Chinese air rifles and Gas spring conversions



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Offline Scotchmo

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Re: Chinese air rifles and Gas spring conversions
« Reply #40 on: November 19, 2011, 03:46:13 AM »
I am getting a Beeman RS2 when I return from Afghanistan.  I will be in Maine where is gets pretty cold but would still like to be able to shoot.  I hear the Gas Springs do not suffer from the effects of the cold like wire springs do.  I like the duel caliber option of the RS2 which is why I am getting it. A gas spring would make this a good multipurpose all weather rifle.  Would the "Red" spring give it the same or perhaps a slight bump in power as well?  I know you do not recommend the "yellow" but I would also like to get a slight to moderate increase in power if possible. ;)
The gas springs do change some with temperature (on an absolute scale). When cold, they do lose velocity.  They warm up after just a few cycles. A "dry" wire spring is probably less affected by temperature. But many tuned wire springs use a "heavy tar" lube. I'm guessing that the "heavy tar" is affected by temperature at least as much as the gas spring. I'm not convinced that either has the advantage with temperature variation.

The red spring is probably close to stock. It may be the same or slightly more powerful than the stock spring, but that is just an educated guess.The only way that I could check for sure is if I knew the original RS2 wire spring dimensions and operating parameters - wire diameter, number of coils, outside diameter, free length, installed length, stroke length. From this information, you can calculate the mechanical energy of the spring in ft-lbs. That is then compared to the different gas springs.

I tested a red label gas spring in my TF99 this week. Even after shortening the stroke a little bit, it still  produced about the same velocity as the stock spring. 720fps with CP 14.3gr. The stock spring in the TF99 was unusually long with a lot of preload.
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Skjold

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Re: Chinese air rifles and Gas spring conversions
« Reply #41 on: November 21, 2011, 03:04:24 AM »
I am told the RS2 spring is a .120 wire dia - 11" free length with 44 coils - inside dia .465 outside dia .715.  Would the Gas coversion maintain at least equal power if not increase it a bit?  I am guessing the gas conversion will make it smoother as well and more accurate.


Offline Dick Tracey

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Re: Chinese air rifles and Gas spring conversions
« Reply #42 on: November 21, 2011, 03:22:00 AM »
PA is/was offering the gas piston conversion for the dual barrel RS2.  You can order the gun and the conversion ram at the same time and they will do the conversion free and ship to you.  The ram is/was about $100.  They have a silver barrel and receiver optioned model with the better trigger and scope combo that I have fancied from afar for some time now.  Might be a Black Friday purchase if on sale.
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Offline Scotchmo

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Re: Chinese air rifles and Gas spring conversions
« Reply #43 on: November 21, 2011, 05:11:31 AM »
I am told the RS2 spring is a .120 wire dia - 11" free length with 44 coils - inside dia .465 outside dia .715.  Would the Gas coversion maintain at least equal power if not increase it a bit?  I am guessing the gas conversion will make it smoother as well and more accurate.

I will have to make some assumptions here. We will say 43 active coils since it probably has at least 1/2 of a closed coil on each end. No installed length or stroke length was given so I will just use the maximum deflection and a 4 inch stroke. Your rifle may have a longer stroke but this will at least give a relative comparison. So the decision on which spring to select should still hold.

I calculate that the force will go from 51lbf to 179lbf, or 115lbf average:
115lbf.x4in/12in per ft=38ft-lbs. of mechanical energy

The blue label spring will go from 100lbf to 130lbf, or 115lbf average:
115lbf.x4in/12in per ft=38ft-lbs. of mechanical energy

The red label spring will go from 150lbf to 195lbf, or 173lbf average:
173lbf.x4in/12in per ft=58ft-lbs. of mechanical energy

The wire springs seems a little short on preload for a rifle of that power level. But if the spring dimensions are correct, you can use the blue label gas spring to get approximately the same power as the wire spring. It should be smoother to cock and shoot. The peak force of the red spring is only about 9% greater than the wire spring but stores 50% more energy. So it is probably within safe limits of the rifle. It will be a little harder to cock but should be smoother as far as torque and more powerful. It will kick harder. Double check your wire spring dimensions. The last post mentioned that this rifle is available with a gas spring installed. If you have not already bought the rifle, that may be a good option.
« Last Edit: November 21, 2011, 05:14:36 AM by Scotchmo »
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Offline Dick Tracey

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Re: Chinese air rifles and Gas spring conversions
« Reply #44 on: November 21, 2011, 08:27:18 AM »
I just checked the PA site this morning.  The dual air beemans are still available and so is the gas ram.  You can purchase both together and the ram will be installed and shipped, or you can purchase the gas ram and ship your gun to PA to be installed.  I would recommend calling PA to make sure it will work before ordering.  Also PA will not sell ram without the installation.
http://www.pyramydair.com/s/a/Crosman_Nitro_Piston_Conversion_Fits_Many_Newer_Gamo_Rifles/2103
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Offline Dick Tracey

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Re: Chinese air rifles and Gas spring conversions
« Reply #45 on: November 21, 2011, 04:16:20 PM »
OK My bad.  Called PA and was told they do not sell gas pistons for beeman guns.  Specifically asked about the beeman elite dual Caliber rs2.  They do offer for gamo however.
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Offline ray in wi

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Re: Chinese air rifles and Gas spring conversions
« Reply #46 on: November 22, 2011, 11:57:39 AM »
Fantastic Post!! Thanks for the info
Ray
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Skjold

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Re: Chinese air rifles and Gas spring conversions
« Reply #47 on: November 22, 2011, 12:26:50 PM »
Where can I buy a red piston for the RS2?  Do you do the conversions?  If so what would you charge?

Offline Scotchmo

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Re: Chinese air rifles and Gas spring conversions
« Reply #48 on: November 22, 2011, 03:26:06 PM »
Where can I buy a red piston for the RS2?  Do you do the conversions?  If so what would you charge?
I assume that your asking me. I don't do conversions for others but I think mikeiniawoa does them. I believe he is at Flying Dragon Air Rifles - 515-924-3699

If you do it yourself, you need to measure the exact stroke length of your rifle before you order a gas spring. I gave some sources at the beginning of the thread but you need to know what to order first.
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Offline Smackey54

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Re: Chinese air rifles and Gas spring conversions
« Reply #49 on: November 22, 2011, 03:33:28 PM »
Where can I buy a red piston for the RS2?  Do you do the conversions?  If so what would you charge?
I assume that your asking me. I don't do conversions for others but I think mikeiniawoa does them. I believe he is at Flying Dragon Air Rifles - 515-924-3699

If you do it yourself, you need to measure the exact stroke length of your rifle before you order a gas spring. I gave some sources at the beginning of the thread but you need to know what to order first.

I looked at McMasters, MSC, and Grainger, but could not find a retailer for the particular  sizes. Should I go to a manufacturer's site and then look for a distributor there?
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Offline Scotchmo

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Re: Chinese air rifles and Gas spring conversions
« Reply #50 on: November 22, 2011, 04:30:05 PM »
Yes, check with the different manufacturers. Most of them will refer you to a distributor. I posted some information earlier in this thread. N-Forcer will deal direct.

...
So far I'm preferring to use the N-Forcer products. It seems to be a smaller company that is willing to deal directly with end users. Just deal with them in a professional manner and it should go fine. They cost about $45+/- for the airgun sizes and they give a small discount for ordering 10+ of any one item.
...
« Last Edit: November 22, 2011, 04:34:39 PM by Scotchmo »
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D_Weezy

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Re: Chinese air rifles and Gas spring conversions
« Reply #51 on: November 29, 2011, 01:22:18 PM »
Which one of those gas springs could I use for my B3-1's? My B3's are the old ones, with the white spring guide.

Offline Scotchmo

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Re: Chinese air rifles and Gas spring conversions
« Reply #52 on: November 29, 2011, 02:01:30 PM »
Which one of those gas springs could I use for my B3-1's? My B3's are the old ones, with the white spring guide.

There are a few critical dimensions that you need to measure in order to make the selection. Start with:

What is the stroke length of the B3-1?
How much space in the B3-1 for a compressed spring?
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D_Weezy

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Re: Chinese air rifles and Gas spring conversions
« Reply #53 on: November 29, 2011, 03:09:46 PM »
Anyone out there with a B3-1 that has this info needed for a gas ram fit? How do you figure the stroke length of the B3-1 air rifle? Solid length of spring should be (number of coils x wire size = compresed spring length - example/ 36 coils x .117" wire size = 4.212" compresed spring length) These figures are for the B3-1 with standard 9.30" length mainspring.

YankeeDude

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Re: Chinese air rifles and Gas spring conversions
« Reply #54 on: December 16, 2011, 11:00:20 PM »

I tested a red label gas spring in my TF99 this week. Even after shortening the stroke a little bit, it still  produced about the same velocity as the stock spring. 720fps with CP 14.3gr. The stock spring in the TF99 was unusually long with a lot of preload.

Speaking of TECH FORCE airguns . . .

What about the TECH FORCE JET ?

Is a gas ram conversion possible on a .22 TF Jet ?

I am interested in a possible velocity increase with heavy .22 pellets 21.1 gr +/- . . . Would like to see 850 + fps. Also, around  950 fps, w / 14.3 CPHP's.

Dave
« Last Edit: December 16, 2011, 11:05:32 PM by YankeeDude »

Offline blaqheart

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Re: Chinese air rifles and Gas spring conversions
« Reply #55 on: January 17, 2012, 08:42:01 AM »
hi guys, my air rifle is rated at 1250 fps with the standard spring.  If I install the 19mm x 125mm 150 bar nitro ram from n-forcer what velocity can I expect?   
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Offline z28rod

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Re: Chinese air rifles and Gas spring conversions
« Reply #56 on: January 17, 2012, 07:18:55 PM »
That 1250 is with pba ammo ill bet, and the rifle looks preaty powerfull now , why would you need more anyways ? What rifle is it ? And caliber ?
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Offline blaqheart

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Re: Chinese air rifles and Gas spring conversions
« Reply #57 on: January 17, 2012, 07:55:21 PM »
its a hatsan 125 .177.Honestly i am not after more power, i heard the gas ram reduces the recoil so i could squeeze all the accuracy from it. However i would like to maintain its velocity.
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Offline z28rod

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Re: Chinese air rifles and Gas spring conversions
« Reply #58 on: January 18, 2012, 07:22:59 AM »
From what guys have written here and told me , that n forcer gas spring should make your rifle into a super cannon, but the 22 cals with 14.3 gr pellets are going super sonic so a 177 even with the heaviest pellets would be super sonic all the time , so if sound isnt a issue then your the man but if it is, it will be like your shooting a 22 rimfire all the time in youir backyard ? is that cool ? i would get the red spring not the yellow marked spring, or just one level down from the ones installed in the wfh .22 and .25 cal. rifles, so you can keep her under ss speeds.
  • Hopewell Junction, NY
- Crosman Titan .22 Cal. W/3x9 Weaver and Leaper one piece mount and rings, tuna gold trigger. Under dime 25yrds. Cphp's.
- RWS 320m .177 4x RWS scope in mint condition.Getting tuned by dad the pro.
- B-28 .22 Cal. Fully Tuned by my dad the pro tuner. RWS 3x9 AO scope. BKL mount with magnum rings.
- Winchester 1000x .177 made by Hatsan, Turkish walnut stock.
- Beeman G1000 .177 mint.
- Hatsan 85 camo .22 Cal. w/4x Leapers scope.
- Crosman 760 in mint condition. Wood stocks. Oldie but goody.

Offline tjk

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Re: Chinese air rifles and Gas spring conversions
« Reply #59 on: January 18, 2012, 10:40:47 AM »
850 with +/- 21 grain .22 caliber pellets?!?!?! From a bb type rifle??? Thats asking an awful lot. Even if you were to install a ram that could generate the energy to do that, I wonder how long it would be before we hear posts on the Airgun forums of how 'so and so' was seriously injured when the comp-tube walls/retaining pin(s) render and back end of their rifle busts through and causes,..... Sorry to paint such a negative picture, but I just
get a bad feeling about the trend some folks are heading with these 'power' mods. If you need that much power, get a RF or a pcp. Simple as that.
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