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Looking to build a mp5

5K views 13 replies 9 participants last post by  Daryl2cb 
#1 ·
Hello, I am looking to build a mp5. Have a few questions. Would it be cheaper to source the pieces individually or buy a kit. If a kit is the route to go, who has the best deals on them? Would like to do a SD, but haven’t seen many for sale. Is there anyone that sells completed receivers? Not sure about buying the jig to do one or 2 builds. Thanks
 
#2 ·
The easiest and best way is to buy a complete HK parts set. The barrel will be pressed and pinned into the trunnion plus HK parts are the best for quality. Many of the smiths that build the guns do offer retail sales of just the rolled receiver. Expect to pay $500 or more for a rolled receiver that will transfer through your FFL. For a SD you will want a SD can. Again there are several manufacturers. The NFA board would be a good a good resource for that.

Be fore warned, you are talking one of the most expense and difficult home builds possible IMHO. A HK SD parts set in good condition without a bulged barrel (with 147 grain or higher the ports in the barrel can bleed off too much gas and make a squib round stuck in the barrel) as there have been many PD parts sets with bulged barrels. How is your TIG welding skills? Even with a pressed barrel so you won't have to press and pin the barrel, welding the cocking tube and SD cage will not be easy. Like rolling your own flat, builders have heat sinks and jigs to put these guns together. These are trade secrets. Don't expect these guys to post how to do some of the tricky stuff. You will need to figure that out on your own. The guns were originally designed to be put together in an industrial setting not one at a time. The flat rolling jig is the tip of the iceberg. All this learning on parts ( US parts kit https://hkparts.net/product/mp5-sd-9mm-pistol-build-kit-with-flat-top-rail-weldment-set-p18052.htm and is not in stock) that you paid a couple of thousand dollars for. I would expect to pay $2,500-$3,000 for a HK SD parts set. TPM Outfitters has a decent SD can https://www.tpmoutfitters.com/tpmsuppressors for $600 plus $100 - $150 transfer fee to your dealer and a one year wait. Have I scared you yet?

I'd love to try my hand at building a couple of guns and I own a TIG welder. All the reasons listed above, is why I don't. I bought a Coharie Arms CA5 SD about ten years ago for $1,450 including all SS SD can. About seven years ago, I had a couple of Special Weapons receivers I bought from Todd built into barreled SD receivers using SD front end kits (https://hkparts.net/product/mp5-sd-front-end-kit-p2399.htm) by Jeff at PCS for $725 each. His price is now $900 for the same service. A SD is cool. They are not inexpensive or easy to build. YMMV.

Scott
 
#3 ·
Its not that deep building one. Especially if you have a TIG. As for the SD, It looks like all the HK kits and front ends have become scarce recently. New made parts to press a barrel and build one are around though. You will want to find a good tutorial and do some reading on the process. A kit is convenient and sometimes may be cheaper but if you do not have that chunk of change to drop at one sitting peice mealing a kit works as well. I have spent some time doing the same thing and am about to assemble a MP5 Navy. Just decide what the final product should be, which parts you can go cheap on. Etc. I chose an HK Navy front end from Ben at Gatewood which added a lot to the build price, then I have some RCM parts for my 922 count. It could have been a lot cheaper if I went RCM on barrel as well but I while they make good barrels that I have used on other projects, the barrel is the heart of the project and I prefer if I am going to build a clone the critical parts be genuine HK.
 
#4 ·
The guys above covered some of the pitfalls of building this platform. Remember this, these parts aren't made with a CNC, they steel that's bend the old school way. Yes the receivers will have to be true and barrels installed CORRECTLY to get the correct bolt gap. If you are only building 1 or 2 guns buying the tooling isn't worth it in my opinion. At a minimum, I would have a whole and working gun to compare/measure as you went along but like the others said, it's an acquired skill on this platform. Not plug and play like an AR.

Regarding some of the parts selection. I personally don't see the value in having an authentic HK barrel on an MP5. Are you going to try and hit quarters at 100 yds with it? It wasn't meant to be a precision gun and trigger isn't either. Are you going to dump mag after mag until the barrel glows orange? Probably not, so I don't see the reason to spend the extra money. The necessity for those scenarios is still arguable as well. Oh, and forget about 922r altogether, it's dumb. Get what parts you can find. Some of the US parts are good, others you'll probably want to stick with German. That's where some of the experienced builders out there come into play. They know which parts work and/or work together.

There are some guys on here who have taken the plunge and built themselves a working gun. But if you spend that kind of money on parts and then screw it up you might ask yourself why you got into this venture to begin with.
 
#8 ·
An actual HK MP5-10 parts set would be worth some serious money. The 10mm guns were not that popular with PD. The FBI was the one ordering the 10mm. Most PD customers tend to have .40 S&W handguns, so they tended to buy MP5-40 guns. A .40 S&W barrel can be reamed to 10 mm, but the flutes will be short. I don't know of anyone extending the flutes in the chamber.
 
#7 ·
One of my SD's was made with RCM kit and suppressor, had RDTS build it, runs great semi and with sear. No parts count issue, parts were new and it was way cheaper than a de-milled worn out SD to start with.
 
#9 ·
I always have found it cheaper to source parts myself. makes it also easier on the wallet. Every aspect of building is described into great detail, and can be researched. If you have knowledge and are good with a tig welder it would be a rewarding project . Make sure you educate yourself on the legal aspects before you start a build.
Alex
 
#14 ·
I have never seen an 80 percent. Plus there is some opinion on when the bending starts at some point it is a receiver even if not welded, so that could create some logistic issues. Where are you located? Many members have jigs and presses so you may find some one to guide you through this. Again they cant build it, nor press it for you unless they have an FFL. So you need to pull the handle so to speak.
 
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