Fully Custom Benjamin Marauder Bullpup *NEW Hardened stainless steel custom bolt

[William]

Thanks Bob for the compliment, that was a wild guess but the only thing I could think of!
Wish my Cricket had a hollow bolt, that would allow for better and more precise pellet chambering! The hollow bolt type is what I have thought to be a better solution than the probe all along.

Your design would solve a lot of problems with deep or shallow skirted pellets/bullets, the hollow probe design pushes the pellet into the chamber the same distance regardless of how deep the skirt is, due to it seating it by pushing on the skirt or should i say the furthest back part of the bullet or pellet. My Cricket has a probe and from the design of the receiver you cannot really make the bolt probe longer or it would not slide back enough to allow the Magazine to be inserted or if it was shorter, it would not seat most pellets in far enough past the transfer port.

Thats the problem I ran into trying to use the H&N Grizzly pellets (bullets) the skirt is so deep that the bolt probe will not push them past the barrel transferre port and when you fire the gun the air would burst up against the skirt bending it and even causing it to clip the baffles in the shroud not to mention really wild groups slinging lead everywhere but on target.

Maybe some day when I get ambitious I will change that probe to a hollow or even half moon type probe of some sort to get all my ammo to seat the same.

Your ideas are some of the best,

Oh forgot to mention I did resize and shoot my pellets and bullets, what a difference that makes, here is the link if you want to read the review on it,  http://www.gatewaytoairguns.org/GTA/index.php?topic=82720.msg792098#msg792098 

Thanks again for all the info and great customizing reviews, I love that 15 shot Magazine 

William

[scharfe]

Ended up trying to test the breech noise tonight with the different bolts. I also swapped out a new o-ring in the barrel. Results are as fallows.

My old o-ring (original from when the gun was new) was a bit worn. Swapping out the o-ring tightened up the fbs considerably. First 6 shots were less than 1 fps apart.

                 Thru Bolt             Factory Bolt
Min                801.7                  828.8
Max               806.9                  839.5         
Average         804.9                  832.0     

This is the set up I used, for measuring the fps and dBs. Its temporary haven't had the time but build a proper bench. The rifle was clamped into place. I used a galaxy s5 with an app called Sound Meter sitting on the gray pads next to the rifle about 10 inches from the breech.



I don't trust the app just using it as an comparison among other sound levels.

Basement almost zero noise  - 20dB
Basement  central air fan running  - 41dB      -all shots were fired here
Clicking of hammer locking and mag rotating 1 pellet - 52dB

Factory Bolt - 71-73 dB
Thru Bolt  - 72 dB

The sound of the pellet leaving the barrel was louder than the breech noise and thats all the sound meter was picking up. I think I need test it outside, maybe get different results, I thought noise coming from the breech area was louder than the shot outside but maybe Im mistaken.

Fun fact when you unscrew your shroud to remove the breech and swap out bolts you should pull it all the way off and put it back on when done. If you just take it half off and shoot the gun like an idiot. You will destroy some of your baffles.

Another Fun fact a pellet moving at about 800 fps will only go through about 3 baffles before it stops. Luckily I have a 3d printer so printed some new ones.

[scharfe]

Thanks Bob for the compliment, that was a wild guess but the only thing I could think of!
Wish my Cricket had a hollow bolt, that would allow for better and more precise pellet chambering! The hollow bolt type is what I have thought to be a better solution than the probe all along.

Your design would solve a lot of problems with deep or shallow skirted pellets/bullets, the hollow probe design pushes the pellet into the chamber the same distance regardless of how deep the skirt is, due to it seating it by pushing on the skirt or should i say the furthest back part of the bullet or pellet. My Cricket has a probe and from the design of the receiver you cannot really make the bolt probe longer or it would not slide back enough to allow the Magazine to be inserted or if it was shorter, it would not seat most pellets in far enough past the transfer port.

Thats the problem I ran into trying to use the H&N Grizzly pellets (bullets) the skirt is so deep that the bolt probe will not push them past the barrel transferre port and when you fire the gun the air would burst up against the skirt bending it and even causing it to clip the baffles in the shroud not to mention really wild groups slinging lead everywhere but on target.

Maybe some day when I get ambitious I will change that probe to a hollow or even half moon type probe of some sort to get all my ammo to seat the same.

Your ideas are some of the best,

Oh forgot to mention I did resize and shoot my pellets and bullets, what a difference that makes, here is the link if you want to read the review on it,  http://www.gatewaytoairguns.org/GTA/index.php?topic=82720.msg792098#msg792098 

Thanks again for all the info and great customizing reviews, I love that 15 shot Magazine 

William

This probe was made specifically for crossman primer pellets (cheap to test with), it does't fit a jsb heavies as well as I like. The difference in skirts among different pellets is pretty big if you start looking at them. If I was good, I would make a bolt with a removable tip to swap out the tip for specific pellets.

[William]

Your killin me lol
Sorry not making fun of you, its just the "Fun Facts" part, I can only imagine the look on your face when you pulled the trigger! I have done things like that before and knowing the split second before I pulled the stupid move it was going to happen, but still did it anyway!

Kind of like one day I loaded a pellet and didn't know it and as I pulled the bolt back and started pushing a second one in and remembered so I stopped with it half way into the chamber, what a mistake that was! Some how the second one got jammed when the mag tried to rotate cocking it sideways so I tried to force it in behind the other and it bent, no way could I get the mag out with it stuck half in and half out into the mag. You know you would think that lead would give a little, but no it won't, well 20 minutes later with a small hammer and a plastic punch I had to beat the mag out. Believe it or not that Mrod .22 factory Mag actually still works. Should have just kept loading the second pellet and shot them out 

Thanks for the laugh 

William

[William]

I have seen 2 piece bolts that someone made that screwed in/out and with a tiny set screw so he could adjust how far it seated the pellet, so I bet you could make something similar to just swap out the probe tip while the bolt is 3/4 open. Just depends on how you lock it in place so you don't tear up the Oring if the Oring is inside the breech.

William

[Monkeydad1969]

Ended up trying to test the breech noise tonight with the different bolts. I also swapped out a new o-ring in the barrel. Results are as fallows.

My old o-ring (original from when the gun was new) was a bit worn. Swapping out the o-ring tightened up the fbs considerably. First 6 shots were less than 1 fps apart.

                 Thru Bolt             Factory Bolt
Min                801.7                  828.8
Max               806.9                  839.5         
Average         804.9                  832.0     

This is the set up I used, for measuring the fps and dBs. Its temporary haven't had the time but build a proper bench. The rifle was clamped into place. I used a galaxy s5 with an app called Sound Meter sitting on the gray pads next to the rifle about 10 inches from the breech.



I don't trust the app just using it as an comparison among other sound levels.

Basement almost zero noise  - 20dB
Basement  central air fan running  - 41dB      -all shots were fired here
Clicking of hammer locking and mag rotating 1 pellet - 52dB

Factory Bolt - 71-73 dB
Thru Bolt  - 72 dB

The sound of the pellet leaving the barrel was louder than the breech noise and thats all the sound meter was picking up. I think I need test it outside, maybe get different results, I thought noise coming from the breech area was louder than the shot outside but maybe Im mistaken.

Fun fact when you unscrew your shroud to remove the breech and swap out bolts you should pull it all the way off and put it back on when done. If you just take it half off and shoot the gun like an idiot. You will destroy some of your baffles.

Another Fun fact a pellet moving at about 800 fps will only go through about 3 baffles before it stops. Luckily I have a 3d printer so printed some new ones.

Hey Bob,

I like your temp bench.  What lights are you using to chrony with?

Joe

[vinenator]

I build custom guitar effect pedals. For circuit boards I use oshpark.com , if you use eagle for your board layouts, you just upload the file on their website. Otherwise you just send them the gerber files. You order your boards in multiples of 3. Prices are great, and quality is top notch.

i've used expresspcb.com for some projects. they have free software and the prices are reasonable if you need a lot made. you design the board, upload the design and wait for the delivery truck.

speaking of machining (bad segway), there is an online machine shop that looks interesting. emachineshop.com  i've designed a few things but never got them built. again, free design software.

[scharfe]

Joe,

The lights are just stainless steel walmart cheapies with 40 watt bulbs. Nothing special.

[Monkeydad1969]

And those are giving you enough light for your chrony to read?  Nice.

[scharfe]

And those are giving you enough light for your chrony to read?  Nice.

I don't know honestly. I have had constant issues with this chrony no matter what I do, and 40 watts is the max the lamps are rated for.

But I bet these will be more than enough might make 2 more for chrony lights. I made some of these for halloween a while back, they are iron man arc reactors. Went a little over board, every thing is cnced aluminum and bronze and makes a 100 watt light bulb look like a candle.
 


This picture was taken in a bright room, the camera had a bit of an issue adjusting to the light.

[Monkeydad1969]

Yeah, I think those will do the trick, Mr. Stark. 

[scharfe]

Trying to get some data collection for pellet sizes going. If anyone has some data they would like to share, the new post can be found here.

http://www.gatewaytoairguns.org/GTA/index.php?topic=83070.new#new

[scharfe]

When I was trying to do sound comparisons between a custom and factory bolts I thought the shot sound was being picked up instead of the sound coming from the breech area.

Sooo, I decided to make an add on baffle shroud.  I made it as quick and easy as possible since the gun is already quiet enough for me. The pipe I used had an id the same as the od of the current shroud so made mounting it to the current shroud very easy.




I designed some baffles specifically for being 3d printed, each baffle has two strippers in it. The gold ones are printed with a modified $500 3d printer and the black ones are printed with a stock $2800 3d printer. The quality is basically identical.




A tip about 3d printing with a belt driven filament deposition printer is that they have troubles printing perfect circles. I always print the holes undersized and drill them out to the correct size with a drill.

And it turns out my app on my phone for a decibel meter is either a pos or it is picking up something else, the sound of the shot is noticeably quieter but it still picks up the same dB reading as before.  Even gives the same reading if I dry fire it, and the shot report of that is almost not noticeable over the ping of the hammer. Think I'm going to have to make a light weight hammer now to see what that does.

I also got a lead sled from a friend for testing. Never had one before, and not sure if I care for it. It almost takes the sport out of it not much fun putting all 15 shots in a ragged hole.

[William]

I also got a lead sled from a friend for testing. Never had one before, and not sure if I care for it. It almost takes the sport out of it not much fun putting all 15 shots in a ragged hole.

Your killin me, LOL  Going straight to Cabela's and order me a Lead Sled now! If it does its job that good, I may have to get one with an extra large tripod on all terrain wheels and take it hunting with me!

Glad you like the Lead Sled, never had one but I bet it would be a great improvement over the plastic one I have now!

Thanks for the review 

William

[rudd013]

Very interesting design. Thanks for sharing.

[JustinB]

An updates on your bullpup? I've noticed nothing going on in the past months.

[scharfe]

An updates on your bullpup? I've noticed nothing going on in the past months.

Nope not too much new at the moment, too many projects not enough time.

[William]

An updates on your bullpup? I've noticed nothing going on in the past months.

Nope not too much new at the moment, too many projects not enough time.

Just wanted to say hello and I am loving that 15 shot magazine you made for me, works great and no problems at all. If you do get started on your Bullpup again make sure you post some of the things you are doing to it, that is a sweet looking Marauder thats for sure.

Take care and keep us up to date...

William

[scharfe]

An updates on your bullpup? I've noticed nothing going on in the past months.

Nope not too much new at the moment, too many projects not enough time.

Just wanted to say hello and I am loving that 15 shot magazine you made for me, works great and no problems at all. If you do get started on your Bullpup again make sure you post some of the things you are doing to it, that is a sweet looking Marauder thats for sure.

Take care and keep us up to date...

William

Wow, I missed this post, Im just half a year late haha. Hope the magazine is still running good for you.

[scharfe]

Finally getting back to the marauder. Got into knife making, and it is a crazy tolerance, precision , and attention to detail beast. Ive learned a lot since my last pcp modifications so I figured I would put it to good use.

First change, I got access the an old hardinge hlv-h lathe, its much, much, much better than my grizzly lathe. So I decided to make a new custom bolt. With a couple changes.

The first bolt I made was just mild steel. The new bolt is 416 stainless steel, a ss that can be heat treated for maximum wear resistance. It already looks much better than my first attempt haha. But the plan is to harden the bolt (stuff i learned from the knife making haha)  and polish it to a mirror finish for maximum smoothness.

The end goal is to make an lever action with a hardened polished stainless steel bolt and also have a hardened ss sleeve insert for the bolt to ride one. Going for glass smoothness.

Old one on the bottom, started new one on the top,  accurate to less than .001" of my design, man, the hlv-h is accurate