Recent Posts

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Thanks Alan, have tried ballon and soapy water and cant detect any leaks ! Frustating !
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Welcome aboard!

Airguns are addictive !
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Airgun Ammo / Re: Casting with Non-Lead
« Last post by steveoh on Today at 11:45:31 AM »
Interesting. I’ve chewed on this a while hoping for more research as I’m sure the day will come that lead is banned for airguns. In the meantime I think I have 200lbs of lead to hold me over.
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Airgun Meets and Shows / Pacific Airgun Expo 2022
« Last post by steveoh on Today at 11:38:43 AM »
From Michael:

Quote
Hello fellow west coast airgun enthusiasts! The date for the 2022 Pacific Airgun Expo at the El Dorado County Fairgrounds in Placerville (Old Hangtown) moved one weekend to March 19/20 (the fairgrounds had to move my date, but it worked out good with turkey season).

This, the weekend before turkey opens, might be a good one to try to schedule for every year.

As you will read below, there is still an iffy caveat to us having the show or not, but it is now looking promising enough I want to get this notice out to you so you can get it on your calendar.

Finalizing the date and getting this notice out took forever and so the marketing for this next event is getting started quite late primarily because the State of California has made it much harder to put on gun shows. Because they have not been successful at putting an end to gun shows, they have made it almost impossible to get insurance for any weapon show in this state now, "bb gun" (wink wink) shows included.

Our show used to be able to use the very inexpensive state fairgrounds insurance (because we are not a "real" gun show), but that has been taken away, and every insurance provider I called that said they do fairgrounds gun show insurance said they can't do it in California any longer.

After many attempts I did finally get through to the NRA's insurance branch, and while I don't have an actual firm quote yet, I'm told to expect it to be about the $400 range. Four times more than we were paying, but good enough to finally let you all know it's looking like a show will happen.

In the past our show only brought in a few hundred dollars profit, so with increased insurance cost and the increased facility rental (but it's still the best deal I can find with a facility that will actually allow a gun show within a few hours of me), our little Pacific Airgun Expo will have a hard time being on the plus side of zero, but I do this out of love for our sport and in the hope it grows so that our little west coast show could someday make enough money to start paying forward for the next show.

I know at my local gun range there are increasing numbers of airguns showing up. Please help get the word out about the show. I'll send a follow up email to you all when I get the flyer artwork done.

If you all are still in, I'm in!

Michael McKeown
info@pacificairgunexpo.com
www.pacificairgunexpo.com
707-337-9410
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Airgun Ammo / Casting with Non-Lead
« Last post by Loren on Today at 07:29:16 AM »
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Welcome to the rabbit hole. I bought a break barrel at Walmart about 7 years ago and now I have...well, let's just say I enjoy my airguns. Welcome aboard.
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Welcome aboard.

When it comes to casting bullets, there are several guys here who shine brilliantly—literally! Steve, our illustrious Webmaster and co-owner of the site, likes blue really well. I say this, as that is the color he coats his airgun slugs with. Of course, those wouldn't work to well in a firearm. And I must say, Steve does have fire in his life, it just isn't in his choice of guns!
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Airgun Tanks, Compressors and Filling / Re: Proposed Foster Fitting standard
« Last post by rsterne on November 29, 2021, 10:11:58 PM »
Quote
3. The separation force on the coupler and male plug can be calculated;  force = 3.14159 x Radius x Radius x air pressure
for a 1/8" dia. air hole in the fitting, the separation force would be 3.14159 x .125" x .125" x 4,500 psi = 220 pounds force
for a 1/4" dia. air hole in the fitting, the separation force would be 3.14159 x .250" x .250" x 4,500 psi = 884 pounds force

No idea where that math came from.... First off, you used the diameter of the hole, not the radius, so your calculations are too large by a factor of 4.... Secondly, the separation force must be calculated using the diameter of the seal (ie the OD of the male fitting at the O-ring).... If the male fitting is 5/16" OD where it plugs into the O-ring, then the separation force is PI/4 x 0.313" x 0.313" x 4500 psi = 346 lbs.... While you might think that the hole through the fitting affects the separation force, both halves are contained in a closed system at 4500 psi.... Therefore there is a force on the "end" of the tank balancing the size of the hole in the fitting (regardless of the shape of the tank, connecting hose, etc.).... It is only the OD that matters.... I left off the retaining ring on the male, and the details of the female (eg. locking balls, etc.) for simplicity....



If you ONLY had the male fitting plugged into the female, with no tank attached, and the air venting through it, THEN the size of the hole would matter, but it would be SUBTRACTED from the 346 lbs. (55 lbs for the 1/8" hole, and 221 lbs. for the 1/4" hole).... However, the pressure differential would be nowhere near 4500 psi, only a fraction of that because of the venting that is taking place.... While the diameter of the through hole has a HUGE effect on the strength of the male fitting, through hoop strength and axial strength, it does not affect the separation force between the male and female....

Bob

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Airgun Tanks, Compressors and Filling / Re: Proposed Foster Fitting standard
« Last post by cometkid on November 29, 2021, 05:30:44 PM »
Things to consider:
1. The different fittings you are finding may be due to different design specifications/standards.  Verifying with each manufacturer their design specifications will sort that out.  But some of it can be just no uniform industry design standard.  Normally size or configurations are used to mechanically separate the weaker designs from the stronger designs.  i.e backward compatible only for the stronger designs.
2. In that article it is mentioned that quality fittings were used on the FX series air rifles.  Can these be "unofficially" deemed the standard until a more formal standard can be agreed to?  The formal standard most probably will take some time to complete and get buy-in by the industry.
3. The separation force on the coupler and male plug can be calculated;  force = 3.14159 x Radius x Radius x air pressure
for a 1/8" dia. air hole in the fitting, the separation force would be 3.14159 x .125" x .125" x 4,500 psi = 220 pounds force
for a 1/4" dia. air hole in the fitting, the separation force would be 3.14159 x .250" x .250" x 4,500 psi = 884 pounds force
4. yes, more coupler balls will mean less stress on each ball.
5. yes, the larger the coupler ball the less contact stress will be on the mating surfaces (i.e. coupler, ball, and male fitting).
6. I did a brief quarry and found that there are existing high-pressure couplers that now exist.  They are not cheap $80 give or take, but they are out there.  There may be more economical ones, but my task was to see if they existed first.  A special design will cost money too.  The one I found was capable of handling pressures well over the 4,500 psi pressures we see now. 
7. Is there an air gun association out there?  I would propose working with them and form a working committee to study this problem.  I sit on automotive committees (i.e. SAE) to generate automotive uniformity standards & processes.  This would be a more formal path, but the advantages are that it will be a true air gun industry standard. 
Summary;  If you are lacking an engineer on your committee, I would consider working with your team.  I think studying the problem as you are is the right first step, and that is to understand the problem in some level of detail.   
Good luck
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Another new guy from Ohio, a retired Electrical Engineer, an avid re-loader and bullet caster. I am graduating from powder burners to airguns. I have a couple old single shot CO2 pistols, from a long time ago and a no name Chinese break barrel springer rifle from a trade a few years ago. I shot them sporadically over the years, but hated buying CO2 cartridges for the pistols  (couldn't "reload them"), and the rifle because it was junk. Front & rear sights welded to the barrel, and a "2 finger" trigger, groups were "poetic" at 10 yards .

I recently bought a .22  Hatsan 95, to take some pressure off my powder inventory. I thought the Hatsan would be a good choice  because my garden is about 50 yards from the back door. So far, the learning experience has been interesting. Being a re-loader and a shade tree gun mechanic, I'm interested in the mechanics of air guns, in addition to shooting them.

Trapshooter
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