GEOMETRIC
12-19-2017, 04:45 PM
I am just getting acquainted with this web site so please excuse me if this question has already been posted. I know you can research it somewhere on here but I haven't found out how yet.
I have a Pedersoli (Trail Guns Armory) Kodiak Mk. IV in .45-70. I believe the maximum service pressure according to Pedersoli is about 28,000 psi. The gun will probably handle more than that but I have never been one to press the envelope. I feel much better when I know my equipment is well within it's design limits. I see loads from Lyman & Hodgdon pushing 400 & 420 gr. CB's at 1875, 1934, & 1845 fps. @ less than 2800 CUP. Yes, I know PSI is not the same as CUP but Lyman states they are very close in a .45-70. Push the velocity up 100 fps. & pressure jumps on the order of about 10,000 or more PSI. Now, I have no desire to make a .458 out of my .45-70 but there are times when the higher end loads could be useful. A Cape Buffalo hunt is pie in the sky for me but if you think a 400 lb. boar with 4+ inch tusks can't hurt you, you better think again! He can kill you with his dying breath.
That brings me to my question which is two fold. First, do you really get enough out of that extra 100 fps to justify the cost in pressure, recoil & wear & tear on you & the equipment? The other part of the question has to do with the fact that I have read discussions on rechambering .45-70s to .45-90. I have actually seen a Kodiak Mk IV advertised that was so altered. Could that increase in powder volume give you more velocity for the same or nearly the same pressure?
Actually, I am more worried about recoil. The gun will shoot loose long before it blows up but more recoil than it can handle will destroy it. A lower chamber pressure is indicative of a more gradual increase in velocity. The rate of energy transfer is a key element in any engineering or physics formula describing destructive forces.
There is new research on the effectiveness of .45 cal. bullets at various velocities but I could only find one guy that wrote that he used a double rifle in Africa in .45-70. His experience spanned a number of years & he reports good results. Other than he used .500 gr. bullets, I don't believe he said what the load was. Research in recent years shows that penetration starts to decrease over a certain velocity, as I imagine most of you already know.
BTW, I also have a Kodiak Mk. VI in .58 cal. Both are regulated far better than I expected. I thought I was going to have to do a lot of load development to get decent groups but both rifles produced great groups at any range that they should be used. The .58 shoots RB's as well as it shoots conicals. I usually use RB's for deer as that is more than adequate for any deer under 100 yds. I have a custom mold that produces a 420 gr.+/- bullet (.45-70) that I had made for a Ruger No. 1 but it works fine in the Pedersoli as well.
I have a Pedersoli (Trail Guns Armory) Kodiak Mk. IV in .45-70. I believe the maximum service pressure according to Pedersoli is about 28,000 psi. The gun will probably handle more than that but I have never been one to press the envelope. I feel much better when I know my equipment is well within it's design limits. I see loads from Lyman & Hodgdon pushing 400 & 420 gr. CB's at 1875, 1934, & 1845 fps. @ less than 2800 CUP. Yes, I know PSI is not the same as CUP but Lyman states they are very close in a .45-70. Push the velocity up 100 fps. & pressure jumps on the order of about 10,000 or more PSI. Now, I have no desire to make a .458 out of my .45-70 but there are times when the higher end loads could be useful. A Cape Buffalo hunt is pie in the sky for me but if you think a 400 lb. boar with 4+ inch tusks can't hurt you, you better think again! He can kill you with his dying breath.
That brings me to my question which is two fold. First, do you really get enough out of that extra 100 fps to justify the cost in pressure, recoil & wear & tear on you & the equipment? The other part of the question has to do with the fact that I have read discussions on rechambering .45-70s to .45-90. I have actually seen a Kodiak Mk IV advertised that was so altered. Could that increase in powder volume give you more velocity for the same or nearly the same pressure?
Actually, I am more worried about recoil. The gun will shoot loose long before it blows up but more recoil than it can handle will destroy it. A lower chamber pressure is indicative of a more gradual increase in velocity. The rate of energy transfer is a key element in any engineering or physics formula describing destructive forces.
There is new research on the effectiveness of .45 cal. bullets at various velocities but I could only find one guy that wrote that he used a double rifle in Africa in .45-70. His experience spanned a number of years & he reports good results. Other than he used .500 gr. bullets, I don't believe he said what the load was. Research in recent years shows that penetration starts to decrease over a certain velocity, as I imagine most of you already know.
BTW, I also have a Kodiak Mk. VI in .58 cal. Both are regulated far better than I expected. I thought I was going to have to do a lot of load development to get decent groups but both rifles produced great groups at any range that they should be used. The .58 shoots RB's as well as it shoots conicals. I usually use RB's for deer as that is more than adequate for any deer under 100 yds. I have a custom mold that produces a 420 gr.+/- bullet (.45-70) that I had made for a Ruger No. 1 but it works fine in the Pedersoli as well.