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Posted: 1/18/2014 3:33:02 PM EDT
[#1]
Quote HistoryQuoted:
The devil is in the details. This is what i'm finding. Lets compare to the Tavor with an 18" barrel. The Tavor has a 15.75" LOP and and overall length of 27.625. My initial sketch shows a 20" barrel with a 15" LOP and an overall length of 31.9. If you had an 18" barrel the overall length would be about 29.9. This difference of overall length of 2.3" can be attributed to the BCG. To some the extra 2.3" would be unacceptable, but some may think its ok. I don't think its an open and shut case either way by any means. Quote HistoryQuoted:
Quoted:
In response to the poll--Of course a bullpup that uses an AR 15 gas system and unmodified BCG CAN work. It will just be unnecessarily long, and result in a longer than necessary overall length and length of pull. If you are not going to use the part that is only there to engage the recoil buffer and spring, why not chop it off to achieve a shorter overall length and length of pull? Just so you can use standard, off the shelf parts? If so, that's a valid reason, but IMO minimizing overall lengths is the major "pro" of a bullpup, and excessive lengths of pull is a major "con". My $0.02. YMMV. The devil is in the details. This is what i'm finding. Lets compare to the Tavor with an 18" barrel. The Tavor has a 15.75" LOP and and overall length of 27.625. My initial sketch shows a 20" barrel with a 15" LOP and an overall length of 31.9. If you had an 18" barrel the overall length would be about 29.9. This difference of overall length of 2.3" can be attributed to the BCG. To some the extra 2.3" would be unacceptable, but some may think its ok. I don't think its an open and shut case either way by any means. Nope. Not an open and shut case by any means. And there is something to be said for more parts commonality if you are selling it to the "AR market". |
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Posted: 1/18/2014 5:51:18 PM EDT
[#2]
Quote HistoryQuoted:
Nope. Not an open and shut case by any means. And there is something to be said for more parts commonality if you are selling it to the "AR market". Not looking to sell anything but I would like people to copy what I eventually come up with. Ideally a nice build it yourself project. |
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Posted: 1/21/2014 5:11:50 PM EDT
[#3]
Has been mooted before in other threads, but an electric trigger on a Picatinny rail mounted pistol grip would give one the means to change LOP as needed, for example, when using the bullpup with armor.
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Posted: 1/21/2014 6:10:33 PM EDT
[#4]
Has there been any design that works as a "stock" of sorts so that you can use your own receiver?
Your lower, barreled upper and maybe the lwrc buffer to shorten LOP. The actual design would be fitted like a mako MWG but encompass the whole lower and buffer tube. the grip would be moulded into the front of the lower same as the MWG but a different angle and the "trigger assembly" would attach and be part of a proprietary rail that mounts to a regular barrel nut. magazine release would work through the trigger area so it could be ambidextrous the trigger would work through two transfer bars similar to an 870s pump but they would run through channels in the stock from the bullpup trigger to the modified stock trigger. Modified by a pin to hold the bars to the trigger. Hell if you use a self contained upper or if you're only running 22 in it eliminate the whole buffer and create a butstock?/pad threaded to fit where the buffer tube should. ... I think I'm going to need to MS paint this or mock it with a lower on cardboard. I've wondered for several years why this hasn't been done. |
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Posted: 1/22/2014 2:06:40 PM EDT
[#5]
AR-15 based bullpup? "nevah been done before!"
http://www.youtube.com/watch?v=zmOFTc8omd4 http://www.youtube.com/watch?v=-gbfmejxjIM Edited...VA-gunnut |
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Posted: 1/22/2014 2:46:43 PM EDT
[#6]
Quote HistoryQuoted:
Has been mooted before in other threads, but an electric trigger on a Picatinny rail mounted pistol grip would give one the means to change LOP as needed, for example, when using the bullpup with armor. My only thing is i'm personally an electrical dunce..I don't know if i could confidently make it safe for myself. I'm sure it could be made safe and reliable tho. |
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Posted: 1/22/2014 3:34:50 PM EDT
[#7]
Quote HistoryQuoted: AR-15 based bullpup? "nevah been done before!" http://www.youtube.com/watch?v=zmOFTc8omd4 http://www.youtube.com/watch?v=-gbfmejxjIM Edited...VA-gunnut If you're going to be sarcastic, at least don't copy links from your open tabs when some of them are to sex sites.  |
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Posted: 1/22/2014 4:21:39 PM EDT
[#8]
Quote HistoryQuoted:
If you're going to be sarcastic, at least don't copy links from your open tabs when some of them are to sex sites.
Were there shemales? Please tell me there were shemales... 
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Posted: 1/22/2014 7:10:46 PM EDT
[#9]
I was thinking a plastic lower but I changed my mind. I really like the M43 by keltec so i'm copying them a little. I also gave up on trying to package balanced springs. I just have the springs at 1 and 11 o'clock. I figure with how i'm doing the upper i can have the tilt taken by the "buffer plate" not the carrier by utilizing the dimples in the upper receiver. Notice how the carrier rides in the receiver. I think this is a new idea.
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Posted: 1/22/2014 7:14:29 PM EDT
[#10]
So you've got a charging handle (and charging handle slot) directly above the gas key and gas tube, and directly below the shooter's eyeball...
I'd also say that you need more support on the carrier runners, especially with a sheetmetal design where you can get some warpage. |
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Posted: 1/22/2014 7:16:02 PM EDT
[#11]
ya the slot is blocked by a charging rod. the charging handle pulls the rod which pulls the carrier
There would be no avoiding warpage after a heat treat. My thoughts would be a mandril to true it up after the quench. |
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Posted: 1/22/2014 7:18:42 PM EDT
[#12]
The problem with a stamped design is the cost of dies, until you go into mass production, whereas something machined can be cranked out in any decent machine shop while you perfect the design.
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Posted: 1/22/2014 7:23:42 PM EDT
[#13]
Quote HistoryQuoted:
The problem with a stamped design is the cost of dies, until you go into mass production, whereas something machined can be cranked out in any decent machine shop while you perfect the design. This is the truth. I need to shop around for custom sheet metal parts suppliers. I was trying to keep the punch formings to a minimum in the hopes that small cheap dies could be machined to make it. the bending can be done by anyone tho. |
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Posted: 1/23/2014 2:26:07 AM EDT
[#14]
I thought about it and I am really liking the idea of a milled and a stamped version. it reminds me of the AK. I have a feeling the milled version will be a boat anchor, but its not like I'll be running around with it.
EDIT: Does anyone else have any thoughts on the upper receiver? Its a wacky idea and I thought it would be nice to get some more feedback. |
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Posted: 1/24/2014 6:20:27 PM EDT
[#15]
it would probably be smart to replace some of the non structural upper with wood a wood block that also wraps some of the metal upper. I don't want to burn my face on a hot upper receiver. May need to relocate the charging system tho.
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Posted: 1/24/2014 6:30:24 PM EDT
[#16]
Why not use this:
http://www.whiz.to/~tnwfire/proddetail.php?prod=GPS which is a long stroke piston, and attach it to the gas key, & replace the spring w/ a stronger one? Then you can throw a charging handle anywhere. |
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Posted: 1/24/2014 6:33:45 PM EDT
[#17]
Quote HistoryQuoted:
Why not use this: http://www.whiz.to/~tnwfire/proddetail.php?prod=GPS which is a long stroke piston, and attach it to the gas key, & replace the spring w/ a stronger one? Then you can throw a charging handle anywhere. It might be a long stroke piston, but it's not a ~3" stroke piston, which is what it would take if you were using it as an action rod. The 3/8" ID spring in my uppers goes from the barrel nut all the way up to the face of the gas block, and it comes close to coil bind at the end of travel. Anything shorter is going to run out of room. |
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Posted: 1/24/2014 6:45:38 PM EDT
[#18]
Quote HistoryQuoted:
Why not use this: http://www.whiz.to/~tnwfire/proddetail.php?prod=GPS which is a long stroke piston, and attach it to the gas key, & replace the spring w/ a stronger one? Then you can throw a charging handle anywhere. I'm a cheap-o and i figure I can justify my costs by not having to buy a barrel, bcg, and fire controls. Looking to keep the cost down. The piston would line up with the springs tho which i like. |
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Posted: 1/25/2014 2:21:42 PM EDT
[#19]
I'm narrowing in on how i want it to look. I removed some of the lower and replaced it with wood.
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Posted: 1/26/2014 7:14:36 AM EDT
[#20]
Here are some pics of a dummy my size holding the rifle like i would hold it. as you can see the wrist to the mag is what gives me fits.
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Posted: 1/26/2014 11:44:31 AM EDT
[#21]
Quote HistoryQuoted:
Here are some pics of a dummy my size holding the rifle like i would hold it. as you can see the wrist to the mag is what gives me fits. That doesn't look any more awkward than an AUG or Tavor. There appears to be plenty of room from your mockups. Did you say that the charging handle has a slot cover attached to it? |
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Posted: 1/26/2014 11:46:36 AM EDT
[#22]
Quote HistoryQuoted:
It might be a long stroke piston, but it's not a ~3" stroke piston, which is what it would take if you were using it as an action rod. The 3/8" ID spring in my uppers goes from the barrel nut all the way up to the face of the gas block, and it comes close to coil bind at the end of travel. Anything shorter is going to run out of room. Quote HistoryQuoted:
Quoted:
Why not use this: http://www.whiz.to/~tnwfire/proddetail.php?prod=GPS which is a long stroke piston, and attach it to the gas key, & replace the spring w/ a stronger one? Then you can throw a charging handle anywhere. It might be a long stroke piston, but it's not a ~3" stroke piston, which is what it would take if you were using it as an action rod. The 3/8" ID spring in my uppers goes from the barrel nut all the way up to the face of the gas block, and it comes close to coil bind at the end of travel. Anything shorter is going to run out of room. It doesn't in a carbine config, but it should with a rifle length system. |
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Posted: 1/26/2014 11:53:34 AM EDT
[#23]
Quote HistoryQuoted:
That doesn't look any more awkward than an AUG or Tavor. There appears to be plenty of room from your mockups. Did you say that the charging handle has a slot cover attached to it? Quote HistoryQuoted:
Quoted:
Here are some pics of a dummy my size holding the rifle like i would hold it. as you can see the wrist to the mag is what gives me fits. That doesn't look any more awkward than an AUG or Tavor. There appears to be plenty of room from your mockups. Did you say that the charging handle has a slot cover attached to it? Ya that would be the way to go. The slot cover would ride along and go under the wood. |
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Posted: 1/26/2014 12:42:22 PM EDT
[#24]
What if you cant the pistol grip sideways to the right? Or put it on a swivel, if you want it to be ambidextrous, so it swings to either side, then locks in place.
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Posted: 1/26/2014 12:45:20 PM EDT
[#25]
Quote HistoryQuoted:
What if you cant the pistol grip sideways to the right? Or put it on a swivel, if you want it to be ambidextrous, so it swings to either side, then locks in place. Put some Birdman sights on it while you're at it.. 
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Posted: 1/26/2014 1:57:26 PM EDT
[#26]
Quote HistoryQuoted:
What if you cant the pistol grip sideways to the right? Or put it on a swivel, if you want it to be ambidextrous, so it swings to either side, then locks in place. IF there is an issue, which I doubt, that should work. A few degrees either way would give the access without affecting the trigger pull very much. And considering that it is a linkage, the trigger could pivot as well. |
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Posted: 1/26/2014 2:00:30 PM EDT
[#27]
Quote HistoryQuoted:
What if you cant the pistol grip sideways to the right? Or put it on a swivel, if you want it to be ambidextrous, so it swings to either side, then locks in place. Actually I had an early config not too far off where the magazine would come into the shooter to avoid the trigger hand wrist (think FAD). I chose not to since i wanted to save my FSB/barrel;. Your idea would work if you want to use a different FSB and can reconfigure the trigger. As a side note, one thing that may not be obvious is that keeping the picatinny rail at the right height for the FSB is very challenging. It was hard for the bullpup and I am struggling on how i can do it for the traditional rifle configuration. As for ambi I really don't think it can ever be like RDTCU's pdr and reconfigure on the fly. My thought is you would need 2 ejection ports and the one not in use would be welded or riveted shut (screws also i guess). You would just need a right or left hand bolt and your upper configured correctly. I have been thinking about a way to deflect shells down it may not go anywhere tho. |
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Posted: 1/26/2014 3:33:20 PM EDT
[#28]
Quote HistoryQuoted:
Actually I had an early config not too far off where the magazine would come into the shooter to avoid the trigger hand wrist (think FAD). I chose not to since i wanted to save my FSB/barrel;. Your idea would work if you want to use a different FSB and can reconfigure the trigger. Why does the front sight have to be 180 from the grip? As long as your eye determines that the sight tower is vertical, the grip being slightly off is no big deal. Either way, from your diagrams, it appears there isn't an issue. As a side note, one thing that may not be obvious is that keeping the picatinny rail at the right height for the FSB is very challenging. It was hard for the bullpup and I am struggling on how i can do it for the traditional rifle configuration. As for ambi I really don't think it can ever be like RDTCU's pdr and reconfigure on the fly. My thought is you would need 2 ejection ports and the one not in use would be welded or riveted shut (screws also i guess). You are limiting your self. You would just need a right or left hand bolt and your upper configured correctly. I have been thinking about a way to deflect shells down it may not go anywhere tho. Quote HistoryQuoted:
Quoted:
What if you cant the pistol grip sideways to the right? Or put it on a swivel, if you want it to be ambidextrous, so it swings to either side, then locks in place. Actually I had an early config not too far off where the magazine would come into the shooter to avoid the trigger hand wrist (think FAD). I chose not to since i wanted to save my FSB/barrel;. Your idea would work if you want to use a different FSB and can reconfigure the trigger. Why does the front sight have to be 180 from the grip? As long as your eye determines that the sight tower is vertical, the grip being slightly off is no big deal. Either way, from your diagrams, it appears there isn't an issue. As a side note, one thing that may not be obvious is that keeping the picatinny rail at the right height for the FSB is very challenging. It was hard for the bullpup and I am struggling on how i can do it for the traditional rifle configuration. As for ambi I really don't think it can ever be like RDTCU's pdr and reconfigure on the fly. My thought is you would need 2 ejection ports and the one not in use would be welded or riveted shut (screws also i guess). You are limiting your self. You would just need a right or left hand bolt and your upper configured correctly. I have been thinking about a way to deflect shells down it may not go anywhere tho. |
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Posted: 1/26/2014 6:33:19 PM EDT
[#29]
Quote HistoryQuoted:
IF there is an issue, which I doubt, that should work. A few degrees either way would give the access without affecting the trigger pull very much. And considering that it is a linkage, the trigger could pivot as well. Quote HistoryQuoted:
Quoted:
What if you cant the pistol grip sideways to the right? Or put it on a swivel, if you want it to be ambidextrous, so it swings to either side, then locks in place. IF there is an issue, which I doubt, that should work. A few degrees either way would give the access without affecting the trigger pull very much. And considering that it is a linkage, the trigger could pivot as well. Exactly what the Australian arm pistol built by Bushmaster did. |
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Posted: 1/26/2014 6:37:21 PM EDT
[#30]
Quote HistoryQuoted:
As for ambi I really don't think it can ever be like RDTCU's pdr and reconfigure on the fly. My thought is you would need 2 ejection ports and the one not in use would be welded or riveted shut (screws also i guess). You would just need a right or left hand bolt and your upper configured correctly. I have been thinking about a way to deflect shells down it may not go anywhere tho. http://www.cmmginc.com/product_p/55ba13d-l.htm |
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Posted: 1/26/2014 7:14:40 PM EDT
[#31]
Quote HistoryQuote HistoryQuoted:
Quoted:
As for ambi I really don't think it can ever be like RDTCU's pdr and reconfigure on the fly. My thought is you would need 2 ejection ports and the one not in use would be welded or riveted shut (screws also i guess). You would just need a right or left hand bolt and your upper configured correctly. I have been thinking about a way to deflect shells down it may not go anywhere tho. http://www.cmmginc.com/product_p/55ba13d-l.htm Ya i like that. Good find. I only want it welded or riveted since my face will be right there in the event of an explosion i won't loose an eye. I do agree that ideally you would have something that would be easy to reconfigure. I'm thinking a piece of sheet metal on the inside that is larger than the ejection port. |
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Posted: 1/29/2014 5:49:23 AM EDT
[#32]
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Posted: 1/29/2014 8:52:52 AM EDT
[#33]
Quote HistoryThanks, ponq. I like the way that guy thinks! And, here's one for a lefty (NOTE: The fired cases eject straignt down, with this version.) http://tinypic.com/r/nxp8jn/5 |
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Posted: 1/29/2014 2:07:39 PM EDT
[#34]
Quote HistoryQuoted:
Thanks, ponq. I like the way that guy thinks! And, here's one for a lefty (NOTE: The fired cases eject straignt down, with this version.) http://tinypic.com/r/nxp8jn/5 Quote HistoryQuoted:
Thanks, ponq. I like the way that guy thinks! And, here's one for a lefty (NOTE: The fired cases eject straignt down, with this version.) http://tinypic.com/r/nxp8jn/5 Nice finds. I had the rocket launcher style hold dinking around in my head but then I did some measurements and I think you don't even need to do that if you can relocate the springs. I have been thinking of an adjustable stock that could adjust under the upper receiver to end up giving a rocket launcher hold. I really think its possible to get the ar bcg to eject down with the right system of deflectors/guides but i just can't put my finger on how you would do that. (in an elegant way). That does remind me that i need to figure out a shell deflector geometry that won't ruin the cases on the edge of the sheet metal upper. |
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Posted: 1/30/2014 5:06:49 PM EDT
[#35]
Quote HistoryThe redneck scientist gave me a couple redneck ideas. 1. A cutout in the stock so you can hold it rocket launcher style 2. An extension on the safety selector (kitchen stove style) 
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Posted: 1/30/2014 5:29:10 PM EDT
[#36]
It's a neat hump, but wouldn't seem to absorb recoil very well. You kitchen sink selector would easily be added to a BAD ASS.
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Posted: 1/31/2014 3:18:17 AM EDT
[#37]
Quote HistoryQuoted:
It's a neat hump, but wouldn't seem to absorb recoil very well. You kitchen sink selector would easily be added to a BAD ASS. Honestly i don't think I would ever hold it like that (never needed to clear rooms). It does give the option for a shorter bolt thru the back of the stock to secure the lower rear stock to the lower receiver and saves a few oz of wood. I don't think I like the huge wooden curve so I may make it a little more blocky. That space is not used for anything else so I figured might as well get rid of it until I find I need it. |
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Posted: 2/1/2014 8:43:03 AM EDT
[#38]
Here are some pics using a 14.5" barrel. It does put the rifle within arms reach if you do the rocket launcher hold
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Posted: 2/1/2014 9:22:36 AM EDT
[#39]
that charging handle is non-reciprocating correct? otherwise... FACE
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Posted: 2/1/2014 9:36:59 AM EDT
[#40]
ya non reciprocating. it would use the charging latch of the ar and a plate to cover the slot. I only have half the slot cover drawn it there in red. Need to draw more fine details.
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Posted: 2/1/2014 11:47:31 AM EDT
[#41]
I know your looking to see about using an unmodified bolt carrier, but a design like that of the NEA bolt carrier/buffer/spring may be just the ticket to simplify your design. Take a look at my thread here:
NEA/Shrike |
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Posted: 2/1/2014 1:43:01 PM EDT
[#42]
Quote HistoryQuoted:
I know your looking to see about using an unmodified bolt carrier, but a design like that of the NEA bolt carrier/buffer/spring may be just the ticket to simplify your design. Take a look at my thread here: NEA/Shrike I like it and will read more, tho I feel more like Macgyver (except I like guns) using unmodified gun parts. What numbers are you getting for the rearmost part of the rifle during cycling (measured from the safety selector axis)? Here is what I'm getting. 
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Posted: 2/1/2014 2:13:10 PM EDT
[#43]
I think the best bet would be a piston much like the SIG design where the spring is on the piston above the barrel
I think that would be superb |
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Posted: 2/1/2014 4:07:31 PM EDT
[#44]
Quote HistoryQuoted:
I like it and will read more, tho I feel more like Macgyver (except I like guns) using unmodified gun parts. What numbers are you getting for the rearmost part of the rifle during cycling (measured from the safety selector axis)? Here is what I'm getting. http://i.imgur.com/B2u9KBv.jpg Quote HistoryQuoted:
Quoted:
I know your looking to see about using an unmodified bolt carrier, but a design like that of the NEA bolt carrier/buffer/spring may be just the ticket to simplify your design. Take a look at my thread here: NEA/Shrike I like it and will read more, tho I feel more like Macgyver (except I like guns) using unmodified gun parts. What numbers are you getting for the rearmost part of the rifle during cycling (measured from the safety selector axis)? Here is what I'm getting. http://i.imgur.com/B2u9KBv.jpg I don't know at this point, I've got parts all over the place. The receiver is getting refinished and the BCG is with the smith who's helping me out. I don't think it would be difficult to figure out, as you're only adding about a 1/4 to the bolt which hits the back of the new buffer tube when fully cycled, the maximum bolt travel due to the gas key is like 3.7ish inches. This just combines the bolt and buffer into 1 unit. |
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Posted: 2/3/2014 7:49:58 PM EDT
[#45]
Instead of being productive in my design I chose to piss around and make the bakelite more real looking.
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Posted: 2/9/2014 4:15:50 AM EDT
[#46]
I finally laid out the rough traditional lower. I did a rendering of the concept I'm shooting for with the universal upper. You would be able to configure it with a regular layout or bullpup.
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Posted: 2/9/2014 7:02:16 AM EDT
[#47]
FYI the "rocket launcher hold" was used in the French semi-automatic Faucon-Munier Rifle of 1918. I can't find images online, but if you can get your hands on a copy of Proud Promise: French Autoloading Rifles 1898-1979 there are photos on page 56.
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Posted: 2/9/2014 7:21:47 AM EDT
[#48]
Ya i'll have to search harder to find that french one. Rouge Techie on weapons guild posted this:
I don't know if a 50 cal would be good in a practical rifle match or in close quarters tho. In my design I'm only thinking you could do the rocket launcher hold if you wanted to. Most of the time I would think you would hold the bullpup normal. I'm keeping the lop under 15.75" |
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Posted: 2/9/2014 5:24:31 PM EDT
[#49]
On a separate topic, since i'm going cheap I'm worried the mag well dimple tooling may cost me, so I'm revisiting the idea of using WASR style mag blocks instead of dimples. Anyone have any insight? I'm liking the blocks since you can design it tight then file/machine it down. Thanks.
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Posted: 2/9/2014 8:50:32 PM EDT
[#50]
Going cheap on the mag well? How cheap do you want? Perhaps Airsoft cheap?
http://www.feinsteinproject.org/loes/effortbloomberg/subeffortg36/subEffortG36.html 56K death, BTW. |
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