Slide / barrel lockup question


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Fletchette
December 13, 2006, 10:00 PM
I have been wondering about an aspect of pistol design lately: Why are almost all semiauto pistols made nowadays designed with a single surface barrel / slide lock? This surface would be the front of the ejection port on the slide, and the chunk of metal on the barrel around the chamber. The barrel essentially protrudes into the ejection port when the slide and chamber are locked up.

On older designs, like the 1911 and Hi-Power, there are a series of ridges on both the barrel and inside of the slide that lock up together. This design, although older, allows the barrel to unlock from the slide with less tilting since the locking area is distributed over several ridges. On a modern pistol, like a Glock, the barrel must tilt more in order to disengage its single locking surface.

Is there a hidden advantage to the more modern design? I'd think the older locking method would be inherently more accurate.

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brickeyee
December 13, 2006, 10:06 PM
"Is there a hidden advantage to the more modern design?"

It is a lot cheaper to manufacture.

Jim K
December 13, 2006, 10:07 PM
I haven't done any checking to see if the barrels on the new guns do tilt more (I don't see why) but I do know why they dropped the double lug system - money. Machining the slide and the barrel simply costs a pile, so locking up on the front edge of the ejection port is simple, easy to make, and entirely adequate. Another facet is that the tooling to do those cuts in the slide had to be put in from the front, requiring a large hole that had to be filled in with a bushing, another part and more cost. (Yes, the BHP has a bushing, it is just screwed in and made a permanent assembly with the slide.)

Sometimes folks berate the gun makers for cutting corners and not reducing costs. That isn't always the point; sometimes the question is how much would the cost be if they really did "make 'em like they used to."

Jim

Old Fuff
December 14, 2006, 12:51 AM
Jim's explanation pretty well covers it. However one (and maybe only) advantage of the barrel bushing at the muzzle is that one can be more tightly fitted to both the slide and the barrel for increased accuracy, then that which can be obtained when the barrel is assembled from the rear.

shotgunkevin
December 14, 2006, 12:56 AM
Just a thought, but if pistols that use the chamber edge/ejection port lockup do tilt more, wouldn't that contribute to better feed reliability? It seems that getting the rear of the feed ramp down lower and closer to the top round in the magazine would ease it's transition into the chamber. If things were arranged perfectly, the round being fed could slide straight out of the magazine into the chamber, without hitting either the feed ramp or the top of the chamber.

Useful statistic - Shotgunkevin's total number of firearms designed, improved upon, sketched on a napkin, or successfully modified : 0

PO2Hammer
December 14, 2006, 02:20 AM
The guns that have the old style Browning (?) lock up just seem to be a little more elegant. The 1911 of course, the S&W 39/52/952, and the High Power.
The 1911 and the 952 are my two favorites with the single stack design. Some day I'm going to get myself a High Power.

The 952 and the 1911 have proven to be more accurate for me, but part of that credit has to go to those fantastic triggers.

My P226 is no slouch though.

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