1911 premature slide lock back

For those who like to roll their own.

Moderators: carlson1, Charles L. Cotton

Post Reply
User avatar

Topic author
sjfcontrol
Senior Member
Posts in topic: 2
Posts: 6267
Joined: Wed Oct 28, 2009 7:14 am
Location: Flint, TX

1911 premature slide lock back

#1

Post by sjfcontrol »

Hornady 45 cal 230gr FMJ-RN
Bullseye 5.2, 5.4 & 5.6gr

Everything seemed OK at 5.2gr
All rounds OK at 5.4gr, except the slide locked-back with a single round left in the magazine.
At 5.6gr I had the slide lock-back several times during the 2 magazines of rounds. Also, on the last round I had a stove-pipe (not sticking up, but jammed between the breach and the chamber).

Haven't heard of premature lock-back being a sign of overpressure, but thought I'd ask the experts!
In total I fired 76 rounds today, and this was at the end, so the gun was not particularly clean at this point. But I would think my Kimber Ultra CDP II would handle more than that without needing to be cleaned.

Maybe the extra recoil causing the slide-stop to bounce?

Any ideas?
Range Rule: "The front gate lock is not an acceptable target."
Never Forget. Image

DocV
Senior Member
Posts in topic: 2
Posts: 1127
Joined: Fri Nov 25, 2011 4:29 pm

Re: 1911 premature slide lock back

#2

Post by DocV »

Check your slide stop for signs of brass. The nose of the round can bump on the stop and engage it.
User avatar

Pawpaw
Senior Member
Posts in topic: 1
Posts: 6745
Joined: Sat Jun 19, 2010 11:16 am
Location: Hunt County

Re: 1911 premature slide lock back

#3

Post by Pawpaw »

Premature slide lock is a known issue with Kimbers. Give them a call & they will send you a new slide stop with a slightly modified profile.

DocV is right. It's caused by the the nose of the top round hitting the slide stop.
Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passions, they cannot alter the state of facts and evidence. - John Adams
User avatar

Excaliber
Moderator
Posts in topic: 1
Posts: 6185
Joined: Tue May 27, 2008 9:59 pm
Location: DFW Metro

Re: 1911 premature slide lock back

#4

Post by Excaliber »

Check your grip also.

It's possible to accidentally put pressure on the slide stop during recoil.

This is usually more of a problem with small gun / big hand combinations, but it's something that should be considered if you're not seeing brass marks on the slide stop. Use of an aftermarket extended slide stop can also contribute to this issue.
Excaliber

"An unarmed man can only flee from evil, and evil is not overcome by fleeing from it." - Jeff Cooper
I am not a lawyer. Nothing in any of my posts should be construed as legal or professional advice.
User avatar

Topic author
sjfcontrol
Senior Member
Posts in topic: 2
Posts: 6267
Joined: Wed Oct 28, 2009 7:14 am
Location: Flint, TX

Re: 1911 premature slide lock back

#5

Post by sjfcontrol »

Are you talking about copper from the bullet? The brass shell is about 1/4" behind the stop.
Range Rule: "The front gate lock is not an acceptable target."
Never Forget. Image

DocV
Senior Member
Posts in topic: 2
Posts: 1127
Joined: Fri Nov 25, 2011 4:29 pm

Re: 1911 premature slide lock back

#6

Post by DocV »

sjfcontrol wrote:Are you talking about copper from the bullet? The brass shell is about 1/4" behind the stop.
Yup. The rounds can move forward in the magazine when firing but I would be concerned if the nose of the shell was 1/4" behind the stop. Here is a photo of a 1911's slide stop in a magazine that is being inserted: Image
In the picture, the magazine is not yet seated. Here is a picture with the magazine fully seated. Image
As you can tell the rounds in this picture are jacketed hollow points.

Here is a FMJ brass jacketed Montana Gold in a magazine that is not yet seated:Image

If round moves slightly forward in the magazine it can impact the slide stop. If that is happening you might find marks on the slide stop lug. If so, you can try lightly filing your slide stop to profile it away from the nose of the bullet or just get a replacement slide stop from Kimber. If you reload, you can see what happens if you shoot SWCs.
Post Reply

Return to “Reloading Forum”