Barrel Springing:

I have a Ed Brown Match Barrel and Bushing in my Norinco. The overall fit was very good and much, much easier than installing the same barrel in my 1927 Colt. Just a few swipes of the file in the rear groove achieved full contact with the slide lugs and good FP centering. I checked headspace and found I could get a .016" feeler gauge in between a unfired case head and the breechface. One thing I did notice is just a slight bit of 'springing' when the slide is assembled and held in the hand. The gun will go into battery with just the weight of the slide, so it isn't affecting function. The end of the EB barrel is made slightly larger than the rest of the barrel, so the minute the slide starts moving back, the bushing slips off the larger portion and the barrel is free to link down. How much, if any, springing is acceptable?

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How much, if any, springing is acceptable? Depends on how much of a bend in the barrel is acceptable, I guess.

I can't help you, Robert, but I go to school here, so educate me to what "springing" is.

One of my 45s had barrel spring after I installed a new barrel bushing. I polished the barrel to remove all witness marks and looked for new witness in the areas outside of the normal bushing contact area in battery that showed me exactly where the bushing was binding to create the barrel spring. I then filed the bushing in that area to relieve the bind.

If it goes into battery that easily, I'd say you don't have a problem when its on the frame. Just check lockup when its in the frame and compare to lockup when you have just the barrel in the slide and you feel it springing.

Here is a graphic showing one possible source of barrel spring. Barrel spring is a condition where the barrel bushing fit is too tight to allow the barrel to fully lockup and ends up bending the barrel sort of like someone standing on the end of a diving board before the jump into a pool.

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How much, if any, springing is acceptable? It depends on whether or not you want vertical stringing in your groups.

Is this what 'angle bored' bushings are about?

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Is this what 'angle bored' bushings are about? Yes, but the same thing can be achieved with a too-tight standard bushing by wallowing out by hand or machine. The barrel shown in Erics nice pic looks like a Gov't Issue (not NM) type with no slight OD increase at the muzzle. Bushings for NM barrels with that OD increase at the muzzle don't need as much wallowing - if any. Some NM barrel/bushing sets are supposedly pre-wallowed/angle bored at the factory.

I can assemble the pistol, without recoil spring or firing pin, and cycle a full magaine through it with just my two thumbs. Rear frame to slide match is excellent, so I don't think the slight spring is hurting me. The rear barrel groove has full contact with the rear slide lug when in battery. The hood is about .006" from the breechface with good clearance on both sides. The gun shoots very well. I am just tuning the ejection pattern right now...

Swapped the Ed Brown bushings between two pistols and fixed the problem...