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Discussion Starter · #1 ·
So, I picked out a couple Rock Island doublestack %80 lowers and started to piece together a pistol with them. So far everything seems to be going fairly well. Everything moves correctly, safeties work, trigger feels great, the project pistol passes all the function tests, but when it came to fitting the barrel I stopped the moment I got it to lock up and noticed this little gap at the breech face of the slide:

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My question is, should I keep at the barrel hood until that gap closes, or should I stop now since the barrel is going into lockup to maintain that near-zero gap between the top of the barrel hood and the breech face? It's a Rock Island bull barrel, Stealth Arms slide, and so far the only thing I had to actually file to fit was the part of the hood that contacts the breech face. Needless to say I'm leery about taking off too much, but also about the round not being properly supported by the barrel if that portion is left too long.

And just for fun, the project thus far in the raw:

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That's a Wilson ambi-safety, I just didn't have the right hand switch installed when the photos were taken.
 

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No, do not take any off the hood end. Question, how much can you shim between the hood end and the breech face and still engage the upper lugs?

LOG
 

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Just checked, .010" is all it will allow.
Okay, that will work, however .010" more than it should/could be no reason to have that much. As close to zero is best, the reason is when the gun fires the bullet will pull the barrel forward and the case head will push back on the breech face so every time it fires this space will be taken up in the upper lugs. Also the slide looks as if it would even fit the frame better, as it is forward of the frame and if the hood had .010" more the slide would match, this is common however for a new slide and frame with barrel not to necessarily match and blending is then done. But we learn by experience.

LOG
 

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Discussion Starter · #6 ·
I think you are correct about the slide to frame fit, log man. I was just playing with that a bit, and if I hold the barrel in place with my thumb and draw the slide back to create that .010 gap there would be very little blending required on the back end. I won't blend it just yet though, the ultimate plan for it is to more or less live in a 10mm configuration, and the .40 barrel is primarily for practice so I thought if I was going to make a mistake, I'd do it with that. Every once in a while I do something clever.

Step on the hood end? Negative. If that's a loaded chamber indicator I kind of wish RIA had not gone that route. I'm probably worrying about nothing since that's probably just case rim exposed through the gap but it seemed like a potential problem to me.

Since lock up is achieved (and then some) filing operations shall cease. I'm glad I stopped and asked before I took any more off, thanks guys.
 

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Step on the hood end? Negative.
I realized that, and is why I deleted it. I was looking at the photo wrong.

That gap is between the chamber face and the breech block. Ordnance spec barrels could stop on that with no gap, but would then have a gap at the barrel hood end. Modern fitted barrels stop on the barrel hood end, leaving a gap at the chamber face.

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Discussion Starter · #8 ·
Interesting. The only thing I had to compare to was my Springfield that's probably closing in on 15 years old by now. Needless to say, no gap. If I had realized modern barrel design was different, I'd have stopped filing a few strokes sooner. Ya live, ya learn.
 

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If those are .45 frames, you should check for barrel ramp overhang at the frame ramp.

The bottom end of the barrel ramp sits further rearward on 9mm and .40 barrels due to the reduced chamber diameter.

A 9mm/.40 frame has a shallower ramp, so the bottom edge of the barrel ramp will not overhang the top edge of the frame ramp.

A .45 frame has a deeper ramp and the bottom edge of a .40 barrel ramp can overhang the top edge of the frame ramp.

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Discussion Starter · #10 ·
They're 9mm/40 frames. I already have a .45, so I figured I'd build something a little different.
 

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Discussion Starter · #12 ·
Where did you find the RIA frames?
I went to their site, advancedtactical.com. They're currently half off, so if you're interested in a cheap %80 project frame I'd say now is a good time.
 
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