338 rcm

[J E Custom]

I am starting a project and wanted some info on the cartrige and it's performance on game.

My intent is to build a very light rifle (By my standards) 6 to 7 pounds.
The action will be a Model 7 Remington and a 22 or 23'' #4 contour barrel.

The 200 grain bullets @ 2950 (Factory) look very good to 700 yards on Elk and
almost 900 yards on deer.

I know this is not considered a long range cartrige, But is does have uses at closer ranges.

And looks like it would be a realy good bear cartrige with 3000 ft/lbs of energy @ 200 yards.

Any comments ''GOOD OR BAD'' would be appreciated.

Thanks

J E CUSTOM

 

[Outlaw81]

I'd go with a .300 wsm with a 200gr vld. It'll hit like a mack truck with less recoil than the .338. Plus it'll run faster. The ballistics are better on a .30 caliber 190gr or above than that of a .338 up to .250gr. It's all up to you. To me, the whole point of using a .338 is to be able to utilize the 250-300gr smks. But with the RCM, that will be an impossibility. If you're just gonna build a custom, go with the .338 Edge. Otherwise, the best bet with a short magnum is the .300wsm with a 190-210vld or amax for target and a 200-220gr partition for hunting. Trust me, the 220 partition will roll a grizzly like a raccoon under a car. `Good luck bro.

 

[J E Custom]

I'd go with a .300 wsm with a 200gr vld. It'll hit like a mack truck with less recoil than the .338. Plus it'll run faster. The ballistics are better on a .30 caliber 190gr or above than that of a .338 up to .250gr. It's all up to you. To me, the whole point of using a .338 is to be able to utilize the 250-300gr smks. But with the RCM, that will be an impossibility. If you're just gonna build a custom, go with the .338 Edge. Otherwise, the best bet with a short magnum is the .300wsm with a 190-210vld or amax for target and a 200-220gr partition for hunting. Trust me, the 220 partition will roll a grizzly like a raccoon under a car. `Good luck bro.

Thanks Outlaw.

I guess I should have mentioned that I have 2 of the big 338s and I'm in the middle of a
338 Edge improved to see just how much I can get out of a RUM case.

So this project was for a short handy bear/Elk rifle with plenty of knock down.

There is loading data for the 225 grain bullets.

The 338 RCM was interesting because it matches the 338 Win Mag, only in a short mag.

J E CUSTOM

 

[Akiona]

Thanks Outlaw.

I guess I should have mentioned that I have 2 of the big 338s and I'm in the middle of a
338 Edge improved to see just how much I can get out of a RUM case.

So this project was for a short handy bear/Elk rifle with plenty of knock down.

There is loading data for the 225 grain bullets.

The 338 RCM was interesting because it matches the 338 Win Mag, only in a short mag.

J E CUSTOM

Be sure to post your results. Both 338 RCM and 338 Edge Imp.
Have a 338 Tomahawk (300 Tomahawk necked up to 338) . Very pleased with its performance. Had it for several years. Some say its not worth the extra expense. But its worth it. If your a performce nut. Kinda like fine tunning a big block 68 camaro.

 

[hypersonic]

Interesting project too bad the wife won't let me spend any money on a new rifle right now. The 350 RM case necked down to 338 with off the shelf powders might be somthing to consider also.

 

[J E Custom]

Interesting project too bad the wife won't let me spend any money on a new rifle right now. The 350 RM case necked down to 338 with off the shelf powders might be somthing to consider also.

The 350 Rem Mag case was one of the cases I looked at and even though the 350 case is longer
the 338 RCM is fatter and case capacity is only 1 to 2 grains more in the 350.

If it does well I may improve it with a 40o shoulder and move the neck out a little for all the
capacity i can get.

It is just an experiment that may or may not turn out.

J E CUSTOM

 

[HARPERC]

Just posting to keep watching. Thanks good luck!

 

[AZShooter]

I think you are going to like the 338 RCM. I sure do!

I built a rifle in 338 RCM two years ago. It is a Ruger M77 tang safety with 22" #2 Lilja SS barrel. Has 2-7 VX II with CDS turret. Weight is 7 1/4 lbs and it worked wonderfully on my NM cow elk hunt last November.

The magazine was lengthened and to accomdate an OAL of 3.050" or so. Your model 7 will have to stick with a shorter OAL and this might lower velocities slightly.

I tried a few different bullets and settled upon the 225 accubond.
Ended up with the 225 accubond and RL-17. 2750 fps with 61 grs of RL-17 with fed 210 primer. OAL 3.050" tested up to 80 degrees. Recoil is very tolerable and the lightweight rifle is a joy to carry.

Other loads:

215 sierra fed 215, varget 54.5 most accurate @ 2730 fps some pressure shown at 55 grs vel 2760 groups opening up (66 degrees)

215 sierra, fed 215 RL-17 accuracy fell off above 61 grs vel 2885 fps, 62 some pressure shown (71 degrees)

----------
180 nosler ballistic tip Fed 215, RL-17 62 gr 2916 POI very close to 225 accubond load.
Worked up to 65 grs vel 3075 fps no pressure shown (80 degrees)

--------------
For grins: 300 gr sierra matchking seated close to rifling, too long for magazine
Fed 210 primer, 57 grs VERY accurate, two shots at 200 yds made one hole. vel 2449

-------------------------

This led to an exciting adventure. I made a heavy LA rifle, 29" #7 SS long throated 338 RCM specifically to shoot the 300 gr berger hybrid bullets. The bullets recently came in and the they shoot fantastically. Load: Bullets are .010" into rifling, Fed 210 match,
56 grs for three shots: 2457, 2457, 2457 fps.
57 grs for three shots: 2572, 2572, 2572 fps temp 85-90 degrees

I was stunned to get identical velocities.

Before the hybrids were available I used 300 gr SMK: 57.5 gr of RL-17 vel 2540 fps shot a .312" three shot group @ 200 yds
--------------------------------------------


Build the 338 RCM you'll love it. FYI I bought a FL die set from Redding but I had sizing issues. Hornady FL die solved it.

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Pic of lightweight Ruger before rebarreling to 338 RCM with 2.5 compact leupold

heavy 338 RCM with 300 gr sierra MK

 

[J E Custom]

Thanks AZ !!!!

That is what I had Hoped for because the case looked like it had potential.

The 225 And the 200 Grain Accubond is what I intended to use because I Have a couple of
"long range"338s . But it is nice to find out that it will handle the heavy weights.

And '0' SDs is unbelievable. The best I have ever got is 3, I would love to see that.

When I am finished I will post the results.

Thanks again!
Any more input ?

J E CUSTOM

 

[AZShooter]

It is an interesting cartridge. To be honest I wouldn't have thought it would perform that well for such a small case.

A friend recently acquired a 7 SAUM and the case is almost identical to the 338 RCM.

Are you going to get this rifle put together in time for the fall hunt?

 

[J E Custom]

It is an interesting cartridge. To be honest I wouldn't have thought it would perform that well for such a small case.

A friend recently acquired a 7 SAUM and the case is almost identical to the 338 RCM.

Are you going to get this rifle put together in time for the fall hunt?

Yes !

As soon as I get My reamer I can start (This week hopefully).

I should have it finished in a couple of weeks and be ready to test it.

J E CUSTOM

 

[Seabeeken]

I have a Ruger in 338 RCM and love it. It shoots .5 with both barnes and Hammers. I can hit 2950 fps with 185 SH in the 20" barreled Ruger. This thing shoots! It is a rifle I would want if I had to go into an alder thicket or similar place. Short, fast, powerful, and short action that can be racked without moving off sights. Will be testing Leverevolution in it soon and should be able to hit 3000 fps, just hope accuracy is there. My ONLY complaint is mag length requires keeping rounds short but the hammers like the long jump

 

[akmtnhnt]

If I wanted a short barrel 338, the RCM is what I'd chose. Something like 18" Over something like a 300wsm since it should be able to utilize the powder a little more efficiently over a narrower bullet in the short barrel.

 

[Seabeeken]

Thats right. Hornady found that the RCM was much more efficient and higher velocities in short barrels than the WSM cartridges.