The Z-hat Hawk cartridge series is easy to find and research. The various '06 based AI cartridges are very easy to find as well. Where do I find comparison's to the PDK series I keep reading about in singular posts?

I have been reading lots of posts on this site but, I still don't see how this cartridge series compares to the '06AI series or the Hawk's.

Specifically, I'm looking for information on the 338 and 375/416 variants.

Thanks!
Sid

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I have been reading lots of posts on this site but, I still don't see how this cartridge series compares to the '06AI series or the Hawk's.

Sid,
I'm not sure what you are wanting as to how it compares. You will not find data on the PDKs other than on this sight. Since they are mine and I only post here. The 280 & 340 were included by accuload (loadtech) in their software.

Below is a picture of the various versions of 338-06. Starting with the 338-06 going up to a 338-66AI. The various AIs give around 4% capacity increase, the Hawk around 7% the Gibbs around 10% and the PDK & Howell around 11%. The Howell is 2.6" so the net capacity increase would be less than the PDK. Making it with thinner brass would help. Simply anything the Hawk line can do the Gibbs, Howell or PDK should do with a little more.

I had always felt that the AIs left capacity on the table. So I built my PDKs. Only to find out that Rocky Gibbs had done the same thing 30 yrs before. As you can see the difference is small. He used a 35deg and 06 brass I used a 40deg and 280 brass. So basically anything you read for the Gibbs fits the PDK darn close. I also like the Howell series from American Hunting Rifles. My buddy uses their brass in his PDKs and we simply cut the neck longer. While the longer case has the same gross capacity as mine the thick walls gives less net and his rifles never reach my velocity.

Do a seach on PDK here on AR or if you have a specific question please ask. While I don't loan out my reamers nor work for others anymore I would be happy to share the dimensions so a reamer could be cut.

Thanks Paul! You cleared up some of my confusion. I'm looking to rebarrel a 25-06 and I want the "best" I can get from a 30-06 case because I want a softer thump on my shoulder then the various Magnums give me.

I'm having a real hard time differentiating the colors in your picture which appears to have a lot of great info in it. My initial goal is to have a superior Elk rifle. It looks like the 338-06 and 338-06AI may not be good choices. I want to end up with a case that won't require a lot of trimming and will be easy to resize. The 338 Gibbs is a 30-06 case with the shoulder moved forward with a steeper angle isn't it? Is this hitting the "sweet spot" for a 338 30-06 variant? I'm really tempted to go with a 338-06 though because it looks like Pac-Nor can put a rebarreled rifle in my hands a lot cheaper then anyone else. Factory brass and ammunition isn't an issue for me as long as I can make my own without excessive effort.

What are the normal velocity differences in the 338's? Do you have a handy reference for these 338 variants? If I went with a 338 Gibbs, is this a cartridge where I could rent a reamer and have Pac-Nor finish ream the barrel (assuming this is the optimal case dimension for a 338-060?

Yep the colors get messed up making the drawing a bit map. They pretty much read left to right in the order of the list. The one missing is the last 338-66AI. Yes the gibbs is a blown out 06 .25" neck and 35 deg shoulder. I've seen the gibbs reamer for rent. I can PM you 338Gibbs info if you want.

I built my case to be optimum for a 280 but have used it with great success up to 416. My 340PDK from a 24" matches my 338mag handloads from a 22" for 225gr or less and I don't wear out my brass. It is my elk rifle of choice I sold the 338.

Like I said the 340Howell is an option as well. AHR has brass, dies and can chamber your barrel. I would also check with pacnor as to the dimensions of their 338Brown-whelen reamer. It should be a blown out 06 case shoulder forward about halfway to the gibbs with a 35deg.

Thanks Paul! That article was really helpful and has convinced me that I should look for something similar for my rifle.

I built a 6.5 Gibbs in 1956. When the .264 Win. mag. came out a couple of years later, a friend and I built one of the first ones in Texas on a Mauser action. We had no chronographs at that time, so compared the two using drop testing at 500 yards. The 6.5 Gibbs seemed to produce very close to .264 velocities with the same bullets using 10 grains less powder. Subsequent testing with a chronograph years later confirmed this.

I don't believe Rocky Gibbs ever got the credit due him during his lifetime. Most pundits of the era, when they did acknowledge his efforts, tended to state that his results were "over-optimistic". And that he was no doubt running his pressures at much higher than safe levels.

What most of these writers failed to realize was that Gibbs had access to ballistic lab facilities at Speer Bullets, and that in addition, he had built himself his own pressure gun, and was measuring the pressures his cartridges produced during load development. The fine selection of slow powders we are today blessed with were not available to Rocky, but one, H4831 in the milsurp variety, was. This one powder would have been sufficient to produce the ballistics he was claiming in MOST of his cartridges.

I believe a .338 using the Gibbs case, or this PDK case, would be about the ultimate in a .338 caliber round using the '06 case.

Many complain that making such cases is a pain. But I do not find it any worse than fire-forming for any version of an improved case. For such a .338" cartridge, I would start with .35 Whelen brass, and just leave a "secondary shoulder" for headspacing purposes while necking them down to hold .338" bullets.

Ramrod340, thanks for your contribution in this field!

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Ramrod340, thanks for your contribution in this field

Thanks but other than reinventing Rocky's wheel can't say I added much.