Tuner/Snubber/Muzzle Brake......pictures

[Greyfox]

This tuner assy including the lock nut weighs 7 ounces. It's on a 32 pitch thread.

I did not make it out of aluminum because I thought the thin sections between the holes might succumb to the heat and erosion of the blast.

The large shift in impact took place with about 1/4 turn, which is a little over .007 advance. That amount of shift is what lead to my hypothesis in Post #4.

I'll be interested in learning what is the reason for the large shift in POI. I have had a POI shift of 3/4" @ 100 yards on occasion with one or two barrels and when you go out to 200 I can see things like that happening. I will say that in my experience 1/4 turn is a huge change for a tuner. However, in many cases it will just repeat the same pattern that you had at the previous spot. Since you appear to have the accuracy you're looking for I don't know that it matters, but I, for one, would like to know.

Rick

 

[John Kielly]

Wonder if it's anything to do with the flat(s) on the lock nut?

 

[alinwa]

It might not be the tuner, but something else that isn't quite balanced left/right. The whole system produces a characteristic muzzle angle pattern in time (like in the figure below) that speeds up when the tuner is turned in and slows down when the tuner is turned out. The bullet exits at a different point on the pattern when the tuner is adjusted. If POI shifts laterally, it means the pattern has a sideways component at the point where the bullet exits. The best tune is where muzzle angle is only moving vertically with exactly the right speed. Another way to test for this is a ladder test. If the muzzle angle pattern is vertical when the bullet is exiting, then the ladder test changes with powder charge should have no horizontal component (and zero vertical for perfect compensation).

Keith

Thank You Keith....."the whole system" with all it's variables. Like balance and stock feedback, and scope ht and bedding angle(s) and flex/windup/torque effects, and, and, and....... this is why I index my barrels, and even re-clock at times.

In alinwaworld sideways=bad

Jackie..... a properly set up muzzle brake will "strip away" gases and absolutely will not cause accuracy to deteriorate. MANY of the accuracy problems associated with muzzle devices stem from improper design spec or improper installation. Harold Vaughn spends time explaining how the threaded joint of the barrel can move, causing accuracy problems, often "2-group" problems as the barrel re-sets place to place. THE SAME SET OF RULES apply to muzzle brakes. They are hammered and shaken mercilessly and absolutely WILL move around if they're not secured at least as well as the back end.

98.63% of muzzle devices (per Pugh, 2015 research paper 34.241 "Applied vib. subchapter 3) are "secured" simply by a small rear abutment to the barrel, many are just hand-tightened to this small abutment.

These devices move, in fact they RATTLE from the forces they're subjected to. And generally they STILL shoot good. Most of the time.

So do hand-tight barrels LOL

Some muzzle devices bottom out inside, some outside, some at 2 or three points, some with a wedging action, and some guys (me) do all three and then EPOXY them on. (Actually I tend toward Rock Hard Putty, but same idea)

But in any case in the hundreds of photos extant I've never noticed the crooked gas clouds which would be the result of a cocked brake.

 

[coyotechet]

Here is the complete link of the bullet leaving the muzzle brake and showing the gas.

Chet

http://kuulapaa.com/home/highspeed/rifles.html

 

[mks]

These devices move, in fact they RATTLE from the forces they're subjected to.

Just wondering if all muzzle devices should have left hand threads, so that they tighten due to the rotation of recoil.

 

[alinwa]

Just wondering if all muzzle devices should have left hand threads, so that they tighten due to the rotation of recoil.

mine shoot tight. But not because of left hand threads. I offset the holes.

That said, I actually make aluminum brake vises and drive them to lock and glue them so that it's a non-issue.

But when playing with the recoil sled, testing hand-tight, they do shoot tighter.

 

[alinwa]

Here is the complete link of the bullet leaving the muzzle brake and showing the gas.

Chet

http://kuulapaa.com/home/highspeed/rifles.html

Thank you, thank you, THANK YOU!!

I couldn't remember how to access the guys site, and me a Suomalainen poika!

His stuff is awesome, and I think that about a third of the way down in the first and maybe second pic of an un-braked setup, where he's setting up a baseline for his Striker Industries tests you can actually see the cone of "clear air" with the bullet riding out of it just before it becomes obscured as the bullet re-passes thee gasses.

Whewww...... now I'm all crosseyed


again

 

[alinwa]

The large shift in impact took place with about 1/4 turn, which is a little over .007 advance. That amount of shift is what lead to my hypothesis in Post #4.

One thing I do do on my own stuff is re-chuck the barrel thru the headstock and go into the barrel behind the brake and align it with the CL of the headstock and check for runout in the installed brake itself, runout to the bore of the rifle.

In other words I do align the final bore of the brake with the last two inches or so of the barrel. But I do not think it's necessary, I mainly do it because I'm running very tight clearances. And just how crooked would one have to be to get angular change in a quarter turn or .007 long. movement??? Maybe I gotta' go back and look HOW your brake/tuner moves.... but I cannot imagine the bullet being "pushed off course" that hard. And I often see huge changes in poi on thin barreled hunting rifles with tuners, enough to say that IMO what you're seeing is a perfectly normal vibration phenomenon.

But that is only my uninformed opinion

 

[alinwa]

hmmm..... I just went and looked again. I take it all back. I really missed the boat when I looked at the snubber pics. This design doesn't have a fixed abutment surface anywhere.

I'm sorry to say, in my opinion your brake CAN pivot on the joint of the device and the locknut although the differential threads make your device more resistant to movement than if it was all one machined thread of 32 or 20tpi. I was under the mistaken impression that the snubber was threaded to travel the outside of the brake body like a Shadetree setup or the like. My mind was all wrapped up with "aluminum discs" and such....

If Harold Vaughn is right and only the 1st, 2nd and 3rd threads from the joint do all the work, in descending order of stress, then that brake flops back and forth. The actual muzzle is not secured.


MY test would be this..... loosen and tighten the snubber between groups BUT DO NOT TURN IT, if I'm right it will tighten up differently each time and your groups will print at different spots.

And all said and done, if it tunes linear and shoots zeros then all my ideas/guesses become irrelevant.

 

[jackie schmidt]

Here is the complete link of the bullet leaving the muzzle brake and showing the gas.

Chet

http://kuulapaa.com/home/highspeed/rifles.html

Chet,that is very eye opening. Thanks a bunch. It does appear that the bullet is encapsulated by hot gasses while still inside the muzzle brake and actually follows it for a short distance as the bullet exits.

I am gowing to redesign this. I m going to tighten the muzzle brake firmly against the muzzle. (Both are Square shoulders machined true). I will do away it's the jam nut, and machine two discs to go on that .950 20 tpi. Those will become the tuning apparatus, while the brake/snubber will be firmly locked to the barrel. That will make the muzzle brake/snubber completely separate from the tuning device.

Keep in mind. The Rifle shoots great. I am just concern about the wide movement of the group when the tuner/snubber/muzzle break is turned.

 

[mks]

If Harold Vaughn is right and only the 1st, 2nd and 3rd threads from the joint do all the work, in descending order of stress, then that brake flops back and forth. The actual muzzle is not secured.

Food for thought...

Ezell's tuner has stuff inside that rattles back and forth ON PURPOSE.

 

[mwezell]

Food for thought...

Ezell's tuner has stuff inside that rattles back and forth ON PURPOSE.

Lol! Yes, there are 9 individual pockets machined into the tuner body that are 75% filled with very fine tungsten powder. This is the dampening agent. It doesn't have room to settle inconsistently, as the pockets are relatively long and slender, with just a bit of air space along the top of the powder column.
I've never heard it referred to as rattling around, but yes, it does have some freedom of movement within each pocket.

The fact that it works at all, dispels any concern about something " rattling around" in there. They've been on record holding rifles, numerous world and national level match winning rifles and many, many other matches.

A good bit of thought and even vibration analysis testing went into the design and is a proven design.

If you've never really looked one over, you should. I think you'd be impressed.

 

[mks]

Mike,
That's my point, that rattling can be GOOD. (You could have called your tuner the "mariachi." ;^) )

Best,
Keith

 

[sdean]

I tried to use a lock nut to tune a brake and a sleeve. Hard to move in precise increments. I like the RAS tuner. It turns on two friction rubber orings. Seems to work just fine.

 

[jackie schmidt]

We had a great day to get some good testing done up at Tomball. Sunny, started out in the 30's, got up to mid 60's in the afternoon.

I revamped my muzzle brake/tuner/snubber to remove the tuning feature from the muzzle brake. The brake still incorporates the snubber.

The brake is now jammed firmly against the muzzle of the barrel. I machined a 7/8 inch long by 1 3/4 OD aluminum ring and threaded it to fit the .950 20 tpi that the discarded jam nut was mounted on. I sawed a slit in it, and added a 1/4 28 pinch bolt to lock the tuner to the barrel. The ring weighs 2 ounces.

It worked great. Due to the temperature, Upped the charge from 55 grn of 4831 SC to 55.4, yielding an average 2840 fps with the 180 Berger Hybrid. With a few 3 shot test groups to make tuner adjustments, it came right in.

Here is a picture of the set up now, and three of the better groups I shot at 200 yards. The shots on the right are my sighters.

http://benchrest.com/attachment.php?attachmentid=20441&stc=1&d=1512957264

http://benchrest.com/attachment.php?attachmentid=20442&stc=1&d=1512957410




I don't think I can make this Rifle shoot much better. The recoil is no so minimal I can free shoot the Rifle like a 6PPC. I think it's ready for 600 yards.
One minor problem. The Rifle is now 3 ounces over 17 pounds. I can either order a piece of titanium and machine the Muzzle Brake/Snubber from it, or order a March 48x to take the place of the big NXS 8-32 Nightforce.

 

[sdean]

Good excuse as any to buy a new scope!! Should be able to write that off as a large bore inspection scope

 

[Boyd Allen]

hmmm..... I just went and looked again. I take it all back. I really missed the boat when I looked at the snubber pics. This design doesn't have a fixed abutment surface anywhere. I'm sorry to say, in my opinion your brake CAN pivot on the joint of the device and the locknut although the differential threads make your device more resistant to movement than if it was all one machined thread of 32 or 20tpi. I was under the mistaken impression that the snubber was threaded to travel the outside of the brake body like a Shadetree setup or the like. My mind was all wrapped up with "aluminum discs" and such.... If Harold Vaughn is right and only the 1st, 2nd and 3rd threads from the joint do all the work, in descending order of stress, then that brake flops back and forth. The actual muzzle is not secured. MY test would be this..... loosen and tighten the snubber between groups BUT DO NOT TURN IT, if I'm right it will tighten up differently each time and your groups will print at different spots. And all said and done, if it tunes linear and shoots zeros then all my ideas/guesses become irrelevant.

Al, Unlike barrel to action thread joints, Jackie's tuner secures like a split clamp locking ring. Opposite the split and clamping screw there appears to be a weakening cut that acts like a hinge. This is entirely different from what Vaughn wrote about barrel to action joints.

 

[alinwa]

Al, Unlike barrel to action thread joints, Jackie's tuner secures like a split clamp locking ring. Opposite the split and clamping screw there appears to be a weakening cut that acts like a hinge. This is entirely different from what Vaughn wrote about barrel to action joints.

Yeahh, I know, he fixed it.

This latest way is very good. I've done some work with securing barrels this way.

Best of all, one can turn the apparatus up tight and then tighten the locking screws producing a tremendous wedging force.

 

[jackie schmidt]

As a followup, we spent all day last Sunday at Walker County, shooting 600 yards.

The Rifle was locked into 3"+ groups. I spent the better part of the day working with everything form seating depth, charges, to neck tension. It just was not shooting.

With about 2 hrs daylight left, I told Ed I was taking the muzzle brake off. I put my standard load of 55 grns of 4831 SC in with .020 off the lands, (180 grn Berger Hybrid), and it tightened right up. I then concentrated on the flags and shot these two groups.

http://benchrest.com/attachment.php?attachmentid=20573&stc=1&d=1516287763

It won't shoot like a Benchrest Rifle with the muzzle brake installed.

I'm going to look at some other types of brakes, my design is flawed somewhere. But for now, I will just put up with the recoil.

By the way. this is the first time I used my new Target Vision target camera. It worked great.

 

[alinwa]

As a followup, we spent all day last Sunday at Walker County, shooting 600 yards.

The Rifle was locked into 3"+ groups. I spent the better part of the day working with everything form seating depth, charges, to neck tension. It just was not shooting.

With about 2 hrs daylight left, I told Ed I was taking the muzzle brake off. I put my standard load of 55 grns of 4831 SC in with .020 off the lands, (180 grn Berger Hybrid), and it tightened right up. I then concentrated on the flags and shot these two groups.

http://benchrest.com/attachment.php?attachmentid=20573&stc=1&d=1516287763

It won't shoot like a Benchrest Rifle with the muzzle brake installed.

I'm going to look at some other types of brakes, my design is flawed somewhere. But for now, I will just put up with the recoil.

By the way. this is the first time I used my new Target Vision target camera. It worked great.

At the risk of stepping out of line....... just to test concept may I suggest you try a Harrell, about a 1" diameter with lots of holes. Machine it to wedge at the front AND butt at the rear and attach it to high torque (60-80ftlb) and epoxy it on. The brake is subject to WIKKID forces and IMO must be made "part of the barrel"

I machine mine off the gun, generally using a one-off fixture (12l14 rod) so's I can drill thru easily, get my tooling thru without worrying about the muzzle and bore to around .020 over I feel that it's "another muzzle" and need be treated as such, good alignment-clean edges.......although I feel absolute TIGHTNESS is more important.

Problem is, this mess won't TUNE, it's just a brake.

I've got 50 "tunable brakes" here in buckets and I'm still not satisfied with any of them, but my hangup is the "tuner" part. I've just never got a TUNER to reliably shoot better than nekkid.

That's just me, my problem....

I have no trouble getting Braked Rifles to shoot.