M
martin hammond
Guest
did Al or anyone answer the question to post #20?
V
Varmint Al
Guest
The muzzle is moving vertically and swinging through angle variations as the bullet travels down the barrel. The plot is where the last half inch of the barrel is pointing at each instant of time. It is as if one were to tape a laser to the last half inch of the barrel and record the trace on a moving background at 50 yards. The flat spot in the curve of where the laser points during the flat spot is interesting, but the bullet is still a few inches back in the barrel at that time. If the muzzle projection were flat at bullet exit, then slower bullets would strike low.
Please do not think that the muzzle projection curve is how the barrel changes shape while the bullet is traveling down the barrel. It is where the muzzle is pointing. The animation gif views shows the barrel shapes.
Good Hunting... from Varmint Al
C
Carp
Guest
B. Harvey,
I'm not a mathematician nor a physicist. But I ask this question to all who think they know. Can a tuner be set to a setting that can have the muzzle pointed at the EXACT same spot from January to December in say Indiana? We see temperature differences from some -15F to 105F. Do steels that barrels are constructed of behave the same in this temp. range at the same exact time? Because the bullet of VARIOUS velocity must do that along with the hardware (barrels).
I ask you Mr. Harvey, is a barrel with a tuner at the end a fixed at both ends or a second mode for fixed free? I know what you would want to believe. But think of the difference in say 40 fps in a say 2 foot barrel. Would the physics be the same in TIME as the said Kettering University attachment that has nothing to do with guns, only physical bending and flexing that does not constitute material. I know that if you bend a brass clothes hanger eough back and forth it breaks in half. But I also know that there are plenty of lots of ammo that chronograph 20+fps off of the listed speed (not an anomaly 10 shot stringns with SD's about +-1). So I ask this, is a stopped muzzle a tuned muzzle for the life of a barrel? I think I'll see at least three rifles with new barrels next season, if not before that shot lights out with the same mindset as you and Lynn. The difference is in rimfire these guys have kind of a great history of success. Just not as much as last year.
Carp
I'm not a mathematician nor a physicist. But I ask this question to all who think they know. Can a tuner be set to a setting that can have the muzzle pointed at the EXACT same spot from January to December in say Indiana? We see temperature differences from some -15F to 105F. Do steels that barrels are constructed of behave the same in this temp. range at the same exact time? Because the bullet of VARIOUS velocity must do that along with the hardware (barrels).
I ask you Mr. Harvey, is a barrel with a tuner at the end a fixed at both ends or a second mode for fixed free? I know what you would want to believe. But think of the difference in say 40 fps in a say 2 foot barrel. Would the physics be the same in TIME as the said Kettering University attachment that has nothing to do with guns, only physical bending and flexing that does not constitute material. I know that if you bend a brass clothes hanger eough back and forth it breaks in half. But I also know that there are plenty of lots of ammo that chronograph 20+fps off of the listed speed (not an anomaly 10 shot stringns with SD's about +-1). So I ask this, is a stopped muzzle a tuned muzzle for the life of a barrel? I think I'll see at least three rifles with new barrels next season, if not before that shot lights out with the same mindset as you and Lynn. The difference is in rimfire these guys have kind of a great history of success. Just not as much as last year.
Carp
B
B. Harvey
Guest
On Lilja's site, Dan talks about a 12.8" to a 16.6" twist needed for optimum bullet stability, which if optimum should net tighter theoretical aggs. This was in a 6ppc just traveling to different parts of the US.
With a rimfire having a barrel time of almost 3X longer, it should then be about 9X more sensitive to this.
I think after getting tuned it is then a case of matching ammo for the conditions, or matching ammo speed to the tune of the barrel, which it is I don't know.
I do have a friend that has shot an 18" twist year round, indoor and outdoor, and had great results. Compare that to before having my rifle tuned, there was one day with my 16.5" twist I was getting slight keyholes and my friend was shooting his 18" on the same day and not getting them. He won the match. I asked how he did not get keyholes with a slower twist than what I had? He said "Cause my rifle is tuned"!
With my current tuner, an RVA, I was finally able to get tuned, the same barrel which I thought would never shoot, and the difference is dramatic.
But, I have only shot it in it's tuned condition since July in 90F, but it is cooler now and still shoots well in 65F.
I don't know for a fact that once tuned, is always tuned, but this is what the top shooters say.
With a rimfire having a barrel time of almost 3X longer, it should then be about 9X more sensitive to this.
I think after getting tuned it is then a case of matching ammo for the conditions, or matching ammo speed to the tune of the barrel, which it is I don't know.
I do have a friend that has shot an 18" twist year round, indoor and outdoor, and had great results. Compare that to before having my rifle tuned, there was one day with my 16.5" twist I was getting slight keyholes and my friend was shooting his 18" on the same day and not getting them. He won the match. I asked how he did not get keyholes with a slower twist than what I had? He said "Cause my rifle is tuned"!
With my current tuner, an RVA, I was finally able to get tuned, the same barrel which I thought would never shoot, and the difference is dramatic.
But, I have only shot it in it's tuned condition since July in 90F, but it is cooler now and still shoots well in 65F.
I don't know for a fact that once tuned, is always tuned, but this is what the top shooters say.
B
BrentD
Guest
If you really wanted to build a gun with a stopped muzzle, why not make one that is bolted and bedded to the stock at the muzzle and free floated all the way back through the action?
Not exactly sure how you would trigger it, but that shouldn't be impossible.
Hell, just bolt a barreled action directly to a bench rest at the muzzle.
Brent
Not exactly sure how you would trigger it, but that shouldn't be impossible.
Hell, just bolt a barreled action directly to a bench rest at the muzzle.
Brent
G
gambler
Guest
once tuned, is always tuned, that's what us Baptist shooters say
i can see it now, when someone has a new rifle built their last question to the smith " are you sure it's tuned, really tuned ?
and those calls "can you tune my rifle Mr. Gunsmith ?"
i can see it now, when someone has a new rifle built their last question to the smith " are you sure it's tuned, really tuned ?
and those calls "can you tune my rifle Mr. Gunsmith ?"
P
Pokerplayer
Guest
Al & Bill,
Bill, I bought one of your XP's to reverse engineer it, VERY nice work. Al, have always enjoyed you engineering pages.
I have been working on this problem in my simple world, by finding a barrel length where I would not need a tuner at all. Below 14" I can control velocity within MS 10 fps. Would not the shorter bbl. reduce the amount of movement by at least half, and get the bullet away from forces other than gravity and drag? Looking at your graph and the graphs that were posted here by others a few year's ago about frequency and amplitude, where the firing pin strike sets the frequency and the primer sets max amplitude, would not a straight taper barrel about 8" long not need a tuner?
Bill, I bought one of your XP's to reverse engineer it, VERY nice work. Al, have always enjoyed you engineering pages.
I have been working on this problem in my simple world, by finding a barrel length where I would not need a tuner at all. Below 14" I can control velocity within MS 10 fps. Would not the shorter bbl. reduce the amount of movement by at least half, and get the bullet away from forces other than gravity and drag? Looking at your graph and the graphs that were posted here by others a few year's ago about frequency and amplitude, where the firing pin strike sets the frequency and the primer sets max amplitude, would not a straight taper barrel about 8" long not need a tuner?
Pokerplayer,
Since you're basically talking about a pistol, I'm gonna assume you would use something like Bill's XP to do this. Some years ago, Stanley Drake, a shooter in Indiana, had an XP with a very short thin barrel. As I recall, and I could be wrong, it didn't have a tuner. I can't remember the entire results, but I think he did have some success with it.
Since you're basically talking about a pistol, I'm gonna assume you would use something like Bill's XP to do this. Some years ago, Stanley Drake, a shooter in Indiana, had an XP with a very short thin barrel. As I recall, and I could be wrong, it didn't have a tuner. I can't remember the entire results, but I think he did have some success with it.