Getting the best out of standard s410

[nikharr]

Hi all,
I have an s410 classic in .22 and want to get the best out of it as standard.
I have polished the hammer rail and the hammer where the spring is guided.
I intend to record a full string from 190 bar some time this coming weekend.
I then intend to adjust the firing valve.
My understanding is to open the restrictor screw so as none restrictive and then adjust the length of the valve to give say 11.5ft/lb at the sweet spot.
Whilst I have it apart is there anything that can be done to improve the valve, ie can I polish the stem and seating face etc.
I have not looked at a valve yet, but have a general idea what might look like internally.
Am I correct in my thinking or am I going about this the wrong way.
Also what is the internal diameter of the cylinder, so I can make a blank to reduce the cylinder volume and not use too much air.

Many thanks Nik.
P.s. any one got a photo of the valve and the internals.

[nice shooting tex]

am a bit of a novice when it comes to tuning guns compared to some guys on here. but when I got my s410 I stripped it down replaced loads of seals and replaced the striker and firing pin assembly. which I got off Julian on the forum. and did a 90 shot string which Mark kindly put on a spread sheet and gave me some data. was thinking about fitting a regulator but not sure as its shooting spot on

hope this helps

[Brooksy]

Just polish the rail and leave the hammer alone, it's an oil absorbent sintered metal. Polish the firing valve shaft but don't touch the sealing face. Personally I would leave the pot alone and adjust via the screw. As fortune air cylinder, why reduce volume?

[simonsays]

Its really dead easy. This is what I have recently learnt and applied:

The hammer and hammer rail are important to clean and polish regularly. In my old S400 its incredible how quickly they get dirty again. No idea where the crap comes from but it just appears. There are guides on youtube and the like how to do this. Dead easy (really!) on pre-AT models.

Check or simply replace your hammer spring (mine was compressed and therefore weak) - they are cheap enough.

Check the fIring pot length should be set at 57mm (screw adjustable) which is said to be the magic number (again google it).

Check firing valve face has not got a minute step on it. If so you can reface (I put mine in a drill and used a stanley blade to reface it - works fine) or replace.

You MUST check with a chrono afterwards as all these mods will increase the muzzle energy. You can tweak with the firing valve.

Little point in filling to 190 bar, you only get lower power shots. Generally most S4**s are happier in the 160-110 bar range anyway. This will effectively provide your smaller volume without any work and reduce filling effort (if you pump it up)!

Use AA pellets - these have consistently performed better than others in all my AA rifles.

Good luck

[Mark112]

Hi all,
I have an s410 classic in .22 and want to get the best out of it as standard.
I have polished the hammer rail and the hammer where the spring is guided.
I intend to record a full string from 190 bar some time this coming weekend.
I then intend to adjust the firing valve.
My understanding is to open the restrictor screw so as none restrictive and then adjust the length of the valve to give say 11.5ft/lb at the sweet spot.
Whilst I have it apart is there anything that can be done to improve the valve, ie can I polish the stem and seating face etc.
I have not looked at a valve yet, but have a general idea what might look like internally.
Am I correct in my thinking or am I going about this the wrong way.
Also what is the internal diameter of the cylinder, so I can make a blank to reduce the cylinder volume and not use too much air.

Many thanks Nik.
P.s. any one got a photo of the valve and the internals.

Hi,

If the firing valve is more than 2 or 3 years old then I would change this and the two springs (hammer and firing pot). The pot is pretty much always set to 57mm protruding from the valve block. I would set power at 130 bar with a heavy pellet such as Bisley magnums to 11.7-11.8 which will give about 11.3 with AADFs. I would leave the seating face of the valve alone personally but I suppose you could polish the stem lightly if it is a bit 'sticky' in the block. Don't overdo it though as it still needs to be an airtight fit in the block (there are no o rings that seal this part in the valve block).

The firing pot is prevented from undoing itself over time by a grub screw (and nylon ball) hidden from view under the alloy block the pressure gauge screws into so you will need to slacken this block and turn it out of the way or remove it altogether. Change the gauge block seals as these are prime leakage candidates.

I've just measured the outer diameter of my tube at 31.5mm which ties in with being told that it's 28mm inside IIRC. Putting something inside the tube can certainly save on air whilst setting up and a length of 1" diameter delrin or Nylon should do nicely.

I get 71 sweet spot shots (within 10 fps) from my S410K in .22 and 'nice shooting tex' gets 77 from his carbine so say 74 average. You should be getting 100+ from the classic version (38% more 216cc/156cc tubes).

Manuals including full exploded diagrams are available from the Air Arms website.

Hope that's of some use

Mark

[nikharr]

Hi all, thanks for all the advice, greatly appreciated, nice to have some insite before I make a start.
My S400 that I previously ownd, had a sweet spot from 160 bar and shooting a string from 190 bar I should see if this is the same. I will check the valve face and replace if marked, lightly polish the stem if sticking and replace at the magic 57mm.
Then shoot another string to set the power legally and see where the sweet spot is.
Thanks again, cheers, Nik.