350 Mag opened up - horrible piston seal condition

[HectorMedina]

Sorry for the late reply.
House is down with SARS CoV-2. And though we are down, we're not out.
Nanny was the point of contact. Kids are reacting nicely and in good spirits, I'm a little "achey", but I have had Flu's worse than this. Niece is fine, and wife is the one that is too tired.
I'm sure we'll get over it.
Anyway.

The 350 had a sleeve because it was originally deemed necessary in light of the two linkages in the cocking lever. Steel sleeves are from the original models, newer ones have a thin PET sleeve, or none at all.

IMHE, the Titan Xs #14 will fit nicely without the sleeve, and the Teflon coating of the spring will preclude noises, as long as the guide's a tight fit.

Because the spring has a larger ID, the guide is also substantially more robust than a "thin-walled tube". Again, longevity and endurance pervade the design. It DOES need to be custom made, Titan does NOT sell guides. AND Titan knows that springs cannot be held to tolerances as close as piston stems, so in essence, you need to have someone to make a really good guide for EACH spring, to get the most out of it.
In some cases, I ship "matched" springs with airguns, meaning springs that are close enough to use the same guide with equally good results (or almost), I repeat it is really hard to get the spring's ID to match with tolerances better than 0.008" and that will mean a spring that yields 20 or 24 ft-lbs in the same gun.

Titan springs CAN be cut, forged and squared, but I know very few persons that do the job correctly, as it entails having a band sander since you need to reduce the spring from the INSIDE as well as from the outside of the last coil. Just look at your spring, if the spring ends in a sharp point (beveled only on ONE side), it is a weak point and a failure-prone spot.
A torch with Butane, or "Yellow gas" works perfectly well. Make sure you heat to bright orange to close and forge (preferably in a mandrel), then allow to cool SLOWLY from dark red. Quick cooling will make the spring brittle, it will break and shards will start flying around the inside of your precious airgun. Once you think you are done, and after sanding/polishing the ends, hit the end real hard upon an anvil, if it breaks, it was going to break inside the gun, so start again and let the spring cool SLOWLY, never quench a high grade steel in water, or oil, unless you really know what you are doing.

If you have access to heat-shrink tubing you MIGHT try to buy an OEM guide and make it a better fit to the Titan using thermo-fit; make sure you use the self-gluing version, that you clean the OEM guide with a good degreaser, and that the shrinkage will be just enough to still allow for proper sliding of the spring coils. I would really get a second guide for that. IF you do decide to go this route, do remember to exercise your gun once every week at least because heat-shrink tubing will "take" the imprint of the spring/coils and if left without some movement every week, you will have a very peculiar situation.

Of course, buying the OEM parts is not a bad advice. If you can obtain them from Spain, or Italy, you will not be sent low-powered springs as "default".

I know it is frustrating, but believe me, once you have done it, every shot becomes much more meaningful.

Good luck!






HM

[Arch_E]

Get well, soon, Hector!

Thanks for all the awesome tips and info that you share.

Archie

[Toxylon]

Hector,

You shouldn't feel the need to apologize for not replying faster - you have no obligation to share your experience here - the effort is a generous gift to us noobs. I read every reply thoroughly and with gratitude, but never wonder why he didn't answer already etc.

Hope the Covid will clear up!

[mcoulter]

X2 to what Duke said here!  ^^^^^

Get well soon!

[HectorMedina]

Thanks to all that have expressed good wishes and kind words.

We truly are a family here.

Keep well and shoot straight!







HM

[WHITEFANG]

Sorry for your misfortunes. As If things in the USA aren't bad enough already.
Speedy recovery HM🎯

[mac]

Hector, I always enjoy reading your post and input on all matters. You are a good writer and a class act. I appreciate you and the others who share their knowledge and experience on GTA.

Best wishes to you and your family !

[Motorhead]

Just reading this Hector ... be well get well one and all !!

[Toxylon]

So, after 5 weeks of waiting, the CAS replacement piston seal for my 350 Mag finally arrived. While waiting, I had de-burred, re-blued and lubed the gun, as well as polished the main spring ends.

I pried the damaged OEM seal off, and managed to put the new one on, with a combination of a plastic cone trick picked up from Youtube and some boiling water to soften the seal. The easiest seal change ever!

Enter the dangerous part: would the new seal go inside the receiver without damage? Sure I had deburred the receiver, but a test run with an old Gamo that I had de-burred as my first went south, as the hole edges in the receiver still cut up the piston seal, to my big surprise. After that, I repeated the whole deburring sequence on the 350 Mag. How would the piston insertion go?

I couldn't get the cut-up aluminum can trick to work, so I just entered the bare seal into the receiver end and started pushing. At every opening, my neck would tighten up in anticipation of S-L-I-C-E. Nothing happened, and the piston reached the bottom without incident. Phew!

A spring compressor I had built, based on advice from here and elsewhere, had given up the ghost sometime back. I had bought a 36" bar clamp as a replacement, and it had proven itself, working much better as a spring compressor than the home-made C-clamp-based one, and taking up any punishment springers could bring on it. It worked perfectly with putting the 350 Mag back together, as well.

I adjusted the horrible, ultra-long-pull, indistinct, mushy T06 trigger by directions gotten here, fixed the irons to the stock and wiped the whole thing with Ballistol.

My 350 Mag still has the original .177 cal barrel on it, while I'm waiting for a .25 cal replacement barrel from Mike Melick to arrive (it seems to take several months, at the present speed). Well, I can break the gun in with the original barrel just as well, and .177 pellets are way cheaper than the .25 cals, so I can push the project forward.

I have shot some 70 shots with the gun so far (that's the max I can stay stationary outdoors, with the mosquito season in peak), basically getting to know the gun. The trigger pull is still way long, but now the beginning of the second stage is a definite wall at the near-bottom of the trigger travel, breaks evenly, and I'm getting used to it. I'm definitely going to make the screw mod learned here that cuts down the first stage distance, though.

The 350 Mag's report is quite modest to my ears, and the recoil is very manageable, as far as power goes. One curious thing is how the gun behaves when fired. It almost feels as if the piston shooting forward would impart a distinct twisting shake to the whole gun; the recoil is not just a forward-backward thing. I'm not sure if it's the new piston seal acting up, or the spring twisting, despite the polished spring ends, or maybe the very tight fit of the heavy H&N Silverpoints (the only heavy .177 cals I have) in the breech creating a too strong air cushion in front of the piston, as per the Cardews.

Considering I haven't even adjusted the Walmart-quality open sights yet, and use pellets I have no idea of their compatibility with my 350, I'm getting surprising accuracy out of the gun. I have read plenty of cautionary stories how the long-stroke 350 Mag is a really hard gun to get accurate with, but I can't concur. With the right pellets, sighting in, and plenty of practice, I can see myself outshooting my HW95L with this gun. It's already a keeper.

[Mole2017]

...
I have shot some 70 shots with the gun so far (that's the max I can stay stationary outdoors, with the mosquito season in peak)...

Do you guys have a product like the Thermocell available in Finland? There was a discussion here about refilling those things and that was my first thought after I read about your mosquittos.

https://www.gatewaytoairguns.org/GTA/index.php?topic=174971.msg155975587#msg155975587

[dtdtdtdt]

Mosquitoes are the reason I quit fishing and spending much time in the woods.  Lots of infected bites and swollen body parts. 

On a happier note, there is a really nice detailed YouTube video about adjusting the t06 trigger. 



Careful description and good views. 

However, near the end he suggests a way to reduce the very long first stage trigger pull that seems to be part of the design!  He suggests bending an aluminum tab toward the trigger blade to reduce it.  I didn't like the idea of trying to bend aluminum as it can be brittle. 

SO; 

I drilled a hole through the tab, tapped it to fit a fine threaded screw of a useful size and length.  I then adjusted the first stage length of pull to fit my fancy..   Many others have done the same thing and it works well.  When happy with the length of pull most put a drop of Loctite (the releasable kind!!!) to keep the screw in position.

One of the neat things about the T06 is the you can do most, if not all, of the installation and adjustment with the gun dismounted.  The trigger can be cocked with a screwdriver as the man suggests.  I did this to both of my d54 rifles including setting the trigger pull with ease.  When returned to the stock, it was spot on and has never been an issue in over two years. 

[Toxylon]

Do you guys have a product like the Thermocell available in Finland?

They are available everywhere here. Haven't tried them yet.

The mosquito issue is heavily dependent on weather, time of day and especially location. My 350 test was at the worst spot in those terms; late in the evening, in the shaded woods, no wind etc. In the mid-day full sun, with a breeze going and out in the open, no worries about the bloodsuckers.

[EricFR]

Hector,
I also tryed the Titan 14 without success. Mine's a not old premium one (less than 4 yo I guess), but there's the metal sheet in the piston to guide the spring and prevent the cocking lever to rub against the coils.
I removed first the sheet, when sliding the spring in the piston, you feel that the spring is too wide, it rubs in every corner (matter of speaking for a cylinder lol). When cocking you feel the lever rubbing against the coils doing "tac tac tac". You also hear the spring jamming inside of the piston (I also tryed with a different spare piston, a bit less but it's still there). It needs a ton of force to be cocked, I think it was during those testings that I go my tendonitis to my elbow in october and only gone away now...
Then i've seen some guys doing their own spring guide and went for that solution too. Took a cylinder of steel and turned it on a lathe to fit perfectly the spring. It was better, the spring was no more going sideways and the lever tended to rub less but still a bit. It worked better but never as smooth as the OEM one. The coating of the Titan was also off at some spots...

End of the story, I used only the OEM to shoot it but the most disappointing part is that instead to be a power monster how it should, it only does 20 fpe so far in .22 cal where the sidelever and underlever models are puting out a serious 23 fpe. So now is the 350 intended to be the most powerful or not or is it only a matter of marketing?
With the titan xs inside it should be able to reach the power of the Webley Patriot or Beeman Kodiak for example.

[HectorMedina]

Eric;

The 460 and the 350 are long stroke guns.
They are predicated on achieving a high "rail speed" at the end of the stroke. The difference is that while the 460 does enjoy the efficiency of a short transfer port (as do all other sidelevers and underlevers), the 350 with a more traditional breakbarrel architecture is saddled with the long transfer port.

So, in THEORY, the 460 can be more powerful than the  350. Not always does, as there are a BUNCH of other things to consider: Guide tightness, Piston seal tightness, Breech seal efficiency,  and Breech closing spring sufficiency. Beyond those factors, pellet weight and fit play a very important role in the performance. AND even hold will play a role, tightly held spring piston airguns USUALLY yield a bit less MV than loosely held ones.

Now, having said all that, given the right pellet, with the right head and skirt sizes, with all other factors well in tune, the 350 should deliver at least 22 ft-lbs (29.8 J).

That is the reason why when we considered a 0.25" cal version of the long stroke gun we were going to start from the 460, not the 350. BUT, different strokes . . .

Keep well and shoot straight!






HM

[EricFR]

Interesting Hector, so it could be the transfert port that has more volume, why not. Even with the piston seal and spring greased light and properly, not possible to go over the 20ft-lbs, whereas the sidelevers are about to reach 23. Too bad the Titan XS 14 is not working there. 
But beside it, it works smooth and how it should.

[EricFR]

Of course, this makes the 350 easier to shoot, as said the shot cycle is quite nice at 20 ft-lbs.

[Toxylon]

Chrono time, and frowny faces

So far I've fired the 350 Mag some 200 times with the new CAS seal and the OEM spring, which has some 300 shots under its belt. I know, I know, too early to tell, but out of curiousity I checked the gun with the chrono. 10-shot averages.


H&N Silverpoint 11.57 gr. :

825 FPS / 17.5 ft.lbs.


RWS R10 Match 8.2 gr. :

1006 FPS / 18.4 ft.lbs.

At present state, my 350 Mag puts out just a little bit more KE than my HW95L, which shoots RWS Superdomes @ 16.6 ft.lbs. This is ridiculous.

I hope that the new seal will improve quite a bit as the break-in continues, but I fear the CAS seal is a under-sized dud. I plan on hitting the 500 shot count with the new seal and re-chrono. If the velocities and muzzle energy don't pick up then...

[EricFR]

Ilimakko,
You won't go any higher as 18 ft-lbs is standard in 177.
https://www.straightshooters.com/ourtake/ourtake350.html

[Toxylon]

Thanks for the link, Eric. Food for thought, for sure.

I have been under the impression that since measured KEs for the bigger-cal., OEM 350 Mags hover around the 23 ft.lbs. / 32 J mark, and that matches the 350's advertised KE of 32 J, this .177 cal should produce kinetic energy close to those numbers. Of course they won't be equal, but I was expecting 20+, based on cross-caliber comparisons of springers.

From day 1 my plan has been to convert this  gun into a  .25 cal. (still waiting for the barrel), so the performance of the .177 cal should be mostly irrelevant. However, if this gun produces only 18 ft.lbs. @ .177 cal, what chance does it have to be a viable .25 cal rifle? Kind of like those much-maligned Diana 48 .25 cals, that simply don't have the power for such large caliber, to most shooters.

The 350 Mag is a very long, quite heavy and awkward-to-cock gun (due to length). If it produced only middling velocities and KEs I would feel it's a failure. It'll be very interesting to see how this project goes.

[EricFR]

IMO 177 cal for the 350 mag is just a waste, more than for the sidelevers also because of the enormous swept volume. The sweet spot for the heavy 177 pellets is near 16 to 20J so 12 to 15 ft-lbs. Over there the 22 takes advantage and you'll notice a gain in energy when comparing both with the same power plant. I've both barrels 177 and 22 for it but never use the 177 lol.
Now for the 25 cal. I was also waiting on it but if the titan spring was working of course. And even if it was the case if it was in the 36J range like the Webley Patriot. Look at those numbers :
https://www.straightshooters.com/ourtake/ourtakepatriot.html
No power gain in 25 so not so interesting since you have more drop in the trajectory... I forgot the idea about it and stick with 22 for now.
I can only recommend you to buy a 22 cal barrel. Also the fact that the barrel is so long is a comfort for me since the required force is quite low for such a monster.