Spring Weight Tuning (Glock)

Overview: Recoil springs are the unsung heroes of pistol function. In Glock Gen5s, the stock dual recoil spring assembly (RSA) is calibrated to handle typical 9mm ammo and ensure reliability across a range of conditions. But when you start adding compensators, shooting specialty ammo, or chasing the softest recoil, changing the spring weight can optimize your Glock’s “timing.” In this guide, we’ll explain when to use common spring weights (13 lb, 15 lb, 17 lb, etc.) with or without comps and +P ammo, and provide a reference chart. We’ll also touch on drop-in spring/guide rod combos and how to interpret ejection patterns to fine-tune timing. A printable table is included for quick reference on spring selection for Glock 17, 19, and 34 setups.

Glock Recoil Spring Basics (Gen5)

Gen5 G17 and G19 use a dual-captive recoil spring assembly. The nominal weight is about 17 lbs for the G17 and ~18–19 lbs for the G19 (due to the shorter slide needing a bit more force). G34 Gen5 uses the same RSA as G17. These springs are a bit stiffer than Gen3 single springs, partly to reduce frame battering and work with the heavier slide mass of Gen5 (slide internals changed, and the ambi slide lock adds mass).

When we talk about switching springs, typically it means using an aftermarket guide rod and 1911-style single recoil spring of a certain weight. Companies sell kits: for example, a Glock 19 recoil spring kit might include a stainless guide rod and a 13 lb spring (plus adapter for Gen5 if needed). Some advanced systems like the DPM Systems or Radian COMPRESSOR guide rod offer multiple spring stages or quick spring changes without tools.

For simplicity, we will refer to spring weights as if using a single-coil spring. If using the factory dual spring RSA, you can approximate it to a weight, but those aren’t user-tunable (except by swapping the whole RSA with one from a different model, which isn’t recommended for fine tuning). So assume you’ll use an aftermarket guide rod to change spring weight easily.

Here’s a quick reference chart for spring weight selection on Glock 17, 19, 34 (9mm):

Glock Model & Setup

Recommended Recoil Spring

Notes on Use-Case & Ammo

Gen5 - G17/G34 (Stock, No Comp)

17 lb

(Factory RSA)

Best overall balance for standard 115–147gr ammo. Ensures reliability even with +P. Use factory RSA for duty/carry unless specific issues.

Gen5 - G19 (Stock, No Comp)

18–19 lb

(Factory RSA)

Stock dual spring unit is slightly heavier. Good for standard and +P ammo. (If using only light target loads, a 15 lb may soften recoil.)

G17 - Compensated (Single Port)

15 lb

A slight reduction helps cycle with the reduced recoil from the comp. Good starting point for most +P or full-power ammo with a comp.

G19 - Compensated (Single Port)

15 lb (or even 13 lb)

Compact slides are more sensitive; many use 15 lb, but some go to 13 lb for weak ammo. Start at 15; drop to 13 if running very soft loads or if slide fails to cycle fully.

Any Glock - Multi Port

13 lb

A larger/more efficient comp (vents more gas) slows the slide more, often requiring a lighter spring. 13 lb is commonly used for race setups. Ensure ammo is stout enough or consider even 11 lb if using super soft ammo.

Light Target Loads (no comp)

15 lb (in G17)

15–16 lb (G19)

If shooting only low-power ammo (e.g. 147gr at 130 PF) without a comp, dropping a couple pounds can improve reliability and ejection. G17 often runs well with ~15 lb for 130 PF loads. G19 might use a slightly higher since its slide is lighter (to avoid over-speed).

Hot +P Defense Ammo (no comp)

17–20 lb

Factory 17 lb is usually fine. If you plan extensive +P use or +P+, a heavier spring (20 lb) can slightly reduce frame battering. However, too heavy can cause failures with regular ammo, so many just stick to stock and replace RSA more frequently.

+P with Compensator

17 lb (stock)

or 13lb , 15 lb

This depends: A comp plus +P kind of counteract – comp slows slide, +P speeds it. Often you can run the stock spring and be okay (the +P “covers” for the comp). If ejection is weak, drop to 15. This combo usually still cycles strong.

Extreme Light Spring (< 13 lb)

Use with caution

Springs below 13 lb are very light for Glock 17/19. Only consider for competition with very soft ammo and a comp. If you go 11 lb or 9 lb, also install a lighter striker spring to prevent the striker from pushing the slide out of battery(the striker spring pressure can overcome an ultra-light recoil spring). These require tuning and may impact reliability.

G34/G17 with Heavier Slide mods (no comp)

15–17 lb

If you’ve added slide weight (e.g. optic, steel sights), the stock spring still works but some shooters drop to ~15 lb to slow the slide’s rearward speed (reducing dip on return). This is personal preference.

Example: A competitive shooter uses a 13 lb ISMI spring with a stainless guide rod in Glock 17/34 and finds it “works best from 128 PF – 145 PF” ammo, with sights settling perfectly. This aligns with our chart for comped or competition G17/G34.

Now, some explanation and tuning logic:

• When you add a compensator, you effectively increase the barrel/slide dwell time and vent gas that would normally help push the slide. This slows down the slide’s rearward movement. To maintain reliable cycling, you go to a lighter spring, which requires less force to compress. That’s why people drop from 17 lb to ~15 lb (or even 13) with comps. A user on GlockMod recommended a 15 lb spring for a G19.5 with comp, even though the comp advertised working with stock springs – because cheap ammo was a bit sluggish with the stock spring. Sure enough, switching to 15 lb made it run everything reliably.
  
  

• When you use hot ammo (+P), the slide is driven back faster and harder. A heavier spring can absorb more of that force, keeping the slide from slamming the frame as hard. But Glock RSA are already built tough; many leave stock springs in for +P and it’s fine. If you’re planning to make +P your steady diet (like some +P+ subgun ammo), you could go to 20 lb to be gentle on the frame – just remember to swap back or be cautious with weaker ammo.
  
  

• Light ammo, no comp: If you have a range/competition gun with no comp but you shoot mild ammo (say 115gr at 1050 fps, just barely making minor PF), the stock spring might be a tad too much, causing the gun to eject weakly or stovepipe. Dropping to ~15 lb can smooth it out. This is common in G34s for USPSA Production – lots of folks found reliability improved with 13–15 lb springs for their minor loads.
  
  

• Light ammo with comp: This is the most sensitive case. Comp already robs energy, and ammo is low energy to begin with. You might end up at 11 lb or even 9 lb to get reliable function. But as mentioned, below 13 lb you must consider the striker spring interplay: one forum expert noted that with <13 lb recoil spring, the trigger bar pressing up the striker (during take-up) can actually push the slide out of battery if pointed upward. This happens because the striker spring (around 5.5 lb) starts compressing and the resistance is greater than the recoil spring’s forward force, nudging the slide back. A lighter striker spring or simply racking the slide to fully cock the striker can mitigate it. Still, running super light springs is generally for competition where guns are babied and checked frequently.
  
  

• Heavier than stock springs: These (20–22 lb) are typically used if one plans to fire a lot of +P+, or in .40 caliber Glocks when converting down to 9mm without changing RSA (less relevant for Gen5 9mm though). One downside of too heavy a spring: the slide closes with extra force, potentially causing more muzzle dip and feeding issues, and if the spring is so stiff that lighter loads don’t cycle, you’ll get malfunctions. Some early-gen Glock users tried 20+ lb springs to reduce perceived recoil, but many found it just moved the “kick” to the front (the gun would jolt downward when the slide slammed home). So heavier isn’t usually better unless needed for a specific reason.
  
  

• Tungsten/Steel Guide Rod: Changing the guide rod material doesn’t change spring weight, but the extra weight (tungsten is much heavier than the stock polymer rod) can slightly reduce muzzle rise by adding mass up front. It also can affect how the spring compresses (steel rods may have less friction than the Glock dual spring assembly). If you switch to a heavy guide rod, you might find you can drop spring weight 1 lb more and still cycle, because the reciprocating mass is increased (the rod adds to slide mass). Also, watch out: pure tungsten rods have been reported to crack (they’re brittle). High-quality ones are usually tungsten powder inside steel, etc., to avoid brittleness. In any case, guide rod swaps are common when tuning springs because the stock RSA spring is captive and not easily changed. Kits from Wolff, ISMI, Sprinco, etc., come with different springs to try.
  
  

Printable Spring Selection Chart

(The above table can serve as a printable quick-guide. You can screenshot it or recreate it as needed for your use.)

To use it: identify your Glock model, whether you have a compensator, and what ammo you predominantly use, then see the recommended spring weight. It’s often a starting point – fine tuning may be needed by testing how your brass ejects and how the gun feels.

Signs of Correct vs Incorrect Spring Weight

Signs your recoil spring is correctly tuned: The pistol ejects cases reliably to the side (about 4–6 feet away), the slide cycles smoothly without excessive slam, and the sights track back to target without big overshoot. The gun should feed the next round even if you’re shooting one-handed (insufficient spring can sometimes cause sluggish feeding, but too much spring is usually the culprit for failures to feed low-powered rounds).

Too Heavy spring symptoms: Brass dribbles out or ejects weakly (maybe at your wrist or straight up). The slide may not go fully rearward, causing stovepipes (spent casing not fully ejected). The gun might feel softer initially (because the slide is resisting more on recoil), but it will have a pronounced forward jolt as the slide slams into battery – you’ll see your front sight dip noticeably after each shot. You might also notice last-round hold-open failures (the slide doesn’t lock back on empty) because the heavy spring pushes the slide forward before the slide stop can catch it – this often happens especially if combined with a comp or low-power ammo.

Too Light spring symptoms: Brass is flying very far (8–10+ feet) and perhaps at a more forward angle than normal (like 2 o’clock direction, indicating slide is cycling super fast). The recoil might feel “snappier” because there’s less resistance slowing the slide initially, and the slide might be hitting the frame harder at the end of travel. You may see the slide outrunning the magazine – a clue is nose-dives or failures to chamber a round, particularly the last rounds (since mag spring is weakest on the last round). If extremely too light, the gun can even unlock too quickly, but Glock’s design usually prevents out-of-battery firing. One subtle sign is if your primers show unusual smear or drag marks – that can be a timing sign (though often more related to striker timing). Another sign: if the gun feels great to shoot but occasionally fails to pick up a round from the mag or you get “bolt over base” misfeeds (slide closing on top of a round that didn’t rise fully), it’s cycling too fast – a slightly heavier spring can help.

Tuning by ejection pattern: A quick method: fire 5-10 rounds of your typical ammo and observe where brass lands.

• Ideal: consistent pile a few feet away at 3-4 o’clock.
  
  

• Lands very close or stovepipes: spring likely too stiff (or ammo too weak for that spring).
  
  

• Launches brass into low earth orbit: spring might be too light (or ammo hotter than expected).
  
  

• Brass to face: could be heavy spring or could be extractor issues; if it only started after you changed spring, likely the spring.
  Remember, changing ejector or extractor can also tune where brass goes, but spring is the easier variable in recoil tuning.
  
  

Drop-in Spring Combos by Model: Many companies sell pre-packaged spring sets they suggest for certain setups. For example, Killer Innovations notes that if you run their comp on a G19, “you will need a 13 lb spring” and they sell one with their guide rod. That’s a strong hint of what works for that configuration. Similarly, some comp makers include a recommended spring weight in their instructions. Always read those – they’ve likely tested with common ammo. It saves you some trial and error.

Printable Chart Tip: It might be useful to print the chart and note down any adjustments you made in your particular gun. Each pistol can be a little different. Also, season to taste: if you prefer a softer recoil impulse and don’t mind chasing brass, you might run a slightly lighter spring than the chart says for your ammo – that’s fine if your gun is still reliable. The chart is about function first.

Slide Speed, Ejection, and Timing Impact

We’ve touched on this, but to tie it together: the interplay of slide speed and the gun’s timing affects not just reliability but also how the recoil feels and how your sights behave.

• A faster slide cycle (from lighter spring or hotter ammo) will complete the recoil cycle quicker. This can mean your dot or front sight returns to alignment faster in time, but it might overshoot due to inertia (the frame gets a harder jolt). Some top shooters actually prefer to tune the gun to cycle slightly slower, so that they can track the dot through the shot and back without a sudden snap. How do they do that? Often by using the lightest ammo that functions and not going too low on spring (to avoid excessive slam). Or in compensated guns, using a comp to slow the slide plus a spring not too light results in a very flat, slightly slower cycle that feels like a “roll” instead of a “snap.”
  
  

• Ejection angle: Timing issues can cause erratic ejection. If the slide is moving too fast, the case might be extracted before the ejector optimally hits it, or while the gun is still recoiling, throwing brass at odd angles. If too slow, brass can barely trickle out. When you get the timing right, brass tends to eject consistently. A smooth pattern of ejection usually indicates your recoil spring and ammo are in harmony with the gun’s mechanics.
  
  

• Frame wear and slide drag: A spring that’s too heavy can beat up the locking block and frame because the slide isn’t slowed enough on recoil but then is slammed forward viciously. You might see peening on the barrel lug or frame inserts. Conversely, a spring that’s too light can batter the frame on the rearward stroke (slide hitting frame at back harder). Glocks are durable, but extreme setups can cause accelerated wear. That’s why moderate tuning is advised unless you’re strictly competition and don’t mind replacing parts eventually.
  
  

• Lock-back timing: Recoil spring affects when the slide is at the right position for the slide stop to engage on empty. If your gun sometimes doesn’t lock back on empty mags, and you’ve ruled out thumb interference, consider spring weight. Too heavy a spring can shove the slide forward before the stop can catch (especially if using reduced power ammo that just barely pushes it open). Too light a spring usually isn’t a problem for lockback (if anything, slide might hit the stop harder).
  
  

In summary, spring tuning is about finding the Goldilocks zone for your setup. The provided chart and guidelines give you an excellent starting point. Always make changes incrementally and test. It can be fun – you’ll actually feel differences and see it in your sight tracking. And springs are cheap, so many enthusiasts keep a set of 13, 15, 17 lb springs around to experiment with various loads or if switching comps on/off.

 Still confused? So was gravity before Chuck taught it how to drop bodies. Hit up our no-BS guides on Ammo Matchmaking, Compensators 101, Parts Compatibility, Spring Tuning, and Trigger Upgrades — before your gun calls you a disappointment.