Semi auto loose barrels?

Prof Young · July 24, 2011, 03:09 AM

Gun smiths:

Went to a gun auction and handled a lot of semi auto hand guns at the preview. I noticed that on every one of them, with the magazine removed and the slide locked back . . . the barrel was loose and i could wiggle it around.
These were all used guns, but they were many good brands. Is this normal?

Live well, be safe
Prof Young

T. O'Heir · July 24, 2011, 03:29 AM

Hi. Perfectly normal with the slide open. The barrel on most pistols isn't 'locked' into the slide when the action is open.
A 1911 barrel, for example, is only 'locked' in the slide when the slide is closed. Have a look at this. The 'bands' on the top of the barrel mate with recesses in the slide and the pistol is locked into 'battery' only when the actionis closed. http://stevespages.com/ipb-colt-1911.html
Most pistols aren't a whole lot different. They can and do 'lock' differently though.

Prof Young · July 24, 2011, 02:00 PM

T.
Thanks for the info. It just surprised me. I only own one semi-auto and assumed the barrel had some wiggle room cause it's a very cheap gun.
Thanks again.
Prof Young

James K · July 24, 2011, 09:56 PM

Well, it is normal for a locked breech pistol, where the barrel and slide are locked together until the bullet is out of or almost out of the barrel. But on a blowback pistol, a really loose barrel could be trouble, though some barrels that have to be removed for disassembly are a bit loose.

Examples: A 1911 barrel that is loose when the slide is open is perfectly normal. A Colt Model 1903 barrel is a little loose as it has to turn and unlock from the frame so the pistol can be taken down for cleaning. A Walther PP with a loose barrel indicates there is something wrong.

Jim

Prof Young · July 26, 2011, 03:31 PM

Jim:

I guess I don't know the difference between those two types of systems. There is a lot to learn. I guess I should find a book on hand guns or some such.
Thanks
Prof Young

drail · July 26, 2011, 08:23 PM

The only thing that matters is play in the barrel/slide fit at full lockup at the front and rear of the barrel. Play between the slide and frame doesn't really hurt accuracy any but the barrel has to lock up snugly and in the same position every time it cycles.

brickeyee · July 27, 2011, 09:42 AM

Quote:

Play between the slide and frame doesn't really hurt accuracy any but the barrel has to lock up snugly and in the same position every time it cycles.

And in the 1911 design the barrel is still in contact with the slide stop pin.
The effect is not very large unless the play is excessive, but it shows at higher levels of Bullseye.

chasep255 · July 27, 2011, 01:37 PM

Yeah that is because they are recoil operated. When the slide comes forward it locks with the barrel and pushes it all the way forward. When the gun fires it recoils and the slide and barrel travel back together slightly and then unlock. This backwards travel of the barrel is why it wiggles when the gun is open.

brickeyee · July 27, 2011, 03:38 PM

Quote:

This backwards travel of the barrel is why it wiggles when the gun is open.

And the clearance required for barrel tip down.

July 24, 2011, 03:09 AM	#1
Prof Young Senior Member Join Date: August 21, 2007 Location: Illinois - down state Posts: 2,403	Semi auto loose barrels? Gun smiths: Went to a gun auction and handled a lot of semi auto hand guns at the preview. I noticed that on every one of them, with the magazine removed and the slide locked back . . . the barrel was loose and i could wiggle it around. These were all used guns, but they were many good brands. Is this normal? Live well, be safe Prof Young

July 24, 2011, 03:29 AM	#2
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	Hi. Perfectly normal with the slide open. The barrel on most pistols isn't 'locked' into the slide when the action is open. A 1911 barrel, for example, is only 'locked' in the slide when the slide is closed. Have a look at this. The 'bands' on the top of the barrel mate with recesses in the slide and the pistol is locked into 'battery' only when the actionis closed. http://stevespages.com/ipb-colt-1911.html Most pistols aren't a whole lot different. They can and do 'lock' differently though. __________________ Spelling and grammar count!

July 24, 2011, 02:00 PM	#3
Prof Young Senior Member Join Date: August 21, 2007 Location: Illinois - down state Posts: 2,403	Thanks. T. Thanks for the info. It just surprised me. I only own one semi-auto and assumed the barrel had some wiggle room cause it's a very cheap gun. Thanks again. Prof Young

July 26, 2011, 03:31 PM	#5
Prof Young Senior Member Join Date: August 21, 2007 Location: Illinois - down state Posts: 2,403	Lots to learn. Jim: I guess I don't know the difference between those two types of systems. There is a lot to learn. I guess I should find a book on hand guns or some such. Thanks Prof Young

July 24, 2011, 09:56 PM	#4
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Well, it is normal for a locked breech pistol, where the barrel and slide are locked together until the bullet is out of or almost out of the barrel. But on a blowback pistol, a really loose barrel could be trouble, though some barrels that have to be removed for disassembly are a bit loose. Examples: A 1911 barrel that is loose when the slide is open is perfectly normal. A Colt Model 1903 barrel is a little loose as it has to turn and unlock from the frame so the pistol can be taken down for cleaning. A Walther PP with a loose barrel indicates there is something wrong. Jim

July 26, 2011, 08:23 PM	#6
drail Junior member Join Date: February 2, 2008 Posts: 3,150	The only thing that matters is play in the barrel/slide fit at full lockup at the front and rear of the barrel. Play between the slide and frame doesn't really hurt accuracy any but the barrel has to lock up snugly and in the same position every time it cycles.

July 27, 2011, 01:37 PM	#8
chasep255 Senior Member Join Date: December 21, 2009 Location: NJ Posts: 727	Yeah that is because they are recoil operated. When the slide comes forward it locks with the barrel and pushes it all the way forward. When the gun fires it recoils and the slide and barrel travel back together slightly and then unlock. This backwards travel of the barrel is why it wiggles when the gun is open.