16 replies to this topic

[diamondbacknf1626]

So, I began thinking about this idea quite awhile ago, when I was trying to figure out where homemades could go from this point. Pump action guns have become so commonplace, and the RBP fit the bill quite spectacularly. Then, Kane posted his original string plunger "rod" blaster, the predecessor to the Bullpump, and mentioned that he would tie it around his arm and use it with one hand. The fundamental problem I see with this, though, is that in order to fire the blaster, your arm would have to be in a bent position. Basically, to prime, you'd extend your arm, and because your outstretched arm would still have tension on the string, the blaster wouldn't fire from that position, forcing you into an awkward, arm-bent position. That was my logic anyway...maybe that was just me. So, finally, I got to building, and this was the solution:

In order to prime the blaster, you simply pull your hand on the handle back towards your shoulder like so:

And then return it to the forward position with the aid of a strap keeping the back end of the blaster tight to your shoulder (I've been using a cheap belt that I never wear. I hope to set up something with a simple buckle that I can snap on quickly):


And the blaster is primed. The catch is an upgraded Rainbow catch discussed here. The handle is secured to 2" Polyester, which fits over the 1 1/4" PVC and under the 2" PVC, which has been cut to allow the handle to slide through it, but keeps all other moving parts contained, the sliding ring attached to the handle included). The whole blaster is almost exactly the length of the Rainbowpump, but being that the handle, at rest, sits about three inches farther forward, most of the weight/length is kept to the back end, which, being secured to your shoulder, makes the blaster as a whole quite comfortable to operate (with one hand). You can use it with two hands as well, of course, which also works real nice. I'm super duper happy with the way this turned out. It works real smooth, and shoots real hard. I did take down the volume a bit from a standard Rainbow draw, to keep the size reasonable, and it still shoots super nice. There were also quite a bit of new things I did to this blaster, but I will, of course, be doing a full writeup, being that this will be one of my contest submissions for ryan's homemade contest, so I will discuss them then at length. But for now, what do you guys think?

EDIT: Also, this would, in theory, be entirely operable with one hand. However, in order to make it really work smoothly, you'd need a low torque ball valve, or some sort of dart door on the end of the hopper. Otherwise you'll need the assistance of the other hand to open the hopper and to load darts. I don't want to call it entirely one hand operable, just because people may have limited access to either of these things...or may just like end caps.

Edited by diamondbacknf1626, 15 May 2011 - 01:51 PM.

[WicketTheModder619]

Wow....nice work! I remember Kane talking about how he had plans to make a blaster that is primed and fired with one hand, but was unaware that you had something in the works. Looks sweet, but how much strain does it put on the user's wrist? Also, clever idea with the shoulder stock, before I got that far into the reading I was imagining it slipping off of the shoulder while priming and sending the power of a [k26] into the user's face...ouch.

[shardbearer]

Holy crap...Im going against both this and Kane's blaster for the contest? And of course someone is going to combine them...I give up on placing.

Anyway, what is behind the handle slots? That seems like just deadspace to me.

Edited by shardbearer, 15 May 2011 - 02:48 PM.

[diamondbacknf1626]

'WicketTheModder619', on 15 May 2011 - 6:54 PM, said:

Wow....nice work! I remember Kane talking about how he had plans to make a blaster that is primed and fired with one hand, but was unaware that you had something in the works. Looks sweet, but how much strain does it put on the user's wrist? Also, clever idea with the shoulder stock, before I got that far into the reading I was imagining it slipping off of the shoulder while priming and sending the power of a [k26] into the user's face...ouch.

It doesn't really put any strain on the user's wrist. See the below response. Also, the stock doesn't really try to slip off your shoulder, even without the strap. The strap is only there to hold the blaster in place while returning the handle to the forward position.

'shardbearer', on 15 May 2011 - 7:35 PM, said:

Holy crap...Im going against this for the contest? I give up.

Anyway, what is behind the handle slots? That seems like just deadspace to me.

The "deadspace" that you're referring to is in place in order to keep you from having to pull your hand almost to the point of touching your shoulder in order to prime the blaster. It could be eliminated entirely, but it would be less comfortable to prime. The slots, though, actually, are too long. As you can see from the primed picture, they could be 1 1/2"- 2" shorter. Other than that though, the "deadspace" was intentional.

[shardbearer]

This needs slam fire.

[KaneTheMediocre]

Nice job diamond. You're absolutely correct that the necessity of firing from a bent-arm position was the deal-breaker for the one-handed string priming business. A short video would go a long way to demonstrating the ergonomic properties of this thing.

Also, as a judge, it would be a conflict of interest for me to enter the contest. So no one is competing with me on that count.

[diamondbacknf1626]

Here's a quick vid of it operating. I noticed after watching it that it looks uncomfortable...it's really quite comfortable to prime without issue. The strap is all that needs work, and once that's all said and done, it'll work flawlessly.

Thanks a lot, Kane, btw.

Edited by diamondbacknf1626, 15 May 2011 - 05:44 PM.

[diamondbacknf1626]

I hate to double post, but I added another video demoing a bit more of the blaster's function:

[Phree Agent]

I know we talked about this some in the IRC a looong while back, so I am glad it came to be. Looks good, and I know it will only get better from here. Congrats.

[Ryan201821]

Very cool. The ability to not have to have your hand in the bend position when firing is nice. This also requires you to have the pump all the way forward to fire, preventing the steel rod from slamming against the polyester.

The only thing that sucks about using the RBP as a template compared to Kane's design, is that it's inherently huge, even if you have shorter draw. Ideally if you want to use these one-handed, you're going to want to make them 6-8" shorter to make them easier to dual-wield, at least in my opinion. One thing idea that's plausible is taking this idea and combining it with my plan to make a Super-RBP, sizing up the plunger tube so you can have a shorter amount of draw, while still creating more than enough volume.

Otherwise, good work.

[KaneTheMediocre]

'Ryan201821', on 16 May 2011 - 9:30 PM, said:

Very cool. The ability to not have to have your hand in the bend position when firing is nice. This also requires you to have the pump all the way forward to fire, preventing the steel rod from slamming against the polyester.

The only thing that sucks about using the RBP as a template compared to Kane's design, is that it's inherently huge, even if you have shorter draw. Ideally if you want to use these one-handed, you're going to want to make them 6-8" shorter to make them easier to dual-wield, at least in my opinion. One thing idea that's plausible is taking this idea and combining it with my plan to make a Super-RBP, sizing up the plunger tube so you can have a shorter amount of draw, while still creating more than enough volume.

Otherwise, good work.

Having seen the video, I have a much better idea of how everything comes together. In particular, I appreciated the explanation of the ergonomic necessity of a long stock.

The enormous size of this thing does seem to preclude the pistol-style maneuverability that I'd like in a OHPB, and to some extent this forces an extended arm while shooting-Vastly preferable to forcing a bent arm, but still not the ideal OHPB. It's worth noting that this blaster is also unambiguously 1-handed fireable. Most homemade pump action blasters, including everything that Ryan or myself has produced, have a "floating" priming handle when the blaster is primed. This sometimes results in some ruinous external movement and noise if the blaster is fired without a hand on the priming handle, depending on where the priming handle happens to be at the time. That's always been on my "to-do" list of things to fix about my homemades, but you beat me to it.

Don't underestimate the challenge of making a good strap. My experience has been that the 1-loop shoulder harness will work its way off my shoulder regardless of how tight I make it. Fortunately for you, it's not fighting the priming force, so it's got a much smaller job than my shoulder loops did.

[VACC]

Another strap, running perpendicular to your original shoulder strap, is the easiest way to ensure that it won't move. I'd probably make two shoulder straps, and link them with a strap across my back in order to hold both in place. This also has the benefit of allowing you to use two of these things, which I always assumed was the primary objective of one handed blasters. Don't underestimate how important it is that the shoulder strap not budge while running.

[ricochet]

I like it! I don't know if the thought occured to you, but the strap could possibly (I emphasize possibly) eliminate a need for a sling if you carry more than one blaster during your wars. A second thought to eliminate the slipping issue is if you use a second strap on the opposite shoulder, linked to the other across the back of your body. This would form the shape of an "H", working in a similar fashion to a backpack. I bet my explanation may be a bit fuzzy, but it's only an idea. I'm glad to see a new breed of blasters! Props, you deserve a cookie.

[diamondbacknf1626]

'Ryan201821', on 16 May 2011 - 9:30 PM, said:

Very cool. The ability to not have to have your hand in the bend position when firing is nice. This also requires you to have the pump all the way forward to fire, preventing the steel rod from slamming against the polyester.

The only thing that sucks about using the RBP as a template compared to Kane's design, is that it's inherently huge, even if you have shorter draw. Ideally if you want to use these one-handed, you're going to want to make them 6-8" shorter to make them easier to dual-wield, at least in my opinion. One thing idea that's plausible is taking this idea and combining it with my plan to make a Super-RBP, sizing up the plunger tube so you can have a shorter amount of draw, while still creating more than enough volume.

Otherwise, good work.

Thanks. Yeah, that was one of my key focuses...firing from that position is just awkward to me. Also, using larger plunger tubes could be a potential development from this point. If I get a hold of the materials to do so, I will give that a go. As big as it is though, as I described, having most of the weight to the back makes the potential for wielding two very feasible.

'KaneTheMediocre', on 16 May 2011 - 11:03 PM, said:

Having seen the video, I have a much better idea of how everything comes together. In particular, I appreciated the explanation of the ergonomic necessity of a long stock.

The enormous size of this thing does seem to preclude the pistol-style maneuverability that I'd like in a OHPB, and to some extent this forces an extended arm while shooting-Vastly preferable to forcing a bent arm, but still not the ideal OHPB. It's worth noting that this blaster is also unambiguously 1-handed fireable. Most homemade pump action blasters, including everything that Ryan or myself has produced, have a "floating" priming handle when the blaster is primed. This sometimes results in some ruinous external movement and noise if the blaster is fired without a hand on the priming handle, depending on where the priming handle happens to be at the time. That's always been on my "to-do" list of things to fix about my homemades, but you beat me to it.

Yeah, that's the thing. The blaster is intentionally about 4" longer than it needs to be to "function." The added length to the back is simply to improve ergonomics. The fact that the handle does not "float" is a nice plus to this design, though not one of my original project goals. It's nice to not have to worry about firing it from a position that could harm the blaster. The handle also has a perfect fit under the 2" PVC, so it never jiggles around, even when I'm not holding it- a product of cutting a portion of the 2" PVC out, so that it tends to constrict a little more than it otherwise would on the sliding handle, which I quite like.

'VACC', on 16 May 2011 - 11:25 PM, said:

Another strap, running perpendicular to your original shoulder strap, is the easiest way to ensure that it won't move. I'd probably make two shoulder straps, and link them with a strap across my back in order to hold both in place. This also has the benefit of allowing you to use two of these things, which I always assumed was the primary objective of one handed blasters. Don't underestimate how important it is that the shoulder strap not budge while running.

I absolutely agree, and have put some thought into this. Early configurations involved me trying rig one strap to serve the purpose of the two that you're mentioning. One thing I had in mind was a backpack sort of system like ricochet described. You know those back packs that have a cross-strap that runs across your chest? Maybe one of those could be used...a camelbak even...hydration and domination...hmm.

'ricochet', on 16 May 2011 - 11:26 PM, said:

I like it! I don't know if the thought occured to you, but the strap could possibly (I emphasize possibly) eliminate a need for a sling if you carry more than one blaster during your wars. A second thought to eliminate the slipping issue is if you use a second strap on the opposite shoulder, linked to the other across the back of your body. This would form the shape of an "H", working in a similar fashion to a backpack. I bet my explanation may be a bit fuzzy, but it's only an idea. I'm glad to see a new breed of blasters! Props, you deserve a cookie.

Oatmeal raisin, please.

Edited by diamondbacknf1626, 16 May 2011 - 07:37 PM.

[soloz1]

One word: Dual-Wielding.

[diamondbacknf1626]

'soloz1', on 17 May 2011 - 06:02 AM, said:

One word: Dual-Wielding.

That has been discussed and was a main focus when theorizing/building OHPBs. Please read above.

[diamondbacknf1626]

Finally got my ass to work on the upgraded design. Took about two days of on and off work...so not really that much time. This one uses 2" pvc, with shorter draw, and thus a pretty short final size in comparison to the original.


I <3 it.


This will, of course, have a full write up comin' soon.