Another piece of the puzzle.....

Another piece of the puzzle.....


CYA friends:


Back about 2005 or 2006 I had Tim North, Broughton Barrels, build me two of his standard 4 groove barrels profiled for my XP pistols.


They had an enlarged breech end for about 5 inches, then stepped down to about .825" for the balance of the barrel.


A couple years later I decided to fit one of these to SPEC 4, Merlin....


And the one I fit on Merlin turned out to be killer, with Todd Wooten winning a PSL with it.



Anyway, I never fit the other barrel because it was very cooked.....


I don't believe I can determine how straight the bore of a barrel is, perfectly, but, I can point a barrel at the contrasting edge of something, like a white target against the green grass background and see the shadow line down the bore....


If I move my eye around and that shadow line seems to extend from breech to muzzle, I suspect the bore is fairly straight.


OK, here's why I'm telling you this:


This second 4 groove Broughton, that is really crooked on the outside, seemed like it had a fairly straight bore since a shadow line seems to extend from the muzzle to the breech when I look through it.


But it was too crooked for me to fool with, because if I turned it down to straighten it, the OD would probably go down into the .700" diameter range.


So it sat for years....


_______________________________



Some years back I decided to run a spearment with this crooked Broughton.....


I machined cooling fins into the enlarged breech end to see if that might help displace heat near the chamber and keep the viscosity of the wax more uniform throughout the entire bore...


I only shot it one time, never did cut extractor slots, and it shot so-so......


Course my machining the cooling fins distorted the bore, so I really needed to re-lap it, but never did....


So it laid around....


__________________________



Since I'm building myself a new MD-PAS triple pistol, and need a barrel, and remembering how killer the one on Merlin is, I decided to profile this barrel down, remove the cooling fins, and reduce it enough to straighten the outside......


I put a maximum reduction size limit of .775".......


In other words, if I could straighten it out without going less that .775" I'd try it on my new pistol....


CYA friends, I have to leave for an appointment.....


I'll finish this story later......


Your friend, Bill Calfee


_______________________


Here's the Broughton profiled with cooling fins......I never did cut extractor slots.......which is good as things have turned out.

Walking in high cotton after yesterday at the range...

Walking in high cotton after yesterday at the range...



CYA friends:


Too much to discuss at one sitting.....


Here's a couple of pictures from yesterday at the range..


____________________________



This has been a learning experience and a conformation of existing knowledge experience..


Before anything slips my mind, here's what I want to discuss about re-profiling the this 4-groove Broughton, which is the twin to the one on SPEC 4, Merlin.


1. How the profiling went.


2. Lesson maybe learned about "straight" barrels.........(maybe)


3. MD requirement for very flexible barrels.......( a re-conformation)


4. Discovering that this barrel may wind up with the same consistency as the one on Merlin....

___________________________


Todd Wooten called me after he won his PSL, with Merlin.


He said Merlin was the most consistent rifle he'd ever shot......


His only complaint, was that he had to hold it, because with a tiny .825" diameter barrel and an angle butt stock, he probably did have to control initial retardation someway.......and holding the rifle will do that.


But his main point was how consistent that Broughton on Merlin was.


He said it went exactly where he pointed it, every time.....it simply didn't throw shots.


________________________



I'll get back to this later....


Your friend, Bill Calfee

_________________________


Here's the barrel fit to the triple lug action I'm building my new MD-PAS triple pistol on....


This is the same action, and Peightal stock, that Robert Oates kicked out that amazing PSL card with year before last.



Before it slips my mind, if you look closely, right back of the MD, you can see a line around the barrel....


I had already turned my muzzle target on this barrel back a few years ago when I chambered and crowned it...


So the first two and a half inches behind the crown were already on centers with the bore.......so I did not turn this part of the barrel...


I only turned from the ring back to the breech....


By the way, I turned the barrel down without touching either the chamber or crown, as they were perfect.

Here's my test target........


It was cold yesterday, but sunny, and I got my feet soaked putting up the target, so when I got done I tried to take this picture through the Leupold Comp.


I only shot about 25 rounds......but that's all I needed to determine if I'm going to cast a lap and re-lap the bore after my profiling.


And yes I'm going to re-lap the bore.......


More details about all of this later...


By the way, there's 8 rounds in the group behind the cross hair..........


If you look down at the bulls, the vertical hair is resting on the left side of them.......


If you use your imagination, and bring a line up from the right side of the bulls to the 8 shot group, you can see that all 8 of those rounds will make ARA 100's.


CYA friends, yes I did distort the bore with my profiling, and yet this thing now shoots like this, while using the rejected test lots that Tom Wilkinson and Chuck Morrell sent me a couple years ago.......


What's this thing going to do when I re-lap the bore, and get some of that killer ammo that's finally being brought into the country?




The shots in the sighter bull to the right are where I sighted in......

I shot the first round, after bore sighting, down on the blank backer board, then moved the cross hairs to that shot, then fired on the right sighter bull....

What looks like a single round low, is actually two rounds fired RTB....

I then clicked the cross hairs down to those two rounds, then fired several rounds in the group above them..


I had set the HH/MD to 250, because the barrel is very flexible.......and had vertical...

So I turned it out to 300, and then shot the 8 shot group behind the cross hairs.

I'm so cited CYA friends

I'm so cited CYA friends


CYA friends:


I put the ARA 100 scoring ring around the 8 shot group I fired yesterday with the 4 groove Broughton that I re-profiled so I might be able to use it for my new MD-PAS triple pistol build.

As you can see......all 8 shots easily make ARA 100's.


Can you imagine what this Broughton will do after I re-lap it!..........................bc

Holding in the lathe

Mr. Calfee,

How are you holding the barrel in the lathe? I have a dummy female threaded section that I screw onto the tenon and place Teflon washers between it and the shoulder, then the threaded section has a 60° angle cut on the outside end to catch on a live center. Then I put some brass shim stock between the chuck jaws and my muzzle target, clamp down and this is how I hold a barrel to polish it in the lathe. I in no way would trust this to make cuts on the OD of a barrel but works like a champ to polish one.

I just wondered what arrangements you used to keep from putting centers into the ends and if you completed the profiling all in one setup without having to flip the ends around. I am sure you used the steady rest but unsure where you had the barrel placed in it. May be dumb questions but am unsure how I would go about re-profiling an already finished barrel.

Tad

Friend Tad E

Tad Earhart said:

Mr. Calfee,

How are you holding the barrel in the lathe? I have a dummy female threaded section that I screw onto the tenon and place Teflon washers between it and the shoulder, then the threaded section has a 60° angle cut on the outside end to catch on a live center. Then I put some brass shim stock between the chuck jaws and my muzzle target, clamp down and this is how I hold a barrel to polish it in the lathe. I in no way would trust this to make cuts on the OD of a barrel but works like a champ to polish one.

I just wondered what arrangements you used to keep from putting centers into the ends and if you completed the profiling all in one setup without having to flip the ends around. I am sure you used the steady rest but unsure where you had the barrel placed in it. May be dumb questions but am unsure how I would go about re-profiling an already finished barrel.

Tad

Click to expand...

______________________


Friend Tad E:


To draw file and polish my barrels I have a fixture made up that resembles a lathe....


It spins the barrel at 1500 RPM.........I can't get that kind of speed out of my old lathe, plus, I keep polishing grit off the lathe bed.


I use a spud in the chamber end that has a 60 degree center in it, and, I use a fiber washer between the shoulder of the spud and the face of the barrel to cushion it.


I clamp a small lathe dog on the relief at the starting of the threads on the tenon, to drive the barrel....


On the crown end of the barrel I use a leather washer that rides on a live 60 degree center that spins with the barrel.


With this set-up I can polish the entire barrel end to end.



The way you're doing your polishing is excellent.


______________________



Now, for the way I re-profiled this Broughton, that was chambered and crowned:


I had my muzzle and breech targets on the barrel, so both ends were centered with the bore perfectly, already.


My muzzle target was about 2 1/2" long......so I did not need to re-profile it......


Therefore, I ran the muzzle in my steady with the rollers torqued at the minimum.


I put an aluminum shim around the threads on the breech end and chucked it in my 4 jaw.


Since the breech end also has a target already machined, I could dial it in perfectly with the 4 jaw.


I left the barrel shoulder pulled away from the face of the chuck jaws slightly, so I could machine all the way to, and past, the edge of the shoulder proper.




I now had my barrel set up allowing me to machine all but the muzzle two inches.....which I left as is.....@ .820" diameter.

_______________________


Tad, I had decided I would go as small as .775" in diameter, if necessary, to straighten this barrel.


The barrel was about .828" in diameter to start with........and of course had the enlarged breech end which I had previously machined cooling fins in for an experiment.....


I first machined the breech end down to the same size as the rest of the barrel.


I then started making full length passes of about .010" each....


And of course on the first two passes I only cut the high side of the crook in the barrel...


I kept at it, about five hours total, until on my last pass I had straightened the entire barrel except for one spot about an inch long and maybe a tenth of an inch wide where the original polish on the barrel could still be barely seen.


I stopped.....


One important thing to keep in mind:


When one machines a long barrel that is crooked, even when you get to the point that your lathe bit has cut the entire OD of the barrel full length, the barrel will still be slightly crooked, since the lathe bit deflects away from the thick side....


So what I did on my last pass, was to just scrape the barrel enough to remove that last little bit of the high side.


This actually took two passes to do......


Each pass took about 25 minutes....


_______________________



Now, here's the kicker....


The barrel wound up at exactly .800" in diameter......and I was so tickled.


I mean, this is perfect.......and I really did not think it would clean up that big........


So to clean up this crooked barrel required .028".......



_______________________



Tad, I only shot about 25 rounds through it after I re-profiled it, but, I've done this for so many years, that after a while one instantly knows whether a barrel is going to be consistent or not....


When I fired that last 8 shot group, after the first four of five shots I knew the rest would go in........


The only reason that last group didn't have more rounds in it, is because I ran out of that lot of ammo...


If I'd had ten more rounds I'd have fired them all in that group, and I'll bet a dollar bill they would have all gone it...



This barrel now acts like the barrel on SPEC 4, Merlin, back 12 years ago when I tested it.



And I've not even re-lapped it yet.........



Tad, I'm very cited about this barrel now......



The bore, as best as I could tell, was fairly straight on this barrel, the outside was simply crooked....


Which means an uneven distribution of material around the bore....


Now both the bore and outside are straight........and this thing shoots...


So have we maybe learned something?


Your friend, BC


___________________


If I'd had them, I bet I could have put 25 rounds in that group and it would not have enlarged any....


And what blows my mind, is I have not re-lapped this bore, and yes, it was slightly degraded from the re-profiling, especially in the breech end for about 4-1/2 inches...


Before I re-profiled it I slugged it, so I knew how it slugged....this is how I know the re-profiling degraded the bore slightly.





_________________


If you look closely right back of the MD, you can see where the barrel steps up from .800" to about .820"....

Thanks for the explanation Mr. Calfee. I really appreciate the time you took to do that.

Tad

Friend Tad E

Tad Earhart said:

Thanks for the explanation Mr. Calfee. I really appreciate the time you took to do that.

Tad

Click to expand...

________________________


Friend Tad E


You're welcome.


Tad, I left the last two inches at the breech about .008" larger than the balance of the barrel....

This gives a little more barrel shoulder, although, an .800" diameter shoulder, with a .750" tenon, gives a .025" shoulder, which is gobs plenty.


So the barrel shoulder is about .808" in diameter.


Below is a picture of Merlin, and as you can see, even though the barrel is .825" in diameter, the shoulder is enlarged.


_____________________



Broughton's original 4 groove barrels were over .2220" groove diameter...


I was talking with Tim North one day, when I asked him about making some smaller groove diameter barrels.


He finally did.....


So I ordered two of them profiled for my XP pistols, which meant they had an enlarged breech end for the giant XP thread pattern.


And I ordered them with the enlarged breech end longer than normal.


I did this to allow me to taper lap the bores, then be able to cut off the restricted part of the bore at the breech end, and still have enough enlarged length to fit them to my XP pistols...


To fit a barrel to an XP requires about 4 inches of enlarged breech end.



If you look at the picture of Merlin, with a 1 inch Turbo tenon, you can see that I cut off all but a couple of inches of the enlarged big end.



But on the barrel I'm using for my new pistol, since I wanted to do the cooling fin experiment, I wound up chambering the original end of the blank.


This left me with enough enlarged length to incorporate the cooling fins...


And to allow this extra enlarged length, required some very creative lapping, since I was chambering the original breech end of the entire blank.


__________________________


If there's a fly in the ointment here, with this barrel, it's that I did not do the chamber end like I did on Merlin's Broughton.


When a bore is properly jig lapped both ends become restricted......


This is great for the muzzle end, and death to accuracy for the breech end....


With the Broughton on Merlin, I cut the restricted breech end off after taper lapping.


This one I'm using, I didn't.........


So I've had to be very creative in the way I've handled the breech end on this barrel.



And I've got to lap the bore one more time, yet.



Tad, if I could start from scratch with this twin Broughton to Merlin's, I'd do it like I did Merlin's.


Although, even with the bore slightly distorted from the profiling, and me chambering the original breech end, my range test was awesome with this Broughton.


___________________



Oh, by the way, I got my stock epoxied together today, and I just checked it and the epoxy cured perfectly....


I still have to install the rear bedding pillar, then machine my spacer, and attach my bi-pod rail, and I'll be ready to actually shoot my new MD-PAS triple pistol.

And of course I've still got to re-lap the bore.


I'm also going to convert a factory trigger to three lever, like the Bond.


When I do this I'll take pictures and post them....


Jeff Patterson is going to have to convert a trigger for his pistol, too.....


So I'll probably have him come out when I do mine.



Man I'm cited.



Your friend, BC


____________________________________


If you notice the 825" Broughton on Merlin has an enlarged breech end.