Search found 56 matches

by Doc j
Tue Nov 28, 2023 6:41 am
Forum: Pneumatic Cannons
Topic: Valve reliability
Replies: 7
Views: 8975

Re: Valve reliability

I like the last animation .
With the Grub screw restrictor to adjust the air port so then adjust closing time of valve .
by Doc j
Thu Jun 29, 2023 7:15 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Beeman P22 Project
Replies: 12
Views: 9622

Re: Beeman P22 Project

Ok, this data was from a springer.
Found on internet .

Transfer ports .
Dunno if adds anything .
But here it is .
by Doc j
Mon May 15, 2023 7:41 am
Forum: BB, Airsoft, and Pellet Guns
Topic: Semi-Auto Mechanisms of Commercial Airpistols
Replies: 2
Views: 2413

Re: Semi-Auto Mechanisms of Commercial Airpistols

Huben K1 manufacturer's diagram:

Here's one I came across .
by Doc j
Fri Apr 28, 2023 12:45 am
Forum: BB, Airsoft, and Pellet Guns
Topic: BBMG detent alternative
Replies: 91
Views: 37089

Re: BBMG detent alternative

Something I acquired recently, a "classic" Coksai/Kokusai CAR-15 airsoft rifle: 20230318_092349[1].jpg It works on the "bullet valve" principle that is relevant to the subject of this thread: bulletvalve.gif Some time in the future I'll do a detailed tear down to elucidate the operating system furt...
by Doc j
Wed Dec 28, 2022 11:29 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Hpa Dump valve ? Discussion points.
Replies: 4
Views: 3346

Re: Hpa Dump valve ? Discussion points.

Hi Maybe someone with more experience with the GGDT , Can explain why in the Dump ( 9999+ ms ) of valve . In the results section : the pressure drop is not equal to the pressure in chamber . ( Train of thought if volume of chamber is completely dumped , it would equal the pressure Drop .?) Outside o...
by Doc j
Wed Dec 21, 2022 1:41 am
Forum: BB, Airsoft, and Pellet Guns
Topic: Hpa Dump valve ? Discussion points.
Replies: 4
Views: 3346

Re: Hpa Dump valve ? Discussion points.

As above .
But in relation to point 2.
by Doc j
Wed Dec 21, 2022 1:33 am
Forum: BB, Airsoft, and Pellet Guns
Topic: Hpa Dump valve ? Discussion points.
Replies: 4
Views: 3346

Re: Hpa Dump valve ? Discussion points.

Ran scenarios through GGDT.
Regards to point 1.
.30 gram BB @ 5.95 mm
.603cm I'd barrel @ 43 cm long
Assuming 1.52cm3 dead space.
Asummed Nozzle , 5 mm I'd . Same as seat ?
by Doc j
Wed Dec 21, 2022 12:04 am
Forum: BB, Airsoft, and Pellet Guns
Topic: Hpa Dump valve ? Discussion points.
Replies: 4
Views: 3346

Hpa Dump valve ? Discussion points.

Hi All , Not promoting anything so altered out names . Product Description : The ****** is a fixed volume system so only the air contained within the ******* cylinder is released down the barrel when fired. Therefore you use pressure to offset the need for more air volume to properly fill the barrel...
by Doc j
Mon Dec 19, 2022 9:15 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Airsoft rifle bolt dimensions
Replies: 3
Views: 2491

Re: Airsoft rifle bolt dimensions

]" Having said all that . For sake of simplicity and functioning . Taking system of A pump Action , type cocking and trigger sear / using altering it , use a floating type bolt pull might be a simpler way to get feet wet , on build ." Above , idea. Watch this , https://youtu.be/VpvzIMOucKk ( vid int...
by Doc j
Mon Dec 19, 2022 8:23 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Airsoft rifle bolt dimensions
Replies: 3
Views: 2491

Re: Airsoft rifle bolt dimensions

Above wrote , Make sense , Check out following pic . https://sniperpedia.com/wp-content/uploads/2022/04/how-spring-airsoft-sniper-rifle-works-768x432.jpg *Note: the spring actually goes into piston itself. Is not drawn in . Does not sit on back of piston. As depicted and not seating in piston ( with...
by Doc j
Mon Dec 19, 2022 9:36 am
Forum: BB, Airsoft, and Pellet Guns
Topic: Airsoft rifle bolt dimensions
Replies: 3
Views: 2491

Re: Airsoft rifle bolt dimensions

Hey Dude , Not that straight forward . Have to sit down and nutt out a plan , design . They are mixed bag really . Differ from makes and models . Sizes may or may not line up with material able to get " off shelf". Starting point and commonality amongst . Comes down too , I.D. of cylinder , piston s...
by Doc j
Wed Dec 07, 2022 6:22 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Benjamin Model 30/30 CO2 Carbine Repeater "Hot Shot"
Replies: 18
Views: 22118

Re: Benjamin Model 30/30 CO2 Carbine Repeater "Hot Shot"

Finally found some time to think about this and I'm happier with this design: https://i.imgur.com/lTrSFY0.jpg Hi Jack , Popped up few times with balanced / timed valves . If I may , Had play around few things on GGDT . Seems 2MS , dwell , or close time . Good number . In the instance of designing o...
by Doc j
Mon Dec 05, 2022 6:34 am
Forum: General How-To & Discussion
Topic: How do you convert in3 into in2
Replies: 2
Views: 2645

Re: How do you convert in3 into in2

Boyle's Law. Not Susan Boyle. For a given mass of confined gas at constant temperature, pressure multiplied by volume will be constant. So for a starting state at pressure P₁ with chamber volume V₁, and a compressed state P₂ with final chamber volume V₂ : P₁V₁ = P₂V₂ This gets combined with Charles...
by Doc j
Thu Dec 01, 2022 9:25 pm
Forum: General How-To & Discussion
Topic: How do you convert in3 into in2
Replies: 2
Views: 2645

How do you convert in3 into in2

Hi . Purpose of question . Work out the atmospheric pressure available within a cylinder , pre compression . So then can work out , a compression ratio . Gain desired or expected psi of the compressed air part / after the compression. Atmospheric pressure is stated at 14.7 psi per inch squares ( in2...
by Doc j
Mon Nov 14, 2022 11:49 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Benjamin Model 30/30 CO2 Carbine Repeater "Hot Shot"
Replies: 18
Views: 22118

Re: Benjamin Model 30/30 CO2 Carbine Repeater "Hot Shot"

I definitely have a weakness for old and unusual airguns :) I like the idea because it comes out of the conceptual "box" and is repeated all the time. There is always a different way to do the same with its pros and cons for sure. I was unaware of this design when I posted almost the same idea 15 y...