Springs for 4.25" 9mm Shooting +P

Reasonable assumption (I know) is your Colt came with proper/adequate recoil/mainspring.
The original 18# Commander (.45 ACP) RS is alleged to be "extra power" spring in 9mm.

The FBFPS (Flat Bottom Firing Pin Stop) helps retard slide velocity, but makes racking slide with hammer down more difficult (duh).
I use them in my gun- I like the perceived recoil impulse. Others will disagree.

I'll add; I prefer the lightest Recoil Spring I can use with 100% function.
The "recoil impulse" not only pushes back, but dips back down as slide goes into battery.

 

Stock spring should be fine. Compared to a 45 there are no hot loads in 9mm. The slide speed is already slow compared to a 45. It’s the same gun with a different barrel.
Just my opinion
I have a full size 9mm and a 4” aluminum frame 9mm
David

 

Factory Standard used to be 23# MS.
In a 9mm. regardless of load, I run 19# to 21#- depending on the guns purpose.

I run 124 HST +P with a 21# MS, which is probably overkill.

MS weight contributes to trigger pull weight- sooo- I tend to use the lightest spring that functions reliable and won't beat the gun to death.
My 9mm 1911's are range guns for the most part, I run 2#-2.5# triggers in these.

 

9mm 124 +P 148 power factor
45 +P 218 Power Factor

David

 

Of course it does.

The more tension/weight applied to hammer in the full cock position (in the form of a heavier rated MS), the more effort it takes for the sear to release the hammer hooks as trigger is pressed.

That is just a contributing factor to sear angle/radius, hammer hook length and sear spring tension.

With respect; I’d advise simply trusting that the manufacturers have all of this figured out and simply shoot your gun.

There is ample time down the road to be concerned about tweaking and fine tuning, when you have a considerable amount of trigger time.
It will all make more sense with that acquired experience.

Power Factor is a method of rating “Power” of a load; Major or Minor.
Bullet weight X Velocity divided by 1K.

 

Yes it does. Wolff manufactures mainsprings in weights all the way up to 34lbs. The mainspring is more efficient at slowing down the rearward velocity of the slide than the recoil spring. So, with a flat bottom firing pin stop and a heavy mainspring you should be perfectly fine using the standard 16lb recoil spring or less. The only question then is how heavy can you go with the mainspring before you notice the trigger pull has become unmanageable. The only way to tell is to experiment with mainsprings of different weights.

The whole spring thing is about balance. How strong does the recoil spring have to be to chamber the next round 100% of the time? That depends on a bunch of things like slide weight, magazine spring weight, friction, your shooting style, etc and these will vary from pistol to pistol.

Informal range testing using various recoil spring weights and any magazines that you might use will tell you which recoil spring weight is best for your pistol. Once you've settled on the recoil spring then you can begin testing mainsprings to find out which one gives you the best recoil impulse with the ammo you intend to use. What you're doing with all this testing is balancing the two springs for proper functioning of the pistol.

Remember, the slide must strike the frame abutment each time you pull the trigger or you risk short stroking the slide which will often result in bolt-over-base malfunctions particularly in shorter than 5" 1911s.

It's a competition thing that makes it easy to group pistols into classes based on the simple momentum calculation. Momentum = Mass x Velocity

Does it have some relationship tp knockdown power? That's a complicated subject. Suffice it to say that with proper shot placement your 9mm will get the job done.

 

Factory spec is 16lb recoil spring and 23lb mainspring. Where you go from there is up to you.

However, the first thing I'd do is what gaijin suggested; fit a flat bottom firing pin stop. I use EGW stops. After you do this put a few rounds through the pistol to see what effect installing the new stop has had.

I suggest shooting with your weak hand only during the testing phase. Shoot slowly and deliberately. Your objective is to observe the functioning of the pistol. It is not to throw lead down range as fast as you can. Nor is it to determine how accurate the pistol is.

You can test how light a recoil spring will feed rounds from the magazine without firing a shot. Fill the magazine to capacity, lock the slide open, insert the mag, drop the slide using the slide stop. Start with the lightest recoil spring and work your way up in spring weight until you get 100% feeding from a full mag. I'm of the gaijin school of thought on recoil springs; I use the lightest one consistent with 100% function and how the pistol feels as I shoot it.

It wouldn't surprise me if the pistol will chamber rounds with the very lightest spring but you probably don't want to run it with anything less than a 12lb recoil spring. So, I'd suggest getting a 12, 14, and 16lb conventional recoil spring for testing. Once you decide which weight recoil spring of the three works best, move on to the mainspring testing.

As has been pointed out, the heavier the mainspring, the heavier the trigger pull will be. But you'll have a tough time discerning the difference in trigger pull by going a pound or two above or below your starting point. Assuming the mission of this pistol is personal defense and not competition bullseye shooting, a 5lb trigger pull is perfectly fine. What I'm saying is, don't be too concerned about getting a heavier than 3lb trigger pull.

As you know, the other effect of using a heavier mainspring is that it slows down the rearward velocity of the slide. I'd much rather slow down the slide than have a 3lb trigger.

Keep swapping out mainsprings and test firing until you find the one that feels the best to you and allows 100% functioning of the pistol. If you go too heavy, the slide may be slowed so much that it doesn't travel fully to the rear resulting in bolt-over-base malfunctions. If you go too light, the slide may slam into the frame hard enough to cause inertia feeds. The Goldilocks principle applies here.

Change only one thing at a time so you can isolate and observe the effect.

 

You may be wondering why I suggested using your weak side hand during live fire testing. It is because it normally provides less resistance to recoil than your strong side hand and certainly less than using a two hand hold.

This tests the pistol in a sort of worst case scenario kind of way. With a rock solid death grip and perfect stance the slide will travel all the way to the rear using a heavier set of springs. With a weak off-hand grip while standing off balance on one foot there is less resistance being applied against the generated recoil forces. Mathematically the pistol will need a lighter set of springs to allow the slide to travel all the way to the rear. Insuring full slide travel is especially important in shorter than 5" 1911s for proper functioning. Never put a shock buff in a shorter than 5" 1911 because it will shorten the slide travel.

This touches on one of my pet peeves. The infamous "limp wrist". Guys on the internet will invoke the specter of a limp wrist all the time and call into question the shooter's lack of muscle mass. What a flippin' joke. All it means is the springs are too heavy for this particular shooter's body structure, technique, the power of the ammo, and/or various points of friction inside the pistol. Solving the problem does not mean pumping iron every day and bulking up with a massive intake of steroids. It means testing the pistol in the way I described earlier including using your weak hand to discover the best combination of springs for you.

Here's a limp wristing video: https://www.youtube.com/watch?v=fsewsolPyBU


Here's a video about the effect of recoil springs on slide movement:

 

Good info Steve. Fortunately, I learned these lessons many years ago while tuning pistols for competition shooters. I've always believed that a pistol properly set up for one person may not work for another shooter without tuning. But that's just me.

 

A 18 pound recoil spring for a 9mm commander?

 

Overkill in my book. Even with +P 9mm.
May not even cycle.
I run 9 or 10# RS in my 5” 9mms.
I’d probably start at 12 or 14# in a Commander 9mm

 

Crap! Sorry about that. Thanks very much for catching a stupid mistake on my part, puddi_nugget.

I'm a .45 guy and was just spitting out numbers by rote. Those itty-bitty 9mm don't generate as much momentum as the big burly .45

I just corrected my previous post which was wrong by suggesting you get a 12lb, 14lb, and 16lb spring and use those for your testing. Since you're running +P ammo I don't know if you can get away with using a 10lb spring but you can always add one of those to the mix for testing.

 

Here are the OEM springs rates for a few of my 9mm’s, got these straight from the manufacturer.

• Guncrafter NM Gov’t is 9# or 10# Recoil and 23# Mainspring
• Springfield Professional is 9# Recoil Spring, 23# Mainspring
• WC Vickers Commander (4.25 bbl) is 12# Recoil Spring and 19# Mainspring

 

Solid information RMF308. Thanks.

The Commander you cite is using a 12lb recoil spring teamed up with a 19lb mainspring.

So, if we use that as a starting point and keeping in mind that the OP is going to be running 125gr +P exclusively, it seems reasonable that he test out combinations of recoil springs (10, 12, 14lb) with mainsprings (19, 21, 23lb). The objective will be to use the lightest recoil spring consistent with 100% functioning along with an appropriate mainspring.

What do you think?