New Disco springs.

[Monkeydad1969]

So I made an order for some Crosman parts, springs included.  I got a beast.  Left to right---Older Disco, 13XX, brand new Disco spring I just received:



What's up with the length?  Same number of coils as the original Disco spring.  No wonder people are getting cruddy shot count.

Joe

[Case Stuffer]

Many are power hungry.  I cut 3 turns from my new Disco's spring added a power adj and spring guide . This resulted in same as approx. 1-1/2 turns being removed .

Summary    of results using     2K start
Stock Hammer Spring

Stock hammer spring

For first 10 shots

930 FPS Avg / 24 Es / 7 Sd

Cut Hammer Spring
First 10 -Avg 933 FPS


First 15

Avg 928
ES 26
SD 8

AVG FPE 18.3


Stock spring had no Bell curve , cut one has a fairly nice one.

[Case Stuffer]

The rest of the story

Stock Hammer spring on one month old Disco

Benjamin Discovery Chrono results with H&N Baracuda Hunter Extreme 9.57 gr. pellets

Hand pumped to 2,000 PSI

943 FPS
935
933
930
936 ( Approx.1,800 PSI here)
926
927
924 ( Approx. 1,700PSI here)
919
919

For first 10 shots

930 FPS Avg / 24 Es / 7 Sd


At approx. 1,050 PSI shot # 21 / 833 FPS


************************************************** ************************************************** **************

7-18-15 Cut 3 turns from Hammer Spring added adjustment screw but left backed out.Head of #10 Allen Cap Screw (used as spring pusher and guide)- equals approx. 1-1/2 coils of spring thus same as removing 1-1/2 turns with no adjustment added.
Same 2.0K starting pressure and same pellets

935 FPS
936
936
940
933 - shot # 5
933
936
933
927
924 shot # 10 approx. 1.7K
924
922
914
917
918 shot#15 approx. 1.4K

1-15
Hi 940
Lo 914
Avg 928
ES 26
SD 8

905 shot #16
903 shot #17 down 4% fro Hi
890
886
887 shot # 20 approx 1.3K
1-20 Hi 940
LO 886
919 Av
54ES
17 SD

868
862
855
841
836
820
816 Shot # 27 1.0 K PSI

[rsterne]

Before I installed that long spring, I would slide it over a 3/16" rod or bolt and collapse it completely until it is coil bound.... This "sets" the spring, and judging by the wide coil spacing I wouldn't be surprised if it came out looking a lot like the original Disco spring.... They have the same number of coils !!.... Setting the spring will not change the spring rate, but will change the free length, and therefore give you less preload.... I have never seen that long spring, but that would be the first thing I would do.... If you don't, and use an RVA and adjust it down to coil bind, you will do it anyways, so you may as well do that to start.... The original Disco spring would "set" to about a 1/8" shorter length than a new one anyway....

Bob