Have anyone have some info about yhis caliber
I'm planning to rebarrel a 25-06 to 25 Gibbs
I think it is close to 257 wby

thanks

I have my own wildcat similar to the Gibbs except I use a 280 case and 40deg and shoulder is just a touch forward. I gain about 1.5-2 net grains of capacity. Easiest way to get a 257Wby velocity is chamber for it.

Here is a write up on the 25Gibbs

Way over bore, with little gain in performance over your 2506. Also, very hard on barrels. Not recommended. If you want more power, I'd recommend the 280 AI for your action.

quote:

Way over bore, with little gain in performance over your 2506.

I tend to agree. I built mine on a 24" and basically burned a little more powered for a very small gain. Remember a 257Wby is about 32% larger capacity. A gibbs will be around 9or10%. If you do it at least go 26". A 26" 25-06 is hard to beat.

as I can read in the above article I can see that I can reach 3550 fps with 100 gs and 3300 with 117

Weathrby 257 with 26 inch barrel doesn't are so different

Over the last several decades, I don't remember any series of wildcat cartridges that has been rumoured and/or shown to operate at higher pressures than the Gibbs line. If you loaded a 257 Weatherby to similar pressures, the performance would be amazing, if you had the nerve to pull the trigger. There is no free lunch (sorry short magnum craze). It's just like engines; everything else being equal, nothing beats cubic inches. There is no way one cartridge with 75% of the case capacity of another will outperform or equal it.

Art S

Don't you think that your comments are too light?

Don't you think that Mr Gibbs had had a little bit more experience than you , and your oppinion that is of course remarcable , despite it is in the conservative experience .
If anybody think like you , there wasn't any wildcat caliber in the world .

There is another thought process that has not been spoken here. In reference to case capacity: Large case capacity with a small hole in the end requires a very slow burning powder. Hence the powder of choice took many inches or the entire length of the barrel to burn powder, with the longer barrels generating the best velocity. Example is the 264 Win Mag with 26+ inch barrels. Any one having spent time with the Gibbs line understands that Good case life
is the determining factor of what reality velocities should be. I for one found that I disliked getting the speeds I wanted and then had to turn around and make new cases after 2-3 reloadings. So one has to back off to accomidate the throw away Domestic cases of today. Rocky specifically state this.(Case life_

However I started using RWS cases many years ago with fast burning powders (4064-H4350). I am past 15 reloads without annealing without one lost case. Yes, pressure is the reason I can shoot a 150 grain 30 cal bullet at 3000fps from a 16.5" Encore pistol. Others are doing it as well so its not just me doing it. 125 grain is at 3240! Two different chrony's.
Yep we were doing this long before the short mags got the same idea. Just for fun measure the wall thickness of a new short mag case. They run .020-.025 and that is neck thickness!
Our domestic cases run .009-011 except for the Nosler case runs at.014 thickness.(my lot any way) The primer pocket and pressure cup is all that I am concerned about and the RWS is flat out the toughest case I have ever used without annealing.
Hammer

Raul,

If you want a Gibbs by all means build one. You just need to be realistic in your expectations. Like I said I built my own wildcat case very similar to the Gibbs. Actually gives me just a touch more capacity. Here is a comparison in 280. Sorry I don't have it in 25.

I have used this case in several calibers all the way to 416. Several using pressure data in the same barrel comparing to std, AI and my case. What I found time after time loaded to the same pressure I got a 1% velocity for 4% capacity increase. To achieve many of the published AI and Gibbs velocities I was often over 70,000. The squared off case hides pressure well. Doesn't mean it isn't there. Achley and I'm sure Gibbs viewed that as long as the case and rifle handle the pressure it was safe. Many reloaders function under the same rule. Thus you hear comments like the load is perfectly safe at 60deg and it blows the primer at 90deg. To me that isn't a safe load but to each his own. I blew enough primers in my early years that if I never blow another that is fine.

Using my case and a 65,000 limit I found its 11.5% increase in capacity allowed me to meet and sometimes exceed the factory Magnum comparisons. I normally can't egual my own magnum handloads unless I use a longer barrel. Remember in the case of a 280 for example the 7 mag is 22% larger than the 280. A Gibbs will be 10% larger than the 280. So efficiency does help. In the case of the 257Wby it is 32% larger than the 25-06.

Unless you are really going to push pressure I would call a Gibbs gain over a 25-06 as around 80FPS go from the normal 24" barrel to 26" and add another 50-60FPS so that puts you at a 130-140FPS gain or around a 4% gain.

Will a Gibbs give you a gain over a 25-06? Yes. Will a Gibbs match a 257Wby? Not in my opinion. You are going to rebarrel. If you really want a 257Wby chamber for it. Minor bolt work required. Dies are easier to find and if the cost of the brass is an issue make it from 7mag. However, if you want a wildcat and to be able to say you are pushing an 06 case to the max the by all means go with the Gibbs just don't handicap it with a short barrel.

Thank you Paul for your oppinion.
In my life I had 2 257 wbys and I have a 280 Ackley , a 6,5 gibbs and a 25 gibbs.

I can tell you that with 24 inches barrel the weatherby can reach 3550 fps max with 100 gs and a hot reload.
With my gibbs I can get 3480 fps and my cases last at least 7-8 reloads.

That is for me equals in performance and better the gibbs because i haven't to do any bolt work

quote:

I can tell you that with 24 inches barrel the weatherby can reach 3550 fps max with 100 gs and a hot reload.
With my gibbs I can get 3480 fps and my cases last at least 7-8 reloads.

In my 250PDK I got just under 3500 with a 100gr and 24". I have a factory MKX 25-06 that will give me 3475 I toss my cases after 5 loading. Slow 250PDK barrel fast 25-06? Who knows. I pulled the 250PDK and used the action and stock for another project.

You consider a 70fps difference in your data as equal results. Many people wouldn't. You are happy with it have first had experience so what is the issue? I would still use a 26" if I was going to the trouble. Same price and can't hurt.

I have more wildcats than factory and will continue to do so.

If you want a nice, accurate .25 that is just about right for that caliber with first-rate performance, good efficiency, and reasonable barrel life, go with the .257 AI. I have one, as well as a 25-06 AI, and the latter is no improvement. In fact, it's just a barrel burner. Knowing what I know now, I wouldn't have wasted the money on the 25-06 AI, but that's exactly what PO Ackley said. He did not recommend the 25-06 AI - like other over capacity .25s its inefficient and hard on barrels.

quote:

If you want a nice, accurate .25 that is just about right for that caliber with first-rate performance, good efficiency, and reasonable barrel life, go with the .257 AI.

As I said my wildcat just burned more powder. I currently have a fast accurate factory 25-06. If I was going to build fron scratch It would be a 257RAI and be done with it. I see it pretty much ideal for the 257 and even the 6mm. Anything more you are just burning powder and barrel for very small gains.

Paul
I currently have the reamer and pilots for a 224 through 6.5 based upon a 7X57 Mauser using a rimmed or rimless 7X57 mauser case. A .200 neck with a 30 degree shoulder. In other words Gibbs did not like Ackleys 40 degree should so went with the 35. I came to feel I was getting diminished returns to fast with the 35 degree shoulder and the longer case so changed the shoulder( less restriction) and a shorter powder column. So far its awesome and I am achieving velocities with good case life using less powder as the 25X06 without the erosion. In other terms, think of a 257AI-push the shoulder forward ala Gibbs and change the shoulder to a 30 degree.
3500fps with a 60gr 224 or 6mm bullet is smoking. Oh and a 17" handgun length barrel.
Neal

quote:

A .200 neck with a 30 degree shoulder

Sounds very interesting. What is your shoulder diameter? Is the neck .2 on all calibers? If so do you simply run the reamer in further changing the base to shoulder distance?

I use my same reamer on various calibers. I leave the base to shoulder distance the same then the neck length will vary. All my chambers use the same headspace guage.

Shoulder is .455 and yes the neck length changes
length. JGS reamer with multiple pilots. Core bore- finish reamer and go back in and cut the neck/throat.
Shortly I will be running the 6.5 version against the 6.5 Gibbs version and see how they stack up. Smaller bullets should be right together. The 142gr MK I am thinking will be faster in the larger capacity case. Still 3 feet of soft slush at the range.

Neal

After not being happy with a 24" 250PDK I built a 6.5PDK with a 29" it beat 3300 with a nosler 140 and MRP and 5+ loading on the cases. Darn barrel was WAY yo long sp I cut it back to 26" and dropped to around 3240fps. Still get 5+ loadings. Really pi$$es my buddy off. His 264 will only get 3200 and stay accurate.

Raul

Sorry to be so slow to respond. I have been away.

The answer is, no I don't believe my comments were "light". I really don't know about Mr Gibbs background, just mine. I will say I have been a shooter/reloader for a lot of years, own more wildcats than factory chambered rifles, and hold advanced degrees in engineering, dealing with pressure, temperature, fluid flow and reaction kinetics every day. No matter what anyone's background, they cannot circumvent the basic laws of chemistry and physics. A bigger case will always outperform a smaller one. That of course assumes that the proper propellent is used. The comment above is correct in that some cases were developed in the past which were so overbore that propellents didn't exist to take advantage of them. That was likely true of the 257 WM. It was true to a lesser extent of the 25 Gibbs and even the 25-06. It is no longer true. That is why, at the time of their developments, there may have been little difference in them. However, even given the propellents of the time, the smaller cases had to be at a higher pressure than the larger ones in order to reach the same velocity. This was due to the relative volumetric expansion ratios.

I love to fool with wildcats, but I have never believed any of them held some magic attribute simply because someone was willing to touch off a round that would cause most people to run away if it were hooked up to a pressure guage. I once had a friend who shot tens of thousands of rounds of reloaded pistol ammo a year. He described his pet 357 load as "mild to shoot, giving 300 fps more than a factory load, and with no signs of excess pressure". This while I was litterally hammering out the spent cartridges with my hand tingling from the recoil. I suspect that was the reason most of his single actions had the cylinders shimmed to close the barrel gap.

Way before QuickLoad, I had a Powley Computer (how many remember those?) PO Ackley is often quoted (for a lot of good reasons) because he wasn't afraid to experiment. However, he was more of a seat of the pants gunsmith than a technician. In my mind, Bob Hutton and Homer Powley and their Rifle Ranch work did more to advance reloading and ballistics than anyone else. Over the years, their work showed repeatedly that internal ballistics came down to the simple variables of internal volume, pressure, and volumnetric expansion ratio. Nothing magic and nothing flashy. Just good solid science. No amount of marketing, such as short fat cases or venturi shoulders etc will have any significant effect (although such things may affect consistency).

As I said, I enjoy fooling with wildcats, as you should too, if that floats your boat. However, don't ever let wildcats fool you. That's a good way to eventually become a casualty.