Generally speaking, if bullets are spun faster than needed for their length, somewhat mistakenly called (I have read) overstabilization, they tend to go to sleep and fly well a bit further out than normal, is all. That is, they might shoot tighter groups at 200 or perhaps even 300yards, than they do at 100yards or 150yards. Much experimentation would have to be done to show anything definite, I's think.

This would not normally be a problem as they are meant for further out shooting, are they not?.

OK - case in point, is shooting 40gr.HP .224's out of a 7 1/2" twist .223, meant for 85 and 90gr. bullets. Most of the guys say they shoot 1/2" or better at 100yards and are much more violent in expansion on rats than if shot from more normal 14" to 16" twists which are better suited for 40gr.HP .224's.

In the .338 calibre, a twist that will stabilize a 300gr., say a 10" twist, is not as radical a change as are the twists mentioned in the .224 example. Since a normal twist in the .338 would be 10" or 12" which is still pretty fast concerning a 105gr. bullet. I did not know such light bullets were available in that calibre. I did know of the 165 and 185gr. by Barnes, and those are longer than a cup and core bullet would be of the same weight, of course.

As far as 2,940fps being hot for a 7x57 - sure is, but the brass did not mind, nor did the rifles, all showing normal pressures. Were they above SAAMI - Definitely. Above CIP - probably there too as the CIP max is only 57,000psi. The 6MM rem, brass I used in my 7x57's as they stores were out of 7MM Mauser brass, is rated at 65,000PSI in those rifles. Thus, the same rifles chambered for the 7x57 are fully capable, as is the brass in handling that "normal" pressure for that round.

Was I loading to 65,000PSI - I do not know, but never had a sticky case, nor loosened a primer with those loads.

The fellows who have those rifles now are still using my original brass and loading those rifles to 2,720fps with 160gr. TSX in the BRNO and 2,940fps with 140gr Partitions in the Ruger #1.