Spring shortening

[HarryPotter]

Anybody recommend somebody for this?

I don't fancy doing it myself and would like it done properly, it's for my FT gun.

It's got the Maccari FT kit in it and has only had around 100 shots through it at the moment but is running at around 13.2fpe

Lord know what it will rise to when it's broken in. Consistent though (7fps variation over 15 shots).

There isn't the slightest hint of dieseling either, it's just running a tad warm

[snock]

I remember Ben T saying that most springs are about 2 coils to long.

If you chopped the last 2 coils off, remember to keep the length above the waste coils damp,in a damp rag, to stop the temper change going too far up the spring.

Pete.

[Gwylan]

I think Snock may have missed out the middle bit about making a new end after you've chopped it. Heat the last coil up, sqeeze it on a steel plate, then grind and polish square, but as he says, don't ruin the temper on the whole spring.
Gus
PS didn't see the non-DIY bit, you could ask Shrendi.

[POK!]

Is the spring for 77/97?

[HarryPotter]

Yep. it's in my MKII 97K (0.177)

[POK!]

I have something here you can try. PM your address I'll try and send this week.

[HarryPotter]

YHPM Mr Pok Sir

[bmp01]

HP,

Is this the kit which uses the "GLOBAL T" spring, with 36 coils x .120" wire with an ID of .495. length of 11"?

The reason I ask - I decided to get a spring from Mr Maccari a little while ago. Had a shortish email exchange where he recommended above spring (I wanted to make guides myself). I expressed concern that this spring would put my rifle (HW97K) over the limit and I got a flat reply that he had never had to chop one of his springs to get the gun under the limit. I had my doubts so I (perversely) chose to go for the stronger "HWHTEL" spring, 37 coils x .128" ID .540" Length 12" on the basis that I would definitely have to cut that one down and I would get a shorter stiffer spring. It also has larger ID to increase guide wall thickness which seemed better to me.....

Before jumping to a bad conclusion have you done other things to your rifle to make it more efficient (and so could expected sub 12 fpe for std rifle)?

Interested to hear what you have to say...

BMP01

[shrendi]

There is an easy way to re temper after shortening the spring. Cover in oil and heat in the oven until the oil begins to flash off. Or you could sapce the spring up and then set it in the gun for 48hrs, remove spacers and you have a shorter spring.

[shrendi]

Send it to me and i will finish it well.

[bmp01]

HarryPotter,

Please could you have a look at my post 3 above? I'm keen to see what you think...

Thanks in advance.

BMP01

[HarryPotter]

The honest answer is I just don't know, I didn't look that closely. All I look for in a spring is a good lock time and legal power. It was a long bugger though.

I got one of them....

But yes the rifle has been tweaked with a Venom Power Pulse Seal, Venom Breach Seal, Venom Piston Liner (to take the play out of the top hat), the cocking slot has been polished and smoothed carefully as has the cocking shoe, all other relevant parts were polished as well (inc slight rounding off of the transfer port edges and a polish in there as well - for no other reason that why not).

Oh, and it's been glided

Maybe that accounts for the little extra 'oomph'?

Interested in your collective thoughts.

[shrendi]

If you follow instrucion outined above ie reset spring with spacers and leave cocked for 48hrs then remove the spring will be shorter and under less pretension.

[HarryPotter]

I might give that a go Mr Shrendi, cheers.

[Acerbus]

Hmm,

I first would try to temper the spring at 210°/220° Celsius in the oven (do not forget to de-grease it 100 % and make sure that your oven has the right temperature, do not trust the numbers on the knob ) for a hour, its colour should be gold-brown. Let it cool down slowly.

Than mount it to the gun and do about 200 shoots before you test again.

If it's still to strong I would start to cut of a one coil heat the chopped end max to a cherry-red and go on as Gwylan described it.

You will have to temper again, you risk that it will break if do not temper .

All in all its a difficult work I've spoiled 2 springs before I learned to do it.

Jochen