mp5 build

[ar15barrels]

not sure how much more detail he could go into. you just press the barrel in until the bolt gap is where you want it. there was never any dimension we cared about as for amount the barrel got pressed in. you just pressed it in until the bolt gap closed down to what you wanted.

I built a cool barrel pressing fixture that stops against the trunion, but gives me a micrometer adjustable length to press in HK type barrels.
It allows me to press a barrel in short, then check bolt gap and then make measurable adjustments on how much further to press the barrel to get correct bolt gap.

[generalpetres]

I think i might just have to buy the jig. Ive messaged people on hkpro forums about possibly building it for me but most don't want to deal with the cadoj. Is there a tutorial for doing the ibolt for the front tree?

[FIREBALL_BRIAN]

I want progress pics....please. Love them MP5's

[generalpetres]

I have a final this week so not much getting worked on. In so deciding on whether or not i want to build it my self or have joe at dakota tactical build it for me. If i have it built will i have to pay taxes on the entire rifle or could i list the cost as only his labor when i goto dros it.

Don't get me wrong i want to build it but being a student and only having a part time job atm i don't want to screw anything up trying to build it on my own. i miss build parties T_T

[generalpetres]

heres a picture of the parts kit just laid out together.




i took the bolt apart and measured the rollers they were just a tiny bit over .314 which is right around 8mm but to be on the safe side i can always replace the rollers if need be. Heres a picture of the locking bar on each side towards the face where it makes contact with the rollers, it doesnt look like there any wear on it.

[FIREBALL_BRIAN]

that's a tough choice. Dakota does good work. If you feel comfortable I would build yourself. You learn so much more and realize its not as hard as you think.

[generalpetres]

I ended up buying the bending jig and barrel pin jig today from Robertrtg, had then for 325 which is a really good deal. Going to attempt to do it on my own. I might have to see if i can stop by Randalls or roccobros if i get stuck. I was really tempted to have dakota tactical build mine but for them money i can have my own jig and a better understanding of the entire process. Hopefully i can get it built properly with mig welds over tig.

[FIREBALL_BRIAN]

nice. glad to hear you went that route. You will be happier in the end i believe.

[generalpetres]

I had started last night to demill the parts kit, I got acouple of the spot welds removed but it was a pita trying to use a regular drill bit, so today i went to harbor freight and picked up a set of center drills, some small files, and a spot weld drill. the spot weld drill was so nice make quick work of the spot welds, its got a spring loaded metal point that you press into the part and a set of cutting teeth. I center drilled spots in all the spot welds then used the spot weld drill. I had also cut the receiver down the middle weld and i finished pulling the scrap receiver apart and cleaning up some of the spot welds on the grinding wheel.

I did go a little bit too deep while removing the spot welds on the charging tube but nothing that will be detrimental to the build.




Here's the trunnion after i got the old receiver off i went to the grinding wheel and ground the welds down till it started to remove a bit of the trunnion and i will finish sanding it smooth with the small files and some sand paper. Nothing to crazy just enough to where it wont cause problems when putting the gun back together.




I also tried using a large hammer and punch to remove the barrel pin but its in super tight so ill have to wait for my barrel pin jig to come to remove the old pin out of the trunnion and press the barrel.

[Wakawaka]

I also tried using a large hammer and punch to remove the barrel pin but its in super tight so ill have to wait for my barrel pin jig to come to remove the old pin out of the trunnion and press the barrel.

If you're planning to check the bolt gap by manually pushing the bolt into battery, aim for the maximum gap (which is .020 thou) because the gap will look different in the finished gun when the bolt is allowed to slam forward naturally and put under spring pressure.


When bending your flat, be careful not to press it too far as to distort the top radius of the receiver. If you bend it too far, that top radius can take on an ogival arch shape and will likely require a mandrel to open it back up enough for the bolt carrier to slide freely. When you're bending it, I'd stop pressing as soon as the two sides are about 1/4" away from coming together. Then take it out and squeeze it together with c-clamps the rest of the way and check to see if your buttstock fits properly and that the bolt carrier will slide freely. If it looks good, weld it, if not, you can carefully align it back into the jig and press a bit more.

[generalpetres]

thanks for the advice, ive seen some videos where they got the flats almost touching then put some nuts and bolts to keep the flat together. In the same video the guys top receiver was a little out of round so he left the bending bar in the receiver and had 2 smaller bars on each side and used his bench vise to press the receiver back round. Luckily for me the receiver flat i purchased was an lcs flat which already has the receiver rails squared up.

How do you guys rivet the sling point onto the mag well bucking bar and a punch? I also am going to have to find some rivets for the shell deflector as the only rivets that came wi th my parts set was the ones for the sling attachment point.

[lostwake]

I'm drooling right now. How much was the parts kit?

[generalpetres]

just under 1500

[lostwake]

That's a pretty good deal I think. 1600-1800 seems to be the going rate. I had to settle for a 9mm ar. I think I'm into for about 500 bucks.

[generalpetres]

i was thinking about doing a 9mm ar but having shot both the full size mp5 and mp5k in full auto i just had to have one. the kit i purchased was for a pistol build but im going to buy the butt stock and a fake can and bullet button and make it into a rifle.

I got a little more work down on the parts kit today, it was a pita trying to press the barrel pin out as i got a little to happy that i bought the kit and took the receiver off it before i pressed the pin out, but i was able to get it out by putting it into a vice and into the 20ton press. i think it is just me but i love the ping sound the trunnion and barrel pin make after you put enough force onto the pin to get it to move.

heres the trunnion completely demilled and the remnant of the old barrel.


maybe this week or next ill start working on bending the receiver and getting that ready to install the trunnion etc. Before i bend the flat i am going to rivet the sling attachment point and the brass deflector onto the receiver