1911 drop-in barrel that's not dropping in

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Dec 3, 2007
deep south texas
hi y'all.
need some expert advice here....
situation: just installed a "drop-in" barrel in my 1911 this afternoon. took a little work with a file to achieve lockup. took the following measurements once lockup occurred: in battery position- .132 in. between top of barrel hood and top of slide. 1/8" out of battery position- .176 in. between top of barrel and top of slide. gave me a difference of .44 in. as I understand, .44 in. is acceptable, so I thought I was making good progress. I cycled the slide with just the barrel and lapped-in bushing installed, and it hung up once in about 15 cycles. i then installed the barrel and bushing into the slide, mated the slide and frame, and installed the recoil spring (18 lbs) and recoil spring guide (short/standard). once I did this, I noticed that in "battery" position, the back of the slide is forward of the back of the frame by .055 in.

While hand cycling, I also noticed a slight "hitch" at the beginning of the cycling motion (about .022 in.) while the barrel still appears to be in battery. from the sound it makes, I believe it is the recoil spring causing the "hitch", but I don't know. What is causing this?

I then decided to install the slide stop to see if that would cure the “hitch” and marry the back of the slide to the back of the frame. No dice. I couldn’t get the slide stop completely installed. When I tried to do this, I had to cycle the slide approximately .25 in. rearward and once the slide stop pin inserted through the link pin, it completely locked up the pistol with the back of the slide resting .017 in. rearward of the back of the frame..

I then attempted to fully cycle the slide by applying downward pressure on the barrel hood, but could not make the barrel hood to drop at all.

In all, it appears that I have multiple issues here. Can’t seem to diagnose the problem here. I'm starting to suspect that the link that was installed on the "drop-in" barrel may be too long, but would this explain the rest of the problems? Checked the manuals and videos I have, but I am seriously confused at this point. Any help would be greatly appreciated.
results of slide stop pin hole diagnostic

did the test you mentioned above and noticed a slight amount of lower lug protruding in the slide stop pin hole. where do I go from here? (Note: don't own a lug cutter).
I agree with Tuner...

Back when, USGI and Colt commercial pistols you could change barrels on a drop-in basis, but not today. Current pistols are not made to U.S. government prints and tolerances. Since each of the current manufacturers does his own thing I don't believe that anyone can make a barrel or other parts that will drop into any and all of the guns now on the market.
Patrolman, If you have a decent set of needle files and the portion of the lug that's showing in the hole is at the forward radius, where the lug starts to curve...you can use the flat file in the set to draw-file the area of interference until it doesn't put the pin in a bind. Be careful to follow the curve, and don't take any more than you need to in order to let the barrel drop to the bed.

Draw-filing is simple. Just hold the file at 90 degrees to the surface to be cut and work it back and forth...toward you and away from you at 90 degrees to the barrel axis. Draw filing also allows you to cut in both directions. Be careful to keep the file bearing evenly on both sides of the lug.

If the area of interference is behind the radius...that's the part that rides on the slidestop pin and supports the barrel. While you can scrape and draw-file that area with a round or half-round file...it's a slow, tedious exercise to get it even from side to side...and I recommend a lug cutter for the first-timer.

If the area of interference is in the rear curve of the lug...where it comes to rest against the slidestop pin...you need a lug cutter. Experienced hands can reshape that part by hand, but it's not a good idea for the beginner.

thanks tuner and fuff.

appears that it's in the forward radius of the lug. will draw file it and see if that doesn't cure the bind.

thanks tuner and fuff.

appears that it's in the forward radius of the lug. will draw file it and see if that doesn't cure the bind.
No change at all? Is the link too short to let the slidestop pin clear the corner?

Could be the rear of the lower lug is against the vertical impact surface in the frame before the upper lugs completely disengage from the slide...or you still need to work with the lower lug a bit.

Hard one to call, sight unseen.
might this work?

tuner and fuff,

measured the location of the slide stop pin hole and appears to be spot-on (relying on Kuhnhausen's schematic). Kinda reluctant to file down the lower lug more than I already have; don't want to end up with a barrel riding the link. got to thinking if it would be worthwhile to install a pack of links (like the ones sold by Wilson's) one-by-one to see if that will clear up the problem... y'all think this may be worthwhile?

Swapping links without checking to see if they're the right length for correct barrel linkdown timing is counterproductive.

Check to see if the link is part of the problem by removing it and assembling the gun. Draw the slide back slowly and see if the barrel drops to the bed and provides the right clearance with the slide. (.015 inch is a good starting place.)

If it does, you can probably go with a .005 inch longer link...but be sure to check the timing and the clearance.

If it doesn't make a difference...you probably just need to take a bit more material off the forward radius.

Riding the link isn't a completely bad thing as long as it's not riding too high. I like to see about .003 inch or so to make sure that the lower lug doesn't beat itself up on the slidestop pin...and the lug isn't supported by the link when the gun is in battery.
link may be suspect


per your last post, I put the barrel in without the link and it did drop into the bed with plenty of clearance between the hood and the slide. more than .015, though. the slide stop pin is still freezing up the gun once it is installed. will try a .005 longer link and try again.

thanks for your help.
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