I just wanted to reach out here to see if I could find folks to trade information with that are pushing lead core bullets over the 4600 fps range. With the loss of Saubier’s website as an information sharing site I’m hoping that some of those folks might happen to frequent this site.
I want to prefac this message that I’m strictly looking for
LEAD CORE shooters that are pushing past the 4400 to 4600 fps range. I am not looking for information on shooting solids. I have a great deal of information on that already.
There currently seems to be a big void on folks trading information on lead core bullets crossing over the Mach 4 range. I would really like to share data on bullet coatings and bullet designs on lead core bullets pushing past the “Red Zone”.
I’m finding a new wall between Mach 4.4 and Mach 4.5 and want to see if others here are seeing the same thing. I’d also like to trade ideas and techniques to cross that wall.
Thanks for any information you can share in its regard and as always stay on target,
Carl C.
Extreme Accuracy
www.14caliber.com
Carl C.-
Howdy !
I have stepped off on my next varmint rifle project:
My intention is to see whether I can coax the Hornady .224” cal 55XS to 4,000fps.
Hornady has cautioned shooters/reloaders not to exceed 3,400fps w/ the 55SX,
because of its .009” jacket thickness. I have already shot them successfully @ 3,700fps for many years…. and have always been curious to see how much more MV the bullet could work with ?
I decided to explore the possibilities, via use of a “ gain twist “ barrel.
The idea being:
- calculate the “ stability factor “ for the 55SX @ 3,700fps, using a twist rate calculator
- adjust the MV for 4,000fps in the rifle twist rate calculator
- determine what twist rate works along w/ 4,000fps, to allow matching the proven stability factor obtained @ the lower 3,700fps velocity level.
That of course, necessitates the selection of a new; more-relaxed twist rate ( IMHO ).
While the arbitrary 4,000fps MV I mention is not Mach 4, I imagine the same approach could be utilized…for upping bullet MV to 4,500fps ( example ) ?
Notionally, the relaxed “ gain twist “ should allow the bullet to begin its initial introduction
to the rifling w/o undue extra stress. I have read that some have expressed concern that lead “ cores “ might be shocked into separating from copper bullet “ cores “
when ultra-high muzzle velocities are present. In that regard, again…. a suitably relaxed starting twist rate in the barrel should help address initial bullet /rifling interface stresses ( IMHO ), and preclude core/cup separation. Anyway, that’s the theory.
I selected a comparatively “ long finished length for my .224” caliber Bartlein gain twist barrel. I also am ( again ) going w/ my “ .22-35 Remington “ wildcat chambering.
This one-two punch was selected to specifically taylor the “ total volume “ of the gun by addressing both key factors in the .224” cal rifle’s “ expansion ratio “…. chamber volumne + barrel bore volumne. My preference is to always have the gun operate w/o excessively high pressure. Like renowned ballistician Homer Powell told us…
“High pressure is high temperature, and therefore; fast erosion. It is as simple as that“
As bullet velocity increases during its travel down the barrel, it gradually is imparted an increasing spin rate, to notionally exit the barrel @ 4,000fps…and w/ the stable spin rate noted above.
Other:
I read a gun magazine article last year, that talked about guns/ammo that were used to reach a “ 1 mile per second “ muzzle velocity. That MV level would fall within your velocity area of regard. While I don’t specifically recall which magazine/issue, I do remember one cartridge used to reach 1mile-per-second vel was a .220 Weatherby
Rocket. And…while I also don’t recall the specific bullet wt employed, I did note that the experimenters used some 44gr of IMR 4064 in the load. If I get a chance, I’ll see if
I can find what magazine/issue contained the article; and let you know.
Another tech article of possible interest would be the DOD project to obtain a cartridge that could propel a bullet to 6,000fps. Wildcatter and famous gun writer Robert Hutton
used his version of the “ .22-284 Winchester “ wildcat to successfully achieve and even exceed the DOD’s velocity goal. It was the cover article for Guns & Ammo Aug 1964 issue, and Mr. Hutton was the author. An internet search revealed a brief synopsis of the 6,000fps experiment, which mentioned the use of custom-made thickly jacketed bullets.
Also, a potential source for some useful info might be tech articles about the “ Powley-
Miller venturified freebore ( PMVF ) cartridge(s). Powley’s tech writings were often featured in old “ Rifle Magazine “ issues. Many of these have been digitally archived, and are available to read off the Net. Powley and co-wildcatter Harvey Miller worked on the project together. It’s another reference I’d have to research, in order to let you know where to find the archive.
I have included a couple of pics, showing the breech end of the barrel; and my .22-35
wildcat.
The rifle smith finally received my Bartlein barrel and a takeoff barrel ( sent to give example of threads used ), my Wichita WBR1375 action, action wrench; and sample inert
cartridge + empty unprimed case for use in setting head space… just last Friday.
The goal is to ( ideally ) have the gun up N’ running in time for my 2026 NE Indiana anti-groundhog work !
I will then report on my project results, fer sher !
With regards,
357Mag
