Whats the difference between 338 lapua and 338 winchester?

[saturno_v]

The 180gr 7mm RM/WSM load has 31% less momentum than the 338WM/300gr load at 1000 yards, and 20% less K.E.

Zak

Why you say 20% less KE??? 1600 ft/lb is more than double 700 ft/lb... I would say the 7mm has 60% less KE than a 300 gr. 338 WM.

I agree that no serious shooter would hunt Elk at 1000 yards with a 338 WM (especially with an inexpensive out of the box rifle)...actually I think nobody should do it, regardless of the equipment available (IMHO).

However, 600+ yards Elk shot with the 338 WM are not unheard of in certain parts of the country.

 

[Zak Smith]

Same data as above, here's the velocity component - run the numbers yourself:

_Bullet_           _BC_ _MV_         0     200     400     600     800    1000 | YARDS
338LM             0.77* 2800 >    2800    2581    2372    2172    1983    1803 | velocity (fps)
338LM 250         0.675 2975 >    2975    2717    2473    2242    2025    1821 | velocity (fps)
7RM 180           0.680 2950 >    2950    2695    2454    2226    2011    1809 | velocity (fps)
7RM 162           0.625 3075 >    3075    2791    2524    2272    2036    1816 | velocity (fps)
338WM 300         0.77* 2490 >    2490    2286    2090    1905    1729    1565 | velocity (fps)
300WM 210         0.640 2900 >    2900    2632    2380    2143    1920    1713 | velocity (fps)
338WM 250         0.675 2765 >    2765    2518    2285    2065    1859    1665 | velocity (fps)
300WM 190         0.584 3050 >    3050    2749    2465    2201    1954    1724 | velocity (fps)
260               0.615 2900 >    2900    2622    2360    2115    1886    1672 | velocity (fps)
308               0.508 2930 >    2930    2593    2281    1992    1726    1490 | velocity (fps)

 

[saturno_v]

I just run them with the JBM Online Calculator

http://www.jbmballistics.com/

Here you go:

7mm Remington Magnum, 168 gr. Sierra Matchking

338 Winchester Magnum 300 gr. Sierra Matchking

As you can see, the 7mm has about 60% less KE than the 338 WM (and a lighter bullet with less SD, obviously)

 

[Zak Smith]

I used our actual 7mm RM/WSM loads: a 180gr Berger VLD at 2950 fps. I figure that's fair if you're using a hopped-up 2555 fps 300gr SMK load in the .338WM (ie, best BC bullet possible at with a stout load). For comparison, the 162-168gr load is about 3050-3100 fps.

ETA: in my tables, those are all loads I - or close friends - actually shoot, with the exception of the .338WM loads which I got from this thread.

 

[saturno_v]

Zak

Actually 2550 fps is still within pressure specs..some guys run reloads at well over 2600 fps for the 300 grainers still without any brass warning signs (but probably they are already overpressure).

However even if you consider a 190 gr. 300 WM at 2900 fps MV, it has 50% the energy of a 300 gr. 338 WM left at the 1K mark.

However you are right, if you miss your target, it doesn't really matter.

 

[Zak Smith]

By my math, a 190gr SMK launched at 2900 fps is going about 1514 at 1000 yards. That's about 61% the K.E. of the 300gr still going at 1547.

If you are focussed on kinetic energy at the target, that will reward the cartridges with high BC values and a high velocity. The 7mm RM/WSM has 1800+ residual at 1000 yards and that helps it "disproportionately" compared to the slower round. 180*1809^2/ (300*1547^2) is 82% of the KE.

 

[saturno_v]

Zak


How you calculate the KE?? Ihe formula should be square of velocity in fps * weight in grains / 450400 right??

I just run the JBM calculator for the 300 WM

The 190 gr. Sierra Matchking (BC 0.533) has 1424 fps left at 1000 yards which translate in 855 ft/lb of KE

This is the output:

The 300 gr. Sierra MK 338 (BC 0.768) is actually the fastest at the 1K mark (1547 fps)

The JBM clock the 7mm 168 gr. (BC 0.488) at 1356 fps at 1000 yards

So I don't know..maybe JBM is off or your calculation is off....

 

[Zak Smith]

I ran all those numbers for 2000' density altitude (ICAO). In my original tables, I was using the 190gr Berger VLD, not the 190gr SMK. The SMKs usually do not offer the best BC values for the caliber/weight combination. This pattern holds in 7mm as well, and I said before I was using the 180gr Berger VLD in 7mm as the comparison. The 162 was the AMAX, however, the 168gr Berger is very close.

The reason I said it would be a "fair" comparison in my prior post to compare what I did is that a 300gr SMK @ 2550 is probably the best .338WM has to offer for long-range ballistics, while a relatively poor 168gr SMK at a mild velocity as the basis in 7mm is not comparing apples to apples.

-z

ETA: kinetic energy is proportional to mass*velocity^2. You don't need to do any unit conversion or use any constants when comparing two to find the relative ratio.

 

[saturno_v]

Zak

Thank you for pointing me to the Berger bullets.

I run the JBM calculator for their upcoming 338 VLD which has a rumored G1 BC of 0.855 (very impressive).....at 1000 yards the 338 WM would have 1800 ft/lb left flying still at 1630 fps!!
At 2000' the value increase to 2020 ft/lb with the bullet flying at 1739 fps (assuming the same MV)

 

[SwampWolf]

For those who believe that the 300 Winchester Magnum is so much faster and flatter than the .338 Winchester Magnum, when comparing apples to apples (i.e., the same bullets), I submit the following ballistic information from Federal Ammunition, where both rifles were tested having 24" barrels and using the 180 grain Nosler AccuBond bullet:

Muzzle Velocity FPS: .300WM, 2960; 338WM, 3120

Muzzle Energy in Foot Pounds: 300WM, 3500; 338WM, 3890

Bullet Drop/100 Yard Zero @ 200 yds: 300WM, -3.0"; 338WM, -2.8"

Bullet Drop/100 Yard Zero @ 300 yds: 300WM, -11.2"; 338WM, -10.6"

Bullet Drop/200 Yard Zero @ 300 yds: 300WM, -6.6"; 338WM, -6.4"

Bullet Drop/200 Yard Zero @ 400 yds: 300WM, -19.2"; 338WM, -19.1"

Bullet Drop/200 Yard Zero @ 500 yds: 300WM, -38.7"; 338WM, -39.2"

 

[Zak Smith]

A 180gr .338 bullet is not "the same bullet" as a 180gr .30 caliber bullet, by definition.

It's basic internal ballistics that for about the same case volume and the same bullet mass, the larger caliber will achieve a higher muzzle velocity at the same peak pressure because it has more surface area (F = M*a, and F=P*Area, so acceleration = pressure*area/mass).

What your comparison is missing is the BC values: .30 cal 180gr ABBT is 0.507, while the 180gr .338 cal ABBT is 0.372. The .338WM starts out 160 fps faster in your example, but its low BC value has bled off that advantage and the .30 cal bullet surpasses it for speed by 250 yards.

_Bullet_           _BC_ _MV_         0      50     100     150     200     250     300 | YARDS
.300WM/180        0.507 2960 >    2960    2867    2775    2685    2597    2511    2426 | velocity (fps)
.338WM/180        0.372 3120 >    3120    2989    2862    2737    2616    2499    2384 | velocity (fps)

Secondly, 300 yards is essentially short-range for rifles. There needs to be a pretty dramatic difference in velocity for any meaningful difference to show up in this range regime.

Thirdly, long-range shooting is mostly about dealing with wind. Long-range loads are usually optimized for accuracy first (to some reasonable point), then wind drift, and drop. Drop is the least important of these. The biggest factor that determines wind performance is BC.

Here's what 160 fps extra muzzle velocity with a BC of 0.372 gets you at long range:

_Bullet_           _BC_ _MV_         0     200     400     600     800    1000    1200 | YARDS
.300WM/180        0.507 2960 >    0.00    2.42   10.31   24.86   47.57   80.24  124.37 | wind (inches)
.338WM/180        0.372 3120 >    0.00    3.12   13.66   33.88   66.85  115.37  179.14 | wind (inches)

.300WM/180        0.507 2960 >   -0.00    0.35    1.65    3.36    5.49    8.15   11.52 | drop (mil)
.338WM/180        0.372 3120 >   -0.00    0.31    1.61    3.43    5.93    9.36   14.01 | drop (mil)

.300WM/180        0.507 2960 >    2960    2597    2262    1955    1674    1430    1232 | velocity (fps)
.338WM/180        0.372 3120 >    3120    2616    2165    1764    1423    1168    1015 | velocity (fps)

Heck, the 180gr .338 bullet falls sub-transsonic before 1000 yards!

 

[SwampWolf]

A 180gr .338 bullet is not "the same bullet" as a 180gr .30 caliber bullet, by definition.

Obviously, a .30 caliber bullet is smaller than a .33 caliber bullet but the ones being compared are as close as you can get in terms of weight and construction if they are to be apples to apples. You can pick and choose what's important to you (drift vs drop; what constitutes long range; advantages/disadvantages to caliber size in terms of killing power, etc.) all day long but it doesn't change the fact that when using the same weight and same constructed bullet, the .338WM is faster and flatter than the .300WM. There are many people who mistakenly assume the opposite (you, yourself termed the .338WM "slow")That's my only point. I'm not saying that sectional densities, ballistic coefficients, wind drift factors aren't important and don't matter greatly as to the understanding of ballistics as it relates to killing efficiencies and effective shooting distances.

 

[saturno_v]

180gr .338 bullet is not "the same bullet" as a 180gr .30 caliber bullet, by definition.

It's basic internal ballistics that for about the same case volume and the same bullet mass, the larger caliber will achieve a higher muzzle velocity at the same peak pressure because it has more surface area (F = M*a, and F=P*Area, so acceleration = pressure*area/mass).

What your comparison is missing is the BC values: .30 cal 180gr ABBT is 0.507, while the 180gr .338 cal ABBT is 0.372. The .338WM starts out 160 fps faster in your example, but its low BC value has bled off that advantage and the .30 cal bullet surpasses it for speed by 250 yards.


Code:
_Bullet_ _BC_ _MV_ 0 50 100 150 200 250 300 | YARDS
.300WM/180 0.507 2960 > 2960 2867 2775 2685 2597 2511 2426 | velocity (fps)
.338WM/180 0.372 3120 > 3120 2989 2862 2737 2616 2499 2384 | velocity (fps)Secondly, 300 yards is essentially short-range for rifles. There needs to be a pretty dramatic difference in velocity for any meaningful difference to show up in this range regime.

Thirdly, long-range shooting is mostly about dealing with wind. Long-range loads are usually optimized for accuracy first (to some reasonable point), then wind drift, and drop. Drop is the least important of these. The biggest factor that determines wind performance is BC.

Here's what 160 fps extra muzzle velocity with a BC of 0.372 gets you at long range:

Code:
_Bullet_ _BC_ _MV_ 0 200 400 600 800 1000 1200 | YARDS
.300WM/180 0.507 2960 > 0.00 2.42 10.31 24.86 47.57 80.24 124.37 | wind (inches)
.338WM/180 0.372 3120 > 0.00 3.12 13.66 33.88 66.85 115.37 179.14 | wind (inches)

.300WM/180 0.507 2960 > -0.00 0.35 1.65 3.36 5.49 8.15 11.52 | drop (mil)
.338WM/180 0.372 3120 > -0.00 0.31 1.61 3.43 5.93 9.36 14.01 | drop (mil)

.300WM/180 0.507 2960 > 2960 2597 2262 1955 1674 1430 1232 | velocity (fps)
.338WM/180 0.372 3120 > 3120 2616 2165 1764 1423 1168 1015 | velocity (fps)Heck, the 180gr .338 bullet falls sub-transsonic before 1000 yards!

Zak, you are absolutely right, a sub-200 gr. bullet in 338 is not very good for long range shooting

However I run few calculations on JBM with two .338 Barnes bullets, the 160 gr. TSX (G1 BC 0.342) and the 185 gr. MRX (G1 BC 0.379)...these are hunting bullets, definitely not with the highest BC possible even in that weight.

Zero Altitude, standard ICAO atmosphere.

At 1000 yards the 160 gr. is barely subsonic (MV 3200 fps) and the 185 gr. is still supersonic.

At 2000 feet of altitude (ICAO) the 160 gr. would still be supersonic at the 1K mark

 

[Zak Smith]

160gr TSX BC 0.342 MV 3200 fps, falls below mach 1 + 10% at about 900 yards

_Bullet_           _BC_ _MV_         0     100     200     300     400     500     600     700     800     900    1000 | YARDS
160 TSX           0.342 3200 >    3200    2915    2646    2392    2154    1930    1721    1530    1363    1223    1114 | velocity (fps)

 

[Zak Smith]

bullet is smaller than a .33 caliber bullet but the ones being compared are as close as you can get in terms of weight and construction if they are to be apples to apples.

Apples to apples would be an approx 218gr .338 bullet to get the same sectional density.

when using the same weight and same constructed bullet, the .338WM is faster and flatter than the .300WM

In the above example, the .300WM is "flatter" by 550 yards, and gets better from there on out:

_Bullet_           _BC_ _MV_         0      50     100     150     200     250     300     350     400     450     500     550     600     650     700 | YARDS
.300WM/180        0.507 2960 >   -2.00   -0.47   -0.00   -0.66   -2.53   -5.68  -10.22  -16.23  -23.83  -33.13  -44.25  -57.34  -72.54  -90.02 -109.96 | drop (inches)
.338WM/180        0.372 3120 >   -2.00   -0.51   -0.00   -0.55   -2.26   -5.24   -9.62  -15.53  -23.12  -32.57  -44.08  -57.85  -74.14  -93.23 -115.44 | drop (inches)

 

[saturno_v]

160gr TSX BC 0.342 MV 3200 fps, falls below mach 1 + 10% at about 900 yards

Zak

Yep, more or less confirmed by my JBM calculation as I mention in my previous post,...at 0 altitude ICAO atmosphere at 900 yards the 160 gr. 338 bullet is at Mach 1.07 (1195 fps) +- margin of error and at 1000 yards is at Mach 0.97 (1089 fps) +- margin of error

 

[gondorian]

Hey guys, the OP already said he was getting a savage 30-06, ok?

 

[JimmAr]

338 wm is a horrible cartridge for long range capabilities. 338 lapua however is not. Cheaper however is the 338 rum not as accurate as the lapua due to the quality of brass in its very name and quality rifles available w/o having to build a custom..

IMO 338's are to expensive to shoot are to loud for hunting and are unbearable w/o shooting with a break, BUT still are very fun.

 

[saturno_v]

338 wm is a horrible cartridge for long range capabilities.

I strongly disagree...is not that horrible at all....

People can hit human size targets with a 45-70 at well over 1000 yards.....

 

[bigalexe]

Not trying to thread jack but whats the proper pronunciation of Lapua? I've never heard anyone refer to IRL and haven't asked because i have no idea how to pronounce it.

 

[dubbleA]

It's proper pronounciation is La pooha.

 

[Wes Janson]

I go watch Dawn of the Dead, and it appears that threads are coming back to life now...

 

[lefteyedom]

338 WIN MAG Perfect hunting

338 Win Mag....Perfect North American Hunting rifle. Whitetails at 500 yards or Brown Bears at 5 yards the 338 Win Mag will get the job done.

338 Lapua..... Perfect Walter Mitty sniper rifle. Yes it is great but it is not really good for much more than bragging rights unless you are in uniform shooting at real bad guy at long ranges.

338 Win Mags kill ELK every year, Lots of them. Most 338 Lapuas punch holes in paper///

 

[MJR007]

I was thinking 30-378 single action 30" barrel for fun GAME rifle. Different is good.
(Hunting - the 338 mag is my choice)

 

[rangerruck]

the biggest diff can be summed up in one word; pain.