Service guide request for Air Arms S410

[kingsnake]

I am very chuffed to have bought a second hand .22 S410 yesterday for a bargin price of £350. Unfortunately the seller had terminal and cancer and was selling off all his gear. The last time the rifle was shot was two years ago and he had never had it serviced ever.

The serial number is 049517 so I am assuming it's a 2004 model. The rifle is in mint condition and looks unused and is holding air. 20 Shots over the chrono @ 150 bar gave me around 8.3 ft/b with 14.44 grain H&N. I have ordered a complete o-ring service kit.

I am hoping someone has a service guide they can send me as I would prefer document style instructions over the YouTube guide.

thank you

[kingsnake]

Anyone?

[premierpistol]

I'm half surprised nobody has posted a link to something? maybe there is no document available?

I do it this way personally, it may not be the best way but it works for me and has worked on 100's of AA S300, S400 and S500 platform rifles to date.

[Sorry, Just read what I typed out once I got to the bottom and had my cuppa it took me almost 2 hours, in which time I could likely have done the job twice over . Lads, go grab a beer or a cuppa before reading this drivel, better still. choose something else to read ]

1, Ensure the magazine is out of the rifle and test fire it in a safe area to ensure there is no pellet loaded.
2, remove any moderator, remove the scope and then remove the stock.
3, Remove the air from the cylinder. Personally, I loosen the fill valve fitting and let it drain out past the seal there. If you are new to this then have spare pants nearby. it can be loud and scary.
4, once all of the air is out, proceed to loosen and remove the fill valve unit and set aside. Then loosen and remove the gauge from the gauge adaptor and then remove the screw securing the adaptor from the valve housing.
5, Loosen the 2 x grub screws that secure the barrel band to the fill valve housing. remove the barrel band from the gun.
6, This part depends on where the breech block screws are mounted. Yours is likely to be the type where all screws are screwed down through the top of the breech block, and tighten into the lower action parts. Later models have some fixings that go through the lower action parts and screw up, into the breech block. much newer models have all 6 screws from underneath for a cleaner look
Irregardless, there are 6 securing screws that hold the breech block to the valve housing and trigger housing (Lower action parts). Carefully remove all of these. On the S*10 models that have a magazine system, the indexing mechanism will need to come off too, this is secured with 3 x cap head screws.
7, on the rear of the trigger housing, there is a single cap head screw (5mm hex) Remove this to access the hammer rail, hammer and main spring. make note of the way the parts are assembled. there should be a rear spring washer too, this can only be used one way round so maybe photograph this being dismantled.
8, You may need a vise for this part and may need a special tool to help..
A, Put the cylinder into a padded vise and clamp it down firmly, then grab hold of the Valve housing and unscrew it from the cylinder, if its really tight, some heat may help? Once out, you can if you wish, remove the brass firing pot (there is a grub screw and often a delrin ball clamping this into position) Loosen that if you wish to remove the firing pot and inspect the main valve and valve spring. You dont need to touch this but if you do, remember to measure the length that the firing pot protrudes from the valve housing and return it to that figure, if you dont, the rifle can change its shot characteristics and lose consistency if you forget, set it to 57mm and it should be somewhere near.
B, On the other end of the cylinder, insert the tooling pins and loosen to remove the fill valve housing from the cylinder. These are often very tight but the correct tooling will stop you marring the finish of the gun. Dont use waterpump pliers etc, you will F it up
That is the basic stripdown done. From here, remove all of the old o rings and fully clean all parts ( I use automotive EGR cleaner to clean any grease or muck from the parts) then dry everything off ready to rebuild. I often lay all of the parts out like a schematic drawing on my workbench and put all of the seals next to the part they came off. that way I can tell which seal goes where when it comes time to re-assemble the gun.

Additional works that are a good idea at this point:

Hammer rail. give this a real good clean and polish it as best you can 2000grit wet and dry is as good as anything. this allows the hammer to run along with little to no friction. Once cleaned, smear a little mineral oil onto it so the thing has less chance of rusting and the hammer can glide along. Dont use any form of grease, it will ruit shot to shot consistency.

Cocking mechanism. On the underside of the breech block, there is a small cap head screw tightened into the bolt probe, loosen and remove to enable the probe to be removed. When removed, again, clean everything down, clean through the probe hole too and ensue all old grease is removed.

Other work that can be done:

Barrel removal and breech/probe seal replacement. So far, it's all gone well, however, this part is a faff in a lot of instances and to be honest, I dont recomend it unless the gun is missing the seal or you absolutely have to...Just incase you are reading this as you go. I will say my best advise here is to leave it alone.
Remove the grub screws securing the barrel to the breech. Some models have one tiny one underneach the breech, all have 2 slightly larger ones on top of the breech. one of which will be hiding under the magazine retaining clip which first needs to be removed by loosening and removing the 2 x button head screws. Once the screws are removed and the barrel is loose, it should pull stright out, complete with the brass end. I say SHOULD They rarely do to be honest and they are a pig if they separate and leave the brass end in the breech but the barrel has come out in your hand, which is more a case on the earlier models like yours.. My advise is still to leave it alone

Reassembly:

Okay, If you followed my advise on laying all of the parts out like a schematic drawing, with the old seals laid next to where they fitted, this bit is a lot easier.

1, locate your new seal kit and start swapping the new seals for the old ones, put the old ones straight into the bin now. That way you wont get muddled up. Your kit may come with seals for updated parts, put these to one side for the time being.
2, locate your silicone grease/oil or otherwise O ring lubricant, put a smear onto each seal as below, once the seal is lubricated, it may as well be fitted to the part it fits on to help keep it clean.
A, Valve body: lube up the seal and stretch it over the thread, roll it down until it seats into the goove (like putting on a condom I'm told) Ensure the Main valve, valve spring and firing pot is fitted correctly and to the right depth (remember 57mm) then assemble the valve housing into the cylinder.
B, Firing Valve Housing: again, lube the seal, stretch it over the thread and roll it down the thread till it pops into the groove. Checking all of the other parts of the firing valve are external of this( pretty sure they are on the AA S3** S4** and S5** series rifles) then fit the valve housing into the cylinder, tighten these up pretty tight but dont go too wild.
C, Gauge and Gauge Adaptor: Fit the new seal onto the gauge and screw that into the adaptor finger tight for now, locate the adaptor securing screw and fit the correct seal to that, again with the lube, stretch and roll sequence. On the rear of the adaptor block there will be a really thin seal (6mm I.D x 1mm C/S) that is simply located into the recess. I fit the thin seal first, place the adaptor into the receiving part of the valve housing and then fit the adaptor securing screw to ensure the seal is sat in the correct position. This screw needs to be pretty darn tight too, be careful that the gauge adaptor is sufficiently tight and very square to the rest of the action, if its not square, the stock may not fit! Oh, now is time to nip up the gauge into the adaptor. it only needs a nip, dont hang on it.
D, Fill Valve: Depends on the type you have, some from 2004 may still be the old push on valve, if so, fit a new bonded seal washer and refit the valve, tighten enough to feel the seal squash. thats all it needs. If its the newer type fill valve, fit a new seal to the valve pin and pop that into the outer body. Fit the spring into the valve pin and then fit a new 12mm x 1.5mm seal to the thread on the outer body. screw the valve assembly into the valve housing on the cylinder and tighten with a 10mm spanner. Fit new 12mm x 2mm outer body seals.

At this stage, the entire air system is complete and it can be filled with air to check for leaks. I do an initial fill to 100BAR and leave it for 10 mins or so. All being well, you have not had any catastophic failures and the gun is probably showing 90 to 95 BAR on the gauge after cooling

3, Locate the hammer, hammer spring, sprong guide washer and trigger block/housing. First, drop the hammer onto the guide rail on the end of the valve housing, fit the spring and then balance the washer on top of the spring. ( I find standing the whole tube up on the fill valve helps here) locate the trigger housing over the top and allow the parts to come together, it may need a wiggle to get the very end of the guide rail to pop into the hole on the end of the trigger housing, once it does, secure with the large cap head screw but dont over tighten it at this stage.
4, locate the breech to block seal (6mm I.D x 1mm thick) and the 6 off breech securing screws. I use a dab of silicone grease to help with this bit.
A: Hold the cylinder in a vise so it is level and orientated with the trigger at the bottom and the transfer port to the top. Put a dab of the grease onto the transfer port, place the seal over the grease. Place the breech into position and start off the 6 screws that secure it to the lower action parts.
B: you need to get the "Feel" for the breech being positioned centrally over the lower parts and nip up the 4 x front screws into the valve block, once nipped up, start to tighten the 2 rear most screws. when you think you have it right, try to cock the gun. Does the bolt pull back smoothly? if not, loosen the 2 screws slightly and try again (this will allow the trigger block to twist slightly on its axis and align the cocking slots on the upper and lower parts. Now, nip up the 2 screws on the rear of the breech. ( you may need to do this several times to get the feel for it, it can be a git) Now tighten up the large cap head screw at the rear of the trigger block.
5, Locate the indexing parts: the black outer part should have the brass magazine lifter fitted to it, this can be greased to allow it to sit in position without rattling. The steel inner part should also be lightly greased to help it glide. hold the assembly onto the side of the rifle and fit the 3 securing screws. dont overtighten, the alloy is this here and threads do strip out.

Nearly there!:

Refit the barrel band to the barrel and fill valve assembly. secure with the 2 off 2mm grub screws. Now fill the gun to around 150/160BAR This is a good place to start and test the rifle. Get your chronograph and test the output.

If all nice and safe, refit the stock, scope, moderator etc and go have a cuppa. You have earned it!
If not, still go have a cuppa and think about what you have done You may need help there that I cannot delve into on open forum Speaking of cuppa's, I think I need one after all this typing! LOL

I wish you all the best of luck. If you get stuck, there are plenty on here that can help.

ATVB

Paul

[TonyL]

Someone was burning the midnight oil! Very well done, sir. I hope you enjoyed that well deserved cuppa!

[kingsnake]

Thanks Paul this was exactly what I wanted. I will use you guide with the exploded parts view available from AA.

Really appreciate the time you put into this. And I think I will give the barrel removal a miss!

[premierpistol]

Someone was burning the midnight oil! Very well done, sir. I hope you enjoyed that well deserved cuppa!

I did thank you. I am enjoying a week off work so my body clock is way out of sync, I was supposed to be out rabbiting but the trip got called shorter than expected.

Thanks Paul this was exactly what I wanted. I will use you guide with the exploded parts view available from AA.

Really appreciate the time you put into this. And I think I will give the barrel removal a miss!

You are welcome.

[On-the-target]

Thanks! very helpful indeed.

[kingsnake]

Manged to get round to doing the seal service, thought I would share my thoughts and the issues I faced.

I was pleased mine was a pre anti tamper so no drilling!
As mentioned above the rifle was putting out <9 ftb and problem was the hammer rail was gunked with a sticky residue, there was also some corrosion on the hammer too. I polished this to a mirror finish and honed out the hammer bearing with 1500 paper.
I reassembled the rifle and was now getting around 9.8 ftb.

Now this is where I got some issues, I removed the security torx screw and opened up the power grub screw until I was getting 11.5 ftb. Put the screw back in did 10 shots and on the last shot the power went over 12 ftb. Another 10 shots 13 ftb!

It turned out the grub screw was moving out from each shot, Google search showed me this was a common issue and people were buying extended screws.

My cheap easy quick fix for this is to buy a clipper lighter (these are sold everywhere) the spring inside the the flint stem is the perfect diameter for this chamber, cut the spring down to about 5mm, the diameter inside of the spring will still allow the Allen key to pass through.

Thanks again for the support.