Home Forums Hunting & Shooting Ask The Gunwriters 270 GIBBS vs. 270 Winchester

Then get another rifle, because you're probably going to spend more than the cost of a new one to have one rechambered, and the necessary action work done, to make the 30/30AI work. I had a 25/06AI, once, when young and dumb, and took 2 trips back to the gunsmith, who was a good one, to get the action rail modified so it'd feed. Also, the I wouldn't be wanting to put a round with 308 pressures in a 94 action. Other than distance, a 30/30 can work fine. There was a post on here last week in the Alaska setion, where a young guy took his Moose with a 30/30, and Col Whelen once said, the 30/30 was the best Elk round he'd ever used. This was back in the days, when it came with a 160gr bullet.

That's about as obsolete a theory as is possible to get. A bunch of powders available today, that Ackley didn't have, have changed the playing field.

Check out the powders that Ackley used in his book. Not much for slow burners there...

You and your smith are the reason God invented Velcro sneakers.


I've run an Ackley or three and haven't had the first problems with feeding.

Of course the more obtuse figure going AI is all about the speed, and it is, the speed in loading cuzz I don't have to trim the damn things.

No reason not to take advantage of a few more ponies under the hood if they are there, but that ain't the main reason I do it.

With some of the newer powders that Rocky Gibbs didn't have to work with the Gibbs rounds really come alive, especially with heavier bullets...check out my thread on Reloader 17 in the 8mm Gibbs. An honest 2894 feet per second with 185gr Rem PSPCL, a 22.5 inch tube and NO measurable signs of over pressure.

Reloader 17 8mm Gibbs

Have you bothered to load some of the new powders?? Precision Shootings folks did, and they don't do anything more. A powder that's too slow in a standard 25/06, is still going to be too slow in the AI version. If someone hasn't had feeding problems with a AI round, it's either because they are jiggling to make it feed, or something. You just cannot take a straight sided case and make it feed right in a sloped sided case action. The gun smith who made the 25/06AI up in 1963, was one of the best around. But lot of lunk heads out there who believe a little jiggling of the bolt handle okay. If you don't trim brass, it's because you're not too bright, as ALL brass stretchs some. Indeed, in a recent article in either Rifle or Precision Shooting (PS oriented towards people who actually know something about guns and shooting), one of the writers said that the claims for less bolt face pressure and not having to trim AI cases were both BS.

ghost, if you need to trim AI cases, that speaks more for the sizing process than the firing process. Think about it.

Squeeze a neck down further than you need to in a standard FL die, then force it back up with the expander ball dragging through the neck. THAT is how you stretch cases.

ghost,

Aparently you have had far more problems with AI's then I. Now, I have had only a few. 250sava 257Robts, 30-284, may son has a 25-06AI and they have fed just fine. I am one who likes messing with the brass, fireforming, measuring, and all that's involved in making them shoot. Velosity gain at similar pressures has been far less than what some project.

As far as feeding I did learn that building them right is necessary. Get them right - they work right. Bolt jiggling has never been a part of my life.

The 270 Gibs would be far more interesting to me then a plain Jane 270. Because I like the brass manipulation. I seriously doubt that I could take game with the Gibs that wouldn't fall to "Plain Jane."

If I wanted to gain velosity the easy way then I would definately go to a WSM or Weatherby but I do like those wildcat cartridges. Just for the fun of it.

Best to you,

Jim

More reading, less shooting...you'll be happier.

I hope your Field and Stream subscription don't run out, you'll have no more gems for the fans.

Do you live next door to Don?

I've owned and test-fired a number AI rifles from the .22 K-Hornet to .35 Whelen, and none had any trouble feeding (though one was admittedly a Ruger No. 1). A friend did have a famous gunsmith rebarrel a Remington Model 7 to 7mm-08 AI and it didn't feed worth a darn, though as I recall the gunsmith did fix it.

In my experience AI brass doesn't require much of any trimming. I'd wear out brass from my NULA .257 Roberts AI without ever trimming it. That in itself would b worth the price of admission on a prairie dog rifle.

The key to forming Gibbs brass, I think, is to make sure that the case fits snugly in the chamber. I've found with my 8mm that if I punch out 30-06 brass with a 338 neck expander, I can feed the cases in the 8mm Gibbs with a good crush fit. I load them with Red Dot and Toilet paper. After firing I get cases that are about 95% formed. Everything is proportioned right, the shoulder is just a touch rounded.

2nd that.

Well, they did come in 307 Winchester.

CowboyTim,

I'm sure your Gibbs rifle is a classic, and obviously you like to fool around with forming brass.

But I simply must make a few comments. First, you mention no "measureable" signs of high pressure. Does this mean you had your ammo pressure-tested, or used a strain gauge yourself? Since you don't mention any PSI I assume you didn't.

It has been proven in recent years that most of the traditional signs of high pressure (whether measuring case heads, hard bolt lift or ejector-hole marks) aren't accurate, and in fact they usually don't show up until pressures reach 70,000 psi or so. I can cite you a bunch of the evidence, if you want.

Second, while Reloder 17 is a fine powder, the early reports of it being a super-powder that produces more velocity at safe pressures in a wide variety of cartridges also proved to be false. Alliant's own pressure-tested data shows that it can result in small gains in SOME cartridges, but not in most.

Third, the standard 8x57 is perfectly capable of driving 180-grain bullets at 2800 fps at modern pressures. Very little published loading data shows this, because of all the old 8x57 rifles, especially those with .318" bores.

But the Norma manual lists 2798 fps with a 170-grain bullet--at only 56,500 psi, well below the 62-64,000 level common among modern cartridges. Using some basic formulas for internal ballistics converts this to about 2850 fps for a 180 at 62,000 psi.

The Nosler manual lists 2698 fps with TWO HUNDRED grain bullets.

Meanwhile, you're comparing a wildcat to the wimpy ballistics for the 8x57 in most loading data. In reality you're probably gaining 50-75 fps over the standard 8x57 loaded to the same pressures as your Gibbs--and you're probably loading your Gibbs to over 65,000 psi.

One more note: While you obviously like forming Gibbs cases (and I would be tempted to myself, if I owned an original Gibbs rifle), the 8mm-06 is a much simpler solution to gaining the same slight advantage over the 8x57. It fits in a standard 98 Mauser magazine and has just about the same amount of powder capacity as the 8x57 Gibbs, and so is capable of the same ballistics.

Of course your article mentioned an AI case will be shorter OAL after the fireform and I'm sure they were astute in the use of a bushing die, since they were "precision" people; two things that pretty much eliminate trimming....Hell, I've got standard 23 degree cases I've never had to trim just by using a bushing die.

Do you think Precision Shooting would be interested in this revelation?

I have seen minor feeding issues in a number of rifles which were AI chambered. Mostly the issues involved the shoulder of the case contacting the top of the chamber before the action rails were ready to let it go. Not too difficult to remedy but there nonetheless.
I have, for years, disputed the reduced bolt thrust claims for AI cartridges. I also dispute the reduced brass flow claims. I do not dispute the claims for reduced trimming but do dispute the cause and effect.
Regarding the measuring of case heads as a pressure indicator: there is no question that, by the time a case head is expanding, you have already exceeded recognized limits by a substantial margin. Rocky Gibbs' belief that the brass was the weak link- in a strong, modern, rifle- while it may have had some basis in fact, ignored industry-established maximum operating pressures.
Ackley wrote of loading until the primer blew then backing off a couple of grains. Again, this was a good way to push the envelope and then some.
When I compared standard, AI, Gibbs, and magnum cartridges back in the day, I used case head expansion because that was all I had as a means to guage pressure. The maximums at which I arrived may have been too hot for regular use (and probably were) but I was at least able to run each cartridge at roughly the same maximum pressure.
I have always been a bit fascinated by the Gibbs cartridges because my grandfather had one and because Rocky Gibbs was the first real gunsmith I met personally (I was 14 at the time). I doubt that I will build myself a 270 Gibbs but I still have a piece of brass from Grandpa's rifle which I used to get my headspace gauge measurment and I've had the reamer for about thirty years. Maybe I will. GD

In the lower 48 if a 30-06 can't do it,its probably worthless anyway...just saying

Well, yeah.

John,beauty is in the eye of the beer holder!

More truth!