Air Arms S200 CZ Mk1 with Altaros Regulator

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mark holding
Posts: 64
Joined: Tue Dec 22, 2015 7:07 pm

Air Arms S200 CZ Mk1 with Altaros Regulator

Fri Jan 29, 2016 6:11 pm

I have cracked the installation and tune of my Altaros Regulator on my Air Arms S200 CZ Mk1 rifle.
I decided just before the new year to invest in a regulator for my Air Arms, after recently having my Webley LiteW8 tuned by Phil Crampton of "The Rat Works". Phil is a great young man, and is very good at his job. He specialises in tuning BSA rifles, but will work on any model, and I would highly recommend him if you prefer your regulator fitted by a professional. He does the regulator fitting as a authorised fitter for Robert Lane regulators. My Air Arms was shooting very well, as they always do, but I wondered if it could be improved with a regulator. I had also thought of letting Phil tune it for me, but after researching the different regulators, I decided to give it a go myself. As with other Air Arm Owners, I wasn't feeling like drilling into my air cylinder, as I don't have the correct bench mounted drill that would make the job easier than drilling by free hand. Also the cost of the Altaros regulators with the £ stirling being strong next to other currencies, meant that the cost was around £66, compared to £89 for the comparable none vented regulators. The Altaros is fitted internally and is just a bit thicker than a pencil, and just a bit longer than a pencil. Some of the tench and Humma regulators that are fitted internally fill the whole width of the air cylinder and this allows the O-ring to be removed between the exhaust valve and air cylinder to allow the regulator to breath if need be. In the case of the Altaros, it is too thin, and removing the O-ring would mean that any air in the cylinder would gradually leak out. I have had my Mk1 for about six years. I brought it to replace my Webley, while that was in for a service. The S200 is a remarkable rifle, and is well capable of keeping up with rifles costing over twice as much.

For anyone thinking of buying one of these regulators, don't think that its just a matter of undoing the air cylinder, screwing it all back together and off we go. I have got through 500 pellets before I achieved my goal, and have been hard at it for almost three weeks.

Stumbling block number one was the air cylinder. For some reason Air Arms or CZ screw these in so tight, you'd think it was screwed on by the terminator. In all the online videos from the main regulator designers, they all say that hand tight is good enough. I had to buy a tool from XTX Air for £7.50 and use a pair of stilsons, a vice, and a hammer just to get it started. Other options are available. Raj, used two nuts and a pair of stilsons, which can be seen on the Altaros page. Others have made a "C" shaped spanner with hook to do the same job. Once I had released the exhaust valve from the cylinder it was simple from then on. While fitting the regulator, I also decided to go the whole hog and fit a quick fill & gauge on the other end of the air cylinder, using the same process of stilsons and vice. This shortens the length slightly and looks neat and tidy, while being able to visibly see how much pressure is left in the rifle. I also replaced the O-rings, which was probably for the first time, and lubricated with silicon grease and spray.

On the Altaros website it is recommended that the hammer spring screw is unwound so that it is level with the back of the breach block and that the venturi screw over the transfer port is unwound all the way out to free up the transfer port. Having followed these instructions I began testing the rifle over the Chronograph, with mixed results. I would get a string of four or five shots that were within 1ft per second, then get a flyer that would be 50 ft per second faster, and be going over the legal limit. I got to a point where I was getting around 120 shots at around 10.50 Ft/Lbs, but still had flyers pushing over the 12 Ft/Lb. Realising that something different needed to be done, finally decided to increase the tension of the Hammer spring. I screwed the Hammer screw 2 full turns clockwise to put tension on the hammer. I also turned the venturi screw 2 1/8 turns clockwise to restrict the air flow through the transfer port. This made all the difference, and I was now getting a shot spring of between 580 fps and 586 fps, putting it just over the legal limit every now and then. Another 1/8 turn of the venturi screw making 2 1/4 turns in total, and I am now shooting between 11.5 Ft/Lbs and 11.8 Ft/Lbs with no rounds going over the 12 Ft/Lbs. This for me is ideal, and I used two very efficient pellets doing the test. This was the 15.89 grain JSB Exact Jumbo and the 15.90 grain Daystate Rangemaster Soveriegn. I also use Air Arms Diablo Field at 16 grains, but I know that these shoot at the same consistency as the two tested. Now for shot count. I fired 70 shots from a 190 bar fill with 20 errors on the Chronograph, I have only shown the 50 shot consistencies below, which for me is just right, knowing that this gives me 7 magazines before filling. As the cylinder is fitted with a regulator I could fill to 200 bar and possibly push this to 90 shots, knowing that I would be getting no more than a 14 ft per second variation over the 90 shots. Also I decided that I would stop shooting at 100 Bar after firing the 70 shots, and could possibly have carried on, but my pellets were running low. On the following diagram it shows 50 shots. The other 20 shots fired as explained previously were Errors on my Chronograph, as I was shooting indoors due to the bad weather outside. I am pleased with the results, which I finally have today after three weeks of trial and error.

Conclusions: I had set my rifle up as suggested, but they didn't say wether they had used a .22 or .177. I can only think that the heavier .22 needed a little more punch with the hammer tension to send it down the barrel, and that the transfer port in the Air Arms and venturi screw is set up that way because it works best in under 12 Ft/Lb rifles. If you had an FAC, it probably makes sense for the port to be fully open. Even with the standard rifle, with a fully open transfer port and hammer spring screwed in by 4 1/2 turns these rifles are capable of 18 Ft/Lb. The hardest thing with this set up for me was keeping the .22 pellet legal, and another good reason for everyone to have access to a Chronograph. I hope that this information is useful for those thinking of taking the challenge of fitting a regulator themselves.

The Chronograph used was a Caldwell.
Attachments
Chrono test page 1..JPG
Page 1. Chronograph test
Chrono test page 1..JPG (55.29 KiB) Viewed 4041 times
Chrono test page 2.JPG
page 2. Chronograph test and information
Chrono test page 2.JPG (68.87 KiB) Viewed 4041 times
Chrono test page 3.JPG
Page 3. Final settings and conclusion
Chrono test page 3.JPG (71.48 KiB) Viewed 4041 times
Last edited by mark holding on Sat Jan 30, 2016 10:38 am, edited 1 time in total.

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Raj
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Joined: Sun Feb 15, 2015 9:36 pm
Location: Rugby

Re: Air Arms S200 CZ Mk1 with Altaros Regulator

Sat Jan 30, 2016 9:14 am

Nice, detailed and well presented write-up, Mark. :)
And thanks for the mention ;)
“It's the Indian, not the arrow"

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mark holding
Posts: 64
Joined: Tue Dec 22, 2015 7:07 pm

Re: Air Arms S200 CZ Mk1 with Altaros Regulator

Sat Jan 30, 2016 10:23 am

Thanks Raj,

I thought I would share my experience, as the Altaros doesn't get much detail, apart from their main website. I was getting to the point of thinking, had I bought the right regulator, but kept at it. I am very happy that it all worked out, and hope that it wouldn't put anyone off. Its all a matter of fine tuning to get the results that you want. The other good thing is that you get to strip down your rifle and know it inside out. I know both my Webley LiteW8 and Air Arms S200 inside out now, and all this has given me the confidence to do my own work in the future. As long as you have the correct tools for the job, and most importantly a Chronograph for keeping yourself legal, it all becomes part of the shooting experience. Not been a member of the Air Arms Owners Club long, but its a great place for information and like minded people. I have done a video of my strip down and installation, which I will post at a later date.

All the best.

Mark H.
Attachments
Altaros regulator quick fill manometer and fill probe.JPG
The Altaros regulator - quick fill manometer and fill probe
Altaros regulator quick fill manometer and fill probe.JPG (30.92 KiB) Viewed 4015 times

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mark holding
Posts: 64
Joined: Tue Dec 22, 2015 7:07 pm

Re: Air Arms S200 CZ Mk1 with Altaros Regulator

Thu Feb 18, 2016 9:24 pm

I took my Air Arms S200 CZ .22 to the Woodend Farm Airgun Complex today to test it for the first time on the range since fitting my new Altaros regulator. After slightly winding down the power using the venturi screw on the transfer port, I am now getting a shot variation of no more than 4 feet per second over the entire 100 shots that a 200 bar fill will give. The power is now just over 11 Foot pounds, or around 560 to 563 feet per second using Daystate Rangemaster Sovereign pellets weighing 15.9 grains.

https://youtu.be/uNbG6ZsDW6o

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