[Robin Hood]

Over the years I have run across some things that are new to me, but I'm sure are not new to many of the talented builders here.
Here is the scenario:

I buy a Bar-Sto 9mm ramped commander barrel with #1 locking lug cut to .050". I fit the hood to the slide and go through the motions cutting the lower lugs with Chambers cutters using .186", .193" and finishing with .195" so that the safety goes into the notch with a sliver of space in front. I'm using a .200" slide stop. I start with a #3 to find to my surprise that it's not gonna work. Not even a #5 will allow the SS pin to fit the cut. I decided to place a .005" shim in the #1 lug slot in the slide and recut. Still the SS will not fit. I place another .005" shim for a total of .010" of extra material to cut off and finally a #3 link works like it should. Of course there is also .010" of space between the upper lugs and slide so it's a no go. I set the Bar-Sto barrel aside and bought a Nowlin barrel which has a #1 locking lug cut to .040", the exact amount I needed to fit the barrel perfectly. When you get a Nowlin barrel there are specific instructions to not mess or file any of the locking lugs. After fitting the hood, I went through the motions once again and yes the #3 link fits and functions flawlessly. Like I have mentioned in other threads, I am getting quarter sized groups with this pistol. The slide had a .702 diameter, but I'm sure that doesn't matter. So my question is why in the world would bar-sto cut their lugs to .050" when that lands your firing pin low and also doesn't give you enough material to cut off the feet when cutting the lower lugs? What's up with this picture? How are people using bar-sto barrels with .050" of lockup getting away with using #3 links? Please explain any help would be greatly appreciated.

 

[Robin Hood]

Yes I have heard that Bar-Sto barrels lockup at 9 and 3, but they don’t in a .702 slide. This is one reason I believe the upper lugs should make full contact all the way around like a rainbow. Slide tolerances vary, barrel manufacturers stick to certain tolerances tightly. If I fit a Kart into a .702” slide it’s not going to fit the same way it would in a .699”-.700” slide. Eventually you lose that “side to side” lockup and the barrel rises all the way to where the top lug is cut. I noticed another forum member from 2015 mentioning the same thing about his Bar-Sto barrel. I’m not saying they are bad, but anything more than .045” of lockup causes problems, unless there is something I am overlooking. I would like to think that any barrel that is within mil-spec tolerances should fit into a slide even if the tolerances are on the opposite ends of the spectrum. So what’s the deal here?

 

[pistolwrench]

Previous BarSto bbls I've fit, had upper contact at 10 o-clock and 2 o-clock. No contact at 12 o-clock.
Think 'v' block.

 

[roaniecowpony]

Previous BarSto bbls I've fit, had upper contact at 0100 and 1400.
No contact at 1200.
Think 'v' block.

Chuck, please clarify. Is the lug cut in a odd shape?

 

[pistolwrench]

Fixed my post above.

 

[Robin Hood]

So apparently it may be the inner diameter of the slide and lug recesses being to wide? How can a barrel manufacturer guarantee their barrels will make contact close to the sides? I figured this would be the case with Bar-Sto. So obviously the barrel did not make contact at 10 and 2 but did make contact at 12, meaning the inner walls of the slide were not close enough to the barrel to get the 10 and 2 lockup. Slide tolerances range from .699-.702. Now I am working with a couple slides that have an I.D. of .701”. I have a KKM barrel for the 9mm build and Kart for the .45, but I’m rethinking barrel choices based on the experience I just had with the Nowlin barrel. The problem of course is the fact that you have to trim the hood before you can even see how the barrel lugs will interact. Barrels are expensive and I don’t want a bunch of barrels with perfectly trimmed hoods laying around and that’s all.

 

[roaniecowpony]

RH,
From my little knothole, if the barrel lug grooves are cut too deeply by the manufacturer of the barrel, there is little you can do to fit it to form a "saddle" in the lug groove bottom contact area to center the barrel. Continuing to remove material at the bottom raises the barrel further, sometimes causing too much engagement of the lugs, off center firing pin, and timing issues.

My thought is that if the lug groove contact at only 12 o'clock and you had a good hood fit, centered firing pin, and appropriate lug engagement, it may shoot great.

 

[roaniecowpony]

You could measure the lug groove depths before doing any other work on the barrels. This should give you an indication of whether it can be more readily fit.

Since the goal line seems to be in the low to mid .040'' range, I think a .035 deep lug groove would be easily fit. I can measure some untouched Clark barrels I have around, if you like. They seem to fit well and easy with minimal filing to get good contact.

 

[Robin Hood]

Like I’ve said, I have fit Kart match barrels and know how they sit at 10 and 2 in order to get the firing pin centered. I realize that the barrel doesn’t make contact at 12 and I do realize that this is a good method considering if your lugs get dirty the grime has some place to go without effecting lockup. I guess my experience with the Bar-Sto barrel and the .702” slide raddled me a bit and made me start to second guess things. Maybe it’s just a bad Bar-Sto barrel. The point that I really wanted to make here is that if you have too much lockup, your cutters will not cut enough material off the bottom feet of the barrel and no link will work. How are some people getting .050” of lockup and still getting a hard fit? How and what link are they using? I’m not going to “egg” out links or change the shape of my SS pin just because the lockup is too much. I’d rather just stick with barrels like KKM and Nowlin that have full contact around the upper lugs as long as the lugs aren’t cut too deep. I know some of you guys out there have the answer to this. If it’s a trade secret, it’s sure an expensive one.

 

[Robin Hood]

RH,
From my little knothole, if the barrel lug grooves are cut too deeply by the manufacturer of the barrel, there is little you can do to fit it to form a "saddle" in the lug groove bottom contact area to center the barrel. Continuing to remove material at the bottom raises the barrel further, sometimes causing too much engagement of the lugs, off center firing pin, and timing issues.

My thought is that if the lug groove contact at only 12 o'clock and you had a good hood fit, centered firing pin, and appropriate lug engagement, it may shoot great.

I wish more folks would chime in on this topic. There are other people that have run into this same scenario using Bar-Sto barrels. Me thinks they are meant for .699”-.700” I.D. frames not making contact at 12 like has been said already. Is the only fix to having too much upper lug engagement to spot weld 2 beads at 10 and 2 either in the slide or on the barrel?

I run into issues similar to this with other parts as well. I can say for sure a Wilson extractor will not have the correct breech to hook gap when installed in a NHC slide.
Why does every part manufacturer have to build thier parts .003”-.005” different so they only work with THEIR OWN products? Seems like false advertising.

 

[rrabullseye]

An "oversized, must be fit" barrel that already has it's upper lugs cut to .050 depth is clearly not oversized to me. Using gauge pins from .180 to .200 can be your friend when fitting the barrel. Fit the hood, then use a gauge pin instead of the slide stop pin to determine how much material should be removed from the lower lugs, measure the lower lugs, measure the amount of lockup, and do the math.

 

[Robin Hood]

An "oversized, must be fit" barrel that already has it's upper lugs cut to .050 depth is clearly not oversized to me. Using gauge pins from .180 to .200 can be your friend when fitting the barrel. Fit the hood, then use a gauge pin instead of the slide stop pin to determine how much material should be removed from the lower lugs, measure the lower lugs, measure the amount of lockup, and do the math.

I have a stack of gauge pins from .190 to .200”. The problem is once the right amount is found and then cut, your barrel link must be able to swing UP into battery AND allow the slide stop pin to contact the back of the barrel feet without “pinching” the pin. In this scenario, not even a #5 link is long enough to allow this to happen and even if it was long enough to allow the SS pin to do its thing, the link would be too long for proper VIS contact. I understand that there is a balance between how everything stacks up and also the amount of VIS clearance or distance for lack of a better word, in order to get the barrel, link, SS pin and VIS all working together as they should. It’s easy math. What I don’t get is why barrel manufacturers are cutting lug #1 deeper than .042”. The slides that I am working with are all .702” I.D. After I fit the hood and place a barrel bushing on, the barrels lockup to 12 o’clock, therefore leaving too much at barrel feet disallowing proper link alignment to the feet and crosspin which will always be ~.200”.

 

[Magnumite]

The Nowlin semidrop in I used in the 10mm build the grooves seemed to exhibit a larger radius arc on the upper barrel groove. That locked the barrel at the sides of the barrel. This was using a Caspian slide. I ended up having to do a full fit.

 

[Robin Hood]

The Nowlin semidrop in I used in the 10mm build the grooves seemed to exhibit a larger radius arc on the upper barrel groove. That locked the barrel at the sides of the barrel. This was using a Caspian slide. I ended up having to do a full fit.

I hear ya. I used a match fit Nowlin barrel and it dropped right in, but the slide had a .702” diameter. Caspian slides I remember have a tighter bore and therefore tighter lug grooves. My first build was with a .700” slide and I had to actually file the upper lug grooves on the barrel’s sides in order to get it to go up into the slide without pinching the barrel. It was Kart barrel. I also had to file the top lug grooves at 10 and 2 to get the barrel aligned with the fph.

The 2 slides and the previous build I just completed have a .702 diameter. I’m thinking that these barrels that are supposed to lockup based on a specific diameter of slide aren’t going to work for me. They seem to require a narrower fit to get the proper lockup for their 10 and 2 “design.”

All the barrel chambers have a .695” diameter and that’s from 5 seperate barrel makers. Some cut the lugs equal depth, some cut lug #2 deeper for clearance, but they all have different #1 lug depths. Nowlin barrel’s keep lug #1 at .040” and specifically say not to alter the lug cuts. The only modifications are to the hood and the barrel feet areas. It’s all quite interesting and confusing at the same time. You would think after 100 years people could agree that there is one best way of doing things(especially when it comes to a 100 year old design) so things like this don’t occur. Nowlin barrel’s are still made the same way they always have been AFAIK the only thing that has changed is the owner. I know that John had quite a bit of respect and knowledge so I would like to think that his ledgened still lives in his barrel design. The only thing I know that has changed is that they base all of their barrels off of a 6” and cut them down for 5” and 4”, then use a hand grinder or something to chamfer the muzzle. The shorter barrels don’t come with the nice 11 degree mirror smooth crown like they used to. I don’t like that this is happening, but I re-crown my barrel’s anyways so it’s not a total loss. It’s sad however that if a company is going to cut corners to save money they don’t drop their prices even a little.

The problem still boils down to what to do when you have greater lockup than .042” and need to use a #3 link and are also using a .200” slide stop. Was it really in JB’s design to make the bigger hole in the barrel link oval shaped in order to accommodate slightly deeper lockup dimensions? Wouldn’t this cause a problem with VIS contact? If you oval out the link to accommodate the SS it’s basically like going to a bigger link?

 

[Robin Hood]

Previous BarSto bbls I've fit, had upper contact at 10 o-clock and 2 o-clock. No contact at 12 o-clock.
Think 'v' block.

What slide did you use and what was the I.D.?