Threaded Muzzle, Calfee

There may just be something to removing a bit of material by threading the muzzel. Last fall I had about 2.5 inchs threaded 36/in on a fairly good shooting Bartlein barrel. The barrel had about 700 or a bit more rounds thru it. I am kind of like Bill here, I ain't no great shooter. After threading was done and before installing a 5.5 oz MD (muzzel device) I shot a couple of groups with one of the best loads that barrel shot. Both were quite a bit larger than what it normally shot. Then I screwed on the MD. Not having a clue as to where to stop. Shot a group....it was somewhat better than the other 2 for sure. Then I turned the MD 1/4 turn in and the group got much smaller, in fact as small as the barrel ever shot. Then I turned the MD in about 1/8 more and the group opened up a bit. Turned it back to the 1/4 spot and that group was just about like the other one shot with 1/4 turn in from the original setting. Since then I had the MD off to reduce the weight as it had put me a bit overweight. The rifle now is at 10# 7.8 oz. So screwed the MD back on but quite a bit farther onto the barrel. Testing again showed me that 1/4 turn total got it right back in tune. Beats me, but I figure with this setup it is never more than 1/4 turn out of tune.:confused: But I do know that it works.........Donald
 
Threading does not hurt

After installing well over 1000 muzzle brakes I can definitively say that properly and carefully threading a muzzle is not a killer on a good barrel.

The threaded .9 barrel on my LV with the Beggs tuner is sure lots of promise--and it looks like some good shooting weather will be here soon to see just how much promise it has.

Jim
 
jim said what i was thinking

bill we are talking about much larger muzzles on centerfire. aren't we recompressing the barrel when the brake is screwed on tight ? one thing that i found is the weight hanging off of the front if the crown area has to be as rigid as the barrel it self,mounting a tuner the same way a brake is mounted keeps that rigidity,at least at the joint ,then it falls back on the tuner body rigidity. the barrel will not bend as much and only the tuner will .it must bend as a one with the barrel for this style to work in my eyes. this syle of tuner is like a lever on the barrel, it seems if it cant bend the barrel then it cannot produce the the calfee affect as well or to the extreme as a tuner mounted over the muzzle just clamped on,or glued.just what it looks like to me bill.still learning everyday. tim in tx
 
In talking with the fellas at Rock Creek Last week about Palma Barrels the information I got from them there was that on Cut rifled barrels, no additional stresses are added to a barrel by single point cutting the relief in the last 1 inch of barrel for the aluminum clamp type mount for Alan Warner type Sights, but on button pulled barreld you had better grind the barrel rather than single point cut.

Friend Kathy, have you found this to be the case with rimfire barrels you use, and if so would grinding rather than single point cutting help with the threading process as is needed with the Beggs tuner? How about you Gene, have you seen any problems here?
 
Bill's Pictures

Here's the pictures Bill requested me to post for him. I'm sorry it took so long, unfortunately I don't have a good way of posting them on the weekend.

Mike Sherrill

03-24-08_Test_Threaded_Muzzle.jpg


Threaded Muzzle

03-24-08_Threaded_Muzzle_target.jpg


Bill's Test Target
 
Cabin Mike said:
Here's the pictures Bill requested me to post for him. I'm sorry it took so long, unfortunately I don't have a good way of posting them on the weekend.

Mike Sherrill

03-24-08_Test_Threaded_Muzzle.jpg


Threaded Muzzle
Click to expand...

Was that burnished ring about 2" behind the muzzle caused by steadyrest rollers? If so, iss not goot!!
 
Bill

-I agree with Jerry

I do not like the look of that steady rest rub--it certainly built some heat there.

Also--the populations and patterns of the before and after do not show what I would see as a definitive difference--they both have problems.


Paul

I have measured before and after threading large muzzle diameter and fairly medium muzzle diameter button rifled barrels putting fine threads on (32TPI) and have found no change in bore or groove size.

I have seen a change when drastically re-profiling some barrels that were button rifles and that may have had questionable lapping and heat treating to start with.

Jim
 
I scanned the target(Picture) and made these assumptions:
1-.50" for outside edge to edge on ARA Bull.
2-50 yards for distance.

No reason for doing this, just bored and playing around while my tractor warms up.
 

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Equaly Bad

I doubt I would base any conclusions on those groups from either session.
Both show a barrel that is a horrible state of tune, or just plain bad. Two bullet holes of verticle, and tons of windage.
If you are going to do a test, would not it be better to use the best of components, and in an inviroment with better controled conditions, (ie,flags, and a good shooter), before coming on this site and making some sort of declaration.
After all, this is Benchrest.com........jackie
 
Friend JerrySharrett

Friend Jerry:

If you read the start of this thread I describe the ring behind the thread..

I use a roller steady.....and no, there was no heat from the rollers....I very carefully adjust the rollers so I can spin them with finger pressure when adjusted against the barrel.....I used light cuts, very light, so the lift of the cutting tool was not enough to cause heat at the rollers....the reason I use rollers is there is no heat on the barrel like there is on solid steady contact points.....

My friends, this is not even a full depth thread......I only plunged .020"......

There is absolutely no way I'd ever reduce the outside of one of my rimfire benchrest barrels at the muzzle either by turning or threading....

I posted this information to assist....it's a free country, I think, so you're absolutely free to thread all the muzzle you wish......

My friends, I'm a funny guy.....I want the whole pie....threading the muzzle of a fine barrel takes a slice out of the pie.......

I have a feeling threading muzzles, for muzzle devices, will die out before long.....there's other shooters who want the whole pie too...

Your friend, Bill Calfee
 
Kathy said:
Friend Jerry:

If you read the start of this thread I describe the ring behind the thread..

I use a roller steady.....and no, there was no heat from the rollers....I very carefully adjust the rollers so I can spin them with finger pressure when adjusted against the barrel.....I used light cuts, very light, so the lift of the cutting tool was not enough to cause heat at the rollers....the reason I use rollers is there is no heat on the barrel like there is on solid steady contact points.....

I have a feeling threading muzzles, for muzzle devices, will die out before long.....there's other shooters who want the whole pie too...

Your friend, Bill Calfee
Click to expand...
Bill, I'm not trying to be picky, just pointing out to folks new to lathe machining of some potential perils. Your roller steadyrest can cold burnish a tight place in the bore. It can also cold work the barrel between the rollers and where the turning tool contacts the barrel by creating a flex induced stress since the barrel DOES bend SOME as you put cut pressure on it.

I know for sure you know how to check for a bore constriction after machining but I have started out enough students in Machine Tool Technology and Drafting and Design Technology to know sh*t usually does happen. Every precaution and consideration for the mechanics of materials is worth presenting to them.
 
Bill

We all want the whole pie and as I said before and Jackie has stated above--the test proved nothing. The groups are equally as bad before and after.

I appreciate your intuition and innovativeness--however, the testing techniques and test reporting could improve. I am glad the pictures were posted as it showed that a real difference for a threaded muzzle did not exist.

Jim
 
It occurs to me that if one were to recess the crown to a point behind the threads, then whether or not the threads affected the ID would be of no consequence whatsoever. But then again if one were to mount a trued sleeve to the outside of the barrel, the steady rollers would not have left a mark either.
 
Jim

This would be funny, if we didn't take this so darned serious.
Bill has to understand that his name carries a lot of weight, and impressionable novice shooters will log onto this site and see that Bill Calfee states that threading the end of a barrel will kill accuracy.
We wonder how "old wives tales" get started. This is a classic example........jackie
 
Single point versus grinding

Just wanted to add a clarification about muzzle diameter change and removing metal from surface.

If a button rifled bore changes size or shape due to removing metal from the outer diameter of the barrel, grinding the material off versus single point turning it should make no difference. The model of stress relaxation for those residual stresses is that the material that is containing the barrel bore is a hoop stress. Whether you remove by grinding or by turning, the material that contains the hoop stress is removed and the bore might change size. If the barrel has been properly stress relieved, that effect should not be seen.

Jim
 
Jim
Absolutely correct. And the only way I see of avoiding that (outside of accepting the bore change will happen, with the intention of trying to replace the removed stress with some form of clamping action - which I'm not convinced will work repeatably), is to allow some extra meat be left on the raw blank beyond where the crown should be. And use this material to incorporate the "Muzzle device" into the profile from the beginning of the barrel design. This avoids the issue of bore distortion from both the material removal aspect as well as the over clamping/over-torquing constriction results.
 
My friends

My friends:

Been busy testing SPEC 4.......I got to eat...

Just looked at my (this) thread.......man!

My friends, when one reduces the diameter of a fine target barrel, at the muzzle, after the bore is finished, the bore is distorted..

It matters not whether you reduce the diameter by turning the barrel smaller, or, threading it.....the bore is still distorted....

It matters not how the bore was rifled....cut, button, broached, scraped...it matters not.......if you cut the barrel at the muzzle, after the bore is finished, the bore becomes distorted....which affects accuracy....

I'm sorry if this information upsets some folks.......you're just going to have to be upset, I guess......because we can not change the physical universe..

I want the whole pie........the days of following what folks have done before, blindly, with no conformation, are gone....

We NEVER cut the muzzle of a fine barrel, for any reason, AFTER THE BORE HAS BEEN FINISHED, without distorting the bore. This affects accuracy.

I am very comfortable with the test results I presented on this thread.

Shortly, threading the muzzle of a fine barrel, to attach a muzzle device, (tuner) will be a thing of the past.

The idea is to "advance" accuracy, not just maintain the "status quo".....

Your friend, Bill Calfee
 
What's behind

.........door number three? By reading a lot of your posts I am not sure if I am afoot or horseback? Seriously you have me quite perplexed in this muzzle device and any form of attachment,maybe you would be so kind as to put this into simple terms so that I may get a understanding as to which way to NOT waste my time IF you've been down the road already and truly wish to support Accuracy for the simple folks. Jan
 
Good Grief

Calfee Quote: "I am very comfortable with the test results presented in this thread".
That Statement speaks volumes..........jackie
 
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