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338 rcm

 
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  #1  
Old 08-23-2011, 10:13 AM
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Join Date: Jul 2004
Location: Texas
Posts: 5,542
338 rcm

As promised this is an update on the latest build.

The rifle is based on a Model 7 Remington with a laminated stock.

Barrel is a 22" #4 Lilja 1 in 10 twist Stainless 6 grove.

Scope is a 2.5x8x40 Leupold.

Ammo used is Hornady Superformance 200 and 225 grain SSTs.

During break in, velocity for 5 shots was 2941,2945,2940,2941 and 2943 (Very consistant
for factory ammo)with the 200 grain ammo.

Recoil was brisk in the 8.7 pound rifle (Scope, mounts and rings included).The most noticeable
thing was the muzzle rise. (May have to install a muzzle break to minimize this).

Temperature was in the high 90s, and the loads appeared to be Max so after shooting 3 rounds
fast and heating up the barrel I chambered another round and let it set for a minute then fired
it to see if it would show signs of pressure. (It did) so I determined that the factory ammo is
a Maximum load in hot weather.

The rifle shot 3/4 to 1.25 MOA at 100 yards with the factory ammo and I feel like good reloads
will improve that.

With almost 4000 ft/lbs of energy at the muzzle, this is a power house for a small carry rifle.

Sorry: no pictures. maybe someday I will learn how to post pictures.

J E CUSTOM
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Old 08-23-2011, 10:22 AM
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Re: 338 rcm

Sounds good I am waiting on my 338 Sin in Tikka T3 Lite. Should be about same going to use cutting edge 225 bullets.
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  #3  
Old 08-23-2011, 11:17 AM
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Location: Allen, TX
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Re: 338 rcm

JE,

Nice review.

How many rounds will the rifle hold?

Does it feed well?

Did you do anything special with the throat/freebore/magazine to accomodate the longer VLD's up to the new Berger Hybrid?

Or, would you recommend doing so for another build in this cartridge in a heavier LRH rifle?

Do you think you need an Edge, RUM, LM to push the 300 grainers effectively?

Thanks
Richard
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Old 08-23-2011, 03:20 PM
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Location: Texas
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Re: 338 rcm

Quote:
Originally Posted by rscott5028 View Post
JE,

Nice review.

How many rounds will the rifle hold?

Does it feed well?

Did you do anything special with the throat/freebore/magazine to accomodate the longer VLD's up to the new Berger Hybrid?

Or, would you recommend doing so for another build in this cartridge in a heavier LRH rifle?

Do you think you need an Edge, RUM, LM to push the 300 grainers effectively?

Thanks
Richard
Thanks Richard.

It will hold 3 rounds in the mag ,but it is full and functions flawlessly with two + 1. There
were no problems with feeding.

I went with the standard free bore to get the max velocity out of the compact case.
and my intentions are/were to use 200 or 225 grain Accubonds and limit the distance to
4 or 500 yards.

I have several big 338s for the bigger bullets and I am in the process of building another
based on a 375 RUM case pushed to the max powder volume.

This project was to build a very compact rifle with plenty of power.

I had even thought about blowing out the case to the same body length as the 7 WSM and
adding another 8 to 10 grains of capacity but went back to my original thought and left
it alone to make it easier to load and buy ammo for.

The closest thing to the 338 RCM is the 325 WSM and the ammo for it runs $50.00 to $65.00
a box. The 338 RCM is from $38.00 to $42.00 so this was a consideration plus there are
Lot's of 338 Bullets to chose from.

PS; I just put a muzzle break on it for the faint of hart and need to see what difference it
made in recoil and accuracy.

J E CUSTOM
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  #5  
Old 08-24-2011, 01:54 PM
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Location: SW Texas
Posts: 288
Re: 338 rcm

In another thread AZShooter said he's getting 2579 fps out of a 338 RCM shooting the 300 Berger with 57 gn RL-17. That's only about 200 yds short of the 338 RUM in terms of down range energy. I wonder what barrel length would be needed to achieve that velocity in a long throated chambering?
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  #6  
Old 08-27-2011, 12:20 AM
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Join Date: Apr 2007
Location: ALASKA
Posts: 504
Re: 338 rcm

Interesting build...that sounds like an excellent rifle for future Alaska hunt

That is very consistent velocities...factory ammo nonetheless makes it that much more special.

Varminator 911-I would guess on 18-21 fps per inch with the slightly quicker powders/200-225 gr weight bullets, and 22-27 fps per inch with slightly slower powders/250-300 gr weight bullets.

JE Custom would know best on what improvements to case capacity might be seen with a different throat. My opinion would be the biggest benefit might not necessarily be a velocity gain from an increase in capacity, but better load density with the next slower/faster powder up or down the chart.

Example-338 Lapua Ackley Improved. It sees a 11 grain increase from virgin unfired brass, to fully formed brass with 2-3 firings. The virgin cases "cube out" before you "pressure out" with Retumbo....in otherwords you can't put enough Retumbo in the case with the 300 grainers to get yourself into pressure trouble....but with H1000 you can "pressure out" before you "cube out"...and definitely get yourself in pressure trouble. After firing, the formed cases now run into pressure/load density constraint at nearly the same time with Retumbo around 103.5 to 104 grains with 300 grain bullets.

The biggest benefit from lengthening the throat on this 338 RCM, may be the same as happens above...you might be able to move into a new class of powders, where as before load density kept you from doing so.

If this is insulting to your knowledge level, I definitely didn't mean it that way at all, just sharing my perspective/experience. I'm here to learn from all the smart fellas like JE Custom on here.
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  #7  
Old 08-27-2011, 12:29 AM
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Join Date: Apr 2007
Location: ALASKA
Posts: 504
Re: 338 rcm

Quote:
Originally Posted by rscott5028 View Post
Do you think you need an Edge, RUM, LM to push the 300 grainers effectively?

Thanks
Richard
Richard-I know you asked this question to JE specifically, but I can't help but to put my two cents in here. Then I'll butt the heck out of this thread for good!

I would evaluate the maximum distance you will engage your intended target. I'm assuming furry critters since we're on LRH Evaluate the ability of your LRH to achieve a reliable, accurate, precise, and repeatable range at that distance on a non-reflective target like a critter. Then I would plug in the atmospherics for your intended hunting AO into JBM, and evaluate wind drift in the worse case scenario for that distance. You'll be able to solve all the other riddles associated with the LR shot with technology/practice (Coriollis, spin drift, elevation solution) but the wind drift will still be undeterministic factor as Mr. Litz refers to it....or the unknown for a common'er like me.

I think when you look at the wind drift differences between a 300 gr Berger for a 2500/2700/2900 fps....you might not realize a real benefit until you start shooting past 1K. Hope that helps!

Good luck.
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