I now have a 338 Gibbs, HVA Mauser Action, 26" Lilja Barrel, Canjar trigger

66 gr. Re17/200 gr Accubond/3006 fps/~4000+ ft# muzzle energy

64 gr. Re17/210 gr Scirocco/2927 fps/~4000+ ft# muzzle energy

64 gr. Re17/225 gr Speer BT/2861 fps/~4000+ ft# muzzle energy

Hot loads, but GOOD solid/tight pockets, easy bolt lift - I'm very pleased.

Sounds like a winner. Your 2" longer barrel will make it easier to reach my max and more than offset the "slight" advantage I have in net capacity.

I will never go back to a 338wmag. If I need to hit harder than a 225gr at 2850 I'll grab something bigger.

Hi Paul,

Nice to hear from you. Also, thanks again for your advice on this project.

Your 340 PDK has a longer neck than the 338 Gibbs, but the PDK and the Gibbs shoulder are very close in position on the cartridge.

I'm thinking that the case capacity that matters is that capacity measured to the base of the neck or top of the shoulder, which should make the Gibbs, Howell, and PDK essentially the same.

The capacity occupied by the neck is essentially "empty" capacity, since the neck volume is occupied by the bullet.

I'm also getting MOA accuracy with the 338 Gibbs.

If somebody has a 30-06, 280, 270, 25-06, etc platform and wants to convert to a "magnum" - but with minimal hassle and expense - then the 338 Gibbs conversion is a cost effective option. It works, and you can use all your 30-06 brass. The 338 Gibbs is an extremely efficient "magnum" and the dies are available commercially.

Regards, AIU

quote:

Your 340 PDK has a longer neck than the 338 Gibbs, but the PDK and the Gibbs shoulder are very close in position on the cartridge.I'm thinking that the case capacity that matters is that capacity measured to the base of the neck or top of the shoulder, which should make the Gibbs, Howell, and PDK essentially the same

You are 100% correct it is the NET volume that matters. Loaded to the same OAL the longer neck adds nothing to performance.

Actually the Howell and PDK neck shoulder is the same spot on the 340 the Gibbs is .017 further back. The PDK has a 40deg the Gibbs a 35 and the Howell a 30(I think). The PDK is .46" at the shoulder the Gibbs and Howell in the .454 range. What all this says is the PDK "MIGHT" give 1-1.5gr more capacity. Heck the difference between manufacturers can give you more than that. Or set up your chamber to allow a 3.4 vs 3.34 OAL can give you 1.5gs.

As I said back when you are asking about building the PDK build the 338 Gibbs you will never see the difference.

Paul, I have a bunch of guns, various calibers, and many wildcats; and, I'd rank the 338 Gibbs near the top as a great wildcat. Yet, this topic is generating very little interest. Go figure. AIU

AIU
Yep strange isn't it. I used my basic PDK case (basically the Gibbs using 280 brass) and chamber for everything from 243 to 416. For me there were 4 keepers. the 6.5, 280, 338 and 400. I loved the 400 but it got pretty much a yawn and now the correct dimensioned 400 Whelen has everyone's interest.

I found that in the other 3 I could easily match factory magnum loads for all but the heaviest bullets. Using less powder and a heck of a lot less blast and recoil. It gave me exactly what I was looking for. Heck if I used an extra 2" of barrel I could beat my own magnum hand loads.

The major problem is we are going wildcat to give the same velocities of the magnums. So if velocity is your main target why bother.

If you want 2 more down, less powder more efficient, to be different then the PDK and Gibbs make sense. I do always find it interesting that people will brag about their AI(4% volume gain) and the GREAT VELOCITY GAINS and give a thumbs down to a Gibbs style 11-12% volume gain. When was the last time you needed to fire a std in an AI chamber in an emergency situation?

Paul,

You're correct - if one only wants velocity increase, get a 338 Win Mag or the like.

But, if you want to inexpensively convert your 30-06/280/270/etc. platform to a magnum and use your old cases, all one needs to do is re-barrel. No need to modify the bolt (my gunsmith does not like changing the bolt face). If you want to go back to your 30-06/270/etc. screw the barrel off and put the old pne back - switch back and forth as needed.

Cases are easy to make from 30-06 cases, and the 338 Gibbs reamer and dies are available commercially.

My 338 Gibbs conversion was simple and cheap. The same would be true of the other Gibbs wildcats - I could not find the PDK or Howell reamers or dies.

The 338 Gibbs is an astonishing magnum improvement over the 270/280/30-06 and 338-06. I love it! I don't need a 338 Win Mag - I have one called 338 Gibbs.

I'm surprised the 338 Gibbs did not become commercially available.

Regards, AIU

quote:

Originally posted by Ackley Improved User:
Paul, I have a bunch of guns, various calibers, and many wildcats; and, I'd rank the 338 Gibbs near the top as a great wildcat. Yet, this topic is generating very little interest. Go figure. AIU

Thats because the 338 WM is a much more useful all around cartridge--




With factory ammo for sale everywhere no less

quote:

My 338 Gibbs conversion was simple and cheap. The same would be true of the other Gibbs wildcats - I could not find the PDK or Howell reamers or dies.

Wayne at AHR at one time sold Howell, ammo, brass and dies. However, just looked today and he doesn't list them on his website. He might be totally focusing on the Larger calibers and his CZ workovers.

For the most part it is my family and friends that have PDKs. While Hornady has the die info on record it is a custom order and as you stated in our PM Hornady is focusing on commercial stuff at this time. It sure wasn't of interest to me to push the PDK if someone wanted it I was happy to share.

The Gibbs never went commercial probably because of Rocky himself. He was a pain to deal with, didn't share his info and for the most part if you wanted a Gibbs back in his day you had to deal with him. Heck I think even the shoulder angles used for the Gibbs now days is a guess because he didn't share and a large majority of his data was destroyed.

As Sean says the WM is for sale everywhere. But saying it is a more useful all around cartridge is like saying you should always use a 300wmag vs 30-06. For the non reloader it is hard to beat. If you reload like to be different and for sure more efficient there are a number of alternatives the Gibbs being one of them.

Back in the late 70s when I started with the PDK idea if I had know about and investigated the Gibbs I'm not sure the PDK would exist. The Gibbs would have gotten me the majority of what I was designing for.

The masses will stop with the 7MM 300 338 magnums and be totally happy as they should. There will always be a few of use who like to play around and be different. Do we really give up anything to the magnums? Not in my opinion other than not being able to go into walmat and buy a box of ammo. The few fps we give up the animal will never feel. The extra 2 down might come in handy.

Just think how boring the campfire would be if everyone shot the same thing.

quote:

Originally posted by Sean Russell:

quote:

Originally posted by Ackley Improved User:
Paul, I have a bunch of guns, various calibers, and many wildcats; and, I'd rank the 338 Gibbs near the top as a great wildcat. Yet, this topic is generating very little interest. Go figure. AIU

Thats because the 338 WM is a much more useful all around cartridge--



With factory ammo for sale everywhere no less

Sean,

If availability of 'factory loaded' ammunition was a 'primary' criteria you wouldn't own a 416 B&M and I wouldn't own .423 and .500 caliber Lapua Magnum wildcats! LOL...

Anyway, if FN/Winchester was that bright, they'd have released a factory 405 WSM cartridge/M70 rifle combo to take advantage of the current popularity of the 405 Winchester in the M1895. Go figure - I'd think it ought to be a big seller in NA and likely Australia.

Paul,

Folks including wildcatters are fickle critters. Yes the .400 Whelen derivatives have a current resurgence of popularity but who knows how long that'll last.

I personally prefer the slightly greater net capacity of the Gibbs and PDK and the longer neck of the PDK vs the shorter neck length of the Gibbs. Perhaps you'd have gotten more interest if you'd used 'Gibbs PDK' as the nomenclature for your cartridges. LOL...

Keep the faith...

Jim, et al

I know I and like wildcats myself--but I can load a 338 down to 338-06 levels or hotter than the gibbs-and still have the fall back of factory ammo, from low recoil to heavy mag.

Wild cats are fun--just don't try to tell me that they are more useful than a great cat ridge like the 338 WM.

no sweat--just pointing out reality--

quote:

Perhaps you'd have gotten more interest if you'd used 'Gibbs PDK' as the nomenclature for your cartridges. LOL...

Yep then I wouldn't have to say "like a Gibbs + a gr or 2 and longer neck" Could have saved me all that typing.

Sean I wouldn't tell you that!

quote:

Originally posted by Ackley Improved User:

But, if you want to inexpensively convert your 30-06/280/270/etc. platform to a magnum and use your old cases, all one needs to do is re-barrel. No need to modify the bolt (my gunsmith does not like changing the bolt face). If you want to go back to your 30-06/270/etc. screw the barrel off and put the old pne back - switch back and forth as needed.

Regards, AIU

My main point is as stated above. I can get this 338 Gibbs conversion done much cheaper than I can buy a whole new gun.

Nobody's denigrating the 338 Win Mag - it's great magnum.

Regards, AIU

Some updated information..

338 Gibbs, 26" barrel, HVA Mauser action

68 gr. W760, 200 gr CT ballistic tip, using Winchester 30-06 cases converted to 338 Gibbs,

3060 fps, 4158 ft# muzzle energy, MOA accuracy, very firm primer pockets, easy bolt-lift.

Amazing...hard to believe, but true.

Regards, AIU

PS. I'm finding W760 to be the ball powder form of Re17, almost grain for grain.

From left to right...

338-06 225 Accubond, 338-06 Ackley Improved 225 Accubond, 338 Gibbs 210 TTSX, 338 Gibbs 210 Swift Scirocco.

quote:

338-06 225 Accubond, 338-06 Ackley Improved 225 Accubond, 338 Gibbs 210 TTSX, 338 Gibbs 210 Swift Scirocco.

Nice picture. I always felt if you are going to the trouble of building a wildcat why stop with the AI. Going to something like the Gibbs doesn't really cost you any more. I've used various versions since around 1980. Never had a issue where I needed to run down and buy factory ammo so can't really see the need for an AI

If you had built it using 280 brass you could have probably caught that cannleure.

Paul, just measured the H20 capacity of a 35 Whelen Norma case converted to 338 Gibbs and it was 77 grs H20...that plus some "Weatherby-like" freebore explains the exceptional 338 Win MAG performance I'm getting.

For more information on the 338 Gibbs go to...

http://forums.accuratereloadin...=445105028#445105028

AIU

quote:

"Weatherby-like" freebore explains the exceptional 338 Win MAG performance I'm getting.

yep giving the bullet a running start can do wonders. My 375 and 400 have in excess of a bullet dia. Not like I'm going to be using them for bench rest.

Further update...338 Gibbs

70 grs. W760//26" barrel//210 TTSX//3005 fps//~4200 ft# muzzle energy//sub-MOA accuracy//easy bolt lift//firm primer pockets

Hard to believe but my chronograph is working great. Velocity checks on other cartridges are spot on.