Post by Bullshop on Apr 11, 2019 7:31:52 GMT -7
This was a conversation with a customer that I want to share as it may be helpful to others that may have the same questions.
Q - I have a curiosity question.... I will be shooting a 30-30 Ackley improved handi rifle. Using cast bullets 150gr up to 170grs. What kinda speed can I push these bullets to? I would like to hunt with the bullets. So expansion is a must.
Thank you for your time.
And your knowledge.
A - Your question is maybe a little bit confusing. The first question “” What kind of speed can I push these bullets to ? “” Are you asking what the limitations of cast bullets are or are you asking what the limits of the 30-30 AI are ?
Secondly you mention wanting to hunt with them but don’t mention what you want to hunt. Thirdly you seem to have the pre-conceived notion that non-expanding bullets are not acceptable for hunting and if so a point on which we disagree.
Regardless, a formula I have developed to determine maximum bullet alloy hardness for expansion is as follows,
Bullet hardness in BHN x 100 = (or exceed) impact velocity (not muzzle velocity)
We offer bullet alloy hardness from 5 to 25 BHN. Bullets that will be fired to 2000 fps and above should not be much softer than about bhn-15 and should be gas checked. For velocities below 1500 fps alloy hardness is not critical and gas checks are not needed.
Q - I apologize for the lack of information. In my request.
I am curious just how fast cast bullets could be pushed to? I know they have limits.
I would use them for whitetail deer.
I do agree with you about cast bullets don't need to expand to kill. I was figuring a 30 cal would be kinda small. With some expansion. I shoot a 44 special and 45 70. I have never cared if they expanded.
Please continue to share your knowledge on this subject. I want to learn. I appreciate your time!
A - As in most endeavors terminal ballistics with cast or jacketed bullets is not precise science where we can say that 100% of the time given a specific set of parameters the same results will always occur. The best we can hope for is the largest percent of the time.
To have at least a working grasp of terminal bullet performance requires a masters degree level of investigation into the results of every possible combination of possibilities, a lifetime of study.
To try and keep it as simple as possible the main things to consider about terminal bullet performance are #1 expanding or non-expanding, #2 nose shape, #3 impact velocity #4 sectional density or bullet length/weight related to momentum. Each of these factors effects to permanent wound channel and its volume of displaced tissue and the amount and degree of trauma around the permanent wound channel.
Expanding bullets tend to have a shorter length of permanent wound channel with a larger mid length diameter. Non-expanding flat nose bullets tend to have a longer permanent wound channel of a more uniform diameter for the length of the wound. The degree of either is dependent on the momentum of the bullet and its ability or lack of to maintain its terminal velocity.
A heavy for caliber flat nose non-expanding bullet can create a permanent wound channel equal to or greater in volume to an expanding bullet of the same weight and caliber at the same impact velocity. This because the expanding bullet increases in frontal area as it penetrates and as it does so does resistance to penetration. Because of the increased resistance of the expanding bullet it looses terminal velocity at a higher rate than a non expanding bullet. As terminal velocity decreases so do all other factors involved in creating the permanent wound channel.
High terminal velocity causes the splash effect of soft tissue displacement acting as secondary projectile and is what makes the permanent wound channel many times larger in diameter than the bullet diameter. The higher the terminal velocity the more acute the angle of displacement of tissue away from the bullet nose in terminal penetration. The more acute the angle of tissue displacement the larger the diameter the permanent wound channel will be. The expanding bullet will have a shorter fatter permanent wound channel but the non-expanding flat nose bullet will have a longer deeper permanent wound channel but the percentage of meplate diameter to bullet diameter will also have some affect on the diameter of the total volume of the permanent wound channel.
The larger the volume of the permanent wound channel the greater and more rapid the blood loss and drop in blood pressure and so incapacitation.
In short if you are to hunt big game with cast bullets and the initial muzzle velocity will be fairly high of necessity to withstand the chamber pressures required to produce the desired velocity the bullet alloy must be fairly hard. In this case you can expect the best terminal performance from a non-expanding bullet with fairly large percentage of meplate to caliber in a heavy for caliber weight.
Q - I have a curiosity question.... I will be shooting a 30-30 Ackley improved handi rifle. Using cast bullets 150gr up to 170grs. What kinda speed can I push these bullets to? I would like to hunt with the bullets. So expansion is a must.
Thank you for your time.
And your knowledge.
A - Your question is maybe a little bit confusing. The first question “” What kind of speed can I push these bullets to ? “” Are you asking what the limitations of cast bullets are or are you asking what the limits of the 30-30 AI are ?
Secondly you mention wanting to hunt with them but don’t mention what you want to hunt. Thirdly you seem to have the pre-conceived notion that non-expanding bullets are not acceptable for hunting and if so a point on which we disagree.
Regardless, a formula I have developed to determine maximum bullet alloy hardness for expansion is as follows,
Bullet hardness in BHN x 100 = (or exceed) impact velocity (not muzzle velocity)
We offer bullet alloy hardness from 5 to 25 BHN. Bullets that will be fired to 2000 fps and above should not be much softer than about bhn-15 and should be gas checked. For velocities below 1500 fps alloy hardness is not critical and gas checks are not needed.
Q - I apologize for the lack of information. In my request.
I am curious just how fast cast bullets could be pushed to? I know they have limits.
I would use them for whitetail deer.
I do agree with you about cast bullets don't need to expand to kill. I was figuring a 30 cal would be kinda small. With some expansion. I shoot a 44 special and 45 70. I have never cared if they expanded.
Please continue to share your knowledge on this subject. I want to learn. I appreciate your time!
A - As in most endeavors terminal ballistics with cast or jacketed bullets is not precise science where we can say that 100% of the time given a specific set of parameters the same results will always occur. The best we can hope for is the largest percent of the time.
To have at least a working grasp of terminal bullet performance requires a masters degree level of investigation into the results of every possible combination of possibilities, a lifetime of study.
To try and keep it as simple as possible the main things to consider about terminal bullet performance are #1 expanding or non-expanding, #2 nose shape, #3 impact velocity #4 sectional density or bullet length/weight related to momentum. Each of these factors effects to permanent wound channel and its volume of displaced tissue and the amount and degree of trauma around the permanent wound channel.
Expanding bullets tend to have a shorter length of permanent wound channel with a larger mid length diameter. Non-expanding flat nose bullets tend to have a longer permanent wound channel of a more uniform diameter for the length of the wound. The degree of either is dependent on the momentum of the bullet and its ability or lack of to maintain its terminal velocity.
A heavy for caliber flat nose non-expanding bullet can create a permanent wound channel equal to or greater in volume to an expanding bullet of the same weight and caliber at the same impact velocity. This because the expanding bullet increases in frontal area as it penetrates and as it does so does resistance to penetration. Because of the increased resistance of the expanding bullet it looses terminal velocity at a higher rate than a non expanding bullet. As terminal velocity decreases so do all other factors involved in creating the permanent wound channel.
High terminal velocity causes the splash effect of soft tissue displacement acting as secondary projectile and is what makes the permanent wound channel many times larger in diameter than the bullet diameter. The higher the terminal velocity the more acute the angle of displacement of tissue away from the bullet nose in terminal penetration. The more acute the angle of tissue displacement the larger the diameter the permanent wound channel will be. The expanding bullet will have a shorter fatter permanent wound channel but the non-expanding flat nose bullet will have a longer deeper permanent wound channel but the percentage of meplate diameter to bullet diameter will also have some affect on the diameter of the total volume of the permanent wound channel.
The larger the volume of the permanent wound channel the greater and more rapid the blood loss and drop in blood pressure and so incapacitation.
In short if you are to hunt big game with cast bullets and the initial muzzle velocity will be fairly high of necessity to withstand the chamber pressures required to produce the desired velocity the bullet alloy must be fairly hard. In this case you can expect the best terminal performance from a non-expanding bullet with fairly large percentage of meplate to caliber in a heavy for caliber weight.