I see something of a parallel between rifle cartridges and automobile engines, in that the easiest way in either venue to increase power is by increasing capacity.
In engines, if there is a size restriction, like in F1 racing, you add a tubo-charger to the engine to boost performance, but you make the engine work harder and shorten its functional mean time between failures.
In cartridges, you seek the combination of powders and bullets that will give you the performance profile that you're looking for. We all know that manufacturers build some degree of safety into their rifles and ammunition, it is only prudent to do so. Our individual tolerance for risk generally determines how far into that safety zone, or mine field, we are willing to venture. If we go too far, we could be risking injury on every subseqent sqeeze of the trigger. Worth it to you? Maybe. Worth it to me? Maybe not.
The key weak point to hotrodding the 35 Remington, that I can see, is the brass. Since the 35 Rem was never intended to be hotrodded, the brass is made to be in sync with its mild factory spec pressures. OTOH, the 356 was intended to function at higher pressures in a rifle, the Winchester 94BB, that doesn't possess the (critical point!) escaping gas handling qualities as most modern bolt action rifles. The cartridges designers at Winchester/Olin worked in sync with the rifle redesigners at Winchester to arrive at a safe and functional integrated "system".
For the nominal cost of having Nonneman rechamber a Marlin 336 from either 30-30 to 307 or 35 to 356, I can't see any reason to incur unnecessary risk of hotrodding either the 30-30 or 35. In either case, if you want to use rimless cases, 308 and 358 brass will function through a Nonneman conversion's magazine, if you stick to 307 and 356 OAL criteria.
Jeff
