Does someone have the dimensions for the .338 Gibbs cartridge that you could post? I'd appreciate it. Thanks ahead of time. Regards, AIU

Reloading data:
http://www.loaddata.com/member....cfm?MetallicID=2719

Could not find much relating to case dimensions:
https://www.google.com/search?...sAQ&biw=1237&bih=564

The best is to contact Dave Manson at Manson reamers.

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If the 338 Gibbs is related to the 270 Gibbs, then it is a .473 casehead.

Here is Ammoguide 270 Gibbs:
http://ammoguide.com/cgi-bin/a...pDmcxAkWwr&catid=595

Here is Ammoguide 30 Gibbs:
http://ammoguide.com/cgi-bin/a...pDmcxAkWwr&catid=444

There is some comment about a "front ignition" cartridge, whatever that would be. PErsonally I don't like the rather small subcalibre necks. (the neck on the 30 gibbs is only 0.21"!)

I have a 338 Gibbs built on a Mark X. I make my cartridges out of 30-06 Lake City brass. I use a 8mm-06 die first then a 35 Whelen and finally the 338 sizing die. The 35 Whelen makes a false shoulder when you fireform. The 338 Gibbs is like an Ackley Improved cartridge only with a 30 degree shoulder. Midway had brass at one time but the headstamp was 340 Gibbs. It has been said that Gibbs overstated the performance of the cartridge.

Very early on I had a 6.5 Gibbs and a 358 Gibbs.

I had hydralic dies to blow out the cases with 30 wt. oil..Gibbs sold them, had a plunger and you used a heavy hammer to hit the plunger and the oil "fireformed" the case...It didn't work well at all, blew oil all over the operator!

It was more trouble than it was worth, but at the time I was an avid Wildcatter and was amoured by the Gibbs cartridges..

Then one day I had access to a chronograph. The 6.5 was nothing more than a 6.5x57 or perhaps an Ackley. The 358 was a Whelen when loaded to real world pressure, but it worked at probably 75,000 PSI or there abouts ..

The 358 was a mod. 70 fwt and it kicked like a mule according to half the population of Lusk Wy. Not to mention I ruined what later became a rare collector item..

After those chronograph sessions, I allowed the Ackley was a better option anyway I cut it, so set the barrel back on the 6.5 to a 6.5-06 and traded the other off for a minty 94 oct. rifle in .25-35

If I had a .338 gibbs today, Id set the barrel back and make it a .338 Ackley Imp. and save myself a lot of work, or more likey I'd rebarrel it..but, that said, I'm no longer a dyed in the wool wildcatter, and have lost that desire...

I have to say wildcatting is very interesting and you learn a lot about calibers, their abilities, real and otherwise, balistics, pressure etc. and its a heck of a lot of fun, and if it blows your skirt up don't let this post deter you from jumping in their head first, its fun and can't hurt a thing.

My 6.5 Gibbs on a rem 700 with a 26" lilja barrel is so fast I use less then max loads.
A 6.5x57 it's not.

Thanks for replies. I appreciate it. AIU

I could send you a fired case if you need one to measure.
Ray Romain in Pa built my gibbs, he had his reamers made to use 270 brass, so you gain a little neck length.

I now have a 338 Gibbs with a 26" barrel. With Re17 and 210 gr. Swift Scirocco's I'm getting 2950 fps. Although primer pockets are good, this is max IMO. I'll settle on 2925 fps. Also, accurate. I believe the 338-06, 336-06 AI, 338 Gibbs, 340 PDK, etc. are very efficient cartridges and one way to convert that 30-06 into a near-magnum without modifying the bolt. AIU