ir655,
No, a trigger adjust should not keep the bolt from closing.

You say that you are using factory Remington ammo, so there are 2 things that can cause the bolt to keep from closing.

1. The belt of the cartridge, is too long/too thick, causing excessive headsapce.

2. the overall length of the cartridge is too long, causing the bullet to jam the lands.

A very remote and slim chance is that the bullet is a different caliber, like .30 cal.

Try a different lot of Remington or try a different brand, like Federal, Hornady, Winchester, etc. asn see if that corrects the bolt from closing problem.