Home Forums Hunting & Shooting Hunting Rifles 20" 338 Win. Mag???

I really like my Ruger M77 MK II in .338 WM. However it is pretty heavy and long IMO. I prefer 20" barrels on my rifles just for ease of handling and what not. Would I just be destroying the calibers performance by lopping 4" off the barrel??

Thanks for any input.

When shortening a barrel, the variables to look at are muzzle velocity, pressure at muzzle and percentage powder burned.

For your question Quickload data reads:

Barnes 250 gr. TSX bullet
59 gr. IMR 4320
COAL 3.340

24" barrel:

MV 2560 fps
MP 8326 psi
Pb 100 %

20" barrel:

MV 2460 fps
MP 10464 psi
Pb 100 %

So the answer to your question is:

No, you will not destroy the cartridges performance, as only ~ 100 fps MV are lost.

But -

You will have quite an increase in noise and have that closer to your ear.

Judicious handloading allows to tailor the loads to the barrel, of course.

In summary, I would recommend taking 2" off - for a 22" barrel.

Why not try it at 22" first?

I have a 22" 375/338 CT. It works very well at the length.

AL, I've had a pile of 338's (was a cartridge I doted on for years). I had at least three shortened to 22". Personally I wouldn't go less than 21" or more than 23" so 22" always struck me as just right. Plenty handy, but not overly obnoxious in the noise department.

NOISE will be there in a 20" tube and I'm personally past the age I want to do that to my ears. When I was younger I was a carbine nut. Still am really, but some rounds lend themselves more to 20" (and less) barrels, not because of velocity loss, but because of noise. The 338 WM isn't really one of them IME.

At least that's the way I see it...

SC,

Can't say I know much about the .338, but I do know good looking rigs. That one is REAL nice!

I'd go 21" if I wanted it short, if not then 23".

Dober

But you're an "odd" ball... (grin)

Oddly enough...I get it...

Dober

(check out the pics I put up in the fly fishing for pike section...grin)

Noise just is what it is--you can just "deal with it." If you can't deal with it, don't got there. But...

Balance is the real key. Build for balance and the rest falls into place.

Thanks guys. Yeah its 24" right now plus a muzzle break (so you think 20" barrel is loud ) But really I don't feel I need the muzzle break anymore. So its getting lopped off in addition to whatever barrel length I settle on. I carry ear plugs when hunting all the time so the noise isn't an issue unless its in a bear defense situation and I have to sacrifice a little hearing possibly in order prevent getting mauled is worth it to me. I like the sounds of a 22" or even Dobers "odd ball" 21 inch. I guess I should add that I will be having open sights and QD rings to this setup in addition to bobbing the barrel.

One of the things you can do to "evaluate" an idea such as yours is to compare the volume of the case to the area of the bore (or the volume of a certain bore length) and compare that to other "knowns" you are familiar with.


Case Volume (CC) Area Bore Radius Radius squared V/A
338 Win 5.55 0.08968154 0.338 0.169 0.028561 61.8856455854795
30-06 Spr 4.4 0.07446824 0.308 0.154 0.023716 59.0855913876842
308 win 3.468 0.07446824 0.308 0.154 0.023716 46.5701888482929
270 Win 4.36 0.060232265 0.277 0.1385 0.01918225 72.3864526761529
7mm-308 3.38 0.06331496 0.284 0.142 0.020164 53.3839080053119
243 Win 3.42 0.04673576 0.244 0.122 0.014884 73.1773699625298
300 Win Mag 5.85 0.07446824 0.308 0.154 0.023716 78.5569794586256
25-06 4.21 0.051848465 0.257 0.1285 0.01651225 81.1981608327267
375 H&H 6.24 0.110390625 0.375 0.1875 0.03515625 56.5265392781316


The copied spreadsheet data isn't so easy to read, but the last "column" of data gives you some idea how a few common cartridges compare. As you can see, the 338 is very close to the 30-06 and makes a lot more sense than a shortened 243 or 270.

Thanks ....... Only taken one moose with it so far, but it's going to the Yukon with me this fall for another go.

.

I have a 20" 338 Win Mag. It's actually a pretty sweet rig. SS Mod 70, in a McM Gap swirly. My brother will be playing backup with it on my kodiak brown bear hunt. It'll be shooting 225gr North Forks.

I really don't think their is much of a difference between shooting a 26" 338 RUM and a 20" 338 Win Mag. My ears rang just fine for about 3 days with both rifles.

I also have a 21" 338 WSM that is a joy to run and handle...grin

Dober

My 350 RM MkII SS was not too heavy, think it was a 22", would have No problem cutting one of those to 20", but in 338, I agree w/Brad and others.

No doubt, a well balanced 20-21" is handy, but some rounds are either not as efficient, and/or blast can be an issue. Blast vs. speed loss should be your question. Can you deal with it. I would not want it.

FWIW I had a 338/06 in 23" and had a Win Mag I chopped from 24 to 22.5 and was happy w/both. Good luck.

believe Phil Shoemaker has his .458 win mag. down to 20"....same brass but....bigger bullet. Must be loud as well.

Whatever you shoot isn't going to notice that 100 fps velocity difference in 4" less barrel.

........................A few are trending toward shorter OAL rifles these days. I`ve been in that camp the past 3 1/2 years after many years of owning longer tubed rigs. Carbine lengthed rifles or there-abouts (40" to 41" in OAL and less), are easier in every respect in the field. And there isn`t alot of overall velocity loss by sacrificing a few inches of barrel length; certainly not enough to make any killing difference on game.

Shouldn`t be any problem taking your 338 WM rifle down to a 20" barrel length. A few always gripe about the extra noise from the shorter barrels as this subject pops up from time to time, when in reality,,,good hearing protection for the range and for use in the field as well, should be worn when shooting "ALL" rifle barrel lengths!!!

Because of wearing good range and field hearing protection, my hearing is still great (100%), with no hearing loss from either ear after firing my 20" barreled 375 Ruger Alaskan for 2 1/2 years and a 16.5" tubed 300 WSM Ruger Frontier carbine for nearly 3 1/2 years. Those two cartridges are excellent performers (perhaps two of the best) from shorter barrels. Common sense is what prevents hearing loss, rather than shorter barrels causing the hearing loss.

You also read of possible rifle "balance" issues that come about after the cut-downs. Based on alot of experience, that is simply a matter of getting use to it and can easily be solved with a just a little practice here and there.

Whichever you choose, a 20", 21", or a 22" barrel, there will be an improvement vs a 24" er in the field.

Good luck and have some sweet handling fun!

I would strongly suggest that you go with the 22".