As I'm sure plenty have said before me, Mark 23's are cool but $2K is a bit steep.  On the other hand, I've seen some .45acp USP Expert's around the ballpark of $999 new on some online gun stores (sometimes even less but they're usually sold out fast).  That's still pretty steep for a handgun but a lot more reasonable when talking H&K products.  I was wondering if I could have some help on planning out what could amount to a Poor Man's Mark 23: a USP in .45acp with certain mods that replicate the look and feel of a true Mark 23 as closely as possible.  I know it will never be perfect, but the closer I can get it the better.  And who better to ask about H&K aftermarket products than the H&K board.

As far as what to change, really the only things that would make it "close enough" are the slide, barrel, and part of the frame out front.  The more research I do, the more it looks like I'm not going to find some kind of Mark 23 Clone slide/upper that's USP frame compatible (although if any of you know of something like this that exists please let me know, this would solve all of my problems right away).  It looks like what I'm going to have to do is work with a USP Expert to make it match the look as closely as possible.  It'll be a bit shorter, but still close enough to be a decent Poor Man's Mark 23.

(Cutting my post in half since I'm limited to 2000 characters per post as a new account)

Second half--

It looks like threaded barrels for the Expert exist, they're right under 300 bucks form Jarvis Custom.  It doesn't list the length of the threaded barrels, but if I had to guess it's probably going to add about 2 or 3 tenths of an inch which would bring it at 5.5 inches at most.  A bit short of the Mark 23, but close enough.

The big thing here would be some kind of frame mounted under barrel piece that would extend the pistol frame out further.  The Mark 23's frame extends out the whole way right to the end of the slide: long slide AND long frame.  The USP's falls shorter, leaving a good amount of the slide at the end exposed underneath which kills the look.  Is there some attachment that would visually (and as discretely as possible) help extend out the frame to the end of the longer slide?  It doesn't have to be one of those giant Match compensators or bulky weights sticking out front, just something smaller and more discrete that helps the frame blend in with the extended Expert slide more

Thanks in advance for the help.  Let me know what you'd think or change to make it better, I'd appreciate the guidance

No dice on the slide, but you could try a match weight.

https://www.matchweight.com/products/compensators-steel-for-heckler-koch-expert

Edit: Oops, didn't read.

Honestly, just pony up for a Mk23.

This.  The cost to sorta replicate a mk23 will cost more than the actual mk23.

Now you could get a usp expert and roll with that, sure....

But the HK world isnt like glockland.  It's not legogunland.

Just buy the gun you want.  All this jacking
around and it still won't be the same gun.

https://www.matchweight.com/products/compensators-steel-for-heckler-koch-expert

I like that match weight that one of you suggested, that might be my backup should this not work out.  It looks awesome, but just a bit thick around the sides. Maybe if I did get that there'd be a way I could thin it all out.

Now I could always use a buddy's printer and 3D Print something for the underbarrel.  This would obviously take a lot of time to design, but it would be exactly the thickness and shape I'd want it to be.  Of course if I did do this and I do get something worked out I'd upload the 3D Model I make for everyone else to use as well.

At this point I'd need to refinish it all with my device on there to get it to a consistent color.  Maybe a cerakote finish in a darker marine blue.

All in all this would drive up the price a lot.  If I find some really good deals, like a good price on a used USP Expert maybe then I'll go forward with this, but otherwise it's probably gonna be similar to a real deal one anyway by the time I'm done.  Thanks for the input anyway guys!

OP.....you're gonna piss away $1300 or more and not have a mk23.  You will look at it each day and think "it's not a mk23."  Soon you will hate it...although any USP is great...because it is not a mk23.

Save up enough and get the m23.  Any thing less "is not a mk23".

Buy once, cry once.

Like I said in my other recent thread here about the MK 23; if you have an itch for one, it isn’t going to be satisfied until you own one, even if the USP Tactical/Expert is a better shooting gun.

More than that - the Mk23's party piece is it's utter reliability. Probably the only 45acp handguns on the market that are "as reliable" are the USP 45 and USP 45 Tactical. The Tactical has obviously a different/threaded barrel but also has the Tactical-specific recoil spring assembly, specifically designed to react and work better when the pistol is suppressed. (It also has some components of the HK Match Trigger kit in it)

The Expert looks great, but it's barrel is hand-fitted IIRC. It is not going to be in the same reliability league as the Mk23 or even your vanilla standard USP or USP Tac, simply because of the much tighter tolerances in the barrel fitting.

Just get a USP 45 Tactical...hell, that's what SEALs and other SOCOM elements did, rather than use Mk23s in the first place anyway.

The cost difference between a 45 expert and a MK23 isnt THAT vast. Just save and get what you really want. It'll never quite scratch the itch anyway.

That said, I'd PREFER an Expert with threaded barrel and picatinny rail adapter and night sights over an actual MK23 but thats just me

Buy once, cry once.  

I concur. I have been there more than once and always do the same thing and regret it. The Mk23 is an itch you have to scratch.

Op.
You’re over thinking this really bad. By the time youre done doing what youre doing, you will spend almost the same for a REAL  “MARK23”.
I have seen them go for as low as $1500 for a used one to $6500 for a collectors (some are actually higher).

I just recently saw one go for approximately $1800 NIB. CA date code.

Shop around and be patient, you will be surprised at what you will find.

Hope this helps.
M.