Fiftydriver
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Just finished up initial load development and accuracy testing of my new 458 Maximus wildcat. This wildcat has been in the works for many years on paper but have had to deal with some delays and other issues in the shop that prevented me from taking the time to dive into the project with both feet. Originally this was to be my 458 Allen Magnum which was also to be simply my 510 Allen Magnum necked down to 458 caliber and neck trimmed to a more appropriate length.
At the time I was drawing up this wildcat, the only bullets on the market for the 458 that were suitable for long range shooting were in the 525-560 gr range. Not bad and all had decent BC values but with that weight, would be marginal for the practical use of the capacity of the Allen Magnum case design on the BMG parent case. This was the reason I decided to simply go with the 510 Allen Magnum necked down to 458 cal.
However over the years, I got several contacts and while at first we were looking at making 550 gr class projectiles, now I was dreaming of 650 grain class projos, which is the same as the bottom end 50 BMG class projectiles but with a much higher sectional density. As such, I decided I would try to get a bit more capacity out of this new wildcat and basically split the difference between the capacity of my 510 Allen Magnum and my 510 Maximus wildcat. And with this change would call the new wildcat the 458 Maximus. See pic below:
Left to right: 510 Maximus prototype, 458 Maximus, 510 Allen Magnum, standard 50 BMG.
Now as you can see, the 458 is loaded with a rather long, monolithic bullet. I am not going to give any SPECIFIC bullet details at this time but will talk about the work going into designing this new projo.
I contacted Lehigh Bullets and Hammer bullets to see if they could get me some test bullets. Have had great results with both in different calibers and Lehigh already had a 525 gr and had send me some custom 550 gr 458 bullets a couple years earlier when I was starting the work on this wildcat.
I had used a lot of Hammer bullets for my smaller caliber wildcats for big game hunting and they had always shot extremely well and performed very well on game when used with the appropriate twist rate. However they had always been a bit lacking in BC which is not a fault of theirs, its hard to get a really high BC with a solid bullet design in calibers under 375 and especially under 338.
For this project however I told them I had a 12 twist barrel and wanted as high of a BC bullet as possible and there was no need for their standard HP design as these would be used for extreme range shooting only. They replied that they felt they could get me a 700 gr. bullet weight!!!! I was extremely excited. A couple weeks later a box showed up from Hammer with the new monster 458 caliber bullets and I was blown away.
My goal for this wildcat was always to best the 50 cal wildcats on this same case. As most of you know, I have been a 50 BMG shooter for nearly 3 decades now and truly love shooting and building the big rifles. While they are a small percentage of my customer orders, they truly are my passion to build and as such shaped my entire shop set up with machines specifically large enough to easily handle machining for these big rifles.
Anyway, back to my goals, I always wanted GOOD BC numbers but was just figuring I would get a projo with a G1 BC in the .8 range and would just need to flat out horsepower it out to 3400 fps class. That way I would get the trajectory similar to my 338 Allen Magnums and 375 Allen Magnums but with a kenetic energy payload similar to the 50 BMG. Its always been a trade off, if you want extremely flat shooting, go with the 338 or 375, if you want extreme wind bucking performance, the big 50 cals are great but are not flat shooting.
My idea for the original 458 Allen Magnum was to bridge these two, give the trajectory of the smaller wildcats and the extreme wind drift performance of the big boys..... We would get this with a GOOD bc factor but also with extreme velocity, for a BMG class weapon system.
However, with the new dream and now reality of these SUPER 458 cal bullets, my goals had changes. Taking some measurements and making some comparisions, I was figuring these new 700 gr projos would have a BC very similar to the very best 50 cal 800-815 gr solid designs, in the 1.00-1.100 g1 BC range. Obviously I will be using the g7 scale but most think on a g1 scale so for this article I will talk in g1. Now, my thoughts changed, now had bullets that would likely match the best BC of the 510 cal projos, now it was just time to see what kind of velocity increases we could expect.
In this pic, the Gen 1 Hammer 700 gr. is on the left, the old work horse 750 gr Hornady Amax on the right. The Hammer is 50 grains lighter but measureable longer, even with the huge lightweight aluminum tip on the Amax projo.
I will show this picture of the Gen 1 because we are now onto the Gen 2 version which is significantly different in design so the Gen 1 version is already outdated!!! Just showing for size comparision. This is simply out of professional respect for the manufacturer until final bullet design is set and we are into production models.
With the new 700 gr. Hammers in hand, it was time to start load development. The real reason this project got moving now is that a customer had had one of my 458 Allen Magnum rifles on order for some time waiting for R&D to get done. I asked him if he minded if I used his rifles as the test rifle and he said go for it so we were on our way. Would kill two birds with one stone, get a long overdue project done and get my new wildcat tested and proven. The rifle was based on a medium BR type weapon design using a McMillan TAC50 single shot receiver and 35" straight taper SS barrel with 12 twist. On the muzzle was one of my Super 6 port Painkiller muzzle brakes. The stock was a McMillan 50BR stock and jewell trigger with bottom safety to control the beast.
Now if you have a sharp eye, you will notice that the barrel and brake are not finished in this picture. This is because we were walking on completely untreaded ground here. Had no idea if the new projos would fly and because they needed a very long throat, if they did now work, I may need to set the barrel back to shorten the throat for use with the available 458 bullets out there from the likes of Lehigh.
Initial load development was interesting. Tested H50BMG, US869, RL50 and VV20n29 for commercial powders and also tested three lots of WC860 and WC872 surplus powders. In every instance they all hit a hard pressure wall at 2950-2975 fps. Was quite strange. All used different amounts of powder to get that but every one hit the wall at this point.
Was a bit unimpressed with this as my initial goals were to get 3400 fps with a 550 gr class bullet and hopefully 3200 fps with the 700 gr making my estimates off years of playing with the 50 BMG class weapons and comparing velocity gains and losses depending on heavier or lighter bullet weights. My estimates were around 200-250 fps over what reality was allowing..... This is not something I generally miss this badly on.....
Again, A bit low after seeing this. However, after this velocity load development testing, I decided to try US869 with the custom 550 gr Lehigh solids I had from a couple years earlier. This testing went very smooth, velocity and pressure increases were smooth, predictable and steady, no hitting pressure walls. I was able to drive these 550 gr lehighs to 3400 fps!!! Right where I was expecting them to be out of this barrel length.
This made me take a look at the 700 gr Hammer again. I found several areas which I felt were the reason for the pressure limits with this bullet. Not that near 3000 fps was bad, in fact that's the magic number the 416 Barrett boys look for with their 550 gr CE laser bullets but need 40" barrels to get it. I was there with a MUCH higher sectional density bullet in a 35" barrel so needed to take a breath.
Still I felt there was much more potential with this bullet. Talked to the boys at Hammer bullets and offered them my recommendations, they offered me their concerns and we agreed to just SEE what happened.
Week or so later another box of 25 test bullets arrived. The changes were exactly what I had requested and resulted in a bullet of the same length but now weighed 680 gr. Not a bad thing for velocity potential.
Load development showed that the new design would require a longer OAL to seat to the lands, 5.925" compared to 5.835" for the old design. I just used US869 as a test powder as it works well for performance and I had old data to compare it to. With the old design, 235.0 gr was max load at 2950 fps.
With the new design, I topped out at 265.0 gr which produced 3210 fps but was getting the first hint of primer pocket loosening. At 260.0 gr there was no sign or FEEL of primer pocket loosening with 3185 fps but decided to drop back to 257.0 gr which produced 3150 fps just to get real comfortable and offer the good case life I am always after with my wildcats.
We were able to gain 200-250 fps over the Gen 1 bullet design. I was right where I had predicted I would be for performance numbers. MUCH happier with life now.
Loaded up 15 rounds of test ammo for accuracy testing as now was the moment of truth. Had the performance numbers, now we needed to see if these bullets would shoot as there was a bit of concern about full stability. So headed up to the range, set up at 100 yards with one of my Vortex Razor test scopes in the saddles.
Bore sighted the rifle and took two shots. These landed 3/4" apart but low and left. Pretty good for just mounting a scope. Positive!!! Then made a scope adjustment and shot three rounds for record.
Could not be much happier with those results, Sub .3" group with first shot being the low left and second two cutting basically the same hole. Not to bad for a rifle developing 15,500 ft/lbs of energy!!! Very happy. however this rifle and wildcat was not ment to be shot at 100 yards. Needed to see what they would do at long range. Just took the 1.100 BC of the berger 800 gr 50 cal bore rider to see how close it was at long range. Ran the numbers and then with the remaining ammo, tested at 1105 and 1600 yards..... Dead on the money, very impressed. Going to try to upload some short video clips of that next. All in all very happy and the 458 Maximus with 680 gr. Hammer projo is proven and good to go to customers!!!
So we have proven the 458 Maximus has the ability to drive a 1.100 bc projo to 3200 fps levels with sub 1/2 moa accuracy potential. Next up extreme range testing.
At the time I was drawing up this wildcat, the only bullets on the market for the 458 that were suitable for long range shooting were in the 525-560 gr range. Not bad and all had decent BC values but with that weight, would be marginal for the practical use of the capacity of the Allen Magnum case design on the BMG parent case. This was the reason I decided to simply go with the 510 Allen Magnum necked down to 458 cal.
However over the years, I got several contacts and while at first we were looking at making 550 gr class projectiles, now I was dreaming of 650 grain class projos, which is the same as the bottom end 50 BMG class projectiles but with a much higher sectional density. As such, I decided I would try to get a bit more capacity out of this new wildcat and basically split the difference between the capacity of my 510 Allen Magnum and my 510 Maximus wildcat. And with this change would call the new wildcat the 458 Maximus. See pic below:
Left to right: 510 Maximus prototype, 458 Maximus, 510 Allen Magnum, standard 50 BMG.
Now as you can see, the 458 is loaded with a rather long, monolithic bullet. I am not going to give any SPECIFIC bullet details at this time but will talk about the work going into designing this new projo.
I contacted Lehigh Bullets and Hammer bullets to see if they could get me some test bullets. Have had great results with both in different calibers and Lehigh already had a 525 gr and had send me some custom 550 gr 458 bullets a couple years earlier when I was starting the work on this wildcat.
I had used a lot of Hammer bullets for my smaller caliber wildcats for big game hunting and they had always shot extremely well and performed very well on game when used with the appropriate twist rate. However they had always been a bit lacking in BC which is not a fault of theirs, its hard to get a really high BC with a solid bullet design in calibers under 375 and especially under 338.
For this project however I told them I had a 12 twist barrel and wanted as high of a BC bullet as possible and there was no need for their standard HP design as these would be used for extreme range shooting only. They replied that they felt they could get me a 700 gr. bullet weight!!!! I was extremely excited. A couple weeks later a box showed up from Hammer with the new monster 458 caliber bullets and I was blown away.
My goal for this wildcat was always to best the 50 cal wildcats on this same case. As most of you know, I have been a 50 BMG shooter for nearly 3 decades now and truly love shooting and building the big rifles. While they are a small percentage of my customer orders, they truly are my passion to build and as such shaped my entire shop set up with machines specifically large enough to easily handle machining for these big rifles.
Anyway, back to my goals, I always wanted GOOD BC numbers but was just figuring I would get a projo with a G1 BC in the .8 range and would just need to flat out horsepower it out to 3400 fps class. That way I would get the trajectory similar to my 338 Allen Magnums and 375 Allen Magnums but with a kenetic energy payload similar to the 50 BMG. Its always been a trade off, if you want extremely flat shooting, go with the 338 or 375, if you want extreme wind bucking performance, the big 50 cals are great but are not flat shooting.
My idea for the original 458 Allen Magnum was to bridge these two, give the trajectory of the smaller wildcats and the extreme wind drift performance of the big boys..... We would get this with a GOOD bc factor but also with extreme velocity, for a BMG class weapon system.
However, with the new dream and now reality of these SUPER 458 cal bullets, my goals had changes. Taking some measurements and making some comparisions, I was figuring these new 700 gr projos would have a BC very similar to the very best 50 cal 800-815 gr solid designs, in the 1.00-1.100 g1 BC range. Obviously I will be using the g7 scale but most think on a g1 scale so for this article I will talk in g1. Now, my thoughts changed, now had bullets that would likely match the best BC of the 510 cal projos, now it was just time to see what kind of velocity increases we could expect.
In this pic, the Gen 1 Hammer 700 gr. is on the left, the old work horse 750 gr Hornady Amax on the right. The Hammer is 50 grains lighter but measureable longer, even with the huge lightweight aluminum tip on the Amax projo.
I will show this picture of the Gen 1 because we are now onto the Gen 2 version which is significantly different in design so the Gen 1 version is already outdated!!! Just showing for size comparision. This is simply out of professional respect for the manufacturer until final bullet design is set and we are into production models.
With the new 700 gr. Hammers in hand, it was time to start load development. The real reason this project got moving now is that a customer had had one of my 458 Allen Magnum rifles on order for some time waiting for R&D to get done. I asked him if he minded if I used his rifles as the test rifle and he said go for it so we were on our way. Would kill two birds with one stone, get a long overdue project done and get my new wildcat tested and proven. The rifle was based on a medium BR type weapon design using a McMillan TAC50 single shot receiver and 35" straight taper SS barrel with 12 twist. On the muzzle was one of my Super 6 port Painkiller muzzle brakes. The stock was a McMillan 50BR stock and jewell trigger with bottom safety to control the beast.
Now if you have a sharp eye, you will notice that the barrel and brake are not finished in this picture. This is because we were walking on completely untreaded ground here. Had no idea if the new projos would fly and because they needed a very long throat, if they did now work, I may need to set the barrel back to shorten the throat for use with the available 458 bullets out there from the likes of Lehigh.
Initial load development was interesting. Tested H50BMG, US869, RL50 and VV20n29 for commercial powders and also tested three lots of WC860 and WC872 surplus powders. In every instance they all hit a hard pressure wall at 2950-2975 fps. Was quite strange. All used different amounts of powder to get that but every one hit the wall at this point.
Was a bit unimpressed with this as my initial goals were to get 3400 fps with a 550 gr class bullet and hopefully 3200 fps with the 700 gr making my estimates off years of playing with the 50 BMG class weapons and comparing velocity gains and losses depending on heavier or lighter bullet weights. My estimates were around 200-250 fps over what reality was allowing..... This is not something I generally miss this badly on.....
Again, A bit low after seeing this. However, after this velocity load development testing, I decided to try US869 with the custom 550 gr Lehigh solids I had from a couple years earlier. This testing went very smooth, velocity and pressure increases were smooth, predictable and steady, no hitting pressure walls. I was able to drive these 550 gr lehighs to 3400 fps!!! Right where I was expecting them to be out of this barrel length.
This made me take a look at the 700 gr Hammer again. I found several areas which I felt were the reason for the pressure limits with this bullet. Not that near 3000 fps was bad, in fact that's the magic number the 416 Barrett boys look for with their 550 gr CE laser bullets but need 40" barrels to get it. I was there with a MUCH higher sectional density bullet in a 35" barrel so needed to take a breath.
Still I felt there was much more potential with this bullet. Talked to the boys at Hammer bullets and offered them my recommendations, they offered me their concerns and we agreed to just SEE what happened.
Week or so later another box of 25 test bullets arrived. The changes were exactly what I had requested and resulted in a bullet of the same length but now weighed 680 gr. Not a bad thing for velocity potential.
Load development showed that the new design would require a longer OAL to seat to the lands, 5.925" compared to 5.835" for the old design. I just used US869 as a test powder as it works well for performance and I had old data to compare it to. With the old design, 235.0 gr was max load at 2950 fps.
With the new design, I topped out at 265.0 gr which produced 3210 fps but was getting the first hint of primer pocket loosening. At 260.0 gr there was no sign or FEEL of primer pocket loosening with 3185 fps but decided to drop back to 257.0 gr which produced 3150 fps just to get real comfortable and offer the good case life I am always after with my wildcats.
We were able to gain 200-250 fps over the Gen 1 bullet design. I was right where I had predicted I would be for performance numbers. MUCH happier with life now.
Loaded up 15 rounds of test ammo for accuracy testing as now was the moment of truth. Had the performance numbers, now we needed to see if these bullets would shoot as there was a bit of concern about full stability. So headed up to the range, set up at 100 yards with one of my Vortex Razor test scopes in the saddles.
Bore sighted the rifle and took two shots. These landed 3/4" apart but low and left. Pretty good for just mounting a scope. Positive!!! Then made a scope adjustment and shot three rounds for record.
Could not be much happier with those results, Sub .3" group with first shot being the low left and second two cutting basically the same hole. Not to bad for a rifle developing 15,500 ft/lbs of energy!!! Very happy. however this rifle and wildcat was not ment to be shot at 100 yards. Needed to see what they would do at long range. Just took the 1.100 BC of the berger 800 gr 50 cal bore rider to see how close it was at long range. Ran the numbers and then with the remaining ammo, tested at 1105 and 1600 yards..... Dead on the money, very impressed. Going to try to upload some short video clips of that next. All in all very happy and the 458 Maximus with 680 gr. Hammer projo is proven and good to go to customers!!!
So we have proven the 458 Maximus has the ability to drive a 1.100 bc projo to 3200 fps levels with sub 1/2 moa accuracy potential. Next up extreme range testing.
