Barrel wearing alloy frame in Kimber Ultra CDP

[warmrain]

I have a 2002 Ultra CDP Elite II (stainless barrel) with about 700+ rounds through it. It has been 100% reliable since NIB. Yup, as hard to beleive as that is, I've not had a single failure of any kind.

I am developing a wear area on the alloy frame, right side, where the barrel slides along what I think might be called the barrel bed. I think that most of the wear has stopped but I am concerned about the burr at the aft end of the wear area. I'm thinking that the sharp edge of this "hang nail" is going to be a potential stress riser. I think this should be easy file smooth by continuing the wear area aft in the same plane. However before I do this I'd like a "sanity check" and some advice (e.g. type of file).

The photo is the best I can do... The large red circle is what I call the barrel bed. The smaller circle is the area were the burr has been raised.

http://i27.photobucket.com/albums/c151/warmrain/EliteFramebarrelbedwearmarkup.jpg

[warmrain]

SharkZF6 indicated to me that picture and text were difficult to interpret...

I offered this and it seems to make what's happening more clear:
"Picture this in your mind. Sitting on the sand at the beach, knees up. Push you leg out and let your heel push up the sand... At the end of the trough is a raised area. That is the burr I'm referring to that has developed at the rear of the barrel bed, in the smaller red circle..."

If you look at the finish in the photo you will see that very little is worn at the front. It appears that as the barrel moves back and cams down it has worn into the frame. At the rearmost travel it has left a burr of metal pushed up.

It like to correct this to prevent any stresses on the frame before I shoot it anymore. Eventually this will go to Robar for coating (so I have no concern over the bare alloy), but I'd like more rounds through it to ensure functionality and reliability before coating...

[1911Tuner]

Offhand, I'll call a linkdown timing issue. Barrel is hitting the bed before it stops against the vertical impact surface in the frame...which is much reduced in height due to the cut for the full ramp.

Correctly timed, the barrel should stop against the impact surface just
as the barrel is settling down to bed...with maybe .002 inch of drop left.
Possible that the link is too long...the vertical impact surface is located too far rearward...or the lower barrel lug is located too far forward. Also a slight possibility that there's insufficient clearance between the top of the barrel and the slide as the slide moves over the barrel...and it's forcing the barrel downward against the frame. If this is happening, you'll notice that the front corners of the barrel lugs are starting to take on a rounded shape.

Bad JuJu at any rate.

[warmrain]

Barrel lugs don't look deformed and wear of the frame seems to have stopped... Still an issue?

[1911Tuner]

Barrel lugs don't look deformed and wear of the frame seems to have stopped... Still an issue?

Hard to say without seeing the gun. Barrel to slide clearance look okay at .250-inch of slide travel? Slidestop pinhole in the link oblong/stretched?

[warmrain]

Remind me how to check the barrel/slide clearance. The slide stop hole in the link and frame seem to be round and non-oversized... Is it significant that just the right side of the frame is showing wear...?

[1911Tuner]

Remove the recoil system and assemble the gun. Pull the slide rearward slowly .250 inch rearward. At or slightly before that point, the barrel should be fully bedded with a minimum of .010 inch clearance between the top of the barrel and the bottom of the first lug bridge in the slide. No pushing on the barrel to get the clearance. It has to drop. Use strips of paper for feeler gauges. 20-bond typing paper is about .004 inch thick.

This is a field expedient test. If the barrel drop occurs too close to the .250-inch mark to be sure that it IS fully down at .250 inch, you may need to do a more conclusive timing test using dial indicators to determine the exact distance of slide travel. Full linkdown/Drop can occur earlier than .250 inch...but no later.

Back the slidestop out far enough to let the arm hang vertically. Push it against the frame lightly and pull the slide fully rearward. Push the barrel down and back and hold it. The slidestop arm should swing freely with no binding...or just a tiny bit at most. if it does get into a bind, see if it will move by flicking it lightly with a fingernail. If it's free, or will move with
minimal force...about what you'd use to scratch a baby's chin...the barrel is being stopped by the frame's vertical impact surface instead of the link
in extension.

The one-sided wear/impact on the frame is sifnifigant...but without being able to see the gun, i can't make a call on exactly what it is.

[warmrain]

Thanks Johnny,

Remove the recoil system and assemble the gun. Pull the slide rearward slowly .250 inch rearward. At or slightly before that point, the barrel should be fully bedded with a minimum of .010 inch clearance between the top of the barrel and the bottom of the first lug bridge in the slide. No pushing on the barrel to get the clearance. It has to drop. Use strips of paper for feeler gauges. 20-bond typing paper is about .004 inch thick.
The barrel becomes fully bedded, that is it is down as far as it will go, right at .250". The feed ramp off the barrel appears to be bottomed out on the feed ramp extension of the frame. This appears to occur at the same time the right side of the chambers aft surface is at the barrel bed "burr" that I described. Curiously enough, I could see that the barrel feed ramp has been lightly contacting the frame's feed ramp from the wear of the black coating. The barrel's feed ramp contacts across the frame, but the wear is slighty more apparent on the right side (and this can be seen in the photo).

I used common office printer paper as a gauge. I found that 2 and 3 layers would slide into place (easlily) as you describe, but four layers was snug (though it went in).

This is a field expedient test. If the barrel drop occurs too close to the .250-inch mark to be sure that it IS fully down at .250 inch, you may need to do a more conclusive timing test using dial indicators to determine the exact distance of slide travel. Full linkdown/Drop can occur earlier than .250 inch...but no later.
As near as I can tell with a draftsman's scale it is occuring right at .25". The only precision instrument I have is a dial caliper if that will help...?

Back the slidestop out far enough to let the arm hang vertically. Push it against the frame lightly and pull the slide fully rearward. Push the barrel down and back and hold it. The slidestop arm should swing freely with no binding... ...If it's free, or will move with minimal force...about what you'd use to scratch a baby's chin...the barrel is being stopped by the frame's vertical impact surface instead of the link in extension.
It is swinging freely, enough to fall out if I tip the pistol while pushing the barrel down and back...

Is this good, is the barrel supposed to be stopped be the frame's vertical impact surface instead of the link in extension?

Does it seem that the pistol has worn in to the point of proper dimension...? Or is this just hopeful thinking? Still, I'm thinking that burr should be removed... Do you agree, and how?

[warmrain]

Where do I go from here Johnny... Run it and see?

[warmrain]

Should I remove this burr before more firing? Even though the wear seems to have stopped a am concerned about what looks like a stress riser and the potential for a frame crack to start from this area...