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Caliburn: Mag-Fed Pump-Action Springer

 
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Caliburn: Mag-Fed Pump-Action Springer
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Captain Slug
New Member


Joined: 14 Sep 2016
Posts: 11
Location: Sterling, VA



Post Caliburn: Mag-Fed Pump-Action Springer  Reply with quote
The prototype is finished. I just need to finish testing this over the next few days.






Since making the design and making the prototype I've made some small adjustments. The bolt now seals inside the plunger tube using a skirt seal, just like the plunger head does. The rubber washer was fitting too tight in the plunger tube and made the pump-action too friction heavy.

Photos and videos of the finished blaster will be showing up over the next few days. A write-up may take some time since that requires making another one. I will however make the templates and partlist available once testing is complete.

Special Thanks to skullface44. This design is directly inspired by the Rev-Shot, even if it doesn't really share any dimensions or parts.
Tue Sep 20, 2016 1:21 pm View user's profile Send private message Visit poster's website
Aldegar
Veteran Member


Joined: 29 Jun 2014
Posts: 252
Fav. Blaster: Hammershot
Location: Gig Harbor, Wa



Post Reply with quote
That is one bad ass homemade!!!! Nice work!

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Custom Nerf guns and Nerf modification kits
Wed Sep 21, 2016 12:42 pm View user's profile Send private message Visit poster's website
Captain Slug
New Member


Joined: 14 Sep 2016
Posts: 11
Location: Sterling, VA



Post Reply with quote
Work is still ongoing since I want this to function flawlessly yet still be adaptable to multiple ammo types.

Special thanks to jwasko for inspiring this update. Ahead of the magwell is a "chamber" made out of .527" ID aluminum. This looser fit on every size of dart means that darts won't buckle in the process of being pushed out of the magazine. The updated ram rod seals inside the chamber using an o-ring instead of sealing into the back of the barrel.



The chamber has a clear PETG coupler added to the end of it. This coupler allows the barrel opening to be adjusted to multiple dart lengths so that when the dart is rammed through the chamber, only the very tip of the dart has to be loaded into the back of the barrel.



The window cut into the top of the front tube allows adjustments to the barrel to be made by eye based on where the tip of the dart ends up after being fed into the chamber by the ram rod.

I've done testing with the aluminum barrel and it's shooting beige foam slugs 90 to 110 feet. That's pretty good for a 10-inch long barrel with a somewhat loose fit.

Next I'll make a frame piece for the 1/2" ID clear barrel and test it with multiple lengths of men-gun darts.

First tests with full-length darts are a success.

Going to do a full set of range tests with both barrels and three types of darts, then make a demo video.


OCT 26 2016


Today I did about one third of the testing I intend to do with the chronograph. The results are pretty interesting so far though. I wanted to see if it matters if the barrel position affects muzzle velocity at all. So I ran two lengths of darts, and three different types of foam through the same barrel.
Code:
Beige Slugs - PETG Barrel - Head-Spaced
208
211
206
207
208

Beige Slugs - PETG Barrel - Not Head-Spaced
204
205
208
206
210
200

Red Men-Gun Short - PETG Barrel - Head-Spaced
210
198
205
193
198

Red Men-Gun Full - PETG Barrel - Head-Spaced
199
206
194
192
213

Elite Full Length - PETG Barrel - Head-Spaced
192
208
200
210
204
202

It looks like range isn't impacted at all by having the barrel in the "wrong" location for shorter darts. When loaded wit a dart that's too short to reach the barrel, the chamber that the dart is being pushed into by the ram-rod is acting like an RSCB that only holds a single dart. The initial puff of air into the chamber is loading the dart into the barrel, even if the ram-rod hasn't pushed it far enough to reach it yet.

This is nice because it means that the location of the barrel can be fixed and doesn't need to be adjusted for different lengths of darts.

I did a handful of tests with an aluminum barrel, but as expected it's not a great fit on the foam of any of the darts I currently have, so the muzzle velocity for all of those shots was 30 fps lower than the shots through the PETG barrel.

The next set of tests I will do will be to see how much the muzzle velocity drops when the o-ring isn't on the ram-rod.

I also have a minor tweak to make to the bolt assembly.


Last edited by Captain Slug on Thu Oct 27, 2016 1:21 am; edited 2 times in total
Sun Oct 16, 2016 2:11 pm View user's profile Send private message Visit poster's website
OldNoob
Foam Data Collector


Joined: 07 May 2013
Posts: 4886
Fav. Blaster: Xtreme 180 Rapidstrike
Location: In the Boonies



Post Reply with quote
EDIT

Fixed that double post for you, please edit your last post if you have more to add between comments.  



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Big_Poppa_Nerf wrote:

Boff whats the damage? I have spent over 3 times my Nerf budget this month already. Part of me is trying to be a responsible parent/husband/house owner. The other half is just says 'Ahhhh, Screw it!'.
Mon Oct 17, 2016 9:45 pm View user's profile Send private message Send e-mail
Captain Slug
New Member


Joined: 14 Sep 2016
Posts: 11
Location: Sterling, VA



Post Reply with quote
Build is completed.

Tons more photos in the gallery below.
http://imgur.com/a/3FVV3

CAD Files and templates will be available soon.
Fri Oct 28, 2016 1:46 am View user's profile Send private message Visit poster's website
old_man_nerf
Game Organiser


Joined: 25 Jan 2013
Posts: 868
Fav. Blaster: I wanna Nemesis!!
Location: Leeds



Post Reply with quote
An excellent piece of workmanship. Sets the standard high!
Fri Oct 28, 2016 8:20 am View user's profile Send private message Visit poster's website
Aldegar
Veteran Member


Joined: 29 Jun 2014
Posts: 252
Fav. Blaster: Hammershot
Location: Gig Harbor, Wa



Post Reply with quote
This is bad ass! How do you like the mengun short darts?

_________________
www.tacticoolfoam.com
Custom Nerf guns and Nerf modification kits
Fri Oct 28, 2016 1:30 pm View user's profile Send private message Visit poster's website
Captain Slug
New Member


Joined: 14 Sep 2016
Posts: 11
Location: Sterling, VA



Post Reply with quote
Aldegar wrote:
This is bad ass! How do you like the mengun short darts?

I'm buying the full-length ones and cutting them down. They're really really good at artifact length. Good enough that I hesitate to bother making or buying slugs anymore.
The foam in particularly is very consistent in diameter and very firm with dense cell count.
I have some newer blue ones that I need to test in comparison with the red ones.
Fri Oct 28, 2016 5:22 pm View user's profile Send private message Visit poster's website
Captain Slug
New Member


Joined: 14 Sep 2016
Posts: 11
Location: Sterling, VA



Post Reply with quote
Construction Write-up is finished. Just finished Blaster 002 of 006.



Write-Up: http://captainslug.com/caliburn.html

Partlist: http://captainslug.com/Nerf/caliburn_partslist.xls

Templates: http://captainslug.com/Nerf/caliburn_templates.doc

Solidworks CAD files: http://captainslug.com/Nerf/Caliburn_Solidworks.zip(2.6mb)

STEP 203 CAD files: http://captainslug.com/Nerf/Caliburn_STEP.zip(436kb)


Wed Feb 15, 2017 10:08 pm View user's profile Send private message Visit poster's website
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