Home Forums Hunting & Shooting Custom Rifles & Wildcats 30 Gibbs

All,

Anybody here every have a rifle chambered for said round? I may have a line on a smokin deal for a donor Rem. 700 in 30-06 with a 24" barrel. I've always wanted to play with a 30 Gibbs , but never really had a chance to. Thinkin this may be my chance, but wanted some input from the "Fire" experts!

Thanks for your replies in advance!

Elk Country

My favorite rifle for 25 yrs. We have a shooting gallery of sorts here and after thousands of round the throat was getting out there so I had it bored to 35 Gibbs bye JES. I killed 2 40ish bull moose with 1 shoot use 165gr Hornady SP. I bought mine from a fellow in Florida who'd moved from Idaho and said that Rocky had done the work. It was (and is) a beauty of a pre-64 mod 70.. We still plink with 250 Speer Hot Cores @ 2500fps, for moose and bear I crank 280 SAF @2450.

Waterrat,

What load and velocities were the 165gr. Hornady's? Just trying to get a feel for the difference between the Gibbs and plain jane 06!

Elk Country

Elk We just put a new floor in and everything is in crates some around here, biirc I was use IMR 4350 and with WW cases 62grs or close to that. Wildcat has Bob Hagel using 67gr for 3083 and Stover at 65 just over 3000,, I could barely get 62 in and it was pretty hot at that!! Mine was accurate with 62 @ 2900fps.

Case Capacities:

30-06 - - - 68.2 gr

30 Gibbs - 71.12 gr

3 gr of powder... I have better use for my money and time.

I appreciate the Gibbs as a theoretical concept but I like the 30-06 more, it always does everything I need a rifle to do.

If you're impressed with the 30 Gibbs my 300 WM will absolutely blow your mind...!

Been kicking this one around myself as I happen to have stumbled on some .30 Gibbs dies for a song, have a mountain of ‘06 brass and .30 cal bullets of almost every flavor, a potential donor .30-06, and a good gunsmith that will punch it out for a reasonable fee.

No doubt gains are modest but most real world reports show 100-150 FPS gains (some of which could very well just be from hiding pressure signs).

I kinda view it as a long action .300 WSM with cheap brass and 4 in the magazine.

What kind of velocities are people getting with the 30 Gibbs.I'm not talking about 100-150fps gain over the 30-06,I'm asking for actual load velocities.

If I do mine the plan is to thoroughly wring the rifle out first as a .30-06 with a variety of 150-180 class bullets and then see what happens with it punched out to a Gibbs. Should give some pretty real world data but may be a year before it all gets done as fall is approaching and won’t have time for bench testing.

I've measured the gain in based on water to the top of the neck right @ 10%, not the <5% you have posted.

It's certainly a couple or more than the highly praised Ackley!

It's unclear where your numbers come from. I have a 30-06 Ackley & here are the weights I got with fired brass filled with water to the base of the neck at the shoulder junction. The #s are the water weight. Gibbs will be more of an increase, so your 71.12 may be right.

Sorry it's all different makes of brass but that's what's in my notes.

W-W standard 30-06.......... 55.6 gr
R-P 30-06 Imp.................... 63.3 gr
Federal 30-06 Imp.............. 62.7 gr
R-P 300 H&H .................... 81.7 gr

I got my Ackley in late 1990. It wears a 26" Douglas barrel. My Oehler 33 says I'm getting over 3300 fps with 150s, just under 3200 with 165s, & just over 3000 with 180s, all with good accuracy. It's warm but not excessive with my components in my rifle. Just this year I fireformed some new brass for this rifle due to some necks finally splitting. The old brass still works after quite a few firings but is tired after 30 years. Primer pockets still hold primers. Not bad for an 06 case burning under 65 gr of IMR-4350 & more recently some RL-17. Gibbs should do a bit more.

You mean the Ackley you can shoot factory ammo in? It's real pisser when you can do that.

Yeah. That one.

Bucket list curiosity items for sure for me. I'm to cheap to spend the dollars to rechamber for an Ackley imp or 30 Gibbs but if I saw a 03 or 1917 that it was done to I would be very interested especially if they had left the barrel full length at 24 or 26". Cheapest velocity in the world comes from a long barrel and I sure do like them. MB

If I saw the right m1917 chambered for the gibbs, I'd buy it. As of now, I'll just use my 30-06 or 308 Norma.


The 30 Gibbs is one I've thought about for a long time. It is intriguing, I'll give it that much..

I hear you, especially on good deals. That said, I can't think of a single time that I missed a shot and said 'Gee, I would have made that if my barrel was 3 inches longer (ex-wives and girlfriends not included)'

YMMV

BSA1917 and Rem mod 8 I have a lifetime supply of 22" and shorter barrels and I hunt mostly open country nothing gained by less barrel length on my end. I have an 03A3 Remington sporterized in 308 Norma mag 24" and 22.5" barreled 03A3 Springfield in 300 Win mag.,a couple of sporterized 03a3 in 30_06 with 24 " and 1 1917 Eddystone 30'06 with the full 26" in 06.i like long barrels cheapest velocity gain there is. I have allways believe you buy someone else's custom work for about a 1/4 of what they had to pay makes more sense than you paying out the butt. MB

A longer barrel seems to really get a few more fps out of a standard 30-06.Playing with different powders also makes a big difference in velocities too.I was working on some loads on a 23" Rock Creek barreled 30-06 a few weeks ago.I found 55.5grs of Big Game,Win Case,WLRM Primer,168gr Nosler Ballistic Tip gave me 2955fps.That same load gave me 2985fps out of my 24" Sako rifle.That same load out of my 28" Pac-Nor barrel was 3043fps.

That line is so good it should be a tag line. it's so good it's damn near profound.

Always thought it was interesting how a 30 Gibbs and a 223AI have similar dimensions in proportion to case size.

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.

358wcf it's a 03A3 Remington 4,000,xxx range no worry there. I thought before I started leaning on it I would use fireformed brass, newer commercial variety at that. Right now I'm just shooting it and fireforming some mil brass I have, but If I had a hunt tomorrow I sure would be confident with it for as far as one would care to shoot at a game animal with a K4 weaver.
3584elk, while I just retired the last 35 years I've worked in the geo technical and civil engineering fields. In engineering the first thing they teach you is the word "assume" means ASS U ME. So out of habit I never assume very many things. I certainly did not assume that you knew the things I mentioned or that you would be offended that I would courteously bring them up. So I will in the future not reply to any of your posts. MB

I had an 8mm Gibbs built for Dad about 20 years ago, using his first ever deer rifle(98 Mauser) for a donor(needed a new barrel anyway). It's been a lot of fun, it's that rifle that got me started reloading.

That being said, I don't load it much past full house Euro 8x57 anymore. Some of the "published" loads for Gibbs rounds are blasted HOT!!!. The 30 Gibbs comfortably fills the gap between the 300 Win Mag and the 30/06. If you enjoy it for what it is, a neat retro oddity(probably a design ahead of it's time), go for it.

Too short of a barrel is the story of my life

I like the feel and balance of 20-22” barrels for my all-purpose hunting rifles. I am not worried about maxing velocity of the case...more interested in real world improvement in the same barrel at a finished length that I want to pack around.

Dropped it with my ‘Smith today and rented a reamer. Could be shooting a Gibbs next week!

I have a copy of Ackley's book which I got as a Christmas gift 56 years ago, when I was fifteen. I am very familiar with his theory on reduced bolt thrust and believed it until I was 16. It was then that I separated a case with a hot load in my Lee Enfield. At this point my thought process was like this; if the case separated, the forward portion of the case must have been gripping the chamber wall sufficiently to remain in place while the base moved back. If this was the case, why would gripping the chamber wall even more tightly reduce bolt thrust? If the 303 british case (plenty-o-taper) could hold on tightly enough to not move back, what difference would the improved case make? At the time, I decided the difference might have been in Ackleys use of the 30/30 in his tests. Maybe 30/30 brass behaved differently.
It was a few years later that I started gunsmithing myself and was able to try testing some of these things on my own. I am convinced, practically speaking, case taper makes no difference in bolt thrust though it may have some effect within a very narrow range of pressure; with this depending on brass thickness and hardness. At high pressures, ALL cartridges grip the camber walls sufficiently well to allow the head of the case to blow off if not adequately supported. In addition, the amount of deflection of the bolt at a given pressure most certainly comes into play. A strong, front-locking, bolt action will deflect very little at 70,000 PSI. So little that brass stretch is largely meaningless. If the bolt face deflects by .001", the amount of pressure required to stretch the brass that much is insignificant.
If unsupported, brass can only do so much. Primer pockets expand at the same pressures regardless of shoulder angle or case taper. Rimmed cases which are fully enclosed in the chamber, as in most single shot designs, may be able to withstand higher pressures than rimless designs but I'm not convinced enough to say it is so. GD

Just a question, does the Gibbs actually clean up the shoulder of an Ackley ?

The examples of Gibbs cartridges I’ve seen have diameters closer to the Standard .441”, just pushed forward some. I’ve also seen some which were actually botched Ackley rechamberings, with .455” shoulder diameter.
Created without being properly set back and then reamed forwards deeper,
to create an Ackley/Gibbs chamber. Usually involving similarily bubba’d dies

A Roger Stowers drawing lists the shoulder at .455", so it should clean up an Ackley chamber.
I guess it all depends on the final chamber dimension, like the old saying...cut with a fresh reamer or a well worn reamer.

Thanks for the info, I quickly googled to confirm that shoulder dimension.
Trust but Verify.

A 35 degree shoulder angle is pretty trendy. Maybe the short neck is the off putting part.
Surely it isn’t the case forming steps. 🥴

I had one built on a Savage 110 back in the 90's. It was my first experience with a wildcat.

I'd have to look for my data on it but, but I seem to recall 3050 FPS with a 165 grain NBT and RL22 gave me good case life, this was out of a 22 inch barrel. I finally figured out it was easier to just get a 300 Win Mag.

WHY?

Got mine back from the gunsmith last week. Got some cases formed and some rounds loaded for velocity testing. The fireforming loads I made with 150 Hornady Spire points seems to shoot really well so I may take them antelope hunting this weekend. Did some with Bullseye and cornmeal last night also. I have good data from the original factory 22" barrel that I tested a couple weeks ago with the 165 Hdy BTSP, 180 NBT, and 200 NAB, all with RL 22. Planning to reshoot the same bullet in the same barrel (now with a Gibbs chamber) to see what I actually gained. I will post the results. I may start a new thread that goes through the whole process and testing.

Is the question why a Gibbs?

I can't answer for others but for me it is simple...I found dies cheap, .30-06 guns and brass are everywhere (and cheap), I can probably approach .300 wsm velocities with four in the magazine, the chambering work is not crazy expensive, I like dinking around with this stuff.

No more, no less.

I already have an accurate .30-06 and .300 Win Mag so it really won't do anything for me that I couldn't do with the others but it has been a fun project and a little nostalgia makes hunt prep more enjoyable for me.

I think Patches O’houlihan summed it up best...