches I made.  I primarily use 115 gr. round nose ammo or 115 gr. hollowpoint and have even used a few 147 gr. Rangers.  I have not had any problems at all with Colt 32 rounders and the few problems I did have with Uzi mags were quickly traced to a couple of questionable mags.  I don't use a special buffer, just a plain old heavy 9mm buffer (5.4 oz.) and my bolt isn't ramped either.

Some other folks I know who run "full auto" w/ a 9mm is the Cav guys.  Back in the day, the 9mm upper they had was from ASA.  Not sure if they used an ASA block....but they didn't have issues.....

Non consistant malfuctions.....hate those..... guess I'm in the same boat w/ my upper..... actually, my mags drop...like they disengage from the catch......every few rounds.... go figure.  And it short strokes (must be the ammo I used last)

The next time I get a chance I will do a little more tinkering with it and see exactly what it is doing and see if I can get some help here.  THanks

I just came from the range.  I am having two types of jams. The first is a failure to eject the spent shell   completely but the action comes back recocking the hammer and then strips the next round but the spent shell is riding sideways on top of the next round as they both go into the chamber and thus they clog up and jam.  The next type of jam is for some reason it ejects fine but as it strips the next round the round gets pointed too high and jams in the corner of the reciever  missing the whole hole of the chamber    Any advice on this is appreciated.  My uzi mags seemed to work semi reliably but if it is of any difference I have a real factory colt 20rd mag that ABSOLUTELY JAMS EVER ROUND with a failure to eject as stated before.  Thanks

THomas

Hummmm..... BUT, the question is, how far does the bolt/carrier assembly have to move to cock the hammer vs ejecting the spent case.

Might I ask what ammo you were using.  I'm wondering if it was "short stroking"....enough "umph" to re-cock, but not to go far enough to ejector.

(Doing a little mental time travel here.....)

First of all, w/ the whole set up assembled, see if the ejector is riding in the groove in the bolt/carrier assembly.  I've seen them when it is too low or off to one side.... sometimes tweeking the ejector helps.  If it's too low, bending slightly up works (caution, ejector is hardened, or should be- might break if you bend too much).

Okay, another thing for your rounds not ejecting.  They might not be making it back the the ejector EVEN though the rounds have enough power to cycle.  Let me explain.  Take some spent 9mm cases.  Drop one into the chamber, close on it.  Pull it out to eject semi fast, slow enough to watch, but not slow enough it will fall down mag hole.  Next, put spent case back in.  Put empty mag in.  Now pull back bolt/carrier slowly.  Watch the round. (Make sure you are NOT resting the gun on the mag!)  See if the ejecting extracting round makes contact with the magazine.  IF it does, odds are, the extracting round is not making to the ejector and the mag is nocking it out of there leaving it lay and causing problems.  Repeat w/ mag resting on table (hey, all it takes is a few .001" sometimes).  Watch the results.  Now, Repeat last experiment but now load the mag w/ "dumby rounds" (or live if you wish if that's all you have)...2 -4 rounds only  (rifle resting and not resting on mag).  Now, pull back the bolt slowly and see if the extracting case hits any of the rounds sitting there.

If the magazine is hitting the extracting round, sometimes the offending lip can be bent  to correct the issue.  Same w/ the rounds riding up too high, the mag lips can be tweeked so that it clears.

Now, for the nosing up rounds.....
Again, check the mag lips to see if they are allowing it to nose up too much.  Depending on when in the loaded mag they jam (ie first few in a fully loaded mag, middle or last few rounds). ...it might be different things.  If it's the last, it might be the follower angle or magazine tention.

Well, that's about all my brain has thought up of for this session.