I have contracted Erik at HP molds to HP one cavity of the RCBS 257/120 gr FT. I have built a 25-06 AI on an Encore system with Bullberry barrel. Twist is 1-10 so long bullets are happier than short.
My intent with the mod is to get good to very good expansion with the rifle on coyote at 200 yds +. Maybe I am nuts. I have no issues with hitting the target, but simply having a solid bullet go THRU a dog does not lend itself to humane kills. I am lookignfor the violent Barnes varmint grenade type of action but cast!! I now I am maybe stretching the requirement refering to Barnes VG bullets, but thats the effect. Not knockdown, it's have a ton at 100 yds. More trauma in tissue, bloodletting,that sort of effect. In the LASC articles, the Lyman devastators fired into water, they look like roses fired at 100 MPH. Really opened up, scarry the trauma they would have caused. The pictures are nbasty looking. thats what I am looing for.
So I have given Erik the design job of modding the 120 grainer with an HP on a larger meplat. Most loading data that can be found is based on 100 gr, Saeco is the only mold mfgr to date with an applicable mold. I opted not to go that route.
Here are the questions:
Erik is putting up to .19 meplat on the bullet with a fairly significant HOLE in it. The hole has been defined as one that at 2500 FPS, it would NOT blow the bullet up midflight. I am looking for starting data on SLOW powders, such as 4895, varget, BL-C2, etc. Ones similar to the pressure/vel curves used by R. Lee in the Second Edition for the cast bullet section. Pressure is under 40kpsi, vels pushing 2800 fps (I know it's going to lead, but how many dogs can one kill on a single stand!!) Generic references to work up from would help. I don't shoot Accurate Arms powder. I have 4831, H4895, WW2 4895, BL-C2, Varget, Reloader 19 , Win Mag Rifle (yep 2 pounds), 4350, etc.
Secondly with a check, looking for max vel but WANTING FRAGMENTATION and bullet separation, what should the hardness (strength) be at. If the check is protecting the base, white label 2700+ carnuba red lubed with a good fit, should the bullet be SOFT or HARD. I don't want to waste Lino on these bullets if I can help it.
Third, with leading....... what velocities MIGHT I get with a 120 gr bullet and slow powder??? The Lyman 45 or 48 handbook shows at 29kPSI, pistol powder producing about 2200 fps. Similalry, I ahev gone slow powder in my 357 to boost vels beyond what most people shoot, 1300 fps + at 158 gr, plain base, with very good accuracy and leading that is easy to deal with. Bullets go thru rabbits at 100 yds, they are SWC's. Bullets are REAL hard, but not moving fast enough to fragment. there are NOT brittle. They are heat treated ww, mono and EH shot.
Can I do the same sort of pressure curve with this bullet on slow powders??
Fourth, do I need 2500 plus FPS to get the bomb to go off on impact, full fragmentation?? Will the bullet seriously deform and lower velocities in flesh without bone?? And if so, what BHN/alloy level would do so??? I have read the LASC pistol HP articles, thats fine but the velocities are lower, HPs are HUGE cavities and ballistically challenged calibers are used like 44 mag. It's not flat at 200 yds, unlike a .320 BC bullet will go at 2500+ velocity.
Thats a mouthfull I have spewed, hoping to catch the interest of the wise ones. I don't want to be restricted to 100gr jacketed spitzers the rest of my life, as accurate as they may be. They are expensive. Powder consumption is a NON issue. I will burn ANY amount of slow powder the case will hold to get the job done effectively. It's a hunting gun, not a bench gun. I can't kill enough dogs in a year to warrant speeding the powder up and sacrificing velocity and trajectory.
Thansk in advance
Mike, the nutty one
