I got a chance to do some velocity testing at 50 yards today, so I was able to calculate the Ballistics Coefficient for the new NOE Bob's Boattails.... I tested five bullets, the RN and HP version of the Lyman 57902 bullet for .25 ACPs, the BBT I designed for LBT Moulds, and the new BBT I designed for NOE.... I also tested the JSB King pellets.... I used two (calibrated) chronographs, at 1 yard and 51 yards from the muzzle, and then calculated the BC, corrected for the pressure, temperature, and altitude of the tests, to NPT conditions.... Here are the results....The difference in the BC with the boattail bullets is significant.... about 30-33% improvement compared to the flat based .25 ACP bullet from the Lyman mould.... The new NOE bullets had an 11% better BC than the almost identical BBT I cast using the LBT moulds, which have a smaller Meplat.... This confirms that there is no disadvantage to having a Meplat as large as 70% on relative short bullets, as proven many years ago by Elmer Keith.... It is interesting what happened with the 25 gr. JSB King pellets.... The way my Disco Double was tuned for the testing today, it blasted the Kings out at over 1200 fps.... What was astounding is that they arrived at 50 yards going only a bit faster than the bullets.... This confirms two things.... 1. That pellets have a poor BC.... and 2. that Supersonic velocities cause pellets to slow down at an extreme rate.... At 50 yards, the Bob's Boattails still had about 78 FPE of energy, but the Kings were down to just 43 FPE.... I then proceeded out to the ranch where I do my Varmint hunting.... I wanted to see how the 47.8 gr. NOE HP Bob's Boattail performed.... All I can say is, that headshots are no longer required, in fact the recovery rate is greater with a shot to the chest.... Not only do you have a much bigger target, but the bullet does a huge amount of damage as it passed through the quarry.... accompanied by a large spray of blood, clearly visible in the scope, and a loud WHACK! as the bullet hits.... Photos of the exit wounds on a Marmot and a Ground Squirrel, both taken at about 50 yards, will be in the hunting gate....Bob
I'm glad guys are having success with the new NOE BBTs.... Any time you change a design, or redesign, there is always a risk.... Using that larger Meplat, to shorten the bullet so that it will fit a Hatsan magazine as well as the MRod mags.... and having the BC actually improve over the previous bullet from LBT was a bonus.... I don't think there is much question that boattails really help reduce the drag and improve the BC to a greater degree Subsonic and Transonic than they do Supersonic.... Most guys told me I was nuts a couple of years ago when I suggested it.... but a BT only reduces the drag at Mach 3 by 10-15% at most.... At airgun velocities we are seeing improvements of about 25-35%, with BCs often improving by a third.... These latest NOE BBTs end up with a Form Factor of just over 1.... For the HP it is 0.109 / 0.101, and for the FN it is 0.116 / 0.107, which in both cases works out to 1.08.... The LBT was only 0.116 / 0.096 = 1.20.... and the .25 ACP RN flat base bullet was only 0.120 / 0.083 = 1.45.... That is a 34% advantage for my NOE boattails.... For the Lyman 257420, using your BC, it works out to 0.151 / 0.129 = 1.17.... I'm really looking forward to finding out what the BC of the boattail version of that a bullet I designed works out to.... You have some, don't you?.... *poke*....BTW, when I get some time I plan to take some BC measurements of the King and King Heavy pellets in smaller increments, to show what happens in the Supersonic and Transonic regions, compared to below 900 fps.... I think it will open a lot of eyes....Bob
Quote from: rsterne on June 21, 2016, 06:03:31 PMI'm glad guys are having success with the new NOE BBTs.... Any time you change a design, or redesign, there is always a risk.... Using that larger Meplat, to shorten the bullet so that it will fit a Hatsan magazine as well as the MRod mags.... and having the BC actually improve over the previous bullet from LBT was a bonus.... I don't think there is much question that boattails really help reduce the drag and improve the BC to a greater degree Subsonic and Transonic than they do Supersonic.... Most guys told me I was nuts a couple of years ago when I suggested it.... but a BT only reduces the drag at Mach 3 by 10-15% at most.... At airgun velocities we are seeing improvements of about 25-35%, with BCs often improving by a third.... These latest NOE BBTs end up with a Form Factor of just over 1.... For the HP it is 0.109 / 0.101, and for the FN it is 0.116 / 0.107, which in both cases works out to 1.08.... The LBT was only 0.116 / 0.096 = 1.20.... and the .25 ACP RN flat base bullet was only 0.120 / 0.083 = 1.45.... That is a 34% advantage for my NOE boattails.... For the Lyman 257420, using your BC, it works out to 0.151 / 0.129 = 1.17.... I'm really looking forward to finding out what the BC of the boattail version of that a bullet I designed works out to.... You have some, don't you?.... *poke*....BTW, when I get some time I plan to take some BC measurements of the King and King Heavy pellets in smaller increments, to show what happens in the Supersonic and Transonic regions, compared to below 900 fps.... I think it will open a lot of eyes....BobI have been using King heavies and I'm happy with them ...... but I waiting to see your test ... I think I may change my hunting pellets to your design as it will GREATLY turn my already very powerful Condor .25 into a Raving Monster of a varmint gun for sure ... this I think could be a real game changer !!! nice going Bob !wll2506
Quote from: wll2506 on June 21, 2016, 08:52:54 PMQuote from: rsterne on June 21, 2016, 06:03:31 PMI'm glad guys are having success with the new NOE BBTs.... Any time you change a design, or redesign, there is always a risk.... Using that larger Meplat, to shorten the bullet so that it will fit a Hatsan magazine as well as the MRod mags.... and having the BC actually improve over the previous bullet from LBT was a bonus.... I don't think there is much question that boattails really help reduce the drag and improve the BC to a greater degree Subsonic and Transonic than they do Supersonic.... Most guys told me I was nuts a couple of years ago when I suggested it.... but a BT only reduces the drag at Mach 3 by 10-15% at most.... At airgun velocities we are seeing improvements of about 25-35%, with BCs often improving by a third.... These latest NOE BBTs end up with a Form Factor of just over 1.... For the HP it is 0.109 / 0.101, and for the FN it is 0.116 / 0.107, which in both cases works out to 1.08.... The LBT was only 0.116 / 0.096 = 1.20.... and the .25 ACP RN flat base bullet was only 0.120 / 0.083 = 1.45.... That is a 34% advantage for my NOE boattails.... For the Lyman 257420, using your BC, it works out to 0.151 / 0.129 = 1.17.... I'm really looking forward to finding out what the BC of the boattail version of that a bullet I designed works out to.... You have some, don't you?.... *poke*....BTW, when I get some time I plan to take some BC measurements of the King and King Heavy pellets in smaller increments, to show what happens in the Supersonic and Transonic regions, compared to below 900 fps.... I think it will open a lot of eyes....BobI have been using King heavies and I'm happy with them ...... but I'm waiting to see your test ... I think I may change my hunting pellets to your design as it will GREATLY turn my already very powerful Condor .25 into a Raving Monster of a varmint gun for sure ... this I think could be a real game changer !!! nice going Bob !wll2506I will testify to it making the Condor .25 into a monster of a varmint gun! I took a starling with this bullet in my Condor SS, and the impact of the bullet hitting the starling in the center of the chest sounded like a .22lr rifle being shot. It dropped then and there, it did not feel a thing. This bullet is a very humane pest getter!
Quote from: rsterne on June 21, 2016, 06:03:31 PMI'm glad guys are having success with the new NOE BBTs.... Any time you change a design, or redesign, there is always a risk.... Using that larger Meplat, to shorten the bullet so that it will fit a Hatsan magazine as well as the MRod mags.... and having the BC actually improve over the previous bullet from LBT was a bonus.... I don't think there is much question that boattails really help reduce the drag and improve the BC to a greater degree Subsonic and Transonic than they do Supersonic.... Most guys told me I was nuts a couple of years ago when I suggested it.... but a BT only reduces the drag at Mach 3 by 10-15% at most.... At airgun velocities we are seeing improvements of about 25-35%, with BCs often improving by a third.... These latest NOE BBTs end up with a Form Factor of just over 1.... For the HP it is 0.109 / 0.101, and for the FN it is 0.116 / 0.107, which in both cases works out to 1.08.... The LBT was only 0.116 / 0.096 = 1.20.... and the .25 ACP RN flat base bullet was only 0.120 / 0.083 = 1.45.... That is a 34% advantage for my NOE boattails.... For the Lyman 257420, using your BC, it works out to 0.151 / 0.129 = 1.17.... I'm really looking forward to finding out what the BC of the boattail version of that a bullet I designed works out to.... You have some, don't you?.... *poke*....BTW, when I get some time I plan to take some BC measurements of the King and King Heavy pellets in smaller increments, to show what happens in the Supersonic and Transonic regions, compared to below 900 fps.... I think it will open a lot of eyes....BobI have been using King heavies and I'm happy with them ...... but I'm waiting to see your test ... I think I may change my hunting pellets to your design as it will GREATLY turn my already very powerful Condor .25 into a Raving Monster of a varmint gun for sure ... this I think could be a real game changer !!! nice going Bob !wll2506
Quote from: deadguy on June 21, 2016, 10:28:30 PMQuote from: wll2506 on June 21, 2016, 08:52:54 PMQuote from: rsterne on June 21, 2016, 06:03:31 PMI have been using King heavies and I'm happy with them ...... but I'm waiting to see your test ... I think I may change my hunting pellets to your design as it will GREATLY turn my already very powerful Condor .25 into a Raving Monster of a varmint gun for sure ... this I think could be a real game changer !!! nice going Bob !wll2506I will testify to it making the Condor .25 into a monster of a varmint gun! I took a starling with this bullet in my Condor SS, and the impact of the bullet hitting the starling in the center of the chest sounded like a .22lr rifle being shot. It dropped then and there, it did not feel a thing. This bullet is a very humane pest getter!Did you make your own Bob's slugs or did you buy them ? And if you bought them, from who ;- )wll2506I made mine. I bought the mold when it was offered as a group buy on the NOE forums.
Quote from: wll2506 on June 21, 2016, 08:52:54 PMQuote from: rsterne on June 21, 2016, 06:03:31 PMI have been using King heavies and I'm happy with them ...... but I'm waiting to see your test ... I think I may change my hunting pellets to your design as it will GREATLY turn my already very powerful Condor .25 into a Raving Monster of a varmint gun for sure ... this I think could be a real game changer !!! nice going Bob !wll2506I will testify to it making the Condor .25 into a monster of a varmint gun! I took a starling with this bullet in my Condor SS, and the impact of the bullet hitting the starling in the center of the chest sounded like a .22lr rifle being shot. It dropped then and there, it did not feel a thing. This bullet is a very humane pest getter!Did you make your own Bob's slugs or did you buy them ? And if you bought them, from who ;- )wll2506
Quote from: rsterne on June 21, 2016, 06:03:31 PMI have been using King heavies and I'm happy with them ...... but I'm waiting to see your test ... I think I may change my hunting pellets to your design as it will GREATLY turn my already very powerful Condor .25 into a Raving Monster of a varmint gun for sure ... this I think could be a real game changer !!! nice going Bob !wll2506I will testify to it making the Condor .25 into a monster of a varmint gun! I took a starling with this bullet in my Condor SS, and the impact of the bullet hitting the starling in the center of the chest sounded like a .22lr rifle being shot. It dropped then and there, it did not feel a thing. This bullet is a very humane pest getter!
I have been using King heavies and I'm happy with them ...... but I'm waiting to see your test ... I think I may change my hunting pellets to your design as it will GREATLY turn my already very powerful Condor .25 into a Raving Monster of a varmint gun for sure ... this I think could be a real game changer !!! nice going Bob !wll2506
Advertise Here
Share This!