Jim Watson
Member
I think extrapolating from rifle internal ballistics to pistol terminal ballistics is a step too far. Probably two steps too far, I don't think your 300 grain nitro "break in" stuff is at all comparable to .45-70-500.
Powder speed effect on recoil?
- Thread starter JimGnitecki
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AJC1
Member
I think your going to derail your recoil discussion....
mcb
Member
You would not be able to tell the different in the actual impact. The amount of damage resulting you would no doubt feel but the difference in time to accumulate that damage is something the human body cannot resolve. One of the fastest reaction a human is capable of the reflex reaction to touch something hot and that take typically 15 milli-seconds and it will be another 15-20 seconds after that before you brain registers the action.
mcb
Member
Felt recoil is such a subjective thing and effected by so many more factors than just the change in momentum (ie recoil impulse as an engineer or physicist would calculate it).
Muzzle blast can change things for many shooters. You can have two loads that have very similar total recoil impulse but if one has a noticeable higher muzzle exit pressure most shooter will perceive that increased muzzle blast as greater recoil even though the actual measured recoil is nearly the same. Suppressors are good for mitigating this plus adding weight to the weapon to reduce free recoil energy.
A simple grip or stock change can make the exact same ammunition more or less pleasant just due to ergonomic fit of the weapon.
Shooting position makes a big difference too. Most shooter can suck up a lot more recoil without pain shooting a big rifle standing than over a bench or prone.
etc
Muzzle blast can change things for many shooters. You can have two loads that have very similar total recoil impulse but if one has a noticeable higher muzzle exit pressure most shooter will perceive that increased muzzle blast as greater recoil even though the actual measured recoil is nearly the same. Suppressors are good for mitigating this plus adding weight to the weapon to reduce free recoil energy.
A simple grip or stock change can make the exact same ammunition more or less pleasant just due to ergonomic fit of the weapon.
Shooting position makes a big difference too. Most shooter can suck up a lot more recoil without pain shooting a big rifle standing than over a bench or prone.
etc
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sage5907
Member
I have a 338-06 rifle that has shown me there is a difference in recoil with slower v faster powders. Every rifle is different depending on the weight, length of the barrel, design of the stock, and how the shooter holds the rifle. When I first started shooting my 338-06 my hunting and accuracy load was 58 grains of Reloader 17 and it is my favorite powder for that particular rifle.
I acquired a second identical rifle and I found that it liked 55 grains of Reloader 15 better. I tried the Rl 15 in the first rifle and accuracy wasn't better than Rl 17 and to my surprise the recoil was more noticeable. And when I say more noticeable i mean the recoil changes from a strong push to a sharper jab. I have been shooing rifles in the 30-06 class for many years and recoil doesn't seem to bother me. I just memorize the sight picture at the time the rifle fires so I can call the shot. For hunting I can shoot both powders at 200 meters without changing the scope setting on either rifle. I am convinces there is a difference is some rifles.
I acquired a second identical rifle and I found that it liked 55 grains of Reloader 15 better. I tried the Rl 15 in the first rifle and accuracy wasn't better than Rl 17 and to my surprise the recoil was more noticeable. And when I say more noticeable i mean the recoil changes from a strong push to a sharper jab. I have been shooing rifles in the 30-06 class for many years and recoil doesn't seem to bother me. I just memorize the sight picture at the time the rifle fires so I can call the shot. For hunting I can shoot both powders at 200 meters without changing the scope setting on either rifle. I am convinces there is a difference is some rifles.
JimGnitecki
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Jim Watson
Member
I was once assured by a guy that Reloder 17 gave markedly less recoil than other powders. He did not offer chronograph readings to say whether he was getting the same velocity, though.
AJC1
Member
Felt means how you interpret it. I prefer a standard like the math. When I get my dad's 45-70 from home and work up loads, I will do the math and determine mathematically what my threshold for that gun is. That's not a perfect plan because things like temperature and clothing can change the perception. I'm inclined to think imr4198 will be good because the pressure spike will opterate the base at a much lower charge weight and result in accuracy at a lower velosity. My goal is a good accuracy at low es, and I'll compensate for the rainbow trajectory.
JimGnitecki
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I too am in it for the accuracy, not the velocity or the power. I like creating really small groups at rather large distances! And I do that best with moderate loads.
Jim G
AJC1
Member
If you are using a single load 45-70 I'd be using more pointed bullets with better bc. The belustics are absolutely abysmal so if you don't need a big flat meplat for a lever I'd not use those...
JimGnitecki
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I have no choice, at least yet. My problem is that nothing else seems to be available to me beyond the 405g RNFP here in Canada. That's why I am abotu to take a serious look at casting my own bullets that can hopefully have (a) better shapes and (b) a choice of weights, in cluding 500g+ which so many buffalo rifle shooters have recommended for long range.
A friend gave me 13 samples of the 500g (actually 498g) bullet he casts for himself that has a pointed shape and is about 40% longer than a 405g RNFP. The statistics on that small sampling were very impressive in terms of consistency:
(Hey, I tried to align the columns, but the system un-aligned them when I hit the "Post" button)
CAS 45-70 bullets Bryan's 500g Sharp point cast lubed - Weight & Dimensions statistics
Weight Length Diameter
grains inches inches
1 498.3 1.4280 0.45850
2 499.7 1.4260 0.45850
3 498.1 1.4250 0.45850
4 501.7 1.4285 0.45850
5 499.3 1.4285 0.45850
6 498.9 1.4260 0.45850
7 498.4 1.4250 0.45850
8 498.1 1.4245 0.45850
9 498.9 1.4245 0.45850
10 498.4 1.4240 0.45850
11 498.5 1.4260 0.45850
12 500.1 1.4260 0.45850
13 502.0 1.4275 0.45850
TOTAL: Weight Length Diameter
Average 499.3 1.4261 0.45850
Std Dev 1.3 0.0016 0.00000
Max 502.0 1.4285 0.45850
Min 498.1 1.4240 0.45850
Extreme 3.9 0.0045 0.00000
% Extrem 0.8% 0.3% 0.0%
But my wife is pretty opposed to my handling molten lead and its fumes.
Jim G
AJC1
Member
Casting here in the US is kinda a hobby I have to control my supply, and not have to redevelop loads all the time. If you pick a decent size company like Missouri or others you get basically the same bullet box after box. In your situation with lack of availability, seems like casting is more of a nessisity. Small run casting for a friend isn't really a big deal, but production with a 2 or 6 cavity mold would suck. You might find yourself a spring and fall caster so you can be outside, while loading during the long winter... seems the cycle of northern foke from minisota to canada.
JimGnitecki
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Interestingly, I AM able to buy 405g Missouri cast bullets with the Hi-Tek coating here from one of the larger reload supply places. here are the statistics on THOSE (attached pdf):
Interesting to compare them to my friend's bullet statistics, especially since his are the "pointed" type versus flat point.
Jim G
Attachments
"It gets SQUARED in the equation, versus mass which is NOT squared"
Not really so in terms of calculating the recoil energy of the gun. Momentum is conserved. So the Mass times Velocity of the bullet equals the Mass times Velocity of the gun. To calculate the recoil energy the velocity of the gun is squared. so both the mass of the bullet and the velocity of the bullet contribute equally to the velocity of the gun and thus to the recoil energy of the gun. Note. The kinetic energy of the bullet is much higher than the kinetic energy of the gun.
Not really so in terms of calculating the recoil energy of the gun. Momentum is conserved. So the Mass times Velocity of the bullet equals the Mass times Velocity of the gun. To calculate the recoil energy the velocity of the gun is squared. so both the mass of the bullet and the velocity of the bullet contribute equally to the velocity of the gun and thus to the recoil energy of the gun. Note. The kinetic energy of the bullet is much higher than the kinetic energy of the gun.
sage5907
Member
I agree with this statement. I have compared Reloader 17 to IMR 4350, H 4350 and Reloader 16 and have found Rl 17 to be my preferred choice out of these four powders when used in 30-06 based cartridges. It can be loaded to a higher velocity without damaging cases. Alliant says Rl 17 has a similar burn rate speed to IMR 4350 with added velocity. They say it provides maximum velocity even in extreme weather. I have used it in 25-06, 270 Winchester, 30-06 and 338-06 with good results. There may be another powder that will provide better groups in certain condition but Rl 17 is very flexible. The long range shooters talk it down saying it is temperature sensitive but temperature change has little effect in a normal hunting situation. It shoots good groups no matter if the temperature is 20 degrees F or 80 degrees F. I like to sight my rifle in at about 50 degrees and I never notice point of impact changes. In the past I would say I have taken more big bucks with IMR 4350 than with any other powder but today Rl 17 has the edge.
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Whose "burn rate"?
There is no consistent industry-wide standard for determining a powders' burn rate. Some burn powder in the open while others use various pressure vessels and means of ignition.
Theoretically, a "slower" burning powder should produce lower recoil than a "faster" powder because the impulse from launching the bullet supposedly happens over a shorter period of time, but the relationship is not linear and is dependent upon a variety of factors such as whether the rifle is a bolt-action or a semi-automatic.
There is no consistent industry-wide standard for determining a powders' burn rate. Some burn powder in the open while others use various pressure vessels and means of ignition.
Theoretically, a "slower" burning powder should produce lower recoil than a "faster" powder because the impulse from launching the bullet supposedly happens over a shorter period of time, but the relationship is not linear and is dependent upon a variety of factors such as whether the rifle is a bolt-action or a semi-automatic.
sage5907
Member
I have no reason not to accept the powder burn rates that are shown the the various reloading manuals. For example, the 1st Edition of the Berger manual calls them "Smokeless Powder burn Rates" and the listing begins on Page 127 of their manual. They say the "powders are listed from fastest to slowest." The burn rates are listed from fast to slow with IMR 4350 being listed as No. 111, H 4350 is listed as No. 112, and Reloader 17 is listed as 113. Reloader 15 has a faster burn rate and is listed as No. 97. The Berger manual has a more complete listing than the listing provided by most bullet manufacturing companies or companies that manufacturer or sell smokeless powder.
