I have fitted a Kart EZ fit barrel into a Caspian slide/ Springfield receiver combo. I have light contact on the barrel pads and correct contact on the tops and bottoms of the lower lugs. The slide/ receiver have loosened slightly so they are no longer jammed into each other by the barrel. My concern is that when locking/unlocking there is a snap as the barrel drops up/down. There is a bit of contact with the end of the hood against the breech face, but no more than a "kiss". This snap has improved considerably during fitting, but is still there. Any ideas would be appreciated Gents.
Your barrel hood to breech face is best as tight as will allow the barrel to drop out of battery by gravity. With barrel, slide, and bushing, barrel held tightly up into battery, and released should drop on it's own. That said, I would leave it just a bit tight as the upper lugs mate and provide more clearance on it's own. This clearance will only wear in a looser direction.
I have fit two easy fits barrels so far. Both were what I consider more "sticky" entering and leaving battery during lock up until I removed a little more material from the fitting pads. By sticky I mean that there was a slight mechanical interference that made the initial out of battery slide movement more difficult. Recall that Kart states that the barrel must "move in and out of battery position without sicking" (pg 10 or installation manual "New Math For Shooters")
Edit: Added, you can always break the top corner of the hood a little to avoid any binding as the barrel swings up into battery.
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Recall that Kart states that the barrel must "move in and out of battery
position with sicking" (pg 10 or installation manual "New Math For
Shooters")
Actually it says... without "sticking".
Oh, I see that you have changed, with to without, but not sticking... yet.
Just a bit more eplanation:
Your ultimate goal it to have the slide stop pin lift the barrel into battery with equal pressure on the pin as shown in these pictures
And have the slide stop pin stop on the back of the barrel knees as show here:
The pin/knees should equally contact here:
Did you file anything on the lower lugs?
I have contact on the lower lugs as in the diagram, plus just a light touch on the upper pads. I will break the corners on the top of the hood and see if that helps.
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The pin/knees should equally contact here:
http://i536.photobucket.com/albums/...t-image0001.gif
Is it safe to assume from your file name for this image that it's from Kart?
The lower lug contact marks look quite good...
Is the link witness mark from the old barrel?
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Hi Eric:Is it safe to assume from your file name for this image that it's
from Kart?
Sorry I forgot to mention that I scanned that image from Kart's instruction manual. I didn't see any copywrite marks in the manual so we should be OK.
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The lower lug contact marks look quite good...
Is the link witness mark from the old barrel?
No, those marks are from the new Kart Easy Fit barrel. The picture is of a a new Colt SS I used for this build because I like the fact that they are forged pins. I stripped the blue from the pin and refinished with cold-blued so I could more easly see the withness marks after each range visit. That photo was taken after about 300 rounds on the Colt pin.
The good news/bad news is that the pistol is out for hard chrome now so I cant show any more views of the contact marks.
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...I scanned that image from Kart's instruction manual.
Copyright stuff's of no concern. I just noticed the drawing showed the modern profile for the lower lugs's "knees". This has the center of the knee radius above and aft of the center of the pin hole, which was adopted on the Ordnance drawings sometime after 1980, as near as I can tell.
Prior to that time the knee radius center was at the pin center. I'm guessing it got moved to avoid contact between the knees and the SS pin, like this:
PICTURE 404
Judging from the "knee bump" problems seen on the Forum, seems there's a few barrel manufacturers still making them the old fashioned way. Nice to see Kart has kept up with the changes.
I see. Thanks. It looks like Kart used that .0095 gap and a oversized rear radius for their Easy Fit invention. Now I just wonder if they started off by filling in the top barrel locking lugs with weld weld to fit a barrel without recutting the knee profile.
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No, those marks are from the new Kart Easy Fit barrel. photo was taken
after about 300 rounds on the Colt pin.
Reason I asked... that is an undesirable condition (if) you are seeking "maximum" accuracy. Won't bother much for general usage... unless you can feel the link high center as it goes into full battery.
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Reason I asked... that is an undesirable condition (if) you are seeking
"maximum" accuracy. Won't bother much for general usage... unless you can feel
the link high center as it goes into full battery.
Fortunately this is a general usage range beater but I was convinced that I wanted as much equal contact on the pin as possible.
Recall that I am doing all of these "upgrades" on the least expensive 45 I could find because I knew I would probably ruin something in the process.
My only guidance, outside of this forum, the Kart manual and Kuhnhausen, was my Springfield TRP Operator (expensive) pistol which is the most accurate 45 I have ever shot. The TRP has the same pin marks and all the literature I that I have read both lead me to believe that those mark where good and where something to strive for when fitting a barrel.
Somehow I choose the wrong path on my journey and I now I am stuck at a canyon... boy it's wide and I don't know how I got here...
Unfortunately the pistol is out for Hard Chrome right now but fortunately it is my "Its OK to beat it up" range pistol.
Your bottom lug contact pattern appears to be very good... It's the link mark I am referring to..I strive for zero contact at that location... but it depends on your desired outcome... general usage will not be effected, unless the link is stacking hard at top dead center... also, if you are going for accuracy, build as much flat into the lower lugs that is mechanically possible... Each pistol will accomodate its own tolerance depending on all the variables... knee bump is a product of poor fitting...
By "that location" do you mean:
1. zero contact anywhere radially between the barrel lugs/feet (implying the link never goes into compression on the way into battery - and the barrel lugs ride the SS pin all the way into battery with the link loose)? Or
2. zero contact between the barrel lugs/feet only when in battery (implying the barrel rides the link (in compression) most of the way into battery and then the link goes loose and sets the lugs down on the SS pin just before battery)?
[Or, do either of these gobbledegooky questions make any sense? ]
#1... as the slide and hood make contact, the barrel begins to rise... the bottom inside radius of the link hole and the bottom outside radius of the SS pin bear the majority of the load as barrel lifts to its max height..the lugs are now in postion to make contact with the SS pin... the link should not stack as it levers over TDC into battery, and there is actually no need whatever for the link to make contact with the SS pin in the area shown by Eric. It is detrimental to precision accuracy, but not for general use, unless the pressure is of such magnitutde as to cause the title of this thread... "snapping into battery."
#2... compression; I don't know where that term originated, but if you have access to a cut away 1911, the link is actually being pulled up with the barrel, and only begins to stack at TDC. If the link is still under tension, while in battery, which Eric's is, it is undersirable. If the link "sets" the barrel down on the SS pin, it's time to refit the system... To enable use of the long lug contact method, very careful fitting of the link is necessary. The dwell time in battery is enhanced by the proper fit of the link to exactly match the lateral movement of the barrel... otherwise, the barrel can't help but travel in the radius the link imparts to the system... but, as I said, none of this really matters for general use... only super accuracy... my passion, you know.
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Eric; It's the link mark I am referring to... I strive for zero contact at
that location.
I may decide to remove just a little material from the top of the link pin hole to eggshape the top of the link hole.
This should unload the link at lockup.(?)