Wednesday, May 16, 2012

Fitting a New Plunger Tube on your 1911

A loose plunger tube can prevent your 1911 from firing

Fitting a New Plunger Tube on your 1911

By Tim Lau

One of the great things about the 1911 is that every part on the gun is replaceable. The downside is that stuff wears out and/or comes loose. Combine this with the proliferation of sub quality parts common with many manufacturers, and this can be a recipe for disaster. I have found that current production Kimbers are plagued with plunger tubes that give way sooner rather than later. If the stakes give way and the tube is not properly supported by the grips as originally designed, the plunger tube can work itself far enough from the frame to prevent you from being able to disengage the safety and fire the pistol. This isn't typically regarded as a good thing.

Here I will discuss how I fit a new plunger tube. Done this way, I have yet to experience one of my stakes come loose (and I have done a few.) You will need the following (Brownells P/N's provided for your reference):

Loctite 638 Retaining Compound 532-000-008
Gun Runners Plunger Tube Staking Tool 634-000-001
Crescent Wrench
Bench Vise

Remove the loose tube with the help of your vise

The first order of business is to remove the loose plunger tube if it hasn't fallen off already. After removing the grips and thumb safety, I will clamp the loose tube in my bench vise and lightly tap the frame with a nylon faced hammer to separate the frame from the plunger tube. Once you have done this, clean the staking holes and the portion of the frame that contacts the plunger tube with acetone or your favorite degreaser.

A drop of Loctite 638 retaining compound on each stake will help reinforce them
Take your new plunger tube and wipe it off with some degreaser. I place a drop of Loctite 638 Retaining Compound on each stake prior to attaching the plunger tube to the frame. The stuff is viscous and significantly stronger than "red" Loctite. Next, install the tube into the frame. Remember the smaller diameter end of the plunger tube faces the muzzle end of the pistol.

The Gunrunners Plunger Staking Tool 
There are several plunger tube staking tools on the market and many of them work well. I prefer the one from Gunrunners. The one fashioned from vise grips works okay as well. I have also used the one from EGW but that one has the least amount of control as far as the quality of the stakes. It works but the Gunrunners one works best for me.

The Gunrunners tool consists of a staking point and a bolt that is mated to a spot faced bar that holds and reinforces the plunger tube. First place the reinforcement bar on the tube and then align the staking point with the stakes on the plunger tube (which should be in the frame by now). The bolt should align with one of the round recesses on the outside of the reinforcement bar. Hand tighten and then tighten with a wrench until reasonably tight. Repeat with other staking point.

Align the staking point with the staking hole on the inside of the magazine well.
Once both stakes are set, be sure to wipe off any excess retaining compound. Check your stakes. They should be strong and even. See below:

Nice strong stakes on both points.
Double check your work by trying to wiggle the plunger tube. Reassemble and check for function. Remember that properly designed grips will support the plunger tube and keep it from coming loose and failing even if the stakes give way. This built in failsafe is gone if you choose to install thin grips or any grips with a differing design than the original.

I prefer full width grips that properly support the plunger tube like these from VZ Grips.
Once you have confirmed function, you can pat yourself on the back and have a beer. Good work!


VZ Grips

10-8 Performance, LLC


  1. Tim, excellent blog! Does the ejector need to be removed to stake a new plunger tube with this tool? I heard from a coworker that this type of tool might cause interference with an ejector. Also, I have an MC Operator ready to be customized by SACS; would you recommend a preemptive plunger tube replacement?

    1. Thanks for the kind words. As you can see in one of the above photos, the ejector can be left in place when using the plunger staking tool.

      I haven't found that the Springfield MC Operators have particularly bad plunger tubes. Use a set of grip panels with good plunger tube support and, like any 1911, keep an eye on the tube during normal maintenance cycles.

      As I mentioned above, in current production Kimbers, it is very common for the plunger tube to come loose so I typically replace the plunger tubes in those guns right out the gate.