Nitrogen gas piston
- Thread starter Garyg
- Start date
- Location
- Niagara Region, Ontario
I have the Trail NP All Weather rifle that does up to 495fps. It's very quiet, and after you put a couple hundred rounds thru it, and it stops dieseling, it will be even quieter. I had mine sited in after approx 12 shots, but it got better after more rounds.
As for your other questions, I'm unable to answer them now, as I've never had a problem yet.
As for your other questions, I'm unable to answer them now, as I've never had a problem yet.
TERMINATOR101CA
CGN Ultra frequent flyer
- Location
- TORONTO, CANADA
Time will tell, they haven't been around long enough to have stood the test of time like springers have. I would have to say seals are definitely going to be the weak link but if they offer replacement pistons I guess it wouldn't be too bad. Springs would still be far cheaper to replace though, something to think about. And they're affected by colder temperatures as well.
These HAVE been around a long time in Europe and are very highly refined. I asked the same questions there. I was told that millions of gas pistons are in use every day; every hatchback car has two in the hatch, most high performance shock absorbers are gas as well. The dumps are not exactly full of these items because they won't hold gas. As for cold weather affecting them; that is supposed to be a myth. The nitrogen gas in these is not air. It is not affected by cold in the same way as air.
The patent was the invention of two local men not far from where I live - Theoben started life as a two-man band, Dave Theobald and Ben Taylor (hence the name). It was apparently Ben's inspiration, which came from the pneumatically-dampened forks on a motorbike, that sowed the seeds for their invention back in 1982.
Ben realised that by replacing the steel mainspring in the compression cylinder with a sealed chamber full of air (originally gas), the characteristics of the rifle could be altered, and a more maintenance-free rifle developed. Basically, as the barrel is broken and the rifle is cocked in the conventional manner, the air (permanently contained) behind the piston is compressed. Once the rifle is fired, this contained air expands, powering the piston. This in turn compresses the air before it, which powers the pellet in as it exits the barrel.
I have an original Theoben Sirocco from 1983, and have to admit that the power HAS gone down in the last 28 years or so. It used to produce an average of 11.8 ft lbs with the preferred .177 H&N Crosman pellets, but now only produces 11.7 ft lbs.
This might be due to the fact that it gets used about three or four times a week as a trainer for young shooters.
I think I'll keep it though.
Remember that others have copied this technology by now, and the company is now owned by a different, but just as dedicated, team of great air-gun engineers who have taken Theoben on into the 21st century.
I get my new Theoben rifle tormorrow morning!!!!!
tac
Ben realised that by replacing the steel mainspring in the compression cylinder with a sealed chamber full of air (originally gas), the characteristics of the rifle could be altered, and a more maintenance-free rifle developed. Basically, as the barrel is broken and the rifle is cocked in the conventional manner, the air (permanently contained) behind the piston is compressed. Once the rifle is fired, this contained air expands, powering the piston. This in turn compresses the air before it, which powers the pellet in as it exits the barrel.
I have an original Theoben Sirocco from 1983, and have to admit that the power HAS gone down in the last 28 years or so. It used to produce an average of 11.8 ft lbs with the preferred .177 H&N Crosman pellets, but now only produces 11.7 ft lbs.
This might be due to the fact that it gets used about three or four times a week as a trainer for young shooters.
I think I'll keep it though.
Remember that others have copied this technology by now, and the company is now owned by a different, but just as dedicated, team of great air-gun engineers who have taken Theoben on into the 21st century.
I get my new Theoben rifle tormorrow morning!!!!!
tac
They have been around since 1982. My old Sirocco [1983] is standing by my summerhouse door, it is -6C inside the summerhouse, but and I'll go try it outside and see how it's performing.
Five minutes later.
Well, it seems just fine to me.
Ah, BTW, it was left cocked from last sunday when I took a magpie out.
Next pearl of wisdom that I can shoot down, please.
tac
TERMINATOR101CA
CGN Ultra frequent flyer
- Location
- TORONTO, CANADA
My good sir, you should take the time to google "Air composition" as it seems to me you don't know what your magic Nitrogen is (hint roughly 80% of what you breathe). My hood struts don't compare in design with these pistons as they're not meant to operate in the same fashion ( hood struts don't snap back in a millisecond), and just to make you happy, they have lasted less(In both my Chryslers 00' and newer) than the springs holding open the huge hood on my Chevy Cheyenne, which still work fine. They get recycled, you should hang out by my work to see how many of these shocks/struts get swapped out every day.
Now to set straight the other guy "shooting down" my "pearls of wisdom"....I only said the weakest link would be the seals leaking the gas, and -6 it's not that cold(enough for your seat of pants to feel the difference it makes), you should try it out at -20 with a chronograph and come back to me about performance being the same.
The OP asked for opinions and I gave him mine on gas pistons, if you feel like you know so much that you feel the need to knock other opinions by sheer assumption power , then please carry on .
idontknowjack
CGN Regular
- Location
- SW Ontario
I certainly hope they are not designed after the struts that they use on vehicles! Every vehicle I've owned that used them I had to cut a prop stick. From the hood on my '84 Trans Am, to the rear hatch on my Safari Van, Those struts are junk. Lets hope they came up with their own design. Like said before, time will tell.
Well, Sir, you obviously know a lot about automotive gas struts, but are you an expert when it comes to the propellant system of the Theoben airgun? As you noted, the automotive strut does not snap back like the Theoben gas-ram does, but then it doesn't have a hundred pound tailgate to lift. They also, I understand, have a built-in throttling valve to actually prevent snap-back, in the event that they become detached from either end. I can only base my knowledge on almost three decades of personal experience with my old Theoben rifle. And the fact that it is usually left cocked ready to shoot at any time I feel the need to use it.
Never been serviced either, more than a cursory glance, and as for the temperature, well, until recently double minus figures were just folklore here in UK.
Merry Christmas!
tac
Tacfoley, a quick question for you (since you do not seem to be the one making "assumptions") or for anyone else with experience with these nitro pistons: How do these guns affect scopes mounted on them? I have read about and, sadly, experienced multiple problems with scopes, inexpensive and otherwise, failing in sometimes spectacular fashion on spring-piston guns. These nitro-piston guns would seem to solve that vibration problem completely, yet I'm not seeing the manufacturers or anyone else mentioning this as an advantage of this technology. I would think that it would be a major benefit of the gas-piston guns. Any thoughts?
John
John
tactical lever
CGN frequent flyer
- Location
- Fox Creek, Alberta
Mind if I address it? It's been mentioned that the Beeman nitro-piston guns have "greatly reduced" vibration or reverse recoil. I'm sorry to say that I can't attest 1st hand although video ads seem to support it. Quite a few of these rifles come with air rifle proof scopes any way. BTW you wouldn't be speaking of air rifle specific scopes failing, are you?
Thanks, tactical lever. The first one I totalled on an air rifle was just a cheapie Bushnell many years ago (Sportsman?) which I tried out despite all the warnings of disaster...naturally, I knew better! It lasted about 200 rounds on a 700fps springer, and then the reticle just went away. I replaced it with a better Bushnell, about which I called and inquired from the service department regarding its suitability. I was told that it was rated for airgun use. The reticle failed on the third shot!
To their credit, Bushnell replaced it without hesitation. I finally bought an RWS-branded scope (no idea who actually made it) that was advertised for airgun use, and it has lasted many years on several progressively more powerful spring guns.
I've heard conflicting things about the firing behaviour of the nitro piston guns. I need to experiment with one.
John
To their credit, Bushnell replaced it without hesitation. I finally bought an RWS-branded scope (no idea who actually made it) that was advertised for airgun use, and it has lasted many years on several progressively more powerful spring guns.
I've heard conflicting things about the firing behaviour of the nitro piston guns. I need to experiment with one.
John
I installed a Theoben Gas Ram unit into a Webley Tracker some years ago (a side lever, tap loading carbine rifle) and it has changed the character of the rifle.
It has a very different feel , shorter lock time, more / sharper piston thump and just a snappier feel. Took a bit of getting use to but I don't mind it now.
On the power / accuracy front I deliberately tested it before and after installation, and it is more powerful, a lot more consistant and accuracy has been slightly improved. Recoil is again different, but not significantly harsher.
On the aspect of temperature, there is a noticeable difference between cold and hot. I have not chrono'd the difference but I would estimate @ 2ft / lb less in the cold. (Its a UK spec rifle, so it is about 11 ft/lb in the main.
In short, its okay. But nothing to really get that excited about.
Candocad.
It has a very different feel , shorter lock time, more / sharper piston thump and just a snappier feel. Took a bit of getting use to but I don't mind it now.
On the power / accuracy front I deliberately tested it before and after installation, and it is more powerful, a lot more consistant and accuracy has been slightly improved. Recoil is again different, but not significantly harsher.
On the aspect of temperature, there is a noticeable difference between cold and hot. I have not chrono'd the difference but I would estimate @ 2ft / lb less in the cold. (Its a UK spec rifle, so it is about 11 ft/lb in the main.
In short, its okay. But nothing to really get that excited about.
Candocad.
