I recently took the plunge and ordered a P320 FCU and was looking at all the options for a build.

What are the pros/cons of using a full length guide rod and 1911 springs (Wilson, Springer, Grayguns, etc) versus the stock captured spring guide rod package?

The 1911 springs are less expensive for periodic replacement and we can be reasonably sure that they will be available as long as 1911 pistols are legal to own.

The same cannot be said for the proprietary SIG springs. That’s why I have Graygun rods.

In addition, and perhaps I’m wrong, but it seems to me that the P320’s rail tabs that are integral to the steel receiver are probably less likely to develop problems if the factory springs aren’t used than SIG Classic line guns with aluminum frame rails.

If you get the proper guide rod for a full size, yes:

https://grayguns.com/product/c...ess-steel-guide-rod/

Along the same vein, I have a Sig M-17. I assume it is a P320F. Am I right?

The Grayguns fat guide rod is great for the full size pistols. It makes for a smoother cycling pistol, and you can tune the pistol to your ammunition by selecting the appropriate weight recoil spring.

The P320 is somewhat oversprung; the full size pistol is prone to muzzle dip when firing a string and a lighter weight recoil spring induces less muzzle dip. Grayguns supplies a 15 lb spring with their guiderod, vs. the factor 18 lb spring, and a lot of competitive shooters go down to around 12 lbs. If you're reloading, especially with lighter loads, the ability to tune to the load helps with ejection consistency and in making a more consistent cycle for control and accuracy at speed. The pistol stays flatter, and one takes advantage more of the reduced recoil.

If you're not shooting a full size, it's a different matter, because your options are limited.

quote:

If you're not shooting a full size, it's a different matter, because your options are limited.

What options are there for a Carry/Compact slide with a 3.9" barrel?

DPM recoil systems makes a recoil assembly for the compact, which has a choice of mix-and match springs to adjust the weight. They won't tell you what spring weights are, and don't advertise replacements; it's a nested spring arrangement with several springs.

The company is from Greece, and appears to be one guy. The springs look like they came out of the general assortment bin at a hardware store. They don't inspire confidence. They seem to work fine, but the factory recoil spring assembly appears to be the best choice.