why left to right ????
- Thread starter romex2121
- Start date
- Nov 4, 2004
- 25,530
- 9,540
Its barrel harmonics, along with bearing surface of the bullet and powder burn rate. Every load is different.
JD338
JD338
Antelope_Sniper
Handloader
- Jan 25, 2008
- 2,618
- 0
When the bullet travels down the barrel, the barrel vibrates like a tuning fork, but in a circular pattern.
what ole JD means is that there barrel is like a wet noodle and it can sling that there projectile in just about any direction.... :lol:
seriously... half a grain of powder can cause a few inches of laterall POI change. the bigger the difference in components, the bigger the change in harmonics.
seriously... half a grain of powder can cause a few inches of laterall POI change. the bigger the difference in components, the bigger the change in harmonics.
- Oct 30, 2004
- 24,409
- 3,394
What JD said . 8)
Think of a barrel as a whip. It goes up and down and in a slight circular motion.
Your sweet spot is either on the top of the " crack" or on the bottom..... where the barrel rests for an instant. That is where accuracy is found.
Bullet weight, powder burn rate seating depth primer burn etc all have a direct effect as to when and where during the "barrel whip" the bullet will exit.
When you find the sweet spot then theoretically at least the bullet is exiting at the same time.
Kid of an exaggerated example but that is it in a nutshell.
Think of a barrel as a whip. It goes up and down and in a slight circular motion.
Your sweet spot is either on the top of the " crack" or on the bottom..... where the barrel rests for an instant. That is where accuracy is found.
Bullet weight, powder burn rate seating depth primer burn etc all have a direct effect as to when and where during the "barrel whip" the bullet will exit.
When you find the sweet spot then theoretically at least the bullet is exiting at the same time.
Kid of an exaggerated example but that is it in a nutshell.
Greg Nolan
Handloader
- Nov 25, 2004
- 2,143
- 18
What they said.
It is common from my reloading that the bullet always moves side to side as much as up and down. Sometimes when shooting at almost the identical velocity. That's why I always sight in with my hunting loads.
Good Hunting
Greg
It is common from my reloading that the bullet always moves side to side as much as up and down. Sometimes when shooting at almost the identical velocity. That's why I always sight in with my hunting loads.
Good Hunting
Greg
roysclockgun
Handloader
- Dec 17, 2005
- 736
- 1
Is it not also true that a faster bullet will be thrown farther left or right than would a slower bullet? This, as with a right hand twist barrel that is shooting zero with a slow, lightly loaded cartridge. Then, one ups the propellant load, thus providing higher MV. The higher MV will cause the bullet to print further right, from where the slower bullet was punching groups, due to the higher rate of right hand spin, imparted by the right hand twist on the rifling.
Harmonics : It appears to me, that with any load, better groups can be gotten by loosening the stock screws and placing business cards at the end of the forestock, between the stock and barrel and then, re-tightening the stock screws. It will take some experimentation, but when the "right" amount of pressure is applied by the cards pushing up on the barrel, better groups will be provided. There is a commercial product that does the same thing, but business cards will work as well. Business card material can be used at other places between stock and metal, to provide a more rigid unit. This is especially true with hard used rifles, like surplus US M1 Rifles, where cards placed in the receiver area, between wood and metal will greatly improve groups.
Steven A.
Harmonics : It appears to me, that with any load, better groups can be gotten by loosening the stock screws and placing business cards at the end of the forestock, between the stock and barrel and then, re-tightening the stock screws. It will take some experimentation, but when the "right" amount of pressure is applied by the cards pushing up on the barrel, better groups will be provided. There is a commercial product that does the same thing, but business cards will work as well. Business card material can be used at other places between stock and metal, to provide a more rigid unit. This is especially true with hard used rifles, like surplus US M1 Rifles, where cards placed in the receiver area, between wood and metal will greatly improve groups.
Steven A.
baltz526
Handloader
- Sep 25, 2005
- 1,074
- 8
A pressure point changes the frequency. In effect giving your barrel two notes it plays, on every bullet down the barrel. The problem with this pressure point is, its constantly changing. Plastic stocks flex with pressure/temprature a lot. wood reacts slower to these changes, but are still effected. A free floated barrel has one note, you can tune by load adjustment.
Ridge_Runner
Handloader
- Sep 29, 2006
- 1,392
- 753
ok as pressure starts to peak sending the bullet down the barrel, there is no way that tight fitting bullet can be forced down the barrel without it flexing a bit, some theorys say its circular, some say the barrel moves in a figure 8 pattern (who the heck studies this stuff)
the main thing is keeping pressures consistant so the bullet exits at the same place in the harmonic travel, thats where ya wanna be.
You can have 2 or more loads that shoot excellant, but due to where the muzzle is in its harmonic travel will drasticly change the POI even though it still shoots an excellant group.
RR
the main thing is keeping pressures consistant so the bullet exits at the same place in the harmonic travel, thats where ya wanna be.
You can have 2 or more loads that shoot excellant, but due to where the muzzle is in its harmonic travel will drasticly change the POI even though it still shoots an excellant group.
RR
Richracer1
Handloader
- May 12, 2005
- 2,141
- 121
You know, I wish I had a camera capable of slow motion as I think it would be very cool to have someone video the rifle while I fire it. Slow motion may show the barrel resonating during the firing process. I know this is a tip for archers to see how their arrows fly and then decide if their arrows are under-spinned for their bow poundage.
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