Mod. 70 .338 - Pistolsmith

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Old 03-22-2005, 11:32 AM   #1
Join Date: Dec 2002
Posts: 48
Mod. 70 .338

Here's a quick question. I have a Model 70 in .338 Win Mag. It sports a 26 inch barrel and is a little awkward. I'd like to cut it back to 24 inches. Will that two inches have any "real world" effect on game? Thanks
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Old 03-22-2005, 05:22 PM   #2
Join Date: Feb 2004
Location: Ohio
Posts: 30
Here's a quick answer. "Nope". There's probably more variation between two different rifles than in dropping from 26" to 24" of barrel length- especially in a .338 Win mag.

I had one in Win 70 "Classic" stainless/ synthetic myself. It had a 26" barrel and I loved the gun. It would routinely shoot 3/4" 3 shot groups at 100 yards and barely over an inch with 5 shots. It was even a skinny barrel with the BOSS on it. It absolutely wouldn't shoot with the BOSS removed (like maybe 6" groups), and I got to where I abhorred the looks of the bulge at the end of the barrell, so I sold the rifle and bought a .375 H&H version of the same gun (without the BOSS).
Old 03-22-2005, 06:43 PM   #3
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Join Date: Mar 2001
Location: Issaquah, WA
Posts: 3,831
At one time I built a number of 338 win mags. We cut barrels all the way back to 18". Stay above 20/22" and there is little effect at hunting ranges under 300 yards. Couple of guys stay in touch that still own the 18" guns and love them. But at 18" you can almost duplicate the 338 with a 338/06...almost. At 20" you can't dup the 338 mag without a long barreled 338/06.

Old 03-23-2005, 09:27 AM   #4
Join Date: Apr 2001
Posts: 194
Nice to see some action in the Big Bore forum.

As has been stated earlier, the difference between 26 and 24 inches is pretty moot as far as practical terminal ballistics and it does afford an opportunity to insure that the crown is perfect if a proper gunsmith cuts it and even add a nice-to-have touch for a field gun like a recessed crown to protect from dings.

That being said, it seems to me that the difference in handling quality between 26 and 24 is pretty moot. Taking it to 22 does make a fair bit of difference, though, especially in a saddle scabbard. That being said, I left my pre-64 alone with it's factory barrel. Do have a pre-64 375 cut back just beyond the factory foresight which was the popular wisdom of such notables as Jack O'Connor back in the 50's and 60's. Left it with Lyman receiver sight and it makes a handy piece in brush or a saddle scabbard. I like short barrels, but as Dane says, cutting back to 18 in a 338 leaves you with a heavy recoiling 338/06.

I do have a Marlin 45/70 truncated back in the 70's to 18 inches after checking with the NRA tech staff for assurance that the ballistics would reflect a minimal difference, and with a cartridge like that, the shorter barrel is handy indeed with pretty minimal down side....witness the popularity of the so-called Guide Guns nowadays. Adding a full length mag tube also adds a bit of muzzle weight which I like for offhand shooting to offset chopping the bbl. The 338 though is a short mag and a niche gun for me for elk out of the black timber, and I prefer the barrel length at standard for whatever ballistic advantage I may get.

Just another FWIW opinion.....
Old 03-23-2005, 09:52 AM   #5
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Join Date: Mar 2001
Location: Issaquah, WA
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Good stuff Rob. Just wanted to be clear for others reading this. A 18" 338/06 is not a 18" 338 Win mag in balistics loaded in the same ranges of stuffed cases and appropriate powders. Not using the same powders mind you.

The 30/06 powder stack doesn't burn as well as a wider and fatter 338 mag stack. 45/70 is a great short barrel gun because it has a very efficient burn from the powder stack. Look at the loads you can come up with on max 45/70 info! Rivals the 458 Win mag.

Really short barrels make slow guns (and generally require fast powders) opposed to a slow powder in a long barrel. 20/22" in either caliber makes between 95/ 98% or so of what they will make up to a 26" barrel. All this basic data is for the 250 to 275 grain bullets. Things change again if you are running the lighter 200/225s.

The more detail I add the more complicated this gets.

Good rule of thumb. The bigger the caliber, heavier the bullet and the shorter the case the better a short barrel will treat your external ballastics. The smaller the caliber and the longer the case the more you will loose by cutting barrels.

Old 03-23-2005, 10:56 AM   #6
Join Date: Dec 2002
Posts: 48
Thanks fellas, that's just the discussion I needed. Matt
Old 03-24-2005, 06:27 PM   #7
Join Date: Mar 2001
Posts: 171
Observation: at work today I got to shoot an Accuracy International in 338 Lapua. Had one heck of a muzzle break. The AI had a 27" barrel and shot softer than my .308 (20" barrel). Fun too shoot. I was dialing-in my .308 for an upcoming course and the AI was banging steel at 900 yards easy. great round.
Old 03-25-2005, 10:07 AM   #8
Join Date: Apr 2001
Posts: 194

The A-I in 338 Lapua is surely an interesting rifle. Clearly a specialized piece of ordnance, though. It's a bit more of a crew served weapon at, IF I remember correctly about 18 lbs less ammo, scope, bipod, sling, etc than interests me personally. The one I tried several years ago surely did shoot.

Still, I think I'll stick with me trusty pre-64 Model 70 Winchester 338 with a 1-5X variable and no brake or holes burned in the barrel atall.... Still a lively handling gun and one can shoot it off hand without a life spent on the free weights....

Old 03-25-2005, 10:20 AM   #9
Join Date: Apr 2001
Posts: 194
Understood Dane. You surely make a valid qualification. My comment was simply geared to the idea of an 18" 338 simply not yeilding enough ballistics over the 06 based case to make it worth the recoil and muzzle blast. As you say the bigger capacity cases work better and even the 375 H&H, I think, is a better candidate for the short barrel. As of course, would be a 458 for North American hunting in the Alder thickets or black timber. I think my 18" 338 vs 338/06 comparison is kinda like the 357 in a short barrel...depending on the weapon, you may not lose THAT much, but in general a 357 out of the same weapon is still going to be more potent than any 38 out of the same weapon and bbl length despite the idea that surfaces from time to time that you might as well carry a 38 as a short barrel 357. Handloading, of course, can certainly help to minimize the differences between ctgs and barrel lengths.

As you know, I'm stuck on having a cartridge for which factory ammo is readily available and only reloading for economy of practice IF I can find a factory load that does what I want out of the specific rifle. I surely paid the price with my Dumoulin 460 Wby by cutting the barrel from 25 inches to 22 to try and reduce the Wby factory ctg velocity a make what I consider a more reliable cartridge for deep penetration in heavy game that was still available over the counter for resupply. Still, I pay the price in increased muzzle blast...which is pretty moot for that round, I reckon.

Old 05-13-2014, 08:34 PM   #10
Junior Member
Join Date: Dec 2002
Location: Oregon
Posts: 17
My Dad had a Winch Model 54 originally 30-06 that was bored out to 338 Magnum. 24" barrel was perfectly ok. And it was very accurate.

Not sure who did the bore. Might have been Bob West in Oregon.

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