What's so darned good about inside rails?

L

Lavan

New member
I suppose there is some advantage but just curious what. If the slide rides inside or outside the frame, it is still riding on the frame.

????
 
As a barrel get hots, it transfers some of the heat to the slide. If a gun has an inside-the-rails slide, the action can get tighter, rather than more loose. This can mean better accuracy if you shoot a lot of rounds at one sitting.

Most inside-the-frame slides tend to have longer slide rails on the frame, too, which seems to help with reliabilty and durability.
 
The slide also doesn't extend as far down the side of the frame. This helps keep fat-handed shooters who shoot with a high thumb (like me)from rubbing the slide when it cycles.
 
Machining the rails on the inside makes the slide to frame fit tighter generally speaking, but supposedly allows more dirt to enter the mechanism. I doubt that that makes much difference in practice though.
 
Wether the slide is on the inside or outside of the frame has no bearing on how tight the fit is, machining tolerances and length of rail contact is what matters there. Also, with the slide on the inside, it will be easier to machine and thinner, but the frame will be harder to machine and fatter. In the end, it cones down to personal preference.


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NRA, GOA
"If you choose not to decide, you still have made a choice"-Neil Peart
Vote in November.
 
I think it just sounds good in a add. The slide on my very old Colt has never flown off when it gets hot do to expansion. You get a big choice, fat upper frame skinny slide or skinny upper frame and fat slide. Some just have to be differant for the fun of it, but thats ok too. :) :)Maddocks thought makes good sence to me in that fat paw bite bit. :) :)

[This message has been edited by radom (edited August 11, 2000).]
 
One advantage the outer-rail/inner-groove style (i.e. the 1911 and descendents) seems to have is that the wider slide allows thicker slide walls and thicker chamber walls.

But as radom noted, there's engineering and then there's marketing. Hint; there is no such thing as "fine Corinthian leather." A bogus name concocted during the filming of the Dodge car commercial.
 
Hi, guys,

Anyone think of something called a "patent"? Inventors have to work around them all the time. If memory serves, a fellow named John Browning got one for a slide that fit over the frame. If you designed a pistol with a slide during the life of that patent, you had best do it some other way.

Jim
 
There's probably less chance of getting dirt in from the top if the slide is on the outside. Other than that, I don't see much of a difference.

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NRA Life Member
Michigan Coalition for Responsible Gun Owners(MCRGO)
 
I have two pistols with inside the rail slides,, A SIG P210 and a CZ97B. Both are very accurate and very reliable.
An interesting bit of historical information. The Swis decided to replace their Luger service pistols in the 1940s. After testing a number of models they settled on the Browning Highpower and the French M1935 Petter design. Both had outside the rails slides.
After extensive further testing they decided neither the HP or the Petter could met their accuracy requirements. The bought the rights to the Petter design and redesigned it to incorporate inside the rail slide design
The new design met Swiss accuracy requirements and was adopted as their Model 1948 service pistol/ THe Commercial version of the M1948 is the SIG P210.
 
As much as I love my CZ75, there is absolutely no practical difference, and the rails in the outside of the frame ussually allow for more cocking serrations area. Have you ever handle a Tanfoglio in .40 S&W? The caliber requires a stiffer spring than in 9mm, and the small grasping area make it a bit difficult to retract the slide.
 
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