I pulled out my P-38/P-1 parts box and took some measurements -
Mainspring
- .038" wire dia
- .225" OD
- 1.516" free length
- 17 1/4 coils
Recoil springs [two slide springs]
- .026" wire dia
- .207" OD
- 5 1/8" free length
- many coils
I don't have an Erma toggle to measure the springs, but I have to say that I'm skeptical of using the P-38
mainspring...