View Full Version : Should I put a paddle-mag on my SP-89?

December 30, 2001, 04:45 PM
I am converting an SP-89 to select-fire. I plan to put the stock, foregrip, and plastic lower. I will probably put on a 3-lug tip but not sure.

I am debating if I should spend $250 to have a paddle magazine release installed to make it more PDW-like. My other options are doing nothing or getting this http://www.taclatch.com/.
The taclatch seems to serve the same function but is $50. The only downside I see is it will not look as supplied by HK. Anyone have an opinion on how far I should go?

Furthermore, I see that many conversions re-lable the weapon MP5K or PDW. How does one cover the old markings and restamp it? Can this be donw without refinishing the entire weapon?

December 30, 2001, 07:59 PM
You're about to embark on a project that is going to cost over $8000 when finished and you have concerns over a $250 part? :rolleyes:


December 30, 2001, 08:12 PM
So far I have the gun and the sear. That is $3200 + $4200 + $200 tax + $230 stock. So I guess I am up to $7850. Now I can stop here, or I can add the paddle, plastic lower, and 3-lug for another $900. Not sure if I want to. I guess I am fishing for people's impressons of how much nicer is an accurate PDW clone than a full-auto SP-89 with a stock. My latest thought is that if whatever I do looks good and works good than it is good.

December 30, 2001, 09:12 PM
You mentioned "sear". Think I'm going to be a fly in your soup. Sorry!

Almost certain that you can't convert a sear gun to select fire. It would require a navy lower, that contains the select fire mechanism and the sear built in. That can only be installed on a registered receiver gun. Kind of answers part of your second question. Marks are on that part.

Again, I'm not even close to being an expert and can possible be completely wrong. Simply deal in the stuff on occasion and shoot whenever possible. Would strongly recommend that you post your question on subguns.com and get a more precise answer or talk to someone who has actually built one of these things, legally. Been around these things long enough and have never seen a successful select fire sear gun.


December 30, 2001, 09:20 PM
I cannot argue this technically, since I am learning now and don't understand the internals, but I am sure you can make a select-fire from a sear, both technically and legally. Just look at the completed guns for sale. There are tons like that. I assure you it is no problem. Once you own a sear, you can sey it up into a trigger pack and get SEF or burst.

Jake 98c/11b
December 31, 2001, 05:06 AM
You are good to go, most transferable HK MGs are sear guns. At least for that price it had better be a registered sear.

It is sad to say that when I read this thread my first thought was '4200 for a sear isn't too bad these days'. Then I remembered that it is no more than $75 worth or work and materials. Something here just isn't right.

December 31, 2001, 08:04 AM
I heard the sear cost $4 to make and ever after the ban in 1986 they sold for $400.

December 31, 2001, 09:24 PM
Sorry about posting the wrong info. Your sear supposedly will work in a select fire lower. Asked a friend of mine over coffee this morning and he is a total HK freak-a-zoid. Only problem he stated was cost and when I checked the cost of a new select fire lower in my HK LE catalog, I was stunned. Four hundred bucks! That's my cost for a new one, so street is going to be stratospheric. Your lugged barrel has to come from the used or surp. market, because HK won't sell those. Looked over my list and saw that.

Was at the subguns advertisement last night and saw a MP5K for sale for $9000 with a sizable list of parts. Maybe a worth while venture either way.


December 31, 2001, 09:35 PM
The Navy lowers can be bought from $350 to $500, depending on the source. It is all under control. I might buy one for $9,000 but I already have two SP-89s and I can buy the stock and the lower and be done, or I can do more to approach the $9,000 mark total cost.

December 31, 2001, 11:17 PM
Found this at HK pro

[LEGAL WARNING! While it may be physically possible to adapt a factory select-fire
ambidextrous style “Navy Group”, or “Burst” type trigger pack and plastic housing to fit a clip-on
semi-auto receiver, it is patently ILLEGAL to simply adapt such a trigger group to fit, and then just
clip it onto a “Registered Receiver” gun using a clip-on style housing attachment as you have just
made a new, unregistered machine gun by doing so¼¼...you’ve just created a complete
conversion device to convert a semi-auto receiver!! The legal issue here, again, is that you are left
with the original, unregistered conversion part being freed up when you swapped them out on
your Registered Receiver conversion. There are currently available many of these adapted
“Navy”/”burst”/Ambidextrous trigger groups offered for sale, but they are ALL illegal,
unregistered conversion devices!! The ONLY way they are BATF legal is if they have been
NFA registered as a Conversion device! This had to be either before the May 19, 1986
cut-off (which is HIGHLY unlikely due to very limited availability of these styles of factory
parts then), or as a “post-86 Dealer Sample Conversion device”, or made at the request of
Law Enforcement Agencies. ]

January 1, 2002, 02:50 AM

That is only true of a registered receiver gun, and specifically one in which the receiver was not modified to accept a full auto lower before the registration. This is because in a registered receiver gun, the sear was 99.99% of the time not registered and had to be "married" to the existing lower when the gun was registered. Since the new-style Navy lower was not out when people were registering receivers, the ATF knows that you must have upgraded something. By doing so, you must have taken parts out. They consider those parts you removed (the old lower) to be a machinegun. Since you took them out, you have just made a second machinegun, which you cannot do, as that is manufacturing a machine gun after May 19, 1986.

This is not true of sear guns, which are 99% of HKs. My gun is a title-1 semi-auto in which I will fit a registered sear. It is ok to put a registered sear in a new-style lower and change parts at will. So I can use a Navy lower as can most people.

I am new to this, but I read that page in detail recently.

January 1, 2002, 02:51 AM
This also came from HK Pro. What a cool web site!

The ONLY LEGAL WAY to install a newer style “Ambidextrous” or “2-shot/3-shot Burst”
style trigger group is if the original, registered or unregistered, conversion sear (or “catch”) can
be mated to function in the “Ambidextrous” or “Burst” trigger pack mechanics. This means you must
discard the factory “sear (‘catch’)” that came in the new pack and affect installation of the original
registered or unregistered conversion “sear” that was utilized in the original fire-control pack. Some
few proprietary “sear” designs can be adapted to fit and made to properly function, most can’t.

As detailed earlier, the conversion pack frame itself has to have been altered to fit the clip-on
semi-auto receiver, while having the new style plastic housing adapted to fit the clip-on receiver, and
then “blocked” to prevent re-installation of an original select-fire trigger pack. Now often enough this
is done with the newer style plastic S-E-F housings which are essentially identical in function to the
older style metal S-E-F versions, and this poses no legal problems by doing so. Because most of the
“direct replacement” style conversion sears are modeled after the friction sear found in the factory
original metal or plastic housing style S-E-F trigger groups, adapting just the plastic housing presents
no mechanical problems.

The legal and mechanical problems arise when we are trying to adapt a newer style
“Ambidextrous” or “2-shot/3-shot Burst” style trigger group. And there is a very good reason not to
simply go ahead and have such an adaptation performed by simply discarding the originally installed
conversion pack and clipping on a newly adapted one. The mechanics of the Ambidextrous or burst
trigger groups are VERY different than the standard S-E-F type of fire control pack, with many of the
component parts totally redesigned to properly function with the burst counter clockwork mechanism
installed. Ambidextrous style trigger groups only offering selective, but not burst, fire modes are also
arranged identically and so suffer this same problem. H&K GmbH actually offered two very distinct
styles of “burst” mechanisms. The first version externally resembled the S-E-F type of housing and
located the burst clockwork mechanism in the rear lower portion of the pack frame. This is
significant as it left the front ‘catch’ position identical to the S-E-F fire control pack!! This means that
this style burst pack, and only this style, can be readily adapted to function with those conversion
sears resembling externally the factory friction catch!! These very rare fire control packs command an
extreme premium in today’s market as they can be easily adapted to function with the most common
versions of conversion sears, and the market for using them to install registered conversion sears
primarily, is very strong. The second style of burst pack located the clockwork mechanism more
toward the frontal region of the pack frame and this forced a complete redesign of the internal
components. These new style burst packs cannot be easily or readily converted to use a NFA
conversion sear!! Many styles of proprietary NFA conversion sears simply cannot be adapted to
function without major mechanical redesign. Due to this fact, there is a large temptation to avert the
hassles in doing so by simply adapting the entire trigger group and exchanging it on a “Registered
Receiver” guns’ receiver that formerly used an unregistered conversion sear. Attempting to do so
leaves one extremely vulnerable in a legal sense¼.

You just opened a can of worms in my brain! And I thought I was suppose to be the ViLLain.....

January 1, 2002, 02:59 AM
It takes a while to digest. I need to read it twice more, but one think someone once told me and that that seems to confirm is that if you want to be able to easily swap trigger packs between housings, then avoid burst. So I plan to look for a Navy style plastic with just SEF. No burst. Easier to install and work on and while I used to think burst was cool, I no longer find it interesting after trying it. It is too easy to fire 2 or 3 shots anytime you want in full auto with trigger control but if you really need to rock you don't want to flip a switch again to do so. You just want to step on the gas!

January 1, 2002, 03:22 AM
Scary thing is that I work in this business and don't know squat!

Burst is what I thought you were referring to when you said select fire. Again, sorry!

And, now that we're on the same page. There's another guy at subguns.com that has two (SEF) housings. Thought I saw something about 125 bucks. May want to take a look.


January 1, 2002, 11:48 AM
I saw those. He emailed me photos. They looked good. But they have no internals. I want to buy a sear-ready (with modified trigger pack) navy style housing with SEF controls. I want it for the SP89. But I am hesitent to post for this because Special Weapons is making ones in the US with very low prices (I think $28 for the housing alone, and $250 for the entire deal with guts). I am waiting until I can determine if I want the US made one or if I must have a German one. I think I need to wait until I see them at the Shot Show.

January 1, 2002, 12:21 PM
I saw those. He emailed me photos. They looked good. But they have no internals. I want to buy a sear-ready (with modified trigger pack) navy style housing with SEF controls. I want it for the SP89. But I am hesitent to post for this because Special Weapons is making ones in the US with very low prices (I think $28 for the housing alone, and $250 for the entire deal with guts). I am waiting until I can determine if I want the US made one or if I must have a German one. I think I need to wait until I see them at the Shot Show.

January 1, 2002, 05:09 PM
Guess you'll see the fireworks at the HK booth at Shot Show too. They're cutting off all but ten HK LE dealers and forming a cartel. Each LE dealer will have an exclusive territory and will determine the prices for its own region. Expect large price increases and restrained supply! Yesterday, December 31, was the last day older LE dealers could place orders for LE product and parts. We're one of the largest HK dealers in the country and invested heavily in LE last year. We lost the LE portion of the business, including all the work in opening door for HK in the local LE market. And post samples that won't make us money either. We're having a little chat with them of our own and may end up dumping them all together. Good product, but their management and support sucks!


January 1, 2002, 05:15 PM
Maybe you will know. I am trying to determine which groups I want to buy for an SP-89, HK-94, and HK-93. If you told me that 99% of the new HKs sold had Navy lowers, I would want that. If you said, "Well, it is about 60% of the other plastic style and 40% Navy" then I would get the older style because it is cheaper and easier to work on because it is non-ambidexterous. I look at that Elian-raid photo and that was the older style. So, what is the split between groups that are currently sold to LE?