10BA .308 Steath bullet weights

[CFJunkie]

I have two Savage Model 10 .308s, both with 24-inch barrels.

Both shoot accurately, with a variety of weights, but when you measure lots of groups, I discovered what I didn't expect.
One shoots 150 to 168s better than 175s and heavier and the other shoots 175s to 200s better than the lighter 150s through 168s.
Both shoot 168s about the same.
Both with Federal GMM SMKS and with hand loads using Sierra SMKs with different powders.
The rifles show a preference for weights and the weights are different.

I have three Savage 6.5mm Creedmoor rifles. Two shoot 142 to 147 grain bullets the best and the third shoots 130 and 140 grain bullets slightly better.

It depends on the barrel in an individual rifle, IMO.

Better try different weights to be sure.

[Ted_Feasel]

I have two Savage Model 10 .308s, both with 24-inch barrels.

Both shoot accurately, with a variety of weights, but when you measure lots of groups, I discovered what I didn't expect.
One shoots 150 to 168s better than 175s and heavier and the other shoots 175s to 200s better than the lighter 150s through 168s.
Both shoot 168s about the same.
Both with Federal GMM SMKS and with hand loads using Sierra SMKs with different powders.
The rifles show a preference for weights and the weights are different.

I have three Savage 6.5mm Creedmoor rifles. Two shoot 142 to 147 grain bullets the best and the third shoots 130 and 140 grain bullets slightly better.

It depends on the barrel in an individual rifle, IMO.

Better try different weights to be sure.

I know the steel type is a big factor as 416R has a whip frequency thats different from say 4150 but each alloy givin that it is compared to the same alloy resonates at the same frequency. Are both barrels you are talking about the same steel?

Sent from my SM-N975U using Tapatalk

[CFJunkie]

Yes, both are Savage factory barrels made of their standard 3% carbon steel (reflection speed of 19,107 fps).
4140 or 4150 stainless steel has a reflection speed of 19,969 fps and 416R stainless steel has a reflection speed of 20,014 fps.

The Savage 6.5mm CMs also all have Savage factory barrels with the 3% carbon steel as well.

It is possible that there could be slight differences in the % of carbon in the steel each barrel because their manufacturing dates are each more than 1 year apart, but interestingly, they all shoot best at the 19,107 fps calculated exit times so I don't believe that minor variations in the steel alloys are the source of the preferences.

[Ted_Feasel]

Yes, both are Savage factory barrels made of their standard 3% carbon steel (reflection speed of 19,107 fps).
4140 or 4150 stainless steel has a reflection speed of 19,969 fps and 416R stainless steel has a reflection speed of 20,014 fps.

The Savage 6.5mm CMs also all have Savage factory barrels with the 3% carbon steel as well.

It is possible that there could be slight differences in the % of carbon in the steel each barrel because their manufacturing dates are each more than 1 year apart, but interestingly, they all shoot best at the 19,107 fps calculated exit times so I don't believe that minor variations in the steel alloys are the source of the preferences.

I think it was you in a different thread that was explaining some of the science behind exit time and load dev. I've been doing ALOT of research on it and it occurred to me (because music inclination runs strong in my family) that even on barrels that are the same alloy that there will be slight variations in them. I was thinking about a way to account for that and I think I have hit it. A light strike from a stick or rod will reveal a specific pitch that is purely a result of the alloy make up. We have instruments that can pick up pitch differences that are nearly infinite. There should be a method of plugging in the pitch or note your barrel produces to get the exact frequency at which it resonates and in theory that you allow finer control of figuring timing.. what are your thoughts on that?

Sent from my SM-N975U using Tapatalk

[Robinhood]

I think it was you in a different thread that was explaining some of the science behind exit time and load dev. I've been doing ALOT of research on it and it occurred to me (because music inclination runs strong in my family) that even on barrels that are the same alloy that there will be slight variations in them. I was thinking about a way to account for that and I think I have hit it. A light strike from a stick or rod will reveal a specific pitch that is purely a result of the alloy make up. We have instruments that can pick up pitch differences that are nearly infinite. There should be a method of plugging in the pitch or note your barrel produces to get the exact frequency at which it resonates and in theory that you allow finer control of figuring timing.. what are your thoughts on that?

Sent from my SM-N975U using Tapatalk

Stress/stiffness can change harmonics also. Diameter and length obviously does as well.


Get yourself a accelerometer and an oscilloscope and do a ring test. Good time to start that research and develop a system that can integrate to the popular loading software.

[Ted_Feasel]

Stress/stiffness can change harmonics also. Diameter and length obviously does as well.

I get that but they should be able to use pitch to correlate to a consistent harmonic. Harmonics are a direct expression of certain aspects of pitch. For instance on a guitar there is always certain frets the above them always display a harmonic that is identical to the pitch. The octave may vary but the harmonic to pitch is always identical

Sent from my SM-N975U using Tapatalk

[Ted_Feasel]

I get that but they should be able to use pitch to correlate to a consistent harmonic. Harmonics are a direct expression of certain aspects of pitch. For instance on a guitar there is always certain frets the above them always display a harmonic that is identical to the pitch. The octave may vary but the harmonic to pitch is always identical

Sent from my SM-N975U using Tapatalk

Direct example, 12th fret, above it is ALWAYS the harmonic that is identical to the note you have tuned that string to. If you tune that string a half step off then its harmonic will be identically a half step off and so on

Sent from my SM-N975U using Tapatalk

[Robinhood]

Im not familiar with the vernacular of the guitar even though I have two. I veiw harmonics when two items have a same or similar natural frequency. Im not smart enough to justify harmonics in this conversation. To me, Harmonics with regards to a barrel would be a negative. Vibration frequency is the data your after. that will give you time to distance in waves...yes ...no...?