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UMP-45 Redo Answered

Alright so I was getting frustrated with my shotgun concept. Someone else can perfect it. I decided that after being asked if my old UMP-45 was worth building that it could probably use a tune up. So here's the new one. It's very similar to my old one but there are two main differences. First off, the barrel is longer. My old one was probably a tad too short. I have a feeling this one is too long but you can't really make one in between without getting complicated and it's pretty comfortable this way. The second main change is the barrel and firing pin. I used a hybrid type barrel using both a rod and connector barrel so that the ammo can fit through but so that the pin won't wobble. The firing pin uses the concept from my shotgun to be like a charging handle. It's a little further back but this was so the pin wouldn't fly out and I didn't want to move the trigger up + back barrel up.

Sorry, I didn't bother taking a picture of the stock. I just made a quick, crude wire stock because I didn't have the pieces to make the full one from last time. I was hoping someone else would be able to take the gun and add a folding stock for me. I'm still working on the handle and thinking about changing the trigger guard because it'll get in the way of the trigger unless you hold it down. Finally I have to test the reliability of this gun. After all that, I'll post it. I'll get a video tomorrow if I get the chance. I might be going out of town though.

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Mkay, I'm done with school so I think I might post it tomorrow. It has a somewhat cleaner design this time but the range doesn't seem as good this time for some reason. I guess I'm just not using a lot of bands but I could've sworn is was a little better. Oh well, as long as they leave the barrel without making the pin impossible to cock, it fires.

Nevermind, I need to build something new and didn't have the patience to take pictures for a full instructable. However, I did get many more pictures than last time so an experience builder should be able to build it and make an instructable for me. I'll post them later tonight if I get the chance. In the mean time, I'm just gonna mess around with my K'nex and see if anything decent comes out of it.

Could you post it right now anyway? I think if i have the concrete gun i should be able to enhance it a bit more and add a full stock

I destroyed it again. I got a picture of my second redo which made the front design a little better and the handle more comfortable though it lacked a good trigger guard. I'll grab it later. It still shouldn't be all that hard if people looked carefully at the internals. Most of the gun is empty space on the inside, really it's just paying attention to the barrel that you need to worry about.

However, I'm getting bored and lacking ideas, so I guess I might rebuild this and finally post instructions this week. I just want someone to help me improve it first.

Hm. The only improvements i think i can do from the picture above, is to make a more solid system and a stock. Other than that to be honest, it looks quite instructable worthy

Solid system? It's about as solid as it can get with the way it is designed. I did fill it in just a tad more. And then of course I want to add a stock but I just don't have the pieces to do so in this version. I figured it'd just post it and hope that finally having the instructions would be incentive enough for people to build it and try adding a stock of their own.

Whoops, meant to say "solid AIMING system". My mistake there.

...so sights. Well I used my old sights from my posted UMP. They look better than what I have on the picture here but not quite realistic enough. I can't be bothered to make them look any better, they're already too big technically.

Yeah, while I wait for Oodassault V4 ideas to ferment, I'm going to redo the redo. I'm looking for someone who will help with the stock and anything else necessary.
I have a question, though. Would you rather I keep the firing system the way it is or should I try making an actual charging handle separate to the firing pin? It would probably be weaker but more realistic this way. The tricky part is that the charging handle would probably be the top of the barrel so that they would both fit. Again, if you guys don't want me to bother, I'll save myself from wasting time experimenting and just finish it as is.

Never mind, I just went ahead and remade it like it was before but with a few small mods here and there. I think I might just post it as it is and let others improve it as needed.

Any chance you could rebuild and post this gun? Its amazing and I think we would all want to built it. Could you?

I have it rebuilt actually. However, I don't want to post it as it is. I'll give someone else detailed pictures and he can post it only if he completes it. I wanted someone to go over it, improve it, and add a good stock and maybe a top rail first.

Do you have pictures now? I think you should post them as soon as possible so more people have a chance go over the gun, build, and add a stock and rail.

I'm getting to it. I didn't want to have to rebuild the gun so I was going to do it when I got bored of it and disassemble it while getting pictures then.

Please take very detailed pictures of small components of the gun!!! We'll be so happy!

where did you buy the pieces for this and can you use legos?

Brian M Bernal

K'nex are an entirely different construction series than legos. In America anyways, they're usually in all major department stores, or you can order them online from the K'nex website.


7 years ago

by the way, i have an idea for the rail... (where its going and what type) and im gonna have to try some folding stock concepts...

You should try making a stock with hinges from a break barrel shotgun.

Alright I'm gonna get pictures later today. Think you could just post it for me? I don't know where my digital camera is and my camcorder's camera is horrible. I wanna move on with this pin concept though and see what I could do with it. Any suggestions?

kool, thanks! id love to post it! put it in a gun so its rate of fire is high and fire rod ammo.

Hmm I was thinking about doing a Magpul Masada (pre-bushmaster ACR) possibly because the charging handle location is perfect and I just love the looks of it. After that I'll see if I can put it into practical use.

that would be pro. have you got enough knex to make one? ill get to work tommoro if you have the pics.

I don't think I could make the stock but I should be able to get away with the body if I play my cards right. I'll either: A. Make the stock quickly and make instructions on it being connected to the back but then destroy it for the rest of the gun. Or B. Just have someone else build and post it for me again seeing how my camcorder sucks.

Yellow connectors are my main concern and then greens. In fact, I should order in only yellow connectors and green rods and I could make so much more without really needing all those other pieces.

Anyways here are a couple pictures. I told you my camcorder sucks. I hope you get it because I'm destroying it to work on the Masada right away. It's not too difficult anywho.


true. thanks! ill be able to follow them with ease! =D

So you are posting it now are you? cool! BTW I am replying to you on an iPad!

Have you finished? If you can't post just say so and then someone else can take over.

it turned out really bad... (its my fault for over modding it lol)

Alright good luck. And I decided to scrap the Masada already. It just wasn't turning out how I wanted. Plus I really want to turn this pin idea into something useful instead of just a charging handle. I was thinking I'd possibly do a shell gun seeing how we haven't got much of those and they could compete with bolt action and turret guns decently if done right.

thanks! lol, you should make a slide to cover the rod sticking out so it would be a really reliable pistol... like a skorpion that ejects shells or something...

these pics are easy to follow will build tomorrow, i like your idea for the charging handle as the pin. but if i built it and make a folding stock, can i post instructions

Quick question- when did you start this?

Uh either Thursday or Friday I'm not entirely sure. I finished the majority of it in one go though. I just can't remember if I posted the thread that day or the day after.

Either I'm working slow or this gun I'm making is huge then. Probably both.

Well I pretty much visualized the majority of this gun before hand. It was mostly based off my old one. I actually worked from the front towards the back so I was really surprised to find out it actually worked exactly how I intended without much modification.

I visualized the one I'm working on for about 2 months before I actually started building it. And I did work from front to back too.

Trouble is if I do that I don't know how I would put the parts together. If I let it sit in my mind for a few weeks then I get some idea on how to put everything together.

I would be more than happy to build this and give you the pictures.
Just need more pics.

Well, this looks much better then the last one and my guess is that it'll work better. I didn't have much luck with the first one.

ok so to start this gun looks and feels amazing as you may have guest i have built this gun and modifies it i have changed the pin to a yellow conecter with two green rods and a long black rod i have also then had to rework the front as it needs to have the hole on each side so the front has a couple of mods to it and i am now in the process of making a folding stock and i have added a rail to the top of the gun are there any more things you think i should add or change also once i have finished i shall post a picture :)

Nice! My favourite replica redone- hopefully will get decent range from that charging handle- all other gun with a charging handle get rubbish range

Well I'm not entirely sure seeing how this is supposed to be a replica. I'm just making sure it shoots. I've only used a medium sized, decently long orange band that I steal from my school. Cocking it is really easy this way. But I'll see how it works with a 64 later. There will be a point sooner than usual though where it's difficult to cock and/or pieces start breaking.