Re: 25 gibbs? specs or water capacity vs. 25-06?
I'm no expert, but it seems to me that the whole Gibbs line suffers from too short a neck in an effort to increase the case capacity. Feeding problems and split necks have been mentioned. The few owners I have talked to don't seem very thrilled. It's a blown out '06 case, same as the Ackley, although I use 270 Win. brass for a couple reasons.
There is a lot of opinion out there on improved 25'06 cases. I have had two Improved, and a standard 25'06, and really like the Ackley, excellent performance and case life....if it is set up right, and with the proper powder and bullet combination. Sounds easy, but it is possible to pick components that will guarantee mediocre performance.
But, I will share my opinion on a conversion, especially a factory barrel. If it shoots the way it is, leave it alone until it doesn't and then buy a new (longer) barrel. If you rechamber, they say that you will lose at least an inch in barrel length, and on the other hand, the 25'06AI (or Gibbs) needs that longer barrel, to realize the potential, so punching a factory barrel has a couple strikes against you, to begin with.
Better to buy a new premium barrel and sink the money into longer barrel life and better quality.
Strictly opinion, but my conclusions are that 100 grain bullets are the best compromise for my application, which is antelope and coyote at ranges within 600 yards. I have not found a better propellant than R-22. Actually, I'm now using a 96.5 grain Starke, and 100 gr. Nosler Ballistic Tips for coyote. By far the best accuracy (in my current rifle) within 400 yards is the 75 VMax, (different powder) and at longer range, the 110 Berger. If Hornady made a 100 grain VMax, based on performance I get with other calibers, I would buy it in a minute.
Good hunting. LB