Chambers, it's time to call a spade a spade....

B

Bill Calfee

Gun Fool
Chambers, it's time to call a spade a spade....


CYA friends:


I'm probably going to upset some of the RFBR schmidts of the world, but, 90% of the chambers RFBR schmidts cut, are not perfect...

And I'm not leaving myself out, either.

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My buddy Wally, after being in my shop yesterday watching me cut a "perfect" chamber, has agreed to write about his experience, and post it here on CYA.

Everyone involved with serious rimfire accuracy will want to know what he has to say..


And what Wally does say in his story, will be his interpretation of exactly what he saw.......without any input from me as what to say....


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One other point.........finished chambers are more difficult to read for centering and the degrading of the leade, that are "as cut" chambers.


But, even with finished chambers, I guarantee you I could read every chamber in RFBR today, and show that 90% of them are not perfect.


And once again, I'm not excluding myself...


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So let's learn how to detect a "perfect" rimfire accuracy chamber.


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I spent about an hour today, taking close-up pictures of the live rounds that I inserted, then removed, from the "perfect" chamber I cut with Wally yesterday.

I must have taken 100.....


But only two show what I want......


Below are these two pictures........unedited.....

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As soon as I have time, I'm going to edit them, and point out some markers that show a "perfect" chamber.

This to go along with Wally's story, describing watching me cut a "perfect' chamber yesterday..


Your friend, Bill Calfee

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These two pictures are from about a hundred I took today trying to get a good closeup, are unedited, for now.....I'll edit them later..

One other thing....

If you're serious about rimfire accuracy, look closely at these two pictures and see if you can detect how these two pictures demonstrate a "perfect" rimfire chamber.......

Look closely, I'll give you a hint:

The wax serration grooves..........look closely.....what do you see?

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DSC08930.jpg


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Perfect Chamber

The wax serration grooves..........look closely.....what do you see?

Unless my eyes deceive me, the grooves tell the story. I won’t comment further until the guys way smarter than me weigh in.
Jerry Halcomb
 
Here's a closer look....

Here's a closer look....


CYA friends:


Here's a closer look.....

There's a ton of info in these two pictures.......


Your friend, BC

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DSC08930_1.jpg


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DSC08944_1.jpg
 
Additional......

Additional.......


CYA friends:

Here's another picture....

By the way, all of these pictures are of the same land cut in the bullet......

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Also please keep in mind, there's only .085" of engraving shown on this bullet.....

I will come to the final engraving length after I thread and fit the barrel to the action...


CYankee schmidts cut their chambers long, then come back to the engraving length they wish, as they fit the barrel and set the head space....


I'm posting all these pictures getting ready for Wally's story....



Your friend, BC


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In this picture I've doodled the correct engraving "footprint" that a Muller 4-MI leaves in the bullet......

In an unfinished chamber........


The final engraving length will have the "point" of the engraving behind the front shoulder.....

At the engraving length pictured, the "point" of the footprint extends past the front shoulder...

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Bill,

I have it roughed in. Gotta review to see what I forgot. Right now 4 single spaced pages so I think I covered it pretty good. It will probably be posted tomorrow. If you see a mistake feel free to correct it.

WS
 
Friend wsmallwood

wsmallwood said:
Bill,

I have it roughed in. Gotta review to see what I forgot. Right now 4 single spaced pages so I think I covered it pretty good. It will probably be posted tomorrow. If you see a mistake feel free to correct it.

WS
Click to expand...

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Friend wsmallwood:


The rest of the fitting of this blank is just basic machining.......and being careful......


The hard part is done.......


I'll probably do the rest of the machining sometime this week.....


If you can get away, you're most welcome to watch.......although like I said, the rest of the fitting is just basic machining.


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I know everyone will enjoy reading your thoughts.....


And like I advised you the other day when you were up here, feel free to say whatever you wish.....


Your friend, BC


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PS: I'll call you the day before I do the finish machining on this blank.....
 
Chambers

Chambers



CYA friends:


Now that Wally has posted his Chamber's Tale story, I'll get back to explaining some of these pictures...


Some things:


First of all, I've never posted on any of these internet sites a specific engraving length for my chambers..


And the reason, is because there is no "one size fits all" when it comes to the engraving length for a match rimfire chamber.


There are too may factors that go into determining the length of the engraving for there to be a "standard" length of engraving.



Reamer diameter and leade angle........bore and groove diameters......and style of rifling and how restrictive it is...


You can not have as much engraving in a 6 groove Douglas chamber as you can in a Muller 4-MI, simply because the 6 groove Douglas is so much more restrictive.


If you put as much leade engraving in a 6 groove Douglas as you can in a Muller 4-MI, after several rounds you wouldn't be able to get the breech bolt closed.


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Therefore, the only thing I've always stated about the engraving length I use in my chambers, is that I fully engrave my chambers, save for enough room for the CL to grow.

And that "full" engraving length varies, depending on the factors I've stated above.


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There"is" some degree of luck in cutting a "perfect" rimfire chamber.....


However it happened, the chamber Wally watched me cut last week is perfect.



If you look closely at this picture, see how the first band of wax serrations are squeezed narrower than the second band, and extremely uniformly squeezed.


What you see here is .085" length of engraving.......


It's difficult to see in this picture, but, the beginning of the leade is right at the rear edge of the first row of serrations.


And if this chamber weren't perfectly centered, and the bore and grooves extremely uniform, if the chamber was miss-aligned any, that first row of wax serrations would be squeezed unevenly.


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What is the shinny spot at the front edge of the front shoulder, in the land cut in the bullet?


That shiny spot is where the front shoulder of the bullet is just starting to enter the actual bore.


The reason that spot is shinny, is because the bore is lapped, so the lapping texture runs lengthwise in the bore, whereas the reamer marks run perpendicular to the bore.


It is an extremely smooth transition from the actual leade into the bore, but, the surface texture of the reamed leade and the lapped bore running 90 degrees to one another cause the different visual hues....


Once the chamber is properly finished, the hues blend together so as to become one visual hue.


This is why reading all of the markers that determine a perfectly centered chamber, must be done before the chamber is finished....


Don't get me wrong, one can still determine a non-centered chamber after it's finished.


More later.....

Your friend, BC

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Morning Bill, dumb question of the day......what does “CL” mean?

Thanks.
 
Friend LWZ

LWZ said:
Morning Bill, dumb question of the day......what does “CL” mean?

Thanks.
Click to expand...

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Friend LWZ:

The question isn't dumb...............CL stands for "combustion/lead"

This combination of combustion by-products and lead forms at the leade as rounds are fired using waxed, 22 rimfire ammunition.

Your friend, BC
 
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