Kimber ST II Ejection and Durability

[10mm-Admirer]

I have a like new Kimber Stainless Target II.  It has a great trigger, cycles reliably and shoots accurately.  I'm very pleased with it.  I plan to mainly shoot it with moderate 10mm loads.  I have (2) G20SFs for the heavier loads.

I'm wondering about recoil springs.  It throws brass as far as 20ft.  I also don't want to beat up the pistol.  It comes from the factory with an 18.5lb recoil spring.  Is there any wisdom to using a 20lb or 22lb spring to reduce brass ejection distance and protect the pistol with more powerful loads?  I've done some searching but haven't found a definitive answer.

Thanks.

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[The_Shadow]

If I recall some have increased the main spring weight to help with ejection distances.  And still others added the flat bottom firing pin stops.

Good luck!

[10mmfan]

I have the TLE II and I upped the mainspring to 26# put in a flat bottom fps which works great. I tried a 20# recoil spring and I kept getting nose dives so I put the 18.5 is back in it.

[EdMc]

You might read this thread from 'The High Road'.....it's about a Colt Delta but applies, I think, to all 1911 pistols. Then you can decide what you think is best for your pistol.

http://www.thehighroad.org/archive/index.php/t-620760.html

Hope this helps.

[sqlbullet]

After lots and lots of reading I eventually was convinced of 1911Tuners advice in the High Road thread above.

Run a flat bottom firing pin stop as your first upgrade.

Run a 25 lb hammer/main spring as your second upgrade.

Optionally you can run a 20 lb recoil spring.  I personally don't.

The issue with a heavier recoil spring is this.  Heavy recoil to the rear is absorbed by the frame in the area of the recoil block, a big chunk of forged or cast steel.  And by the slide, again in an area meant to handle the force.  Not saying these components won't wear out, just that of all the parts of the gun they are the ones most designed to deal with the battering of recoil.

If we mitigate that rearward force with a heavier recoil spring, we just store the energy and then release it when the slide goes back into battery.  That means additional shock to the barrel link and slid stop pin when it has to stop the slide.  Compare the meatiness of the barrel link, barrel link pin and slide stop pin to the meat of the recoil block in the frame. They aren't made to handle the same magnitude of force over time that the recoil block and slide are.

If, on the other hand, we use a flat bottom firing pin stop and heavier main spring in the gun, we mitigate the force in a way that doesn't release it into weaker parts later.  Only downside is that the action will be much harder to cycle manually when the hammer is down. 

1911Tuner makes the point elsewhere on the interwebs that the original 1911, pre 1911A1, had a "flat bottom firing pin stop".  It was changed at the request of the Army as I recall, to make the action easier to cycle for soldiers.

Hope that helps.

[10mm-Admirer]

Thank you for the explanations and link.  That makes sense for 1911s.  I think I will leave the Kimber as it is and use the Glocks for the heaviest loads.

I suppose the principles for the 1911 do not apply to the Glocks since they have no mainspring.  I understand that Glocks mainly rely on the weight of the slide to manage slide velocity.  Is there a benefit to running a heavier 22lb or 20lb recoil spring in a Glock to slow unlocking and reduce battering?

Is frame/slide battering caused more by the pressure of the rounds or velocity of the bullets?  Does a 155gr bullet traveling 1350fps cause higher slide velocities and more potential frame damage than a 180gr bullet traveling 1200fps?

Thank you!

[spaniel]

Per advice here I shied away from the heavier recoil springs in my Kimber, IIRC I have a 22# installed now.  It also has a 25# mainspring and flat-bottom FPS.   These parts were installed sequentially to assess their impact on the performance of the gun.  IMHO the mainspring and FPS both had much more impact on brass throw distance than the recoil spring.  So I found no reason to risk more frame damage by increasing the recoil spring further.

The brass still flied pretty well with real (not max) 10mm loads though.

[K10]

I just ordered a Sprinco guide rod set up for mine. I used it for the first Kimber I had, and it seem to work great. When I had to sell the gun it was as tight as when I bought it, with no real signs of wear. I am going to put a flat bottom firing pin stop in this one to. I am not saying that you have to have it, but it seems like a good idea. My first one ran like a top with it in, and never did jam.