Tuners what do you think about my first one?

[Richard]

It's not that hard

to make a bbl with a tuner to shoot really well if it is a good bbl to start with. Probably the biggest issue is do you know what to do with the tuner when the tune goes away during a match. It's one thing to fiddle around during practice sessions. But when the heat is on and the clock is ticking can you make the adjustment that you need to shoot a small group without blowing alot of time on the sighter? When you can do that, you will realize just how much a tuner is worth. I would not be with out one. (Ever)

Richard

 

[mwezell]

Thanks for your input guys, I have made a tuner that weighs 12oz for a 30" 1.250" diameter barrel.

My current load for this rifle (105Hybrids from a 6 Dasher) is decent, 5 shots into the mid 0.2s but I will try the tuner on with that and see if it can be tuned any?

If I do any new load development with this barrel I will fit the tuner from the start.

Out of interest what size exit hole do you guys have for 6mm?

Mine is about .760 and a tad over an inch of it is beyond the muzzle, with it run all the way in, toward the receiver. Tuner/brakes are much different in this regard, to dedicated tuners. IMHO, you are very near or over the point where your tuner is too heavy for that barrel. A 1.25 straight, that long, is not as stiff as you'd think. A 24" HV is considerably stiffer. A 28" HV is very nearly the same stiffness as a 30" 1.25 straight.

Dan Lilja has a barrel stiffness calculator on his website. Here's a link to it. http://riflebarrels.com/computer-software/ Its a part of his barrel weight calculator program. Both are very good tools. Barrel stiffness is what we should be talking in terms of, when talking tuners. Many people wrongly assume a 1.25 or other straight contours are stiffer than they really are, compared to standard br tapers. Length is more critical to stiffness than is diameter, in most anything we're likely to see in br rifles.

Plug some numbers into his program and you can see what I mean.

A stiffer barrel..at least in this context, is not always the best thing. They are more sensitive to tune...meaning they have a narrower tuning node width. But..they won't shoot as bad as a less stiff barrel when out of tune. I like to use the phrase, " a less stiff barrel talks to you" more than a stiffer one, as tune issues are simply more apparent. In this day, a gun that's a "little" out of tune won't win.

 

[brickeyee]

Mine is about .760 and a tad over an inch of it is beyond the muzzle, with it run all the way in, toward the receiver. Tuner/brakes are much different in this regard, to dedicated tuners. IMHO, you are very near or over the point where your tuner is too heavy for that barrel. A 1.25 straight, that long, is not as stiff as you'd think. A 24" HV is considerably stiffer. A 28" HV is very nearly the same stiffness as a 30" 1.25 straight.

Dan Lilja has a barrel stiffness calculator on his website. Here's a link to it. http://riflebarrels.com/computer-software/ Its a part of his barrel weight calculator program. Both are very good tools. Barrel stiffness is what we should be talking in terms of, when talking tuners. Many people wrongly assume a 1.25 or other straight contours are stiffer than they really are, compared to standard br tapers. Length is more critical to stiffness than is diameter, in most anything we're likely to see in br rifles.

Plug some numbers into his program and you can see what I mean.

A stiffer barrel..at least in this context, is not always the best thing. They are more sensitive to tune...meaning they have a narrower tuning node width. But..they won't shoot as bad as a less stiff barrel when out of tune. I like to use the phrase, " a less stiff barrel talks to you" more than a stiffer one, as tune issues are simply more apparent. In this day, a gun that's a "little" out of tune won't win.

That sounds like a good way to look at it.

Lower stiffness results in more movement, higher amplitudes, and [XXhigher] LOWER frequencies.
It also decreases inherent damping.

My deformable body and vibration books are around here somewhere but I have not used them much since retiring from aircraft hardware design.

And yes it really matters for electronics also.

It is really bad when airborne electronics fails on noise from mechanical vibration and inherant Piezo components.
And ceramic capacitors are NOT the only items.

 

[Boyd Allen]

I think that lower stiffness will decrease frequency.

 

[brickeyee]

I think that lower stiffness will decrease frequency.

You are correct. I fixed it.

I had originally typed it as 'higher stiffness' and changed it and missed the frequency.