3" Defender 9mm build

[pklin1297]

Gathering parts for my 3" Defender style 9mm build, and while most everything else is pretty standard affair with regular sized 1911s, one of the components that can either give you a flawless functioning, or a jam-o-matic micro pistol, is the recoil spring assembly/weight, that's as far as I can deduce from other's past experiences online anyway...

So far, I've only found one post back in 2011 where someone mentioned that a 3" 1911 in 9mm should use a 17-lb. spring, I haven't found anything else specifically regarding this, so I thought I would ask here...

What's an ideal starting poundage for recoil spring to be used on a 3" 1911 in 9mm? I know some have built this exact configuration using 1911Builders' kit, but they use a dual spring recoil assembly and I'm hoping to use a single spring unless I have to use dual springs.

Thanks in advance for the help!

[Fizz]

Disclaimer; I know nothing about building custom 1911s.

Potentially helpful comment: I have an EMP 9mm with a 3 inch barrel (Albeit, this is purpose made that way) it's a captive dual spring and 'looks' to be two different weights. I can't readily find any info on what those rates are. But maybe if you find out start there and calc some theoretical equivalent.

I'm getting ready to replace mine (still serviceable). You can have the old one if it might be helpful.

[pklin1297]

Thanks Fizz, your comment gave me an idea. A friend of mine also has an EMP 3" 9mm that's practically new. When I get close I'll borrow his recoil spring setup and see if it might work in my build...

Just in case, please PM me and let me know how much you'd want to sell the current one for. Thanks!

[pklin1297]

I wonder if the following Kimber guide rod + spring for their Ultra Carry (essentially the Colt Defender 3" barrel on Officer frame) would work for this build...

http://store.kimberamerica.com/3-inch-ultra-recoil-spring-assembly-9mm

[Kmai24]

No experience on the 3" plkin but I'm running a 12lb on my commander. So far no jams but it's not locking my slide back on the last round. Could be mags or under charged ammo. Probably no help but just thought I'd share

[pklin1297]

Thanks Kmai24!

Regarding your pistol, is it 9mm as well? What mags are you using?

Sometimes with under-powered 9mm, a stout hammer spring, too-squared of an edge of the bottom of the firing pin could cause the slide to not lock...

Are you using a recoil spring buffer (shock-buff)? If yes, remove it and try it again. I put one in my Les Baer and it would not lock back. I remove it and problem solved.

When you hand cycle the gun with empty mag, does it lock back?

When you shoot the gun, do you use a "both thumbs forward" high hold? I've caught myself putting the front thumb on the slide stop, effectively canceling it's intended purpose...

12 lbs. recoil spring, even for 9mm Commander is a bit on the light side in my opinion... Are you using that to see if it'll come back far enough to lock on empty? Or just softer shooting?

Just curious as solving these problems helps me be mindful of my own builds in the future.

[Kmai24]

Thanks Kmai24!

Regarding your pistol, is it 9mm as well? What mags are you using?

Sometimes with under-powered 9mm, a stout hammer spring, too-squared of an edge of the bottom of the firing pin could cause the slide to not lock...

Are you using a recoil spring buffer (shock-buff)? If yes, remove it and try it again. I put one in my Les Baer and it would not lock back. I remove it and problem solved.

When you hand cycle the gun with empty mag, does it lock back?

When you shoot the gun, do you use a "both thumbs forward" high hold? I've caught myself putting the front thumb on the slide stop, effectively canceling it's intended purpose...

12 lbs. recoil spring, even for 9mm Commander is a bit on the light side in my opinion... Are you using that to see if it'll come back far enough to lock on empty? Or just softer shooting?

Just curious as solving these problems helps me be mindful of my own builds in the future.

-Yes 9mm
-Same mags from my SA 1911 9mm target (haven't gotten around to getting new mags)
-square bottom?? Are you talking about the firing pin itself or the fire pin stop? If the stop then I'll have to look into that. If I can recall i rounded off the bottom..
-no recoil buffer shocks
-hand cycle locks back just fine. Strange thing was my first test shot the slide did lock back but then a few mags in it didn't do it, maybe I could of wet her up a little more.
-I'm a lefty so no way I could have my thumb on the slide stop but I do shoot thumbs forward with a high grip. Left thumb actually rest on the thumb safety
-yes 12lbs to see how light I can go without any cycling issues. So far there hasn't been but the slide lock but that doesn't bother me too much anyways because I usually rack/sling shot the slide when I insert a new mag. I also have a 14lb recoil spring that I'll try out next time.

[MosinVirus]

Does this happen with all the mags you have, Kmai?
When you cycle the slide by hand, with each magazine, does it lock open every time?
When at the range, and after your slide doesn't lock back, is the magazine stuck a little? Hard to get out of the gun at first?
Are you using a 9mm slide stop?
Are the followers in your magazines plastic or metal?

Pklin, sorry I am intruding on your thread.

[Kmai24]

@ mosin..

I only have 2 mags right now for it and both locks open on hand cycles all the time l. Both mags have metal followers..I haven't looked into "go to" magazines so any recommendation are appreciated.
As far as the range goes after last shot and no slide lock back, magazine dropped just fine with no resistance.
And yes 9mm slide stop.

[pklin1297]

Maybe the plunger spring is kinked or unusually strong, and preventing the side stop from moving up somehow during firing? I know it cycles fine by hand so that probably ain't it, but worth a check...

Kmai24, beautiful build by the way, very clean and no nonsense. Since you're in San Diego, I wonder if you could ask Kcstott here to check out out and trouble shoot it for you to see what's going on. Better for someone knowledgeable to see and feel it in person, and then share result here because we can all learn from this.

Last thing, what brand of ammo are you shooting?

[MosinVirus]

@ mosin..

I only have 2 mags right now for it and both locks open on hand cycles all the time l. Both mags have metal followers..I haven't looked into "go to" magazines so any recommendation are appreciated.
As far as the range goes after last shot and no slide lock back, magazine dropped just fine with no resistance.
And yes 9mm slide stop.

Then your slide is likely not making it far enough back to lock on the slide stop. How is your ejection?

[Kmai24]

@pklin, thank you for the compliment on the build. If all else fails I'll contact kscott but I like to try and figure things out for myself (not a pride thing, just the type to like to be knowledgeable/self made).

@mosin, if I can recollect ejection was about 3-4'oclock. It's been almost a month since I took it out (2 kids, 2 year old and a 2 month) time isn't on my side but I'll try and make it out there again soon and put some factory rounds down the pipe. My apologies for not mention I was shooting my reloads.

Thank you pklin and mosin for the help and sorry to inadvertly thread jack you pklin.

[pklin1297]

No worries about thread jacking, as my thread wasn't getting as much attention as I'd like anyway, so I'm going to ask my question over at 1911forum or 1911pro forums to see if I get any answers there... Though they tend to frown on 80% builds, but each to their own.

Kmai24, whose frame did you use for your build? Maybe use some Dykem on the frame rails, the ejector, the top of slide stop and thumb safety, etc., basically anywhere that comes in contact with the slide, and see if you see any rub marks (maybe even on the barrel hood)? There might be interference somewhere that you are overpowering when hand cycling. At this point, we should try anything.

[MosinVirus]

No worries about thread jacking, as my thread wasn't getting as much attention as I'd like anyway, so I'm going to ask my question over at 1911forum or 1911pro forums to see if I get any answers there... Though they tend to frown on 80% builds, but each to their own.

Kmai24, whose frame did you use for your build? Maybe use some Dykem on the frame rails, the ejector, the top of slide stop and thumb safety, etc., basically anywhere that comes in contact with the slide, and see if you see any rub marks (maybe even on the barrel hood)? There might be interference somewhere that you are overpowering when hand cycling. At this point, we should try anything.

I wish I had the info for you, Pklin. But I dont. In 1 911 forum just don't say it is 80%. Your questions have nothing to do with that, and you can avoid people limiting their responses to that.

Kmai, try weaker hammer spring, and look into variable power recoil spring, after you check for rubbing/friction.

[Kmai24]

Frame was from 1911builders and slide is fusion's. I will give those all those suggestions a shot.

Thanks!