Today during a routine inspection, I found 2 cracks in a bushing, one at 6 o'clock on the face, extending all the length of the bushing. The other is at 3 o'clock and is starting to run down the length.
This is a custom pistol I built, with a mil-spec barrel, bushing and a Sarco commercial slide. When I shoot hardball ammo, I typically use a standard guide and an 18# spring. When I am practicing with softball 230 gr LRN or target 200 LSWC, I switch to a 16# spring. Recently I have used a FLGR when practicing with lower power loads.
I have not used any +P or max load ammunition. For example, I typically use 4.0 grains of Bullseye with either the 230 LRN or 200 LSWC.
I also use a Wilson Combat Skok-Buff.
I am in the market for a new bushing, naturally. Any thoughts on how to prevent this from happening?
Note that photography is not one of my strong points.
Have you checked for recoil spring coil bind?
I haven't.
First, I don't know how to do that. Second, on the occasions that I use a FLGR, will that not prevent bind? I am assuming that by "bind" you mean "kink". Is this correct?
I usually change out my recoil springs every couple of thousand rounds, or whenever I feel like it.
What do I look for in recoil spring bind?
You basically insure the slide, when it's all the way aft, does not compress the recoil spring to its solid length. If it does, the two ears on the bushing will usually bend or break. Look in the Stickies or Tech Issues section for info on how to make the check.
In addition, when you get your new bushing, insure the barrel is free to go all the way into battery without "springing" on the bushing.
No. Coil bind is when the spring stacks solid before the slide hits the frame and all the "whack" is absorbed by the bushing and plug. Unless you ordered a spring for a longslide, it's unlikely to happen in a 5-inch gun. Bushings that break due to coil bind normally do it at the junction of the barrel... the tube... and the flange at the bottom.
What kind of bushing is it? If you ordered one from Sarco, it's probably a casting. From the way it cracked, I suspect that it is. Are there any parting lines on the bushing barrel?
Yes, the bushing is a Sarco. I think I can see a partial line where a mold would have closed, but am not sure. The springs I use are Wilson Combat and I have never noticed any problem. I did not order for a long slide. This is a 5 inch gun. One time I did break a tab off a recoil spring guide and that's when I started using the recoil buffer.
Get a good bushing and guide rod. Springplug too, while you're at it. Sarco parts are cheap, but what is cheap sometimes turns out to be expensive.
EGW has an excellent steel bushing and guide rod that will last the life of the gun and beyond.
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One time I did break a tab off a recoil spring guide. . .
Well I'll be dipped in... That's the first time I ever heard of one of those getting broken!
Must be some of that modern metallurgy and manufacturing technology, huh?
It used to be a fairly common breakage with the old Thompson Auto Ordnance pistols.
The whole pistol... save the barrel, pins, firing pin, and the springs... was investment cast. Oh yeah! And the grips and screws... and the grips would often disintegrate while-u-wait.
I've seen those bushings split from back to front, all the way through.
You should still check for coil bind. A shok-buff cushions the impact, but it also occupies some of the space into which the spring compresses. Your spring may or may not be close enough to fully compressed at recoil that the added thickness of the buffer could make a difference.
I take it this is not an issue of the strength of the spring, but rather the length of the spring when fully compressed.
Is there a specification for the length of the spring? The expanded length of any spring will change as the spring gets older and loses its strength. I would think that the compressed length would stay the same.
How does one measure this without injuring ones self?
That won't matter, Hawk. While any chance to the recoil system warrants a double-check... the added thickness of the buffer also stops the slide earlier in its travel. The spring is under a little more preloaded length due to the buff... but the total compressed length won't change.
Wick... The bushing didn't break in the way that a stacked spring causes one to break, so that's not the problem. If you want to be sure, assemble the gun and rack the slide briskly. If you hear/feel a distinct steel-on-steel impact... the spring is fine. If it's a dull thud with a "crunchy" feel... the spring is stacking solid. Be sure not to install the buff for the test.
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I take it this is not an issue of the strength of the spring, but rather
the length of the spring when fully compressed.
That's correct
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Is there a specification for the length of the spring?
Yes, it's on the Ordnance blueprint for the recoil spring which is available in our Tech Issues section. But the really important thing is not your springs actual solid length....
....the really important thing is that your gun doen't compress it to that length - whatever it might happen to be.
Just follow Tuner's instructions in Post #14.