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Some links on the 30 Gibbs.You can buy brass,but it is expensive
https://www.starlinebrass.com/articles/how-to-make-wildcat-cartridges-wildcat-ammo-loading-guide/
https://www.rccbrass.com/product/30-gibbs/

In Handloader #73 (May-June 1978) Bob Hagel published a lengthy article on his experiments with the.30 Gibbs.

His summary sentence:
"To sum up the performance of the .30 Gibbs cartridge, it will produce about 50 fps more than the .30-06 with the same barrel length when both are loaded to approximately the same pressure levels."

The key phrase is "same pressure levels". Hagel has a reputation for tipping the powder bottle.

An earlier sentence is significant: "... with the best powders the .30 Gibbs will kick the 180-grain bullet along at between 2,875 to nearly 2,925 fps. This is really quite impressive velocity, and a great deal of improvement over the 2,700 fps considered average for the venerable old .30-06. But when you load the .30-06 to similar pressure, the best powders will show velocities running from 2,825 to 2,900 fps also."

Hagel wrote that the .30 Gibbs has about 5.8 grains more capacity than an unaltered 30-06 case with a 180-grain Hornady bullet seated. He didn't specify the make of case. Nosler manual #8 shows a capacity of 63.9 grains of water with an unspecified 180-grain Nosler bullet seated. Adding 5.8 grains to this shows the Gibbs cartridge with about 9 percent greater capacity. According to the Barsness rule of thumb, velocity at the same pressures should be about a fourth of 9 percent, or 2.25 percent greater for the Gibbs cartridge.

With a 30-06 velocity of 2700 fps, at the same pressure the 30 Gibbs will produce 2760 fps. If you can get 2850 fps from your 30-06, a 2.25 percent increase will yield about 64 fps greater velocity, or 2915 fps.

[Opinion: The 30 Gibbs is a lot of fiddle-dee-dee for about 1.5 inches less drop (26.5 vs. 28.0 inches) at 400 yards.]

--Bob

My best load in my BRNO 30/06 used H205 and drove a 180 at 2860. It shot under 3/4 for five shot groups, pressure seemed fine, and this lasted until I couldn't get 205 anymore! From then on, I stuck with my old 4350 load which was fifty fps slower but shot just as well.
I built a few rifles in 30 Gibbs and most ended up shooting 180's at around 2800. Most, soon enough, realized, if you want a 300 mag, the best way to achieve that was to have a 300 Mag. GD

I'm surprised that no one invoked the article Rick Jamison wrote comparing the 30-06 vs the 30-06 AI vs the 30 Gibb. I tried googling it to cross check my memory, but this is all I could find;


https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/5441455/Re_what_s_a_30_gibbs

Beyond the quote, what stuck out in my mind is that Jamison started with a 30-06 and reamed it out to an AI first then to a Gibb...all on the same barrel/rifle, removing the question of whether it was a fast barrel or not. He also was equipped with an Oehler PLB and measured pressures along the way, so it was truly an apples to apples comparison. I'm amazed that that article did not turn up more in my Google-Fu. ...maybe he is still persona non grata in the shooting world.

Advice to the OP...while I'm prone to spout data and rational thought processes...this is not an area where I would say don't do it because the logic doesn't support it. If you like the idea, you should absolutely pursue it (and write more about it here...so I can live vicariously through your experience!)

You certainly would not be disappointed.

Well got lucky today found a 03A3 Remington in a ram line stock glass bedded, 03 bottom metal, handle modified, drilled and tapped for weaver bases (incl), timmney trigger, 4 groove barrel in good condition in 30-06 Ackley Improved with a set of RCBS group g dies. Went around awhile on the price with the guy and we settled at $330 cash . When I got it home I set a old K4 weaver and weaver rings on it to give it a try. A little bore sighting and on the 3rd round I'm in the black .165 grain Speer flatbase Spitzer and Superformance in SL54 brass. Fireformed perfectly and gave me some tight groups. This is how I like to get into uncommon guns. Mb

If you end up with a 30-06 with excessive headspace, then a .30 Gibbs reamer and headspace gauge may be your Huckleberry.

Seems like to me the 1st step there would be to determine why you have excess headspace and what is causing that to happen before putting dime one in an upgrade? Mb

There's an article devoted to the .30 Gibbs in Wolfe Publishing's "Gibbs Cartridges". It may still be available. A good bit of load data with bullets of all weights, but, as I recall, the data looked pretty warm.

Pretty warm? How so? Why would you drive a Ferrari around in 2nd gear? Barrel length is 26" in the article, but the author doesn't specify what amount of expansion he considered to be standard vs. max. My 26" 30-06 Ackley has beat those speeds by a little bit with admittedly warm loads. Still able to use the same brass more than 4 or 5 times & primer pockets are still snug, the brass is finally giving up to longitudinal neck splits after 30 years. The Gibbs has a bigger boiler than the Ackley so should be able to get faster speeds with all else the same.

Interesting book. Frontal ignition sounded like a good project to check out when I was younger & still had the resources to try it. I dunno about older & wiser, but older & lazier for sure.

When ever you read, "loaded to equal pressures" you know you are reading a pile of bs.

Oh, really. Do you have some objection to valid comparisons? Are you one of those who believe a sharp shoulder makes the brass able to withstand higher pressures? The truth is, whenever you read "when loaded to equal pressures", you know you are probably going to read something you don't want to hear. GD

I have a pile of Ackley reamers, started off with an ohler 33, now 35, and Lab radar. I know what the AI's will do, real world. Retarding brass flow in and of it's self is no small matter.

It is just a hobby. Most do not reload anyway.

Reloading:

Federal brass pressure signs

'06 Lake City Match pressure signs

Remington Brass pressure signs

Winchester Brass pressure signs

Lapua pressure signs

Now, off to the 338/06.........165g Barnes ttsx rock the world on deer.......

Choose your poison............Rifle looney madness.......

...I'm curious...what kind of velocities are you getting out of your 30 Gibb? ...and at what pressure?

I rechambered a Ruger #1B (26" bbl) in '06 to .30 Gibbs. Measured (Oehler 35) 3,050 fps with a 180 gr bullet! Primers fell right out of the pocker upon extraction. Probably about 80 kpsi. Backed off 2 grains, and it would do 2,950 fps. Powder was RL-22 and was known for unexpected/unexplained pressure excursions. I had shot the same charge weight before without any warning signs. Have not used RL-22 since (about 20 years now).

I remember an article in Shooting Times where Rick Jamison (if I spelled his name correctly) shot his rifle and then re-chambered it to the next cartridge.
It showed that the velocity gain was modest from the 30-06 to the 30-06AI and then the 30Gibbs, When loaded to the same pressure!

I'm no expert, I just read the magazine several times as it had an article on 22-250 1-8 twist.

I have no way to test pressure but I have a .30-06 barrel on its way, a donor action found (I think), .30 Gibbs dies, a stock and a nice trigger. The plan is to test a 22” Factory barrel first as a .30-06 with several bullets in the 150-200 grain class and then punch it out to .30 Gibbs and re-shoot the same bullets. Will basically be looking for classic pressure signs, backing off and looking for accuracy. If the Gibbs can offer similar accuracy at .300 WSM velocities then I have gained something. If the accuracy node is down in .30-06 territory then the Gibbs is essentially a waste other then maybe a little less brass trimming.

The only thing I really hope to gain in the 03A3 chambered for 30-06 Ackley improved i picked up last weekend was to experience it myself instead of hearing or reading someone extolling its virtues in Handloader or Rifle or on the fire. All my life I've been one of those people who had to go over the next hill or around the next curve in the road just to see what's there. Satisfying my own curiosity means more to me than the actual results. Good luck with your plan Med river. MB

Greydog... Equal pressure & valid comparisons? SAAMI for 30-06 & 280 is 60K. It's 65K for the 280 Ackley & the 270. The sharper shoulder in itself does not make brass withstand higher pressures. Brass is brass & is still the weak link in the chain. If you can find a copy of Ackley's book you can read his test results for yourself, but you might read something you dont want to hear. Paraphrasing from memory he says that the improved case, upon firing, grips the chamber walls better than a tapered case, thus reducing the bolt thrust. If I remember right there are a few tests to destruction of various actions in both standard & improved cartridges. I think there was a lever action chambered to 30-30 Improved tested with no locking mechanism, but am too lazy too dig out the books this morning. The day's a wastin' & the grass needs cuttin'.

MedRiver, I think you're short changing yourself with a 22" barrel, but your results will be interesting.

Enjoy your Ackley Bob. Dont be afraid to push the envelope a bit with care & within reason. Hoping you got a high # 03. IMR 4350 was the powder when I did most of the development. The 4831s filled the case well before before pressuring out. RL 19 & 22 were showing promise with 150s & 180s respectively. The new (plastic) jug of IMR4350 I got doesn't develop anywhere near the same speeds as the old (metal) can. Very disappointing. With the newer powders, RL17 has given good results with 150s. The biggest gains were realized with 150s & 165s so far, but with the plethora of newer slow burners, who knows? I will be trying some RL23 soon with 150s & 165s & may try RL26 with 180s.

Along with investigating other possibilities- yes. I did not thing I had to list every possible scenario and common sense procedure when I posted. Looking back, I should have taken a moment to realize I was in a forum chock full of narcissists and arrogant azzes.