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Below Barrel Pistol Concept (BBPC) Answered

Hi guys!

This is my new pistol concept! Its mechanism is actually pretty simple, and I have tried it once, and it actually works! Let me explain how it works: As the bullets (in this case white rods) are pushed up the guide (see picture below, it is named "bottom of loading") they are shoved up against the trigger. When you pull back the FP (Firing Pin), and it locks into position, this pushes the trigger up, pulling the first bullet go up into the chamber. When you pull the trigger, the bullet is shot out the barrel, and the next round is ready to go into the chamber. Repeat until your out of rounds.

What do you guys think?

~The Red Book of  Westmarch~

P.S. The image was made on paint.


Yes there is a French semi auto the firearms safety course here uses to demonstrate the importance of knowing your firearm.
In most guns when the breach is open the gun is safe.
In this gun when the breach is open the gun is cocked.
When you pull the trigger the breach and the firing pin comes forward chambering a round and firing it.
Then the breach opens cocking the gun for the next shot.
The bullets stay in the magazine until the bolt and the firing pin comes forward.

Before I lost my eyesight I was a sniper class shooter, I sold my M9130 sniper rifle and other guns along with my reloading equipment since I couldn’t use them safely.

Wow, that is really to bad. I am a gun enthusiast, and when ever I get the chance to shoot, I do so. Popping 9mm rounds into a target is really one of the joys in life, and I really cannot imagine losing my eyesight. Are you totally blind or are you just "semi-blind?" My dad is considering buying a FNH PS90, and I am totally excited. He has been wanting to buy a AR-15/ 5.56 round shooting gun for a long time.

Total loss of central vision in left eye slowly losing right so I am visually impaired, I have Wet Macular Degeneration so I have total blindness to look forward to in the future. I miss hunting, that is one nice piece the FNH PS90 not legal in Canada though to short.


Ah man, that really is too bad. I would be VERY unhappy,. but that is the love of life from a young man. I don't know how you feel, but I am sure you must be bummed. Yeah, the FNH PS90 is a fantastic gun, but it is kinda pricey. I hope that that gun law in congress won't pass. I wish the UN would keep their ugly face out of other countries businesses. I am a speech and debate student, and this year, we are debating on the UN.

FNH PS90.jpeg

Sorry for snooping, but I noticed you enjoy photography. If you don't mine answering, is that difficult being blind in one eye?

Digital cameras do wonderful things I can’t see the screen on my camera clearly no matter what I do, so I take as many picks as I can. The focus beeps and makes a green square over what it is focused on and I don’t waste film. What is hard is finding my way in the bush I don’t go far from the path. Most of all it replaces hunting and if I make a mistake all I lose is pixels and no one is harmed.

Huh well that's great :D. Also, I hope you wouldn't go hunting half blinded.


5 years ago

My Magpul has this......

I think you mean "lever action" not "level action." BTW, how is that MAC-10 coming along?

Haha yes I did mean lever action, and not good. I'm been busy with school and another project. It's hard to do a different style that doesn't have that boring straight handle and crappy trigger.

By the way it is called a tubular magazine.


5 years ago

the hinge/guide would be hanging around freely and rods could jam the trigger.
Try to improve these problems.

very interesting concept. i have one problem with it: it will probably be quite weak. the thing is, if you have the bullet chamber right in front of the trigger block, the ram will get virtually no acceleration, which means a very weak shot. i'd be interested in seeing if you could think of a way to solve this. perhaps make the trigger block further back from the actual trigger, which should give the ram enough space, as the ram is dependent on the trigger block, while the bullet is dependent on the actual trigger. i hope to see you building a gun for an improved concept.

Well, thanks for saying that you think it is an interesting concept! The problem that you stated makes sense, but the laws of motion tell us that when an object is in motion, it tends to stay in motion. In other words, when the FP hits the bullet, it will still accelerate, and carry the bullet out of the barrel. Do you have the URL of the K'NEX wiki that TheDunkis and Oblitivus started? Just wondering.

that's true, but the pin is much heavier than the bullet, and so the little acceleration distance the pin has is enough to get the bullet to fly faster than the pin at the very beginning of the barrel, before the pin has reached even a quarter of it's final speed, which will eventually cause the bullet to be shot very weakly. if you're still not all that sure, look at every single pin gun there is - the closer the bullet is to the trigger block, the weaker the gun; the further, the stronger. that's one of my key aspects when designing guns: i always try to make the bullet as far front as i can in contrast to the trigger block, so that the pin will have maximum acceleration distance and therefor maximum speed (that is what we call an efficient pin gun). the actual distance it takes for the pin to get the bullet (in most cases, definitely with small bullets like white or blue rods) to it's speed is typically no more than a few mm. knowing that, you can see how the layout you offered above is inefficient, and how you can quite accurately calculate the perfect bullet position in your typical pin gun (that's what i do to get my guns to be the strongest they can). yes, i have seen their wiki (a few months ago, but i don't think they've much updated it since), and tbh, it's not all that good. there's very little information in there, and it's mostly regarding what we knex back in the area of '09.

I see your point...hmm it works though, just trust me, I made a simple PAR gun with this mech, and it works great! I had kinks, but overal, the mech works!

of course it works, but i'm saying you could make it a whole lot better and stronger if you follow the logic i noted above.

good. no, i might get back to it sometime, but i just don't enjoy building a gun with no special mechanism. it's just too banal. i mean, building replicas, the way i see it, is just building a shape and making it fire in a boring way. i would much rather tackle something more interesting and complicated. i'm not building anything at the moment though.

Awe, that's too bad. I like models as opposed to concepts, because I don't usually see good new concepts. Well, I would still like to see what you have of and AUG...anyhow. Cant wait to see what you come up with next!

a little late, are we? lol. i don't think i'll get back to the AUG, not soon anyway. i've taken what i had apart already. i had a 99% accurate to the curve and length stock and working mag, which alone took me about 2 weeks to perfect. if and when i make a replica, i take it seriously and take notice of every single smallest detail, not moving on until the area looks exactly as it does on the real gun. that's why i was kind of annoyed at first when you posted all your far-from-accurate replicas that didn't even shoot well. i know what you're saying about concepts, but that's what makes it all the more of a challenge to come up with and/or build the most complicated and new concepts. i would like to believe most of my new concept guns are quite good. my S3 for example, my S2, the next gun i'm gonna build... which brings me on to my next point. i'm very lazy at the moment and i have a lot of schoolwork, and when i don't, i'm playing BO2 or MW3 with my friends. when i'm not doing that, i'm hanging out with my gf, and when i'm not doing that, i'm either eating, sleeping or on youtube. like i said, i'm lazy. i do have an upcoming holiday in mid december (hannukah), so i might build some. anyway, what i am currently interested in is making the first ever fully functional *good* knex lever action. it will probably have a horizontal magazine that i have already made a prototype for about a month ago, and the pin will probably be loaded by a string pulling it, while the string will route it's way around the bottom of the stock and handle to the bottom of the lever, where it will be pulled. it's quite simple in theory, but in practice, it poses a lot of problems that i've already thought of before getting into it. i think i'll manage all the same, but i may have to change it for a vertical mag ; ( are you doing anything atm?

Yes, late indeed. XD Awe that's to bad. The AUG-A3 is an epic gun, I am not sure which of the three you are building, but still, the AUG is a cool series. Well, I am glad you take making a replica seriously, but I did not (with my P90 and DC-15S). I want to make a good, working P90, but I have absolutely not bendy rods, so it is pretty hard to do so. Well, you concept guns are great, but IMO they do not look good. I like good looking, great working concept guns. Your guns work great, but they are...sorta...ugly. XD That is just my opinion, and you need not be offended. I am not surprised at what you say, that you are busy, as am I. I have a debate tournament on Saturday, and all this week is spent working on my debate case. I like debate, but I like K'NEX more...*sigh* I wish I had more time.

Do you like MW3? I have yet to play it, and can't wait. Black Ops 2 Looks sooooo epic, I wish it came out in Wii format...*sigh.* Ah, a lever action. Sounds good, as long as you make sure it looks good...XD I'm just teasing.

ATM I am not doing anything. I am contemplating making a Bushmaster M17S to rival yours, if you don't mind. I hope to enhance yours, make it more accurate, and, of course get a sub from KnexGurl and you.


lol, i am not offended, that's fine, everyone and his opinion is welcome. anyhow, it's true that i give the looks of most of my guns less time than the mechanism, but i do try to round up edges and make my guns as close as can be to good looking. for example, my S3 is a beast of a mechanism, but such a mechanism could not be contained in a smaller case, that's just the smallest, which makes it ugly, it could be made slightly better looking though, as someone (i don't remember who lol) showed me a pic on the 'ible, but i give less time and thought to that.

i love MW3, but my parents won't let me buy BO2. lol wii FPS? sounds a bit odd. whatever floats your boat. i can't promise anything about the looks of my lever action XD

lol, by all means, i'm waiting for it. do notify me if you post it though. i hope you aren't offended that i'm not subbed to you. it's just i only sub to people who i think made a real contribution to knex weaponry and i am friends with. the second part is checked for you, now give the first one a go.

LOL, late again. I don't know why I don't get emails when you write. It's kinda weird. Well, looks on a concept gun are not at all important. It is the concept that matters...XD Well, your S3 is pretty cool anyhow, and I see that it packs a punch. Great work!

Well, Wii FPS's are fun...sometimes. I don't own a PS3 or an XBOX 360, so a Wii is all I've got (besides a PS2). I think your lever action will look fine, as long as you don't intentionally make it look ugly. XD

Well, I don't know that I will make a better M17S, now that I think about it. Look here if you want to know my thoughts...

you don't understand how it works, do you though?

i don't have a PS3 or XBOX either. i play on my pc. it shouldn't be too ugly lol.

yeah, i've seen it, left a comment there for you.

It certainly is an interesting idea! I can see how this'll work, but I'm a bit concerned about the open space in front of the trigger. That part doesn't have connectors to guide the pin. If you put the bands on wrong, that can cause the pin to accelarte wrongly, and crush the hinge.