what does tight lock up mean?

p5200 · #1 10-09-2011, 08:20 PM

Probably a dumb question but what does tight lock up mean? and how do you check for a tight lock up between barrel and slide?

Thanks!

s&wchad · #2 10-09-2011, 08:43 PM

When I think of "tight lock-up", I think of a revolver that's timed properly and has little rotational play in the cylinder when the trigger is back and the hammer is down.

ArmaNotSoLite · #3 10-09-2011, 08:51 PM

Quote:

Originally Posted by s&wchad

When I think of "tight lock-up", I think of a revolver that's timed properly and has little rotational play in the cylinder when the trigger is back and the hammer is down.

That's what I always think of, as well.

Dragon88 · #4 10-09-2011, 08:59 PM

What is referred to as "tight lock up" over in the revolver section of the forum does not apply to your gun. A semi-automatic pistol can still be referred to as "tight" if there is a very close fit between the frame, slide, barrel, and bushing if present. This is more applicable to well made 1911 pistols. Few polymer guns could be considered "tight" by any stretch of the imagination, but they are not suppose to be. They have a different purpose and different tolerances in manufacture.

To check for "tightness" on your gun, close the slide, remove the magazine, and shake it. Does it rattle? Probably so, most polymer guns to. Then with the slide still closed, push down on the barrel through the ejection port. Does it move a bit? Probably so, but again it's not an issue.

p5200 · #5 10-09-2011, 09:16 PM

Thanks very much for the detailed explanations. The reason I asked is I just installed a KKM M&P 40 to 9mm conversion barrel and wanted to know more or less what to look for as far as a good fit. I guess I can try both barrels in the gun and compare the fit differences. Of course I guess the main things are how it functions and accuracy.

Dragon88 · #6 10-09-2011, 09:32 PM

Yup, try the gun with both barrels and compare. Also, remove both barrels, take a round of appropriate caliber, and drop the rounds into the respective chambers. The chamber on your KKM will likely be tighter. This is good for accuracy, not as good for reliability.

p5200 · #7 10-09-2011, 10:31 PM

I thought about adding some Apex parts also maybe, starting with the Apex extractor although, I've read the pins can be a real pita. I have had much experience with handguns just mostly rifles. I am hoping to maybe reload for the 9mm barrel since I already do for my rifles but I guess I'll see how things work out. Thanks!

Dragon88 · #8 10-09-2011, 10:36 PM

I would recommend shooting your pistol a lot before changing anything. The trigger will get better by itself every time you shoot it, and you may find you don't need to spend any money at all to enjoy the gun. I'm kind of a cheap skate and I love getting things for free.

Titegroups · #9 10-09-2011, 11:28 PM

Understand why you are changing something before you change it and not just for the sake of changing it. Once your skills have gotten to the point you feel you need to modify then do so.

p5200 · #10 10-09-2011, 11:31 PM

I see, I appreciate all the advice folks!

p5200 · #11 10-10-2011, 09:55 AM

I found these also and thought I would share for those interested.

Well, I did something wrong the images and print aren't large enough.