I will eventually need to rebarrel my 300 Win Mag big game rifle. I have had great success with the present Lothar Walther barrel but am considering options. I am thinking about possibly going with one of the polygonal 5R rifling types produced by Schneider, Border, Boots Obermeyer or 5C produced by Broughton. Supposedly they are easier to clean and may give higher velocities. I am not really looking for higher velocities (I just need to get the Barnes 180 TSX to go 3080 fps or the Nosler 200 Accubond to go 2930 to match up with my Leupold Boone and Crockett reticle) and premium hand lapped barrels clean up pretty easily in general anyway so I do not really see a great need for these polygonal rifled barrels but may go that route just to try it out.
I am also considering a Lilja 3 groove (supposed longer barrel life). Lilja lists as a regularly stocked item an 11 twist 3 groove in a #2 contour. I think an 11 twist would be adequate (according to the Greenhill Formula as downloaded from the Z Hat website if the bullet starts out faster than 2800 fps then it can be 1.55" long and still be stabilized by an 11 twist). The Nosler 200 Accubond is 1.495" long and the Sierra 220 Matchking is 1.49" long so both of those bullets should be stabilized by an 11 twist. In practice would an 11 twist suffice?
Then there is the question of contour. My current barrel is I guess about a #4.5 contour based off of Lilja charts. It measures 0.675” at the muzzle. I would like to reduce the weight of my rifle somewhat. It weighs 9.3# with the scope. The stock is a Rimrock synthetic. I am guessing that if I went with a Lilja #2 I would lose about 0.75# in barrel weight. But accuracy is very important to me and I wonder if I go with a lighter barrel whether or not I will sacrifice accuracy. With my current barrel I routinely am able to shoot sub 2” groups at 250 yards (today I put 6 shots into 1.8” at that distance). So should I stick with a #4 contour or can I get away with a #2 or 3 and still get similar accuracy?
I also wonder if any of you have had cera-kote applied to the bore of your barrel. If so how has that worked for you? Thanks for any advice you can provide, Rufous.
I can't really advise you on what barrel to get, but I'm sure any of the choices that you listed are capable of excellent accuracy.
What I can tell you is that you should have no problem getting a 200gr Accubond to do 2930 FPS. In my bone-stock Win 70 300WM I can get the 200gr AB to 2950 with a stout load of IMR4350. Brass life is short with my load, so I backed off just a tad and velocity went down to 2850. Others on here seem to be getting over the 2900 fps mark with RL-22 with excellent accuracy.
I keep nature balanced - I hunt everything!
I know a 1-12 will stabilize a 200 gr Accubond in a 300 RUM rifle. With the lower velocity of the 300 Win Mag, I would feel that a 1-11 would work very well and even a 1-10 would not be to fast. Would also allow you to shoot heavier pills if you wanted.
I personally feel a #2 contour is to light in any 30 cal rifle unless it will be used strictly for a general purpose big game rifle for hunting under 400 yards.
Now before some get all hot and bothered. I know full well the lighter barrels can shoot very well. Problem is they are much harder to shoot with fine accuracy. They are light which can cause them to be very lively when trying to settle down for a shot.
Recoil also increases dramatically without a brake.
Personally, I like a #4 contour as a minimum recommendation for a 30 cal magnum. If you want it lighter then get it fluted but I like to see at least this much steel around the bore.
It also depends on how long of a barrel you want. With a 300 Win Mag, 26" would be perfect for a walking rifle and even 24 to 25 would work even better for barrel stiffness and portability.
Anything over 26" I would strongly recommend more barrel mass and bump up to a #5 contour, fluted if wanted.
Any of the top barrel makers will get you a fine barrel. Go with a Lilja, Krieger, Rock, Broughton, Hart or any of the other top end makers.
Then find someone that specialized in building accurate big game rifles. The machining is at least as critical as the actual barrel quality.
My recommendation would be very simple and not so sexy, a #4, 1-10 twist just to cover all the possible bases. I have yet to see a 1-10 30 cal barrel not shoot bullets from 125 to 210 gr extremely well when fitted properly.
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