OK, I'm at the range this weekend test driving my new Rem 700 PSS.

I brought BOTH 7.62 and .308 ammo.

The .308 cycled fine, the bolt handle moving freely.

But the 7.62 I had to whack the bolt handle to get it to unlock completely, so I could draw the bolt back and eject the spent casing.

(Other than this, the 7.62 worked fine)

Anyone know why this is?? I realize .308 and 7.62 are really different calibers, but I thought they'd work in either a 7.62 or  .308 gun

Sometimes they will interchange.  7.62 brass is thicker, which causes problems in some .308 chambers.  

The standard answer is to use only the correct caliber in each gun.  Don't try to mix and match unless you like unexpected results.

grandman here are links to both chamber dimensions from Clymer.

 www.clymertool.com/cgi-bin/reamer.cgi

I also would polish the chamber to get any manufacturing burrs left behind.

I had a bad problem like this also with 762.the ammo was either from Argentina or another South American country. (Cavium is popping into my head for some reason) My Rem 700 hated it and the bolt would not work loose until I had someone hold the rifle down and with two hands I pulled up the bolt. I looked like and Idiot and the range guards were saying crap like "You sure that that ammo is really 762?". But I was victim of garbage ammo.I don't use any ammo in 762.in any of my Remingtions except Lake City 173gr Match,but I prefer to stick with .308 Black Hills 175gr match (moly) or Fed match 168gr. IMHO every other type of 762 is a risk  or should only be used in FAL's for plinkin'

JerrY

Don't use 7.62 in a .308 chamber. They are built to slightly different SAAMI specs. The reason why you have to slam the 7.62 shut is that the case is a few ten thousandths longer and thicker. By crunching in a 7.62 into a .308 chamber, you are also altering the safe amount of headspace. You may get an unwanted spike now and again reducing the life and accuracy of your rifle. Just extra wear and tear.

www3.sympatico.ca/shooters/7_62vs308Pt2.htm

I've got a Rem 700 that doesn't like it either. Now, my HK will eat either with no problems.