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Old March 16, 2013, 11:16 AM   #34
Unclenick
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Join Date: March 4, 2005
Location: Ohio
Posts: 9,991
Quote:
Originally Posted by polyphemus
The spring guide does not bear on the link lugs,please.
It's as 1911Tuner explained. It's because the frame is no longer there when you remove the parts as a unit that it can't be born against by the recoil spring guide any longer. The reasons not to disassemble this way are the chance of the spring and recoil guide launching themselves and the fact it doesn't free the barrel up for cleaning, which is the most common reason to field strip. On the other hand, I've seen any number of people launch the recoil spring plunger when disassembling by the normal method without the aide of a bushing wrench, and if you are field stripping to get at something in the frame rather than to clean the barrel, it's a shortcut.

You do have to slip the slide stop through its assembly notch with the slide held in the correct degree of counterbattery to align it, then push the pin back in with the lever paddle dangling down to let the recoil spring push the slide and barrel back into lockup. Then the pin can be slid out leaving the barrel and slide and spring assembly as a unit.

(For some reason, it's become a popular bit of martial arts movie fiction to have their heroes disassemble opponent's guns in this way with just one hand and faster than the eye can follow. I can see dropping a magazine that way, but line up the assembly notch and get the pin all the way out with one hand in the blink of an eye? Emphasis on fiction.)

My assumption was that RJ had done something like I described above, but if the link pin was dragging in both directions he may have had to hammer the slide open first to get the slide stop out, then forward to get the slide and the barrel off. He could also have driven it back into lockup up as I described, or just pulled the slide stop pin completely and left it unlocked. Either way, once that pin is fully removed, the slide can be driven off.


Quote:
Originally Posted by 1911Tuner
Although most will argue that a squib can't cycle a slide...The barrel bulged radically and split at 3 and 9.
It's astonishing what a primer can do to propel a slide. I always try to remember J. C. Garand's first rifle design had a primer actuated semi-automatic mechanism. It had to be abandoned when the military started crimping primers to keep them from getting loose in machine guns and jamming the mechanisms, but the force of that little cap piston is real.

I've seen a barrel bulged by a double charge, but it was only a couple of thousandths and not enough to cause what Ammo.crafter describes. I once was involved in a burst barrel investigation for a gun maker, and one of the things that came out of it was that Hatcher's description held true, which is that an obstruction close to the throat of the chamber may be expelled with the next bullet without gun damage, but one that's the correct partial distance down the tube will blow the barrel apart. Still further down the barrel will just bulge it. So it all depends where the obstruction sticks as to how much and what kind of damage it does.


Ammo.crafter:

Do you have a recollection of a squib round or coming up short a hole in the paper or any other kind of miss you couldn't account for at around the time the gun started to stick? Did you find an ejected case with high pressure signs around that time? If not, I think we'd all like to know what the load was that you used for most of that 300K rounds so we can avoid it, just in case it's been slowly fatiguing the barrel steel over time. It seems unlikely you'd find just the right load to do that without obvious pressure signs, but regular high pressure could theoretically fatigue the steel until it began to move.

I've always changed or refit hardball barrels at about 25-30K and softball at 50-100K, but this was to maintain match precision and not because there was zero life left. A 300K barrel is not inside my realm of experience, so I'm not really sure what to expect on the fatigue front.

If you don't know how to do barrel fitting, you'll do best to get some instruction from someone who does. If hands-on instruction isn't practical but you still want to learn and don't want to invest in the full array of tooling a gunsmith uses, probably the easiest barrel to fit is Fred Kart's Easy Fit barrel. It saves you link lug cutting, link fitting, chamber mouth trimming and throating, and internal bushing fitting. All you have to do is fit the barrel extension (hood) and the unique lockup limiting pads Kart has in the rear barrel lug recess, all of which files can do, and the outside of the bushing to the slide. He's done the rest for you. I believe he's got a tool kit for fitting them. Call and ask for details (910) 754-5212. I've installed a number of makes of barrels, and found Kart's to be excellent quality and to realize top precision (minimum group size) on targets.

If you want a better-than-typical-drop-in fit, but don't want to go try fitting, an inbetween measure would be to get one of Bar-Sto's Semi-Fit barrels. They say these will drop in about seven times out of ten, but will need minor fitting on the remaining three. This depends on manufacturing tolerances of the gun, of course. I used a fully fit Bar-Sto match barrel on my Goldcup for a long time and it was well made and precision on target was also top notch.
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Last edited by Unclenick; March 16, 2013 at 11:26 AM.
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