Marauder Bullpup cocking conversion
Converted from bolt-action (rear end) to Winchester lever-action cocking for Steyr AUG bullpup (1970’s design) in order to keep aiming and shooting. Actually, the bolt-action is cocking and loading which includes cocking travel about 20mm and 10mm for loading prove movement. So the conversion mod is just like bolt-action to side lever-action conversion.
This cocking conversion is the additional mod on my Steyr AUG bullpup. The all linkage parts are made from steel, with brass and aluminum supporting and bushing parts for long time operation. The total weight of stock became about 2.7lbs.
The inside is shown as below sketch, it shows more details than actual photos.
It is surprisingly smooth and easy operation, you can keep right hand on trigger grip and moving left hand for cocking. Best of all, it is fun to shoot.
I changed the cheek-rest to wider type to hide the cocking wings connected to bolt shaft, so cocking wings are moving under cheek-rest and no bother cheek area. The link-rod is spread two arms before the pressure gauge (like trigger link-rod) and modified BSA’s MMC cocking linkage mechanism to transfer the pushing power to cocking wings.
Usually side lever-action or side bolt-action repeater models (like Daystate models – see below pic) are used for bullpups due to easy cocking operation.
I prefer side lever-action rather than side bolt-action because of less cocking power using lever crank. This modified lever-action may be called Grip guard-action or Trigger guard-action cocking.
I made 4 conversions for M-rod (with AUG stock) at the same time for my hunting group members, and all of them are working fine.
Currently, I am working on BSA Scorpion and Air Arms 4/5 rea-end bolt-action (not side bolt-action) models.
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Very nice design!!! Awesome dude!!!!
I have changed the cocking link to internal link, replacing 3pcs-hammer as below;
Internal Cocking-link Version
Key : Cocking shaft must move the same way as pellet loading shaft.
Hammer#1 is the hammer base to accept the original striker screw, set screw, and binding screw. (It has small flat area to keep grease for long term operation, but not important.)
Hammer#2 has latch-bolt insert block piece (Hammer#3-blue color with cocking screw hole for cocking shaft assembly. This is traveling about 10mm when cocking (actually 13mm movable).
Hammer#3 is latch-bolt insert cap.
Note: Hammer#2 and #3 are one piece construction, and Hammer#1 and Hammer#2 must have enough gaps to minimize friction. The side of Hammer screw (to hook latch screw) was filed as dimensional reason.
First, the cocking shaft is pushing Hammer#2 for about 10mm; then, pushing entire Hammer for about 20mm (totally about 30mm), as cocking/pellet loading operation.
Thanks, I am currently working on my hunting member’s BSA Scorpion and Air Arms rear-end bolt-action S41/51 models.
Different baffle types display was interesting and informative. Odd how some of those designs are so effective, while others are near useless.
Regards,
Uncle H 😯 😯 T
It’s interesting in different noise reduction design and different material.
This material is 20GA steel sheet and A228 high-carbon steel rod
(avoid to use thin aluminum material due to sound enhancement, better use Al blocks).
I made several noise reduction designs, the below is the first made design
that was copied from one of Edgun model (but I did not satisfy the performance.)
I used some info about noise reduction from below sites.
I was surprised so many people are making efforts to figure out effective noise reduction designs.
http://airenlaces.blogspot.com/2011/01/ … dores.html
http://www.silencertalk.com
http://www.silencerforum.com/
That is Bad to the BONE!!! 😎
Noted: the baffles on the Sparrow 22 appear incredibly thin. Is there a purpose there, or simply material available?
Different baffle types display was interesting and informative. Odd how some of those designs are so effective, while others are near useless.
Regards,
Uncle H 😯 😯 T
I also modified the inside of shroud, to improve the noise performance, I made the internal sound structure, modifying from Sparrow22 for .22cal 27 x 129mm (sound reduction: 41dB by Mfr).
The noise reduction is extremely good at 74dB.
The below is the typical noise reduction designs; Type A is same as Marauder shroud; Type B is ACC Titan style (sound reduction: 35-38dB by Mfr); Type C is Thundertrap style (sound reduction: over 30dB by Mfr) ; Type D is low-end Airsoft style.
Note: This is for sound reduction study purpose only.
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Tahnks, best of all – Fun to shoot !