I am very happy to say that all 3 of my 7X57s have long throat.
My smith has 2 reamers for the round. he calls on the american throat, (short) and one the europian, (long)
I can't say it has ben a negative for me to have long throats, infact just the opisate.
the long throat leavs room for more powder and lowers preasures a little.
My Ruger, (#1A) has a long throat snd I shoot 50 grains of H-414 under a 140 grain balistic tip. I get excelent acuracy. .50 to .75 and velocity straddels the 2900 MK.
My other 2 are custom mauser 98s and they to have the long throat. I hope they shoot even almost as well as my Ruger , but I have not tried them yet...tj3006