Book shows: Speer 115gn .277 6.8SPC (277115GDB) Tested OAL 2.260

I’m using a Hornady OAL Gauge on two AR guns trying to get distance to lands.

My numbers are much shorter than factory OAL which isn’t right.

Night hunting gun - 2.1962
Day hunting gun - 2.1901

What am I missing here?

OAL 2.260 is the Overall Cartridge Length from base of brass to tip of bullet. The 2.260 is the max length (or very close) for the cartridge to fit in the magazine on an Ar15 platform. The other measurements you are aiming for is the Base to Ogive of the bullet (where the bullet will engage the lands) which will always be shorter than the OAL.

Are you trying to tune a load with bullet seating depth? If so, the max OAL that will reliably feed from your magazine is as close as you are going to get to the lands. Different brands of magazines will vary in this respect but I've seen as much as 2.290 OAL reliably function in a 6.8 mag.

What he said ^^^

My measurements less .010 free space just seems too short.

Night hunting gun - 2.1962 - .010 = 2.1862
Day hunting gun - 2.1901 - .010 = 2.1801

This is OAL. I’m not using the ojive bushing.

Is that bullet that Federal loads in their 6.8 Fusion cartridge? I’d be interested in your chrono results and powder combo.

I'm confused. If you are "trying to get distance to lands" then you should be measuring to the ogive, not the tip. What precisely are you trying to achieve? Want to help but am not sure what you are attempting to do.

I just load my 6.8 to magazine length and tune the load from there, and I have no trouble printing clover leafs from a 12.5" barrel with any bullet I've shot. What else can you do? No sense in fooling with all the measuring if you cannot capitalize on it. They ain't bolt guns.

Me too in my AR and Ruger 6.8 MINI. I only mess with COL in my bolt gun because I have 2.45 of mag space.

Sometimes I get a false (short)reading when using the hornady oal gauge when my bullet hits the free bore. My process is the first time I check for the lands is to add extra pressure when sliding the bullet in to see if I’m hitting the free bore or lands. Most of the time there is slight resistance at the free bore, then with a little more pressure the bullet jumps past the beginning of the freebore, the resistance drops, then you can feel it hit the lands a little farther in. Yank that bullet out and do it again knowing you will hit a little resistance early and then make sure not to jam it into the lands. You want to be just touching. I usually try to make sure I have at least 3 repeatable measurements before calling it good. It’s difficult to explain with words, but easy enough to feel what’s going on with hands on.