Air Arms S400 Mrp-Ft

[Archer50]

I have fitted both lane and Altaros regulators in S400's. There is not much difference in ease of installation, and not much difference in performance. Drilling the air cylinder for the Lane is not difficult, and both regs require the inside of the cylinder to be smooth, although only a small area, quite near the end of the cylinder matters. I found that a bit of fine steel wool and a Mk1 finger did the job very easily in a couple of minutes with no need for cylinder hones, or anything else. I did use Moly 55 silicone grease which is specifically designed to make the O-rings swell slightly.

If you want any improvement in shot count you will need to either weaken/shorten the hammer spring, or increase pressure on the valve spring, either by tightening the adjustment or replacing with a stronger spring (which is my preference). The fiddling about to get the right balance of springs is not difficult, but can easily start to drive you up the wall, not to mention using a LOT of air (even if you put something in the air cylinder to reduce its volume). With both regs, I found that my shot count was about 75 with the rifle-length cylinder using .177 AA pellets at around 775 fps. When I opened up the transfer port to 3.5 mm each reg gave about 140 shots after a bit more fiddling: I know some people get even higher shot counts using custom hammers and valves, but I happily stopped there. There is very little to choose between the consistency of the two regs at about plus or minus 4 fps from 200 bar to the set reg pressure of about 100 bar and an SD of about 2.

Just to be clear, Although Altaros don't mention it, it is the opening of the transfer port to 3.5mm (for a .177) that gives the big increase in shot count, and if you do it for both types of reg, their shot count is pretty well identical - or at least it was on my guns.

I get the impression that the Lane reg is better made and likely to last longer, but my Altaros is still fine after about 2 years and on the whole, I think I'd use Altaros if there's a next time - or then again, I might try a Huma just out of interest .

Good luck

Alan

[RichieRich612]

I have fitted both lane and Altaros regulators in S400's. There is not much difference in ease of installation, and not much difference in performance. Drilling the air cylinder for the Lane is not difficult, and both regs require the inside of the cylinder to be smooth, although only a small area, quite near the end of the cylinder matters. I found that a bit of fine steel wool and a Mk1 finger did the job very easily in a couple of minutes with no need for cylinder hones, or anything else. I did use Moly 55 silicone grease which is specifically designed to make the O-rings swell slightly.

If you want any improvement in shot count you will need to either weaken/shorten the hammer spring, or increase pressure on the valve spring, either by tightening the adjustment or replacing with a stronger spring (which is my preference). The fiddling about to get the right balance of springs is not difficult, but can easily start to drive you up the wall, not to mention using a LOT of air (even if you put something in the air cylinder to reduce its volume). With both regs, I found that my shot count was about 75 with the rifle-length cylinder using .177 AA pellets at around 775 fps. When I opened up the transfer port to 3.5 mm each reg gave about 140 shots after a bit more fiddling: I know some people get even higher shot counts using custom hammers and valves, but I happily stopped there. There is very little to choose between the consistency of the two regs at about plus or minus 4 fps from 200 bar to the set reg pressure of about 100 bar and an SD of about 2.

Just to be clear, Although Altaros don't mention it, it is the opening of the transfer port to 3.5mm (for a .177) that gives the big increase in shot count, and if you do it for both types of reg, their shot count is pretty well identical - or at least it was on my guns.

I get the impression that the Lane reg is better made and likely to last longer, but my Altaros is still fine after about 2 years and on the whole, I think I'd use Altaros if there's a next time - or then again, I might try a Huma just out of interest .

Good luck

Alan

The package came today . Just one thing, 2 actually. The instructions seem to have been written by a small child and what on earth am I to do with that small rubber stand off piece , absolutely baffles me that part.

[RichieRich612]

Well the reg is fitted, not shot over a chrono yet. When filling the Air cylinder I noticed at around 100 bar a slight grumbling popping noise coming from the breather hole.
It sounded like excess o ring grease being pushed through under pressure.
Has anyone else experienced this?
Rich

[RichieRich612]

13.5ft/lb now

[Archer50]

Sounds like the o-rings haven't sealed properly against the cylinder walls. I suggest taking the reg out, degrease and use a bit of very fine steel wool on the cylinder - repeat as necessary .

If it's any consolation, the first Lane I fitted absolutely haemorrhaged air, and I thought I was in real trouble, but a clean up as above and there's been no problems for over 6 months now. Also, so long as there's no moving parts involved, I'm very keen on the Moly 55, but if you do use it, make sure you clean any other grease off first.

Good luck.

Alan

[TenMetrePeter]

A little soapy water applied with finger over the hole so as to form a bubble will show if there’s a leak from either o ring. But it could well be the springs compressing making a noise. Also the o rings need to deform into their grooves to work, pushing out grease from the groove corner.
Any leak between chambers through the regulator valve will result in the gauge pressure creeping up over time.