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338 AM vs 375 AM?

 
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  #1  
Old 02-12-2011, 08:12 PM
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338 AM vs 375 AM?

which would you professionals out there choose? according to the G7 ballistics chart using a 325 gr. RMB with a bc of 1.035 for the 338 at est. 3300 fps, and a 370 gr. RMB with a bc of .924 at an est. 3200 fps, the 338 has more energy and with a 10 mph wind the 338 only would be pushed 6 MOA vs the 375 would be pushed 8 MOA, which i dont understand because the 375 bullet weighs 45 gr. more, but the 338 bucks the wind better? and the 375 starts off with 8411 ft-lbs of energy and the 338 starts with 7857 ft-lbs of energy but at 2000 yrds the 338 has 1620 fps and 1893 ft lbs of energy, and the 375 only has 1416 fps and 1647 ft-lbs of energy. if this is all correct, considering good 375 bullets are way harder to find the 338, then why have i heard some people say they prefer the 375 over the 338? the only thing i can think of that the 375 has the advantage over the 338 is barrel life?
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Old 02-13-2011, 09:23 AM
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Re: 338 AM vs 375 AM?

I just went through the same thought process in the last day or so and came up with about the same conclusion. I have a 338 AM on order from Kirby and checked in with him to see if I could still change to a 375 AM...... he said yes.

I am a fan of big bore stuff and have several that would qualify, up to and including one of Kirby's 510 AMs. However, I came to the same conclusion. I am not seeing a real ballistic advantage to the 375, although I would expect some terminal performance advantage simply because of the initial larger caliber. There are lots and lots more choices for bullets in 338 and some like the 300 SMK are quite inexpensive. So, it comes down to barrel life seems to be the primary advantage......Oh, and the fact that I just want one!!
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Old 02-13-2011, 05:11 PM
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Re: 338 AM vs 375 AM?

Super:

Bullet weight has nothing to do with wind drift, it's all about BC and muzzle velocity. For your example the 338 wins on both counts. And the BC you posted are G1, not G7. For those bullets the G7 would be better.
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Old 02-13-2011, 05:18 PM
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Re: 338 AM vs 375 AM?

Ok that makes sense thanks varminter
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  #5  
Old 02-13-2011, 06:06 PM
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Re: 338 AM vs 375 AM?

Go with the 338.
Unless you need more down range energy, I don't see the need to go with the 375's.
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  #6  
Old 02-13-2011, 09:46 PM
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Re: 338 AM vs 375 AM?

Quote:
Originally Posted by Varminator 911 View Post
Super:

Bullet weight has nothing to do with wind drift, it's all about BC and muzzle velocity. For your example the 338 wins on both counts. And the BC you posted are G1, not G7. For those bullets the G7 would be better.
Bullet weight is directly proportional with BC and inversely proportional with velocity.


CAL WT BC(G1) BC(G7)

.338RBTAL 225 gr. .773 .356

.338RBTAL 250 gr. .846 .390

.338RBTAL 275 gr. .918 .423

.338RBTHP 300 gr. .892 .418

.338RBTAL 300 gr. .979 .455

.338RBTAL 325 gr. 1.035 .492

.375 RBTAL 370 gr. .926 .451

.408RBTHP 420 gr. .822 .411

.408RBTAL 420 gr. .861 .430

.416RBTAL 450 gr. .923 .445

.50RBTAL 750 gr. 1.005 .502
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Last edited by FEENIX; 02-13-2011 at 11:12 PM.
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  #7  
Old 02-13-2011, 10:44 PM
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Re: 338 AM vs 375 AM?

The BC of the 325RMB is VERY optimistic to say the least... in reality its alot less than 1.0 and over long range the AVERAGE BC, which is the number your interested in to input your ballistic calculator, is much less than this.

The 370gr RMB in .375cal, has an average real world BC of about .87.
The 350SMK in 375cal, has an average real world BC of .78.

Having never shot the 338 RMB, i cannot give you real world numbers, but there is no way its over 1.0. Having shot numberous other bullets in 338cal including super slick solids, so far none of them have exceeded a real world BC of ~0.93 (which was a copper solid).

So, id ask around for an experienced person that has ACCURATELY figured a real world BC for the .338 bullets before you "run the numbers" on paper and base your desicions on that.

I can tell you tho, that with copper solids, the .375 cheytac wildcats whips the .338 cheytac wildcats in ultra long range ability. Out to 1000yds, (which isnt really long range for these calibers) you cant tell the difference between them.
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