S400 Tuning

[bushy72105]

Afternoon All,

I was very fortunate recently to acquire an S400f carbine for the bargin price of £200! Chap at work brought it for his father in law, in short it was a five minute wonder and sat in his safe for years before I brought it. From the sticker on the airtube it was made in 2012. My first outing at the range with it was woeful, 8.4 ftlb at 190 bar and in the sweet spot only 9.3 ftlb.

I set about giving it a service so I've taking it apart, the hammer had rust spots on so everything has been cleaned and polished and I'm just awaiting some new seals and a valve stem as it was extruded, then I'll whack it back together and get it set nice.

My question is regarding the AT, I got the 3 on the bottom out with no issues at all. However when removing the one for the power aduster it went a but wrong, a slip of the drill has meant the threads for the AT are no more so I am unable to replace it with a hex screw. Will this cause me issues? I have read some bits that something is required to go over the power aduster to stop it leaking and moving?

Will I get away with leaving uncovered with no issues or should I try and get a new thread tapped or a helicoil repair, or worst case can you easily buy a new part of that assembly?

Thanks in advance,

Bushy - worst drill operator job the country

[bgaltd]

if it still hold air it'll be ugly but fine (unless you want to adjust it ).

alternatively , I can supply you with a new valve housing and blanking screw making it pretty again ..

rgds.

julian .

[tonyc]

Some Loctite on the adjuster will seal it and stop it moving. If you are going to leave it unplugged I suggest you limit the power by the pot adjustment with the transfer port unrestricted. Then, your gun isn't capable of being adjusted above the legal limit without being disassembled.

[bushy72105]

Thanks Julian I may take take you up on that, is that blanking screw another anti tamper or one that can be removed?

Thanks Tonyc, I had read about this, back the grub screw all the way out and loctite it in play and then power adjustments is via the firing pot if I'm correct. I read that normally the firing pot sits at 57.5mm, is there an average length for it with the adjuster fully wound out or is it a bit of test and adjust a few times?

Regards,

Bushy

[tonyc]

I've not measured the depth of the TP screw, just wound it in and out until you find the point at which it has no further effect. In theory, if you wind it out too far the power should start to drop as you introduce dead space/increased volume in the TP.... so just enough rather than overdo it.

Edit:
Just realised you were asking for the pot setting. I thought there was 1mm difference between recommended settings for carbine and classic... and I'm getting them mixed up... so try 57mm for a start, it may need to be less.

[bgaltd]

Thanks Julian I may take take you up on that, is that blanking screw another anti tamper or one that can be removed?

Thanks Tonyc, I had read about this, back the grub screw all the way out and loctite it in play and then power adjustments is via the firing pot if I'm correct. I read that normally the firing pot sits at 57.5mm, is there an average length for it with the adjuster fully wound out or is it a bit of test and adjust a few times?

Regards,

Bushy

its removable Bushy .