S410 Carbine Superlite - Very fussy on pellets

[MrCobraman]

Hi Guys
I searched for a thread on this but couldn't find one.

I have just purchased a second hand S410 Carbine Superlite (.22) from a good & trusted friend, who bought it new.

It seems to be really fussy on pellets & driving me crazy!

Indexing the magazine seems ok, but the bolt is struggling to push the pellet into the barrel & therefore deforming the pellet making it totally inaccurate. Once you're committed there's no turning back as the pellet is jammed half into the barrel, making it impossible to remove the mag.

I've cleaned out both magazines & added silicone to the rubber bands. I've also replaced the indexing post, BUT still same problem.

Gun seems to hate RWS Super Field (5.52mm) & RWS Superdome (5.5mm), struggles with Accupell (5.5mm) & is just okay on Exact Jumbo Diablo (5.52mm).

All these pellets are working well with my mates HW100, Daystate Huntsman Regal, BSA Gold Star SE & Hatsan AT44.

Air-Arms were convinced the index post would cure the problem, but sadly not. No other thoughts offered.

Can anyone help or suggest a pellet this gun might actually like?

Many Thanks

[MrCobraman]

Just for reference using all listed pellets through any of the other guns, I can group within pound coin @ 50 yards.

[DarrenC]

My S400 .22 loves JSB Express and Falcon AP. It also likes Bisley LRG but they Need an extra push to seat them and drop the power by half a pound. Have you tried feeding them without the mag? If they still don't fit properly then it won't be the mag and there might be missing o ring in the breech. I'm sure someone on here will have the answer.

[Blackbaronfish]

With out the pellets does the magazine index to allow the probe to pass without the magazine moving.If it moves into place to align up it could be the magazine is indexing under or over. You will need to bend the indexing post to compensate either way.
Also without a magazine does the probe slide in easily?

BBF

[MrCobraman]

I have loaded without mag, but sometimes hit & miss to seat correctly. Doesn't look like an o ring is present???

Without pellets the mag does index & probe passes without any movement to mag. Chap @ AA suggested new index post should be okay without adjustment, so left new one alone. Might experiment with older one...

Without magazine the probe slides in easily enough.

Since original post I have also cleaned the barrel & both magazines & experimented with trying to reposition the magazine.

Still no joy

[Blackbaronfish]

Are you saying it hasnt got a breech o'ring?. Try dry firing and with a tissue see if air is blown out of the breech

BBF

[MrCobraman]

Sorry BBF, mate just collected it to take to gun shop tomorrow. I'll update on its return...

[Blackbaronfish]

Fill out your location as someone near you may be able to have a look .

BBF

[granville]

the one i had was stiff on some pellets but i used aa hunter and no problem .
if you want some too try pm me i will send you sample. foc
atb paul.

[MrCobraman]

Okay, so word back from the gun shop is that it was indeed missing the breach o ring. Also it was suggested to lubricate the mag o rings with silicone every 250 pellets.

Now apparently working as the AA Gods intended!!!

Many thanks to DarrenC & Blackbaronfish, cheers fellas! Also thanks to Granville for the kind offer, but will persevere with the RWS.