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STI 2011 DS 5.0 9MM recoil spring weight


Brandon04GT

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So I just bought an STI 2011 Tactical DS 5.0 in 9mm. I want to make sure I am running the correct weight recoil spring as I really want to avoid frame battering. STI's website says that 5" 9mm guns run 10lbs, but it looks like they used to recommend 12lbs. Some quick web browsing seems to yield recommendations from 9-14lbs (but mostly 9-12lbs). I'm guessing erring on the side of going slightly heavier is better than slightly lighter to avoid frame battering.

 

I plan to shoot 115gr RN factory-spec ammo, and perhaps some standard pressure 147gr hollow points just to test for reliability.

 

What would be the best spring weight to start off with? 12?

 

My gun is a full-rail so I'm guessing the slide is slightly heavier than standard, if that makes any difference??

 

My gun does not use the recoil-master setup...

 

 

Thanks!

 

Edited by Brandon04GT
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It really depends on what the FPS and Bullet weight of your ammo is in combination with your slide weight.  Louis's and Sydney's Bianchi guns (the ones I built) runs a 9mm 115gr bullet at 1150.  His spring weight is either 7 or 8 lbs.  and his mainspring is i think 11? it was the lightest mainspring I could find.  Anything lighter and the gun would not cycle.  Louis's Wilson Combat Bianchi gun on the other hand was built by Wilson Combat and I do not know what he has in it.

 

However, your results may vary.

 

David

 

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The factory spring is probably heavier than most people will swap to.  You could but a 12lb and try that as well.  I'm guessing you aren't gaming this gun, so a heavier spring than our competition guns run to guarantee reliability with dirt and grime would be your goal. 

You could try a shockbuff as well if you are truly worried about frame battering. 

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Thanks for the responses, and yeah, I plan to set it up more for "HD/duty" use, so I want reliability. As I understand it, going too heavy may cause shells not to eject property and/or stress the barrel lugs too much, so there has to be a happy medium.

 

I called STI and they said the gun ships with a 10# recoil spring and 15# mainspring.

 

15# mainspring sounds a bit light to me. I'm thinking about starting off with a 17# mainspring and a 12# recoil spring. Does that sound like a good starting point? and if that doesn't work out, go back down to a 10# recoil spring.

 

Oh and one other question, generally speaking, assuming the same powder loads, if I'm going from 115gr to something heavy like 147gr hollowpoints, do you generally want a heavier or lighter recoil spring with heavier bullets?

 

Thanks,

 

Brandon

Edited by Brandon04GT
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