What contour is everyone running with their 338's? I am having my 338 re barreled with a brux heavy palma. Is this a little too light for the 338?
Barrel contour for 338 Lapua
- Thread starter BradleyH
- Start date
I hope I can do that!!I've got a TRG42, which is basically a medium palma contour. It seems to do just fine:
^^ Thats 2 shots in the same hole, a 3rd shot touching, and two "fliers"... ...at 600 yards
"They" say 1:12 won't handle the 300s. I have not found that to be the case (obviously), and I've even tried it down to -1500' density altitude, which was a ~20ºF day at about 1000' ASL.
FWIW, that 90.5gr Retumbo load has CCI magnum primers, the 300SMK loaded *just* shy of magazine length (just barely fits), and I swear I'm not making this up:
Over an Oehler 35 chrono, for 5 shots:
2667
2667
2668
2667
2668
My last .338LM had a GAP #7, which I believe is pretty similar to a M24/M40 (just a bit slimmer than an MTU). My next build is getting a 1.35"->1.00" Bartlein straight taper, since it is not exactly a "walking around" type of rifle.
Holy crap, man - impressive!
^^ Thats 2 shots in the same hole, a 3rd shot touching, and two "fliers"... ...at 600 yards
Holy crap, man - impressive!
The only .338 LM I have experience with had a MTU and it seemed to fit the rifle well. I would think this isn't getting moved around much, so the heaviest barrel that doesn't make the balance of the gun weird would be the way to go.
i just built a 338edge with a 31 AMU contoured bartlein and couldnt be happier. the barrel weighed 8lbs by itself. probly about an 18lb gun built. 243 like recoil
I've had four 338 LM's. Can't remember the barrel contour of the first one (HS Precision), but the second was a TRG. The next was a GAP with a 28" MTU - and I fell in love with this contour. Now I have a 26" MTU - perfect.
According to Litz book, stability factor for a 300 SMK fired out of a 12 twist barrel in nominal conditions(sea level, 50% humidity, 59°f, and 2800 fps) is right at the minimum acceptable 1.40. Litz states that anything over 1 means the bullet is stable, but given unforseen variables he recommend 1.4 just to be safe. Higher altitude, humidity, temp, and mv will result in a higher stability factor for the same bullet/barrel twist.
FWIW...
Lapua 300 is 1.32 nominal (iffy)
Berger 300hybrid is 1.18 - basically a no go.
On a side note, i went with a bartlein p/n t10558 30" 9.5 twist with a 1.35 shank for 5 inches, tapering down to 1 inch. Its heavy, but that's what i want.
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I've got a TRG42, which is basically a medium palma contour. It seems to do just fine:
^^ Thats 2 shots in the same hole, a 3rd shot touching, and two "fliers"... ...at 600 yards
That is some kick-ass shooting...........nice job! How does it do with the 300gr Bergers?
Read my post above. Like turbo said, real world may prove different, but according to Litz, the Berger 300s are gonna struggle in a 12 twist barrel
