Larry Gibson
posted this
14 December 2014
Not sure about being a “wizard” as I leave the “wizardry” over on the other forum to those who conjure themselves to be one. I prefer solid testing and science.
It is not difficult to shoot cast bullets at high velocity with a reasonable, useable and repeatable degree of accuracy. It does not take years of tutelage and study under a “wizard” to do so. It does not take years and thousands of rounds testing every variation of components known to man. The wheel has already been invented so to speak. The knowledge of how to shoot cast bullets at high velocity is known and is not a “secret” known only to the “master". You simply have to have an appropriate cartridge, an appropriately designed cast bullet, know how to cast a high quality bullet, use the right alloy, use the right components and use an appropriate twist in the barrel to control the RPM while adequately stabilizing the bullet of sufficient length for minimal acceleration rate.
Shooting cast bullets at high velocity is not difficult. Bjorn has accomplished it in 6 months. Most of that time was used up with a probable defective barrel and simply learning how to cast a real quality bullet. Now with his good barrel he is moving ahead by leaps and bounds. Anyone can do the same, even you.
I have been doing so for some time with my own 14” twist barrel of 27.6” length chambered in .308W. I have been using 3 bullets; the LBT 30-160-SP, the Lyman 311466 and the NOE 310-165-FN (30 XCB.) Only those 3 bullets have consistently proved accurate above 2500 fps regardless of the cartridge or barrel twist. None of the bore riding designs have done so, not even the modern bore riders. There are reasons for that but I intend to keep this post short simply to make the point that high velocity accuracy is very possible and not difficult to achieve. If you want to achieve the same then do the same. However, let me note that I, Bjorn or you are not going to achieve the same in a milsurp ’06, AR or “regular” rifle using a Lee mould, COWW alloy, beer can GCs, toilet ring lube and 2400 powder. It’s just not in the cards no matter what the “wizards” say, even if you do use “original buffer”. The reason you can do so one way and not the other is found in the laws of physics and ballistics not in the library at Hogwart U.
Right now I’m wrapped up in a lube test of 13 different lubes which will be tested at 2600 fps +/- (195 test rounds). I’m also finishing testing the 30 XCB bullet in a 10” twist and 12” twist .308W rifles at Mach 2+ velocities. When I finish that I’ll move back to the 14” twist Palma rifle and test the LBT 31-150-SP at 2600 – 2800 fps. By then my 30”+ barrel with 16” twist chambered in a tight neck 30x60 (the 30 XCB just deeper is al) which will give a bit more capacity. All of my test data is collected via the Oehler M43 so I get a very good “look” at the velocities, the BCs, the psi and the time pressure traces.
So as an example here’s what the 311466 can do at 2614 fps from the 14” twist rifle. Second post is what the NOE XCB bullet can do at 2704 fps. Bjorn is posting as good and better using breech seated bullets (not really my forte’ but it’s what he’s doing and it works).
LMGN
Concealment is not cover.........
