View Full Version : MP5, Need help before I build,

04-18-2010, 02:08 PM
I am looking for some help answering some questions before I buy the kit and build the gun. I also need to build up my number of posts the rent the flat jig. I am considering the build but I see the Coheir guns and they cost about what the kits cost. I want to build one with the paddle mag release but the shelf is in the way. Is it legal to build one with a modified shelf that allows the paddle mag release to be installed?

04-18-2010, 05:58 PM
No, it is not illegal to build one with a paddle release. Just as long as there is no pin that goes completely trough both sides of the receiver.
You can take a bushing that is the right size to fit through the paddle pivot area, drill an 1/8th inch hole through the right side of the receiver and into the blocking ledge on the left side (don't drill completely through, or you will have made an illegal machine gun.) Then tap the 1/8" inch hole and screw it through the bushing inside the paddle release an into the left side. The trim the screw off on the outside of the blocking ledge and weld over the hole.
There used to be a site that had full instructions with pictures but the site has been down for a couple of months.

04-19-2010, 09:09 PM
Thanks for the reply, I know how the minor details can cause lots of problems. I saw a post where the restoration of a demilled reciever to semiauto was legal. Have you hear that before? Thanks Mike

04-19-2010, 10:36 PM
You have to have a shelf regardless, and it will always be in the way. Once the receiver shelf has been welded into place, and the mods done the way Smokehouse eludes to, you should be OK. A hole that does not go all the way through the receiver, from one side to the other, is the key. But at only $40 for an MP5 flat from ORF, It would be far easier, a better build and no chance of any question to go that way rather than try to put a demilled receiver back together.

04-19-2010, 10:38 PM
I believe that if a receiver is demilled according to the definition of the law then the pieces of the receiver are nothing more than scrap metal. If you successfully weld those pieces together and make a functioning receiver that is modified where it cannot accept parts to make it a fully automatic firearm then you are legal.
However if you re-weld a MP5/HK93/HK91/Cetme or any receiver based on those weapons to completion and do not weld up the mag toggle holes in the receiver first, you have created an illegal machine gun according to the rulings as they stand from the BATF. The there can only be a hole through the right side and it cannot be larger than 1/8 inch in diameter and must be welded shut after the pin is installed.
I know it sounds sort of goofy, but that's the way the BATF wants it, so that's the way we do it.
The whole lower trigger mechanism on these weapons must be modified so that there is no way that they can accept full automatic parts. Blocking the hole and putting the blocking shelf on the receiver is supposed to prevent putting an unmodified lower and trigger pack on one of these rifles.

04-21-2010, 10:03 PM
I thank you for all of your help. I have seen the Special Weapons version of the MP5 I think it is called a Coheir? What is the difference between it and the MP5. I have checked the prices on the original MP5 kits and the other copy's. Is the MP5 that good that the other pail in comparison? I am looking to spend my money effectively.

M1 Tanker
04-21-2010, 10:52 PM
Differences being a select fire and semi auto version are just like the Cetme.

1. Shelf installed in receiver to prevent attaching a unmodified grip frame.

2. Trigger pack modified to remove FA parts but cutting corner out of the grip frame.

3. Bolt carrier is milled out to not hit any FA parts if they were there.

Quality can be an issue with some SW parts, but my parts gun runs perfect. HK parts are definitely more money, but you HAVE to have some US parts for compliance.

As to the hole, its a no no for sure. My grip frames are clipped and pinned to give the appearance of a pin, but its simply the ends epoxied on the frame.

04-22-2010, 09:34 AM
I detect a hint of hype induced aprehension in your questions, and I am in the right mood this morning to give you my opinion.....
Having worked on a lot of Hk MP5's in my time, I can tell you this,,,,They are a stamped steel receivered weapon that is welded together....The quality of the steel in the receiver is no better than the steel in the flats or aftermarket receivers you buy. The reciever is only a container and guide for the bolt carrier group to function in and lock to a barrel. Often times, the fit and finish is no better than the fit and finish I have seen by home builders, (some guys are better than others). Some after market parts, bolt heads and carriers, etc. have had issues. But, so have Hk from time to time. Take your time, concentrate on getting everything as close to spec as possible and spend your money on a quality bolt head and carrier, Keep your 922r parts count right, and you will have every bit as good and reliable a weapon as SW or Hk. Will it have Hk or SW stamped on it? Won't matter to it or you when you pull the trigger and smile..... But don't let anybody convince you that because it doesn't say Hk on it it is sub standard....The price of the Hk parts is a result of that if "If it ain't Hk it's crap" hype, and like M-1 eluded to, there are a lot of parts guns out there that will go head to head with any factory Hk or commercially built piece. And that's what building your own is all about....

04-22-2010, 10:35 AM
these guys are dead on it...

its an easy build and a lot of fun and yeah your still gonna have close to what you pay for a cohaire in it...

the difference is that YOU have the quality control if you build it yourself and can make it as good as you want it.