Hi, I am new to this board. I have several .22 centerfires and a Hart-barreled tight-neck 7mm Mag varminter that I use for PDs a couple times a year. A few years ago, I rechambered a Savage 112FLVSS .22-250 to .22 Cheetah MarkI. It is in a Choate varminter stock, has a Canjar trigger and a 8-32 Burris. Since I have several other .22 CFs, I find that I do not shoot this one much so I have the barrel, dies, and brass sold. I am going to order a PacNor to put back on it. I have been wrestling with what I want. I am leaning toward a 3-groove, 6mm, 8-twist, ss, supermatch with a straight taper. The 8 twist is so I can shoot 105 A-Maxes and 107 MKs. I am not a fan of 40 degree shoulders for several reasons. Based upon case capacity, I am leaning toward a plain old .243 Winchester chamber. Brass is easy to come by, the case is big enough, but not so big that I am restricted to a couple of slow powders...That last couple hundred fps come at a high price.
My question now is since the rifle is already not very portable, how long should I make the barrel? I have a 700 BDL LH with a 28" #5 Lilja that I use as a plains rifle. My thought is to burn what is in the case in the barrel...no need for a bigger case and then only more muzzle flash...so what length should I make the 6mm barrel?
Any input as to cartridges and barrel lengths would be welcomed. After the CheetaH, I am sick of making cases. I'm not opposed to flash hole deburring, neck turning, and annealing, I do that to all of my cases, I am just sick of making a career out of producing a few pieces of brass.
Just one thought; the 6mm barrel with an 8 twist in a 3 groove may be very hard on thin jacketed match bullets. If you want to push VLD bullets at high velocity you may want to consider a 6 groove. Not all match bullets can take the abuse that the SMK's can.
I must agree 3 groove barrels in .243 cal are hell on match bullets if pushed too hard, 105gr Bergers out of my 6-284 3 groove will vaporize leaving the muzzle at 3300fps but on the up side 107gr MK's can be pushed as fast as you want and shoot better anyway.
out of a standard 243 Win you could not approach blowing them up at that velocity but you will be better off going 6mm Rem.
Good Point! With the .243 case, i was intending on staying around 3000fps. I have a 22" barreled 700 BDL that you CAN'T make shoot over 2950 with 100 Sierra flatbases. Also, with a faster twist, the rotational energy component will be higher at the expense of the translational component for the same given pressure (no free lunch). Anyway, 3 grand, or thereabouts, ought to be doable.
I was thinking more in terms of barrel life when I was considering the 3-groove configuration. Can comeone enlighten me on the tradeoffs on rifling configurations (and shapes, like the polygonal, radiused groove, etc.).
One rifling- 5R stands for Russian, not radius- there is no such beast. However the odd number of grooves "work" the bullet less and tend to give faster velocity with a shorter barrel than a standard 6 groove.
Haven't messed with many 3 groove barrels so I can't comment there. Polygonal barrels are good also. Our own Dave King shoots a 243 1-8 with a Schneider polygonal barrel.
For my money, it's the Brougton 5C all the way.
Maybe I'm wrong, but I thought HS Precision was using some kind of radiused groove profile in some of the barrels they were making on site six or eight years ago. Didn't hear much about them, maybe for good reason. Think I saw it in some of their advertising propaganda at the time.
You are probably right, I was trying to clear up a common misconception about the 5R that Boots Obermeyer and Mike Rock both make. Broughton has the 5C Schneider the 5P which are basically the same as the 5R, also.