RSA for Glock™ Sub Compact Frame Pistols G43

Stainless Steel Captured Assembly for
G43 (1-1)

This product is currently out of stock and unavailable.




Completely assembled “drop-in” dual stage unit offered in factory recoil spring weight ONLY.

The recoil spring assembly (RSA) serves three basic purposes. It maintains the firearm in an in-battery condition prior to and required for successful discharge. It assists in the deceleration of the recoiling slide mass post discharge. And, most importantly, returns the slide to the aforementioned in-battery condition completing the cycle.

►Faithfully accurate to the exceptional performance and quality
requirements of Glock™ pistols
►Captured, drop-in unit with smooth spring deflection and component
displacement providing a highly reliable operation cycle
►Made in the United States of America with a 100% Lifetime
►Machined from solid, corrosion resistant 303 Stainless Steel with
finishes to minimize spring compression friction
►Designed to avoid the extremes of solid height loading*

Guide Rod
  1) Spring support shoulder ensures positive spring retention
  2) Appropriate installation pre-load provides good
assembly/disassembly retention between slide and barrel lug
  3) Maximum clearance diameter to prevent spring buckling during
  4) Distinctive exposed crown head available in either polished or
black oxide iron magnetite (Fe3O4) finish

Spring Cup Sleeve
  5) Correct length providing in-battery pre-load required to maintain
positive condition and satisfy the Glock™ In-Battery Test
  6) Flange thickness and cup depth controlled to avoid solid height
  7) Appropriate diametrical clearances for spring expansion during
  8) Spring end stabilization via shoulder supports
  9) Positive contact with guide rod head in battery
10) Equalized spring load from battery, load distribution
11) Synchronized spring deflection from battery to minimize
disproportional fatigue failure
12) Free flow spring lead ins

Retaining Screw
13) Flange thickness controlled to avoid solid height loading*
14) Spring end stabilization via shoulder support

Recoil Springs
15) Closed and ground ends outer, closed ends inner
Newcomb Firearms Components 302 Stainless Steel music wire
compression springs
Heat treated, shot peened and stress relieved
Ensures consistent and reliable return to battery throughout high
count life cycle


*A solid height condition occurs when sufficient load results in adjacent coil contact terminating deflection of the spring. As compression approaches solid height, the spring constant grows deviating from a linear rate. This increased load curve generates high stress leading to plastic deformation and permanent distortion of the spring. While assisting in the deceleration of the recoiling slide mass, if the spring(s) of the RSA reach solid height, the remaining kinetic energy is transmitted into the frame as impact. This loading occurs at the end of the spring tunnel, just forward of the slide lock.

The maximum rearward displacement of the slide relative to the frame is the same with or without the FACTORY recoil spring assembly installed. You can check for a potential solid height issue with your aftermarket recoil spring assembly as follows:

1) Ensure your firearm is in an UNLOADED condition!

2) If your pistol contains the FACTORY recoil spring assembly, simply retract the slide rearward to its maximum displacement and place a pencil mark somewhere along the slide and place a corresponding mark on the frame. (If you do not have the FACTORY recoil spring assembly, this same position can be established by removing both the barrel and your current recoil spring assembly, then reassemble the empty slide onto the frame and mark in the same manner described.)
Now install your aftermarket recoil spring assembly and check to see if it allows for the same displacement. If not, the possibility of the recoil spring(s) being compressed to solid height exists.

**A note about Installation vs Operational position: Field stripping most often results in the RSA being held between the slide end ring and barrel lug when removed from the frame. This is NOT the operational position of the RSA but rather a temporary holding position that simply facilitates easy removal / installation of the RSA. When the slide (including barrel and RSA) is reassembled with the frame, the end of the RSA is picked up by the frame at the end of the spring tunnel just forward of the slide lock. When held between the slide end ring and frame the RSA is in its operational position. Repeated subsequent disassembly likely will yield slightly different positioning of the RSA against the barrel lug notch. In some case, the RSA will not find purchase on the barrel lug at all and may fall out on disassembly. Either case is normal and not necessarily an indication of a problem with the RSA.


DISCLAIMER: “GLOCK” is a federally registered trademark of Glock, Inc. and is one of many trademarks owned by Glock, Inc. or Glock Ges.mbH. Neither Brass Stacker™, nor this site are affiliated in any manner with, or otherwise endorsed by, Glock, Inc. or Glock Ges.mbH. The use of “Glock” on this page is merely to advertise the sale of Glock pistols, parts, or components.

Additional information

Weight 0.0589670081 oz
Pistol Model

Exposed Face Finish



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