Oversize Lead Gas Checked Bullets

[MacDR]

While I cast for several calibre of handguns I haven't done much with respect to rifles. I came across a couple of hundred cast roundnose 185 grain gc for a song that I thought were .308. When I got them home they turned out to be .311-.312. I loaded up a dummy round and the check expanded the neck on a sized .308 case so much that when the bullet was seated to the crimp groove it simply fell into the case. A Lee FCD will hold it in place and I have an IMR3031 load that will keep the fps around 1700 but I am not sure if I should use them in my 99f. They chamber easily so I believe there is enough give for the bullet to release cleanly from the crimp. The lead will swage down but what about that gas check? Anyone have experience with oversized gc bullets care to give me some advice?

[the Ranger]

you could try one of these.
http://www.midwayusa.com/product/501819/lee-bullet-lube-and-size-kit-309-diameter?cm_vc=ProductFinding
.309 is the size you want.

[Ringo63]

Shooting .311 in an .308 is common practice with cast boolits and reduces leading in most cases for it stops blowby. You should be fine.