Threaded Muzzle, Calfee

K

Kathy

Guest
My centerfire firends:

I love accuracy.....

Two things will be different in the development of centerfire muzzle devices, (tuners) than for rimfire.....once these two factors have been confronted, correctly, centerfire muzzle device (tuner) results will be exactly the same as rimfire.

First, is the safety aspect which requires larger barrel breech ends....centerfire folks will not have the luxury of being able to use straight, non tapered barrels as we can in rimfire......testing and experimentation will shortly solve the barrel profile problem.

The second probelm is the attachment of the muzzle device (tuner) to the muzzle of the barrel. Because of the recoil, some method other than clamping is necessary....

One method of attaching centerfire muzzle devices (tuners) that will need to be eliminated is the threading of the barrel at the muzzle.

Yesterday, Mike Sherrill and Mark Meadows were in my shop on some business. We got to playing with a used rimfire benchrest barrel, at one time a killer, but was damaged in the bore about 12 inches from the chamber. The three of us were slugging the bore and feeling the damage.....

When they left my shop I got to thinking......the barrel was damaged, not competitive, so why not run a littlel experiment......

This barrel, accidentally, will screw into my NO. 4 SPEC rifle, which is under construction, and headspace properly. I screwed the barrel in, attached my slave muzzle device (tuner) and carried the rifle to the range....I sighted it in then fired 4, 5-shot groups at 50 yards. Eley Red Box lot 1007-03084 ammo.

I then removed the barrel, set it up, then, using the targets I always machine on my barrels, in my steady, to keep from using a center in the crown, I machined a 1 inch long, 32 pitch thread at the muzzle.....I ran the depth of the thread to .020".....I wasn't trying to fit the thread to anything, I just wanted a thread at the muzzle.....

I screwed the barrel back in, using the same slave tuner at the same setting and the same ammo, carried it to the range and fired 4, 5-shot groups at 50 yards......

It took me about an hour and 20 minutes to do this test.....shooting conditions were, as best as I could tell, exactly the same for both tests...

I sent the picture of the test targets to Mike Sherrill. I asked him to post the picture on this thread when he has time....it may not be till Monday, I'm not sure he can post stuff on the week end....

My centerfire friends, you can judge for yourself when you view the test picture.

I love accuracy...

Your friend, Bill Calfee
 
My friends

My friends:

I got to thinking, some of you might want to see the barrel itself.....so I took a picture of it and sent it to Mike.......I don't think he has access to posting on the weekend...sorry...

Anyway, you will see a ring on the barrel back of the thread....this is where the steady ran so I wouldn't have to marr the crown with a lathe center...

My friends, I'm doing all I can to help.....I am so booked up there is no way I can drop stuff to work with you centerfire folks on your muzzle devices, (tuners).....but, I'm doing as much as I can find time for...

You guys got a couple little problems that must be worked out...that's different from rimfire.....but it's going to happen.....

Your friend, Bill Calfee
 
Tuner

A perfect tuner design ... $1,000,000
Can't post a picture on the internet ... Priceless
 
Another typical Calfee expirerment. Goes somewhere but we don't know where. And again no proof till later. Give us a break Bill...
 
Geeeze

If you'd tell me what you're talking about I'd be able to consider your information....... what kind of terrible accuracy problems does threaded muzzles cause?

Yesterday at Denton I watched Mike Stinnett working up a load for his new 30PPC. His best group was a .050". How much better could he expect to do if the muzzle didn't have those pesky 32tpi threads out there on the .900" muzzle of that 17 twist Shillen and that Shadetree Tuner attached?

Shelley
 
shelley,

and don't forget the conditions were perfect!! FOR DENTON!
 
Shelley

It is a shame that Mike went and ruined that great barrel by threading the end, and putting some old "off brand" tuner on the end. You should have went for that "proven" concept that is shrouded in mystery.
Of course, we all could be jumping the gun here. Maybe threading the end of the bad Rimfore Barrel cut the groups in half on Bill's Rifle.
Did any body by chance catch that "the shooting conditions looked the same, as best I could tell" in that originol post in this thread.
I was not aware that safety was a big issue in the size of 100-200 yrd Benchrest Muzzles either. I have seen 300 Ultra Mags with muzzles less than 5/8 inch ......jackie
 
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As I remember, there is little pressure left in the bore of a .22 rimfire after the bullet has moved 16-17 inches. At least, there is no velocity gain with a longer barrel, so there can't be much pressure.

And lead has no elasticity. So if Bill Calfee says a slight opening at the muzzle end causes harm with a .22 LR, I'd take his years of experience on that.

But neither of these is true for CF. You guys are just beginning to experiment with barrels having thread at the muzzle. 1,000 yard shooters have been doing this for years; 80 grains of powder behind a 200-grain bullet in a 17-pound rifle almost requires a muzzle brake. And while 30-inch barrels are common, there is still enough gas pressure remaining so that there is an increase in velocity with an even longer barrel.

Now if the braked .30s wouldn't shoot with the unbraked 6mms, we'd have something to look at. But they do.
 
Charles E said:
As I remember, there is little pressure left in the bore of a .22 rimfire after the bullet has moved 16-17 inches. At least, there is no velocity gain with a longer barrel, so there can't be much pressure.

And lead has no elasticity. So if Bill Calfee says a slight opening at the muzzle end causes harm with a .22 LR, I'd take his years of experience on that.

But neither of these is true for CF. You guys are just beginning to experiment with barrels having thread at the muzzle. 1,000 yard shooters have been doing this for years; 80 grains of powder behind a 200-grain bullet in a 17-pound rifle almost requires a muzzle brake. And while 30-inch barrels are common, there is still enough gas pressure remaining so that there is an increase in velocity with an even longer barrel.

Now if the braked .30s wouldn't shoot with the unbraked 6mms, we'd have something to look at. But they do.
Click to expand...
Charles E, since I am following you along and being a pest, a 300 Lapua Mag with 80 grains AA 3100 and a 210 grain Berger is about 11,600 psi at the muzzle of a 30" tube according to Quickload.
 
My centerfire friends:

My centerfire friends:

I don't exactly know how it got started about me competing at the Super Shoot....but it's kinda cool in a way, for me, that is...

MY friends, you don't need to read this...I'm just re-living a memory..

If I would have known 30 years ago, as me and John Boardman drove away from the 77' Super Shoot, that I'd still be alive, and, I'd be in a position to have my shooting that year re-lived throughout the entire world, no way could I have believed it...

Before I proceed, I ain't no shooter, never have been...

Anyway, oh, I've already described my shooting on another thread so I won't bore you with that again.....

Anyway, when I went to the SS that year, I carried with me a Sporter rifle, I'd made, for Sal Ventimiglia......Oh, I'm sure most folks know this, but Sal was the founder of Shooter's Choice, bore cleaning solvent. Sal, at that time, ran a gas station in Cleveland and specilized in brake work....matter of fact he gave me a good tip on a brake job I was getting ready to do on my personal car.....

Sal was a little feller, as was his wife....I tell you this cause one evening he and his wife took John and myself to dinner. It was one of them places where you ordered your main meat dish, then went up and filled up your plate from the buffet.....anyway, Sal and his wife ordered ham steaks.....

We all went up and filled up our plates and Sal and his Wife had their tray stacked high...then they brought out them ham steaks and they lapped over the side of a common china plate about an inch all the way round....I mean, Sal and mama was little tiny folks, what in the world was they going to do with all that food?....well my friends, they ate it, all of it, then got dessert, MAN!

Anyway, the first day at the SS I carried in Sal's new Sporter...gave it to him then John and I went to unloading stuff in the new main building.....A few minutes later I looked across the big room and there was Sal with a collimator stuck down the muzzle of his new Sproter.....I screamed at him, "Sal, what the h--l are you doing!" Man, scared him to death.....I went over and explained that we never stick anything in the crown of a fine barrel.....the muzzle is where the final bit of accuracy comes from...(this is one reason we never reduce the size of the muzzle of a finished, accuracy type barrel, or thread it)

The Sporter I had built for Sal was an entirely new design of mine....I had Brown Precision build me a fiberglas stock, leaving out all the hard fill, foam only, the model for a 12 Inch 1.750" sleeve, which reduced its weight to 15 ounces...I then skeltonized an 8 inch aluminum sleeve, on a XP-100 action, glued in of course, using a full heavy varmint taper barrel, and meeting 10 1/2 pounds.......when Sal went to weight that rifle it got a bunch of funny looks, a sleeved, heavy varmint barreled Sporter?

I had not talked to Sal in almost 30 years...about 6 months, or maybe a year, before his death, I got a call from him.....he wanted to drive down to my shop and bring that Sporter......he said it was the most accurate gun he ever owned and he wanted me to look at it and maybe install a new barrel, this time in PPC......My little buddy died before we could do it......

I drew four checks at the 77 SS......I went back and looked at my paycheck stubbs for 77'....in todays money, my four checks would amount to about $2300.00 roughly.......it was enough to pay for my entire trip, lodging, meals, some brandy.......oh, something else was interesting on that trip...Me and John decided we wanted some brandy....but In Ohio back then, I don't know how it is now, but the State ran the liquor stores.....you walked in, there was a guy behind a counter, no liquor on shelves or nothing, he took your order, then came back out with your brandy.....I think I like the way Indiana does it better.....

Three folks beat me for the LV grand that year....they shot better than me and had better equipment....I don't even remember who won the LV....I do remember Larry Baggett won the two gun........So Larry, if you get to read this my friend, Congratulations again on that 77 SS Two Gun Championship.

Thanks my friends for allowing me to re-live a sweet memory...

Oh, I'm sorry, but, threading the muzzle distorts the bore....that's just a fact.....there is absolutely no way I'd ever thread a fine rimfire benchrest muzzle.....my friends, I think there's a way around having to do that threading. Roger von Ahrens has come up with a very clever system....I'm sure when he's completely satisfied, he will announce it........

Your friend, Bill Calfee
 
Bill
Did you try to re-tune the barrel after threading it? Since you removed material in threading the barrel it seems to me that you whould have changed the tune.

James
 
Bill

You need to start using Cut Rifled Barrels.
That being said, I doubt you could get one major custom barrel manufacturer to agree with your assumption. .......jackie
 
My6 friends

My friends:

Talked to Mike Sherrill: He said he'd try to get the pictures posted tomorrow..

Also, Mike has been testing one of RvA's solid muzzle devices.....I think he will be posting pictures on the rimfire side on his thread he started a couple weeks ago......I kinda think you folks will find Mike's work interesting...

My friends, thanks again for allowing me to re-live one of the memories that has made gun making so very special to me these last 34 years....

My centerfire friends......A muzzle device, "tuner" of the proper weight, and, properly placed, ahead of the muzzle, will "stop the muzzle", thereafter, no further adjustment of the muzzle device (tuner) is ever necessary...

Oh, friend Chisolm.....you made a very good observation....no, I did not re-set the muzzle device....I have my doubts that the very little weight loss, especially right at the muzzle, could have caused the difference in the two test targets.........maybe a little.......but, this ain't the first time I've run tests like this.....no my friend, the difference was caused, at least most of it, by me distorting the bore by threading the muzzle......but, let me give you your due; some small percent of the difference may be from the metal removal, from threading.....

Friend Chisolm, You made a serious point.....it deserved a serious answer...very refreshing, thank you.

Your friend, Bill Calfee
 
I don't know Bill

It just might have affected the tune.
With my tuner, which weighs a tad over 5 ounces, and is on a 36 pitch thread, I can realize an affect with as little as 1/4 turn. That is a .007 advance or retract.
Weight wise, what is the difference in weight transfer in relation to the barrel with a 5 ounce object moving just .007 inch. It sure isn't much, and I would bet it is less than the weight of the material you threaded from the end of your barrel......jackie
 
Hal

I talked to the Shilen People at our match at Tomball, and they said that they profile their barrels, which are all buttoned rifled, after they are rifled.
There are a lot of "old wives tales" floating around Benchrest as to what turning steel off of barrels really does to the ID. If they were all true, it would be amazing that any of us could ever get two bullets to touch......jackie
 
The effect on bore diameter change (or lack of) has more to do with the stress condition of the barrel and the turning tool cutting properties.

Barrels that are not properly stress relieved and single point cutting tools that impart heat or surface stress (negative rake, K-Land, etc) into the barrel can be culprits of bore diameter change. Rifling methods probably have no effect on after-rifling modifications.
 
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