I just purchased a 945 from a fellow forum member.
Now I have a couple of questions:
What other magazines will work in this pistol?
What recoil springs interchange?
Any idea what the weight ratings are for the two supplied springs?
The full size, 8-rd 2nd/3rd Gen 4506 magazine is absolutely exactly the correct size, shape and everything to fit the 945 except the magazine catch is cut higher for the 945.
How exactly the same? Well, all the earliest 945 pistols shipped with a dual-cut altered 4506 magazine.
Making the proper modification is easy for those who are skilled at such work, but I hesitate to call it simple. Otherwise, there exists no other source outside of original (and so marked) 945 magazines.
Recoil spring should be exactly the same as OEM 4506 spring... going from memory but not certain, I think the original “hardball” spring is 14 pounds.