Just bought a new 9mm barrel & a few mags for my Kimber Eclipse 10mm & was wondering what weight spring everyone recommends I should run in it with the 9mm barrel. I've ordered an 11 lb spring to start with & with remove the 18 lb spring that came with the 10mm. Thanks.

Dick

Colt puts 14lb. springs in their 9mm and .38 Super pistols, while Springfield Armory puts 9lb. springs in their 9mm 1911s. A lot of people bitch about the Springfields not working well until they swap springs to heavier weights. That might tell you something..............


I bought a new SA Range Officer 9mm about 3 years ago, and had some issues, so I chucked in a 12lb. spring, and those issues went away. Immediately, gone. When I rebarrelled that RO to .38 Super, I did put in a 14lb spring, if nothing else, to keep it from slinging brass into another county. It worked fine.
Another tip, use 124gr. ammo for the first thousand rounds or so, the weak-kneed 115s barely have enough balls to cycle a 14lb. spring. You'd probably get better accuracy, too.

I have not done a 10mm to 9mm conversion, so I don't know if you'll need another slide. extractor, ejector, etc. You'll have to let us know about such things.

All good advise.

Go to

https://www.gunsprings.com/

and buy a few different weight springs to try out. Decide which works best.

Off topic, but how does 9mm run in a 10mm breech face? Is the extractor long enough? I so, then I want a 9mm barrel for my Kimber longslide 10mm!

I did buy an extractor when I bought the 38 Super barrel & I have installed the 11 lb spring in the 9mm & everything is working great. The 128 gr cast, powder coated HP's are shooting fantastic, the brass falls 2-3 feet away & I'm a happy camper. Shooting the plate rack at 40 yds is easy, peasy & gets boring in a hurry.

Great, thanks for the reply.

On a Dillon 550, the 9mm. .223. 38Super, .40 S&W and 10mm (among others) all use the same shell plate (shellholder), but sometimes you have to use different locator pins. That tends to lean towards very similar breechface dimensions (though not identical, they might be within manufacturing tolerances).

Likely as not, the makers probably keep to the same numbers, to keep manufacturing costs down (and make them more money). Whatever differences there are, probably aren't meaningful in real-world terms.

Might want to look into the relationship between mainspring, FP stop and recoil spring.

The mainspring (hammer spring) and FP stop (stronger/weaker hammer spring, round or flat bottom FP stop) will affect the recoil spring selection.

I've always thought that 1911 "recoil" spring should be named "return spring".

Tuning the 3 together can make a huge difference in how well the gun returns to target and felt recoil.

ETA, how well the barrel is fitted will also make a big difference as well. The well fit and timed barrel will stay locked to slide for a longer period. Sloppy fit with little lug engagement = quicker unlock and faster slide speed.

Still too cold to chronograph but not really important, I'm more concerned with function. The 9mm barrel & load is shooting 100%, as is the 38 Super & the 10mm, the only thing I'm changing is the barrel, mags & main spring/recoil spring. But for winter shooting I'll only shoot the 9mm, I'm not into chasing brass in the snow & don't want to mess with putting a tarp down. Mission accomplished!