Pro Elite main spring size

[bootneckbob]

I'm wondering if anyone has any info on the correct size/spec for the sub 12 Pro Elite mainspring. I've ordered one from a well known distributer but its a good inch shorter than the one that was in there and that one had barely any preload.
What concerns me is that some of the parts diagrams online from the gun spares chaps have parts listed as TX****. I know there will be a lot of similarities, but did the PE sub 12 version share a TX spring/top had and guide?

Any history lessons from people with experience of both rifles ideally.

[Mach 1.5]

In the manual I have its part no. BB355A not sure if its the same in the TX manual. Mach 1.5

[Shed tuner]

completely different spring from the TX... the length of the PE spring for a start, never mind the OD. Also the top hat is completely different, as the PE piston rod is larger. The PE piston is also much heaver, so doesn't need a big heavy TH, even at full chat FAC.

[bootneckbob]

That's why I'm asking. The spring I've been sent is an inch short of reaching the trigger block. I don't know the history of the gun but I can't imagine why the piston would be changed to the point the original spring is too short? So it must be the wrong spring. It's also 1mm less internal diameter

[Shed tuner]

yup, wrong spring...

[sherlock1963]

My PE is converted to 25mm.

Just rummaged through my spares tin and I think I've found the old spring.

275mm length
3.73mm wire
22.9mm od
30 coils

Hope that helps.

[bootneckbob]

That's fantastic, thanks gents. What I have on the AA label says AA mainspring std BB351S, it's 21.5 cm long 27 coils.

[S Hebby]

That's fantastic, thanks gents. What I have on the AA label says AA mainspring std BB351S, it's 21.5 cm long 27 coils.

Thats the spring I have in my 0.177 Pro Elite which is also slightly short stroked and is shooting at 11.4 ft/lbs with JSB Exact 4.52s.

[bootneckbob]

That's the spring I have in my 0.177 Pro Elite which is also slightly short stroked and is shooting at 11.4 ft/lbs with JSB Exact 4.52s.

Oh bugger! Well that muddies the water. Mine's a .22 too which I was under the impression would mean I might need to cut down a generic PE spring (being for either .177 or .22.

[bootneckbob]

The top hat on my spring is black (deralin possibly) so not standard if I'm correct with online photos of standard parts. It's shooting nicely at 11.5 with AA but there's no preload on the spring or washers inside. Is it possible someone might have changed the piston which is why I'm seeing this 5-6cm gap when the apparently standard spring is fitted?

[S Hebby]

Oh bugger! Well that muddies the water. Mine's a .22 too which I was under the impression would mean I might need to cut down a generic PE spring (being for either .177 or .22.

I forgot to add,
It is short stroked on the piston front by 15mm. It has the 30mm HW piston seal fitted. The top hat and spring guide are delrin (so not standard). Both are a tightish fit in the spring. The top hat has a 20mm shoulder. Transfer port looks standard (doesn't look to have been drilled out). Spring only lightly greased with moly. It shoots very well and fast with very little recoil and no spring twang at all.

[Shed tuner]

the short stroke nose would have the effect of adding a 15mm spacer to the spring, so giving some preload. It may be perfect in that gun, but I still beleive it's the wrong spring for a std stroke PE. Mine has thinner guage wire to allow it to maintain some preload without going over.

Howewver, I have no doubt that short stroking it gives a much nicer firing cycle that a weak spring.

[bootneckbob]

Ok guys I appreciate your thoughts, feedback. I'm in the process of trying to return the spring and get my money back as I sorted the problem and don't really need the standard one now. Of course if I had got the right spring (assuming it isn't) it would have been interesting to see what power/shot cycle would have been like.