Recoil Spring Assembly (RSA)
Glock recommends replacing the RSA every 5,000 rounds on Gen 3 and earlier, and every 10,000 rounds on Gen 4/5 (dual recoil spring). A worn RSA causes failure to return to battery and accelerated slide wear. OEM Glock RSAs cost $7–$12 from Brownells or Numrich. Aftermarket options from Wolff Gunsprings offer different weight ratings for suppressor hosts.
Connector (Trigger Pull Weight)
The factory Glock connector gives a standard 5.5 lb pull. The connector is the easiest legal modification to reduce trigger pull weight. The Ghost Inc. Rocket (~$12) and Lone Wolf 3.5 lb connector (~$10) are the most popular options.
| Connector | Pull Weight | Best For | Price |
|---|---|---|---|
| OEM Glock (minus) | 3.5 lb | Competition | ~$8 |
| Ghost Rocket | 3.5 lb | Competition/Range | ~$12 |
| Lone Wolf 3.5 | 3.5 lb | Competition/Range | ~$10 |
| OEM Standard | 5.5 lb | Carry/Duty | ~$7 |
Aftermarket Barrels
Glock's factory barrel uses polygonal rifling that does not support lead cast bullets. Aftermarket barrels with conventional rifling (Lone Wolf, Faxon, Agency Arms) solve this and typically show improved accuracy due to tighter tolerances.
- Lone Wolf — conventional rifling, budget-friendly. (~$90)
- Faxon Match Series — match-grade tolerances, excellent accuracy. (~$160)
- Agency Arms — premium match barrel, significant accuracy improvement. (~$280–$350)
- ZEV Technologies — competition-grade, threaded options available. (~$200–$300)
Slide Parts Kit
Glock slide parts kits include the firing pin, firing pin safety, extractor, spring-loaded bearing, and spacer sleeve. Replace this kit every 10,000–15,000 rounds or if you notice any unusual trigger behavior. OEM kits from Numrich Gun Parts are the safest choice for reliability builds ($18–$25 complete kit).