It will alll depend on who's case dimensions your looking at and referencing from...I've found 4 totally different drawings for each cartridge...and depending on which one you use will determine a-lot.
So basically, no one in this thread has any idea what the correct dimensions are for the AI cartridge. It seems to me that its pure speculation to even suggest there will be a .040" difference, especially given this info. Anyone have a reamed gun in .30-30 AI that could actually measure a cartridge. That way, we could have some solid information to go from.
The AI's I have dealt with in the lever guns all had their barrels set back to give a +.004" crush fit to the chamber for firing factory loads..and it will entirly depend on Jasons chamber dimensions now as to which reamer to use..since they have several different sizes available to the different smiths that do these conversions.
A "crush fit" is certainly not a big deal, nor really even an issue. Let's look at it from a Contender stand point. First, there is not way to set barrels back on these pistols. How do you think they are fireforming brass? The same way everyone else does. But, like its been said, it truly depends on the original chamber on whether its reamed or not. But a crush fit is not required for this set up. If it was, no one would use the chambering in Contender pistols and rifles.
getting the velocities up with out increasing the muzzle blast a-lot
I don't know why you are so stuck on this muzzle blast issue. Here's the reality,
there is going to be muzzle blast!! Its an 18" barrel, and with short barrels there is always that side effect. I think maybe you are more concerned about this than I am, as you have mentioned this quite a few times now. Maybe you are sensitive to it, but I have hunted with Contender pistols in .35 Rem, 7-30 Waters, and .44, and muzzle blast is really not that big of a deal to me. Matter of fact, the Waters had a brake on it, which made the blast even nastier. Not a big deal, though. Now, if you want to see a nice muzzle blast, try a 10.5" AR with no flash hider! That will definitely get some eyebrows!
This is not a project that requires a crush fit, or even headspacing on the shoulder. Its a rimmed cartridge, and I have seen too many rimmed guns shoot well to think they must headspace on the rim. Furthermore, this is a hunting gun, not a target rig.
A few people have been a little critical of this project, especially considering the lack of experience some have with the cartridge. I don't know why this is, but it really doesn't help me when I don't know if the info is accurate.
Who here actually owns a .30-30 AI, or has reamed a gun to this cartridge?