How to Select the Proper Recoil Spring

The recoil spring is one of the most critical springs in a semi-auto pistol, yet most shooters install the wrong spring most of the time.  To understand the recoil springs’ function, we need to examine what it does and how it works.

The recoil spring performs 5 tasks, all of which are critical for reliable function:

1. Controls the velocity of the slide when cycling
2. Allows the slide to achieve a full rearward stroke
3. Ejects the spent case the correct distance from the ejection port
4. Picks up and feeds the next cartridge
5. Positively locks the slide into battery

Item #1:  The optimal slide velocity will eject a spent case, on average, 6 – 8 feet away from the shooter’s stance.  This is the ideal slide velocity for reliable extraction, ejection, and subsequent feeding.  Most of the time folks follow bad advice given on YouTube videos and forums telling folks to use a 10 or 11# recoil spring, which is incorrect unless you are using very light loads.  A maximum of 10’ – 12’ ejection distance is acceptable in most cases, however anything more should be corrected in a timely manner.

Item #2:  The slide must travel its full rearward stroke so the slide abuts the frame, just as it was designed to do.  There is no such thing as “slide or frame battering”.  The installation of recoil spring buffers can prevent the slide from achieving its full stroke.  Recoil buffers can cause ejection problems by short stroking the slide as well.  Plus, when the buffer breaks, as they all eventually do, it will drop broken shards into your CZ’s lock work, rendering your pistol inoperative.  A full slide rearward stroke allows the spent case rim to contact the ejector with full force, producing a strong, long-distance ejection, a critical function for a reliably running pistol.  Obviously, you can only determine the correct ejection characteristics outdoors, so if you only shoot indoors, you must find somewhere to do some testing.

Item #3:  There are 2 criteria for determining the correct recoil spring poundage: an ejection distance of 6 – 8 feet, and for competition shooters, how quickly your muzzle gets back on target.  Too heavy of a recoil spring can cause the muzzle to “dip”.  Too light of a recoil spring can make the muzzle rise too much and puts added stress on the slide stop pin.  Finding the optimal spring can be trial and error.  Each pound change in the recoil spring will change the ejection distance 1.5 – 2.0 feet.    EXAMPLE:  An out of the box SP-01 with a 16# recoil spring produces an ejection distance of 2.5 – 3.0 feet.  To get this distance into the preferred 6 – 8-foot range, you would need to use either a 13# recoil spring (ejection distance would be 8.5 – 9.0 feet) or a 14# recoil spring (ejection distance would be 6.5 – 7.0 feet).  Either would work fine.

Item #4:  If your CZ has the correct recoil spring to match the pressure of your load, then mis-feeds, jams, and improper feeding are virtually eliminated.  With the correct recoil spring installed, the main issue will be reduced to the magazines or the ammo.   You DO NOT select the recoil spring based on bullet weight.  You select the recoil spring based on the operating pressure of the load.  A 115 grain bullet can produce as much or even higher operating pressure than a 124 or 147 grain bullet, with the powder charge being the determining factor.   However, bullet weight can absolutely affect operating pressure, if the same powder charge is used across a range of various bullet weights.   The wrong recoil spring can produce double feeds, stove pipes, and angle jams where the slide has “crashed” into the case, pinching the cartridge.  Very light recoil springs can result in failure for the slide to return fully into battery.  Too light of a recoil spring can also allow the slide to impact the frame with enough force to cause the top round in the mag to shift forward, resulting in a feed failure.

Item #5:  All semi-autos are reliant on quality ammo with the proper case crimp, sizing, and proper overall length.  A very light incorrectly chosen recoil spring will not allow a marginal cartridge to not fully chamber.  However, in most cases, a marginal cartridge with the correct recoil spring would have a much greater likelihood of chambering successfully.   It has been proven that too light a recoil spring can cause inconsistent lock-up, which can result in reduced accuracy.  Remember, for any semi-auto to be accurate, the barrel must lock-up consistently, shot to shot.  The correct recoil spring will help ensure a positive lock-up.

Recoil Springs and Hammer Springs

As a side note, we get asked all the time, “If I change my recoil spring won’t I need to change my hammer spring”?  Absolutely not.  There is no relationship between the hammer and the recoil spring.  Here is why:

Some years back an enterprising individual mounted a motion sensor on a 1911 slide.  With full power 45 ACP loads the slides total cycle time was 6 thousandths of a second.  This means the time the slide made actual contact with the hammer was even less.  Much less.  In essence, you select your hammer spring for reliable ignition, first and foremost, then you tune your recoil spring last to match the pressure of your load.     

Barrel Porting

Barrel porting plays a major role in the slide velocity and pressure in the operating system in a semi-automatic handgun. After porting, we are still looking for that 6-8 feet ejection pattern. The more that you port your barrel, the shorter your ejection pattern will be. We recommend testing your ammo after you have ported your barrel to ensure proper recoil spring selection, and maximum reliability from your firearm.  If you would like to learn more about barrel porting, check out our full video on barrel porting: Click Here

Disclaimers

• P10
  • P10 models must use our 30283 with any recoil springs 13lbs or less for proper function. If the recoil spring to striker spring weight is out of balance, slide movement can occur during a trigger pull. This will prevent proper function and can even pull the slide out of battery, causing a failure to fire
• Shadow 2 Carry/ Compact
• • The 11RSP is made for reduced power ammo or a pistol with barrel ports for the Shadow 2 Compact and Shadow 2 Carry. If too light a recoil spring is used, it can cause malfunctions or premature wear. If a pistol is not ported, use the 13RSP instead of the 11RSP for standard and plus pressure ammo.