I agree 338Rules, be sure the 338 RCM will not have issues in a magazine built for the fatter 300 WSM. If it works and the bolt face fit is not an issue give the 338 RCM a try.

The brass is once again available. Bruno's has it on sale:

http://www.brunoshooters.com/product/9778.html



I own two 338 RCMs. Own the SAMMI spec reamer too.

Built a tang safety SA Ruger in a now discontinuted McMillan Ultralight stock Rick sold me. 22" #2 Lilja. Had magazine lengthened to 3.1" for useful OAL of 3.050". Rifle weighs 7 3/4 lbs with scope. Killed two cow elk with the 225 Accubond velocity 2750 fps.

Recently made a super accurate load for this rifle with the 300 gr Berger:

300 gr berger seated to fit and feed from magazine
54 gr of RL-17 fed 210 standard primer virgin 338 RCM brass
Velocity 2349 fps (3675 ft/lb at muzzle)

I used information from from another site and the Berger's terminal performance on elk worked well as slow as 1966 fps impact velocity.

This makes this load viable out a bit over 600 yds!
@ 7000 ft:
POI Velocity Energy
100 0.5 2286.7 3482.5
125 -0.0 2271.2 3435.5
150 -0.9 2255.8 3389.1
175 -2.3 2240.4 3343.2
200 -4.0 2225.2 3297.7
225 -6.3 2210.0 3252.8
250 -8.9 2194.8 3208.4


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For grins I built a 14 lb LA Mark X with 29" 1 in 9 twist barrel in Joel Russo stock. This 338 RCM is long throated to shoot the 300 gr Berger at a mundane 2455 fps using It is a real hoot to shoot and bucks the wind quite well with lots of energy way out there. It can be fired 10 shots in a row and the barrel only gets "warm". Did use it once for a coues wt hunt. Shot a buck at 400 yds. .338 diameter hole through entire animal minimal meat damage.
Load data: fed 210 primer 54.5 gr RL-17 seated .010" into lands

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Some loads tried with the SA:

all loads use fed 210 primers

225 accubonds: worked up to 61 gr of RL-17 / 2750 fps with Fed 210 match primer.
180 nosler bt: worked up to 64 gr of RL-17/ 3045 fps.
215 sierras: worked up to 55 gr of Varget, most accurate 54 gr/ 2730 fps.
215 sierras: worked up to 64 gr of H4350/ 2865 fps