Home Forums Hunting & Shooting Ask The Gunwriters Tell me about the .30 Gibbs

doc..,

Thanks for the info. I'll pass it along.

O

I don't know, a 30 Gibbs might be kind of fun.

But there are a lot easier ways to make brass than the old oil shower method.

Personally, I would run an 8mm tapered expander button through a new 06 case and then neck it down for a crush fit in the Gibbs chamber.

It would then fireform as easily as any other improved case.


Wolfe's "Wildcat cartridges Vol II page 803: Roger Stowers gives reloading data for many bullets with various powders. I would consider his load data as highly optimistic until I worked it up with pressure trace equipment.

For instance he quotes:

3261 fps with a 150 and 59 gr IMR4320
3129 fps with a 165 and 63 H450
3070 fps with a 180 and 66 gr of IMR4831
2871 fps with a 200 and 64 gr of H4831 or 61 gr IMR4350
2688 fps with a 220 and 63 gr of H4831

About 30 years or so ago I had a switch barrel rifle made on a Remington action with barrels in 280 & 7MM Gibbs. After all the fire forming I did get just over 100FPS with the Gibbs & despite shooting some mulies & lopes could see no real difference between the 280. I haven't installed the 7MM Gibbs barrel in over 20 years but was recently given several boxes of new formed & stamped brass. I may decide to load some up just for the fun of it. The switch barrel rifle concept & improved cartridges turned out to be just another PITA to my way of thinking.

Bob Hagel did a piece on the cartridge in Handloader or Rifle many years back . If I recall right , he used a M-70 re-chambered by Rocky Gibbs , and the best that particular rifle did was 2800-2850 fps with 180 gr.

Quick Load, yes I know it is a shacky piece of software, gives the case capacity of a 30-06 at 68 grains and with a 3.45 OAL 62 gr. of powder capacity. The Gibbs, using the same criteria, has 72 and 65.4 respectively. That is a 3.5 gr. burn capacity +/- difference. By my math that is about 5.5% of useable or total capacity increase with a 3.45 in. OAl. Real results should be about 100-125 fps. +/- assuming you load all to the same pressure level.

My presumption on the old data is that the hand loaders pushed up to 65 K (or more) and the factory loads were at 50K so you were comparing apples and grapefruit and selling the grapefruit.

Remember YMMV.

Extra velocity does not follow extra capacity. Instead it is 1/4 of case capacity with both cases loaded to the same pressure.

If the increase is 5.5% of powder capacity, then the increase in velocit would be 1.375%. If we assume the regular .30-06 can get 2800 with a 180 (and it can, easily, from a a 24" barrel) then the Gibbs would be capable of a gain of 38.5 fps-again, at the same pressure.

Trawling in the depths of my memory I seem to recall J.O'C writing one time that he had some dealings with Gibbs. Apparently Gibbs would not let J.O'C into the room where he was chronographing some of his loads. There was a window into the room where the chronying was being done and O'Connor claimed he could see the ejector marks on the case heads shining like a headlight, or words to that effect.

In other words, anything Gibbs claimed may have been true but likely at pressure levels that were far from sane. If venturing into this territory is your bag then be my guest. To my way of thinking you should just be moving up to a factory case of larger capacity where there is proven data available. Of course, some people like to just live on the edge!

Jim

Now that is funny. I'd buy the book.

Ray, that's a HOOT! Long live the H&H!

Yeah, Ray you could gather up the threads you have commented on here and on AR and start the book from there. It would be a good one too!...jim

I have a Ruger #1 in said chambering - 25.5" bbl (cut and recrowned the 26" factory bbl.)

10% case capacity increase to BASE OF NECK over the parent case. Note that the shoulder and base of neck are moved forward. The #1 has a long throat. It was a rechamber of a boring old '06 and my first foray into wildcatting.

2,950 with 180 gr and 2,750 with 200 grain bullets - Over an Oehler 35.

Use 30-06 AI data and work up from there.

The .30 Wha..................?

Oh.

Yes, cases are a pain to form.
Casual perusal shows .300 SUAM case capacity to be very similar.

In earlier times the Gibbs gave guys with a lot of GI brass a rifle that could get an 180 grain bullet to 2900+ and hold 5 cartridges in the magazine. I have had 180 gr. Hornady's
do 3000 FPS with good case life.

Does this do any better than the .30/06 with modern
bullets & powders? Not really. 100-150 FPS does not do much
over normal hunting ranges.

I feel Hagel's article did not do the Gibbs any justice. A friend of his had a post 64 M70 with 22" barrel that had been shot a lot. In the article Hagel said barrel length was 24", but pictures showed that it was the short barrel.
Friend lost confidence in the rifle after the article......... I think that he posts here sometimes (TW).

Today I still see people trying the Gibbs concept.

I have loaded .240 & .25 Gibbs rounds for youger guys recently. Usually rifles get rebarreled to standard cases after the novelty wears off and the barrel wears out.

I bought my pre-64 .30 Gibbs from a guy that was out of work.


I have killed one medium bull elk and a few pigs with it.

I have the feeling thst it will soon turn into a .25/06 for my 14 year old son!

Best cases for forming are arsenal brass. I use LC National Match 69. Newer commercial brass yields higher case loss in the shoulder area. Neck case up to .338, then size in a Gibbs sizing die for a crush fit. Fireform with 50 gr.4895 and a 168 - 180 gr. bullet.

As always, YMMV

The 30 Gibbs was a follow-up to his first cartridge which was the 270. Tales of 3000fps with 180's were mostly just tales but I don't doubt Gibbs did achieve that velocity in at least one rifle. His belief was that any load which did not destroy the brass was a good load. In other words, he felt the weak link was the brass case. He found one lot of GI brass which was very strong and which would handle higher pressures without loosening the primer pockets and it was with this brass that he achieved his best performance figures. I suspect the standard 30/06, loaded to the same pressures in the same brass, would have reached close to 2900 with 180's.
I have, on several occasions, improved 30 Gibbs rifles at the request of their owners. This improvement consisted of rechambering to 300 Win Mag or, in some cases, to 30-338 (required setting back) or 308 Norma (ditto). In all cases the owners reported they were now getting the velocity they had been led to believe they would get with the Gibbs.
The first time I was in Gibbs' shop, I was 14 years old and was just in awe. I mean, here I was in a shop where a guy actually MADE custom rifles. In addition, I knew his name not just because he made my grandpa's rifle but his cartridges were shown in my PO Ackley handbook. Pretty exciting stuff!
I'm not a fan of wildcats in general; factory cartridges will do whatever we need. If one has a real need to spend some time fireforming and stays away from the chronograph, the 30 Gibbs will be a good fit for him. GD

I vaguely remember this was DEN 43. Could somebody with access to the Gibbs literature confirm or correct this? Thanks.

--Bob

Great post, Ray!

Write that book, I will put my order in as well!

I vaguely remember this was DEN 43. Could somebody with access to the Gibbs literature confirm or correct this? Thanks.

--Bob [/quote]


YEP!

Thank you!

(If I am able to recall factoids like DEN43 is the strongest brass Rocky Gibbs found for forming his cartridges, then why am I not able to remember where I put my key ring last night?)

--Bob

hummm. too many years? too much old Stump Blower? my wife doesn't know where she sat last. Just happens,i guess.

O

I loaded my 180 grain Nosler partitions today with 61 grains of
IMR 4831 in Federal fire formed cases and Winchester large rifle
primers. Chrony said that the first shot was 2902 FPS. Velocity ranged from
2858 to 2902, most shots in the 2875 area.

I also loaded some "condor loads" with 150 grain E-tip and 51 grains of
IMR 4320 for 2850 FPS. This is a LONG bullet. Accuracy was ok.
I will use this load on the California coast so that no condors are poisoned :-)




I have used 63 grains of IMR 4831 and Hornady spire points for 2965 FPS
and 62 grains of RE22 and the 165 Nosler partition in prior years.

The 61/IMR 4831 180 Nosler is a very accurate and mild kicking load.
These loads worked well in my rifle. Your friend needs to work up to them
in his rifle!

I will take these to Colorado in November for elk.

Sighted in 2+" high at 100 the 400 yard drop was 15".

Would I make a .30 Gibbs? No.

My rifle was re-chambered when purchased.

And once this barrel is gone the pre-64 action will become a .25/06.

In the mean time be I will be able to send a 180 grain bullet at 2900 FPS at sane pressure and good case life.

This has been a very interesting and informative post. Thanks to all who have contributed. I would also like to register a vote for Ray to write a book. (Perhaps there is some way that we could start a movement to force him to do so. :)) His description of oil-forming the Gibbs cases sounds an awful lot like what happened to me when I got one of those handy-dandy mail-order kits to reload your own ink cartridges for the computer printer. One further point on rechambering to Gibbs - I think that I remember reading that there are a lot of folks who rechamber to a "Gibbs" that isn't a true Gibbs chamber. Best to all, John