Question on springs: What is a "good" mainspring?

[pedro.m.reis]

Hi all, newbie question again .

I'm in the process of changing my TX200 mainspring. I bought it 2nd hand and I'm doing a change on springs, guides, seals, o-rings, etc. For now I'm going with a factory one.

But, I' wondering, what makes a mainspring a "good" one. What makes an aftermarket spring "better" than an original one? And, in your opinion, what is the "best" mainspring.

I'm looking for accuracy and consistency not power. My main objective is Field Target practicing.

BR

Pedro

[Timmytree]

"Better" is down to the user. Many people change springs, buy kits, different seals, top hats and guides and then swear that their rifle is so much better than standard. Personally I've tried all of that in my Prosport over the years and gained nothing. The standard spring is good as long as the ends are finished properly. A well fitted guide will always be better than a sloppy one.
Decent lubrication and finding the right pellet is far more important, pellet weight will affect the "feel" of the shot cycle, you can fine tune by altering tophat weight with washers or altering preload at the guide end.

[pedro.m.reis]

[...] you can fine tune by altering tophat weight with washers or altering preload at the guide end.

Tks for the insight!

What is the difference on adding washers on the guide (back) or on the tophat (front)? Dont they just "compress" the spring?

And what is a "shot cycle"?

[Timmytree]

Shot cycle is the interval between pulling the trigger and the pellet exiting the barrel.
The "feel" can be affected by piston weight, pellet weight and fit, even the lead compound can make a difference. Raising power with washers can actually make things worse because it can increase recoil. Adding or subtracting weight at the tophat can balance the piston weight to match the pellet being used. With a springer lighter pellets are usually better anyway.
The two main characteristics you will encounter whilst "fiddling" are bounce and slam. Slam is when the piston hits the end of the cylinder wall, bounce is when the piston rebounds off a cushion of air, usually because the pellet is too heavy or too tight or sometimes because the spring is weak or hasn't got enough preload.
Springers are a dark art!
With your TX I would start by looking at guide and tophat from Tinbum Tuning to fit a standard spring and try that for a while. After that you have the option of short stroking, sleeving and alteration of transfer port. I've only tried short stroking and didn't like it!

[GrandadG]

Very good explanation there Tim

[pedro.m.reis]

With your TX I would start by looking at guide and tophat from Tinbum Tuning to fit a standard spring and try that for a while. After that you have the option of short stroking, sleeving and alteration of transfer port. I've only tried short stroking and didn't like it!

Im doing that already, waiting for the spring and kit to arrive.
Thanks for the explanation!

One funny fact, everybody on my FT club uses JSB exact or express, springers and pcp alike.

[FPoole]

Many guns have factory springs that are less than good. AA factory springs are high quality and have given me good service. I also use springs from Air Rifle Headquarters, here in the U.S., and they are of excellent quality. I've also found springs will vary from spring to spring even though they are the same part number. Luckily with the TX200, a spring change takes only a few minutes.

[pedro.m.reis]

Got the mainspring.
Did the "roll in the table" test on it. It is not "perfect" but I think it's normal a little "wobbling". Also inspected the spring ends. Seemed ok for an untrained eye .
Now lets wait for the Tbt kit to arrive