A Question for All Kimber CDP Owners

[Mtn. Medic]

Well, my thinking is that a broken spring is rare. Most likey they just gradually lose their poop.

If that happened... For me anyway... I'd have to decide of a good cleaning and oiling would see me through the five days or so it took for the new spring to be shipped from the east coast to the west.

Or, just carry one of my other pistols during those days.

My reccomendation to Kimber Dude was to order the springs and have them on hand. My spring assembly is far more expensive and I probably wouldn't order one till I needed it.

[sholling]

In general the shorter the barrel the more critical the timing and the more important it is to have a fresh spring. I'll say it again, if it's a 3" or a 4" - both of which have known timing issues I'd stay on top of the spring. I choose to change out fairly often because its hard to talk a bad guy into letting you go get another gun in the middle of a gun fight. It also seems pretty silly to skimp on replacing worn out $8 parts when you've invested $1000 in the gun. But that's up to each individual.

[napaCCW]

I was told by a well know smith that the springs take a lot of wear on the 3" guns and to change them closer to every 600. And no he doesn't sell the springs. the ultra springs are not cheap but for added insurance it is worth it. Now I dont quite keep that regimen but I do change it when I think of it at least every 1200 rounds. I personally feel a difference with the new springs.

[dave1911]

I have a Pro Carry and had to change mine at about 1500 rds.
For the Pro Carry springs are $15.00 for a three pack.
For the Ultra the outer spring costs $4.95.

[X-ffdo]

I believe the manual says 1500 rounds. I am in a remote location and don't have access to the manual now.

[inboost]

For any who might not know the 'Ultra' series by Kimber (3" guns) have a dual spring set-up where one is easily replaced (larger, outer spring) while the inner spring is 'permanently' captured. The expense people are referring to is due to the total assembly price which included a guide rod and spring cup to go along with the two springs. Kimber offers to replace springs if you send this assembly in to them.

To DIY, the system must be disassembled with care as red locktite is used to bind the threads of the recoil rod to the spring plate. There are no tool interfaces on the short little recoil rod to properly grab on to it to unscrew it, so the likelyhood of damage is high. One would also need to apply heat to break the red locktite bond and this makes working with the assembly that much more awkward. I purchased a new assembly when I got my Ultra (I read the manual on-line and saw the dismal numbers so I had one shipped with the gun). I will likely buy a set of springs from Wolff and try the retrofit. If I fail I'll send the old unit in to Kimber while I enjoy shooting with my replacement.

That said I've got ~1500 rounds through my gun and have not yet had any trouble with it. I also have not observed any frame battering that would also be indicative of worn springs (they loose the ability to decelerate the slide along with returning to battery). I would suspect this is a larger concern as it may bang the frame up a bit before it starts with consistent failure to feed (FTF) issues.

[inboost]

Ok, you peaked my curiosity and now I'm in with both feet. I subjectively tested my current recoil spring assembly (~1500 rounds of WWB) against my new one and there was absolutely a difference between the two. With a little SWAG testing with a scale I come up with about a 20% loss in compressive power between the new and old. This is significant enough to me to want to make a change. I decided to build a tool set to allow me to tear these down and rebuild them. I was successful (see below). Now I've got springs coming from Wolff. With any luck I'll be able to test out my retrofit the next time I go to the range. If this works out we'll set up a maintenance program via 'A Guy' we know!

[PUNK]

^^^^^ You are Amazing!

[PirateQueen]

awesome

[emc002]

Originally Posted by WKC

I am throwing that question out to all.

I can see using the if it ain't broke, then don't fix it philosophy on a range gun. But a carry gun?

If it's your carry gun, I presume you regularly train/shoot it?
I take whatever gun I'm carrying at the time (XD in the winter, Ultra CDP in the summer) out to the range at least once a week. Given the frequency of that shooting versus times it's deployed, I'd take the statistical odds that the malfunction would happen during training, not need.

Of course if somebody didn't shoot their gun but except to qualify once every few years, I'd worry more.

[inboost]

I called up Wolff springs today and confirmed that the industry measurement for springs, noted as pounds, is the compressive force required to move the spring to the full recoil position (not in coil bind, slide fully to the rear). On my Ultra Carry this equates to 1.75" of reward travel from the slide's forward 'at-rest' position.

I made a test rig to simulate this condition. I placed a gram scale on our mill table and set the vertical axis of the head to travel exactly 1.750" from the point where the recoil rod was flush with the bushing. I measured the force at these two positions three times for each spring, articulating them each time to bounce out any hysteresis.

I determined that my used spring set, as an assembly, required 16.2 pound of force to compress to the fully recoiled position. When I tested the new unit I have it took 18.7 pound of force to compress to the same position (Wolff & Kimber both list 18# as stock). That's an honest 10% decrease in spring force from the published value. I have a feeling if you call Kimber and ask them if it's ok to put a 16# spring set in the ultra they would say no. It's also worth noting that the new spring assembly free length is a full 0.150" longer than the used assembly. There is no doubt that the old springs have been collapsed and weakened by shooting just over 1500 rounds of WWB 230gr ammunition.

Additionally, the force in the old spring set at slide forward was down 27% from the new unit which measured 5.88 vs 4.24 pounds of force. This means a few things but mostly of interest to me is that the slide is going to get a much bigger run at heading to the rear of the frame as there is 27% less resistance to overcome. This additional acceleration potential will result in a few things notably:

• The recoil spring assembly will go solid, hammering the frame just forward of the slide stop
• The barrel will be accelerated into link down faster resulting in barrel to frame impacts higher than normal. This causes peening of top of the frame in the area just forward of the mag well

The bottom line is that this is going to show up as excessive frame wear on these aluminum guns. Perhaps this doesn't stop the gun from shooting, but just like the extended oil change intervals mentioned above, those engines will be incrementally worn down faster just as the guns will. I like to change my oil on time

[inboost]

Originally Posted by inboost

I made a test rig to simulate this condition.

[WKC]

Dude,

You're outrageous!

[inboost]

I'll take that as a compliment!

[WKC]