Making a 2011 Run Long and Short Loads

[feederic]

I often run across people stating that their 2011/1911 runs ammo perfectly reliably from long to short OALs, and also that a gunsmith can setup a gun to do so.

I always thought that the headspace of a round dictates the OAL used. How does one setup a gun to run long and short loads?

[tk2]

When I set up my guns, I cut the chamber and throat it to accept long ammo, up to about 1.20". Then I cut the feed ramp so it will feed any length ammo, even empty cases.

The 9mm and .40 S&W headspace on the case mouth, so the OAL doesn't really matter as long as the round will chamber freely.

With the short ammo there might be a little more space between the bullet and rifling, but I haven't noticed any difference in accuracy between my long and short loads.

Edited January 12, 2012 by tk2

[feederic]

When I set up my guns, I cut the chamber and throat it to accept long ammo, up to about 1.20". Then I cut the feed ramp so it will feed any length ammo, even empty cases.

The 9mm and .40 S&W headspace on the case mouth, so the OAL doesn't really matter as long as the round will chamber freely.

With the short ammo there might be a little more space between the bullet and rifling, but I haven't noticed any difference in accuracy between my long and short loads.

Excellent advice! I figured the chamber had to be cut and chambered for long ammo, but I wasn't sure how that would affect short OALs for accuracy. I think you put those curiosities to rest.

What is your take on this subject for a ramped barrel, considering you can't really re-cut the ramp in this instance?

[JaeOne3345]

You can still change the geometry of the ramp.

JoJo Vidanes did it for a friend of mine who had some trouble running a specific profile bullet that he really likes to shoot.

I know Virgil Tripp is often credited here on the forum for fixing early .40 Trojan guns that had issues. He reworks the barrel ramp.

[Braxton1]

I often run across people stating that their 2011/1911 runs ammo perfectly reliably from long to short OALs, and also that a gunsmith can setup a gun to do so.

I always thought that the headspace of a round dictates the OAL used. How does one setup a gun to run long and short loads?

OAL really has nothing to do with headspacing. Theoretically, the length of the case itself is what headspaces on most autoloading pistol rounds (although in reality, the round is actually retained by the extractor hook before it hits the forward edge of the chamber). The notable exception to this rule is a standard 38 Super chamber (not the "Nonte" chamber). It headspaces on that little bit of rim that the Super has.)

Throat depth is the deciding factor, chamber-wise, in whether a round will work if long-loaded. Most Para-Ordnances have short throats, so they must have the throat lengthened if you want to run 1.200 length rounds.

All of my factory STIs have been able to run long or short, but they seem to cycle smoother with the longer rounds. I think that it is because the rounds can't move back-and-forth in the magazines. Having short 1.135" rounds stacked in a magazine that can handle 1.220" length ammo seems wrong to me....

[feederic]

Throat depth is the deciding factor, chamber-wise, in whether a round will work if long-loaded. Most Para-Ordnances have short throats, so they must have the throat lengthened if you want to run 1.200 length rounds.

Roger that. I confused myself on the terminology with regards to headspacing and proper throat depth. Now I got a clear and concise explanation

[Aircooled6racer]

Hello: The feed lip width on the mags will also help alot with feeding ammo of different lengths. With wider feed lips the round comes up higher making it a straighter shot to the chamber. Thanks, Eric

[seadevil10]

Also depending on the caliber you are using you may have to buy Spacer kits and different followers. But long or short ammo will head-space the nearly the same in you gun. pull the barrel and drop a round in the chamber there should be a small difference in height from the bottom of the case to the barrel hood. If you run your finger over the bottom of the case and over the hood you should feel a bump as you hit the hood. if your gun has a smooth surface here it may need to be chambered farther to accept long ammo.