What Advantages Are There To Lock Up On Hood Of Chamber?

[Bartholomew Roberts]

It seems like nobody makes a new pistol anymore that uses a JMB inspired set of lugs on the barrel to lock into the slide. All of the new pistols I see have a big squarish slide and lock up on a big squarish chamber hood.

I am curious as to what advantages this system of lock-up gives to either the manufacturers or consumers that has made it so popular?

If the only advantage is ease of manufacturing, I think I'd be willing to pay more for the old JMB style lugs in order to keep the slide as slim as possible.

 

[George Hill]

It's easier and cheaper to do. There is nothing wrong with the 1911's locking up inside the slide, but when you want to make a product fast and dirty, you do it like how SIG and Ruger and everyone else does.
Another advantage, if it's really an advantage, is that it gives you a nice big ejection port big enough to eject empty beer cans out of.
(Unlike the Beretta 92, which let's you eject longneck bottles)

 

[stans]

Ease of manufacturing, maybe a little stronger, since locking lugs on 1911's can shear, although I think that is a rare malfunction.

 

[George Hill]

Anything can shear. That's not an issue. If you lock up there, you could with the same argument say that since there is less slide, it's weaker and more likely to break. Again... that's not the issue.
The issue is getting the gun to lock up nice and square really easy and not spend a lot of money to make it happen or to train the apes putting them together.

 

[Correia]

If you look at it from a machine time point of view, it is a lot easier to just cut a big square ejection port (which you need anyway) and cut the barrel hood in one big square, than it does to machine metal off of the top of the barrel in several different locations. (sorry, I'm an accountant at a manufacturing company, I can't help myself!)

 

[MrPink]

Related to what George said, the SIG external lock up has a very positive engagement of the barrel and slide surfaces. With the JMB 1911 design, there is usually not complete engagement of the surfaces.

 

[Sean Smith]

Cheap. That's it.

Downside? The slide winds up being a big square brick to accomodate it.

Probably a coincidence, but nobody makes a truly accurate autoloader (I'm talking P210 or bullseye 1911) with that lockup scheme.

 

[rbernie]

Probably a coincidence, but nobody makes a truly accurate autoloader (I'm talking P210 or bullseye 1911) with that lockup scheme.

Hmmm - how about the CZ97B?

 

[prisoner6]

Doesn't the CZ97 use the Browning design as well?

 

[Sean Smith]

Doesn't the CZ97 use the Browning design as well?

Nope, it locks up in the ejection port.

Hmmm - how about the CZ97B?

It is nowhere near as accurate as a P210 or purpose-built bullseye 1911. Show me 3cm @ 50 meter test targets from one and I might change my tune.

 

[George Hill]

Look at the pictures on this page:
http://www.madogre.com/Interviews/CZ97B_Review.htm
The CZ-97 for a 500 gun is more accurate than any other automatic that costs under 1500 - out of the box. Most really accurate guns are custom made... with people putting in a grand or more into the gun. If you wanted to pay a gunsmith to accurize a 97 - the results would be beyond fantastic. I'll put a CZ-97 up against ANY production .45 automatic.

I'm not saying that the lockup us inferior... it's easier to make guns that way.

 

[Sean Smith]

I notice you didn't list a distance those groups were shot at. I'm guessing less than 50 meters.

Nice gun. I'm sure they are accurate by the standards of mass-produced guns. I just made an observation about the top 1% of EXPENSIVE guns.

And I'd love a 10mm 97B.