Cut ISMI 13# Recoil Spring in G23?

[Sparky5019]

Hi guys,

Was installing an ISMI 13# recoil spring in my wife's G23 and noticed that the slide did not have full travel. Before anyone asks...it is the spring for the G23 and is a little shorter but I have heard that you have to cut them but how much and how will it affect the 13# rating of the spring?

Thanks again y'all,

Sparky

[Dragon Slayer]

What is an ISMI #13 recoils spring? Also I have never heard about cutting a recoil spring on a Glock 23 or 19. How do you cut a spring that is captive anyway?:rolleyes:

[1oldgrunt]

You shouldn't cut recoil springs...buy a new one , jezz even a Wolff is only $5! Besides length , there is # of coils, spacing of coils, is the spring a variable load spring, there are many variables besides length! As I tell all my ladies...."length isn't the only thing that matters...girth, now that matters"! :-)

[Sparky5019]

OK...let me expound!


I was replacing the spring; the factory spring is 18# (# = pounds = lbs. = 0.45 kg.). I was using an ISMI (well respected brand that is flat stock like the factory spring; Wolff spring are round wire stock) 13# spring that is rated for the G23. The free length of the spring is too long secondary to the slide not acheiving full rearward travel (the slide bottoms on the spring not the frame). I have read that it is COMMON PRACTICE to trim these springs so that there is full rearward slide travel. My question was aimed at finding a starting point and if it would mess up the spring rating as it feels too heavy ( greater than factory) when it is in the gun.

GLOCK uses slide weight (mass) to determine speed not spring weight as most of the factory springs are within a pound or 2 as the factory rating.

2. Using a lighter spring requires less force and shortens the recoil cycle = less muzzle flip and less felt recoil, it also reduces the possibility of "limp wrist jams". Hence a heavy spring spreads the recoil over a longer period of time requiring greater force and increases felt recoil and risk of "limp wrist jams". Frame battering in the GLOCK is not an issue as the top GLOCK competitors like Dave Sevigny use extremely light recoil spring in their guns (even their production class guns that have not had the slides lightened).

Using a round wire spring like the Wolff (which I use in my 1911s with great success) requires a me to use their GR. I wanted to stay with the factory style spring as that is what the GLOCK was designed to work with.

I renew my question to see if anyone has heard of or can direct me to a strategy to start off with.

Thanks,

Sparky

[LL6]

Don't know if I'm reading this part wrong.

(# = pounds = lbs. = 2.2 kg.)

but 1kg=2.2lbs

[Sparky5019]

Sorry...I got my tongue caught in my eye tooth and I couldn't see what I was saying!

1# = 0.45kg.


Corrected...question still out there!?

Sparky

[Robb Jensen]

A 13lb spring is far too light for a .40 Glock using factory ammo.
If you're using extremely light reloads that would be one thing.

OEM Glock springs are 17lbs. If anything since we know .40 Glocks beat themselves to death I'd recommend a heavier spring like up to 20lbs.

[Sparky5019]

Robb,

Thanks, how have your .40s held up and what spring setups do you use? Do you agree that the gun will return better if you change/tune the spring to your grip? Have you SEEN evidence/had experience with a .40 causing frame wear?

Sparky

[Dragon Slayer]

Sparky take it from someone that has been using Glocks since the first month they were available , do not change the Glock spring with any other springs Glocks work best with original and factory parts.

Every problem I ever heard (except for sights) happened with after market parts, why would you want to screw with this anyway specially if you think it should be cut down?:confused:

[Sparky5019]

DragonSlayer,

Did you read the explanation of my intent above? I understand and appreciate the response from the "keep it stock" crowd and appreciate their input but am looking for information based on the practices from those who might have knowledge of the gun tuning techniques that work for those who compete at the highest levels...this (changing/tuning springs works well for them).

I have used this theory with my 1911s and it has been proven to me that the gun recoils "better" with a softer recoil spring. I am just looking for some info on the original question not starting a debate on "to change or not to change".

I have changed and will change these springs as the gun feels better. If it disintegrates prior to 5000 rounds I will buy a new one and change my theory but until then this is my chosen path and I will not change my mind as I have evidence that this works for me. I am sorry you have had problems. Apparently this practice is not common by those who frequent this forum (which is ok) but it is a common practice nonetheless.

I would still love to hear information on the original question!

Thanks for your input!

Sparky

[Robb Jensen]

Robb,

Thanks, how have your .40s held up and what spring setups do you use? Do you agree that the gun will return better if you change/tune the spring to your grip? Have you SEEN evidence/had experience with a .40 causing frame wear?

Sparky

I've owned a G35 which was a competition only gun. I used a tungsten guide rod and a 15lb ISMI spring and light handloads just making power factor for USPSA Limited.

My current .40 cal Glock is a Gen 4 and I use a factory rod/spring in it.

[Dragon Slayer]

DragonSlayer,

Did you read the explanation of my intent above? I understand and appreciate the response from the "keep it stock" crowd and appreciate their input but am looking for information based on the practices from those who might have knowledge of the gun tuning techniques that work for those who compete at the highest levels...this (changing/tuning springs works well for them).

I have used this theory with my 1911s and it has been proven to me that the gun recoils "better" with a softer recoil spring. I am just looking for some info on the original question not starting a debate on "to change or not to change".

I have changed and will change these springs as the gun feels better. If it disintegrates prior to 5000 rounds I will buy a new one and change my theory but until then this is my chosen path and I will not change my mind as I have evidence that this works for me. I am sorry you have had problems. Apparently this practice is not common by those who frequent this forum (which is ok) but it is a common practice nonetheless.

I would still love to hear information on the original question!

Thanks for your input!

Sparky

Sparky I have competed with 1911's for many many years and it is a completely different ball game then the Glock. I just tried to give you the best advise I could give of course you do what ever you want and enjoy yourself also it is OK to play with things for competition but for SD carry only stock.:)

BTW I never had any problems because I never went to after market springs in my Glocks also I have competed with Glocks in IDPA matches and I have been carrying 24/7/365 since they came out and shooting Glocks thousands of rounds every year for many years and i never had any problems.;)

[Sparky5019]

Thanks Robb, I can see how a Gen 4 would be a tough deal to change things in. This is a competition gun...were you making major or minor? Have you heard of problems with ISMI free length being too long in G19/23 and if so how did they remedy the problem?

I have a 15# also and will try it first!


Thanks so much for your help!

Sparky


DragonSlayer,

I appreciate your help in that department and I would not alter that much for a dedicated carry gun. Obviously I would want full reliability for competition as well and was trying to get the best "bounce". Thanks!

Sparky

[Robb Jensen]

Thanks Robb, I can see how a Gen 4 would be a tough deal to change things in. This is a competition gun...were you making major or minor? Have you heard of problems with ISMI free length being too long in G19/23 and if so how did they remedy the problem?

I have a 15# also and will try it first!


Thanks so much for your help!

Sparky

My G35 was a comp. only gun for Limited Major PF. I was using 180gr rounds loaded long and doing 925fps for 166PF ammo with VV N310 and N320 you can load them pretty soft.

My current Limited gun is my STI and I use Atlanta Arms Ammo reloaded 180gr TCJ Long which is loaded to 1.180" (too long for Glocks) for Major and for Minor (for Steel Challenge) I use Atlanta Arms Ammo 180gr Minor which feels like 115gr 9mm standard pressure, really soft.

[Sparky5019]

Thanks Robb,

I have a case of BVAC 180gr. FMJ @ 960 fps = 172 PF coming and will be loading after that! I really appreciate your help! I have a few other feelers out on the original question!

Thanks again all!

Sparky

[Sparky5019]

FYI:

ISMI recommends...

If spring too long and impeding full rearward slide travel to trim coils necessary to achieve full rearward travel and ensure positive forward lock up as the linear compression rate (i.e. 13#) is unchanged. If the above conditions are met then one should be GTG.

Thanks for all the help!

Sparky

[jsharp]

It's nice they said it will work, but what they said doesn't make sense. Discounting a coil bind condition, as you shorten a spring the rate increases. A coil spring is nothing more than a torsion spring wound into a cylinder. Make the torsion spring shorter with all others things equal and the rate increases.

Cutting coils has the effect of shortening the torsion length...

[Sparky5019]

Whatever...all I was saying is what he told me and my experience has proven out. Anytime I have shortened a coil spring in ANY application is has become lighter. This time the end game was not to make the spring lighter but to fit in a certain space and the man who designed the spring said it will work given the flat wire design of his spring. I was just reporting what he told as he was the manufacturer of said spring, I thought those in the preceding conversation would like the outcome of that discussion.

This conversation is over on my part...y'all can debate physics to hearts' content!

Sparky

[jsharp]

Hey, no problem. Amazingly enough, my G23 works just fine with the stock spring. I guess if you're going to chase ghosts, do it in a reality where Hooke's law doesn't exist...

[wha-tah-hey]

FYI:

ISMI recommends...

If spring too long and impeding full rearward slide travel to trim coils necessary to achieve full rearward travel and ensure positive forward lock up as the linear compression rate (i.e. 13#) is unchanged. If the above conditions are met then one should be GTG.

Thanks for all the help!

Sparky


Hi Sparky -

Searching for posts on springs & ran across this one.
If you never got a useful answer to your (reasonable) question:

The length of compressed spring length you need to remove = the distance the slide is short of full travel, since the only thing in the way is excess compressed spring, right?

If you can measure the desired extra travel accurately, divide that distance by the individual coil thickness to give number of coils to remove.
Simple, nez pah?

regards,