Reforming .30-06 Brass to .270

Q: I just sold my Marlin XL7 .30-06 and 
replaced it with the same rifle in .270 
Winchester. I have on hand over 200 
once-fired .30-  06 cases. Is it harmful 
to neck down .30-06 brass for use in my 
new .270?  Is the shorter case length 
likely to cause increased  erosion in the 
chamber throat?Vincent ForemanA:  No  harm  will  result from this practice.  
Back  in  my  roo  shooting days during the 
1960s I used to neck-down .30-06 cases  
for use in my .270 all the time. In fact, I 
wore out several  barrels with them, one 
lasting over 5000 rounds. During this time  
I was never able to determine any ill effects 
caused by the use  of reformed .30-06 
cases in the .270 chamber. Actually, the   
.270 case is only 1mm  longer and the '06 
case could grow that  much after being 
necked-down.