Hornady OAL gauge and AR15

[crackleback]

I've tried measuring several AR15's with the Hornady OAL gauge to determine where the bullet contacts the lands. I don't have the curved version for semi-autos, but I am using the straight version, the one for bolt rifles, and simply removing the bolt carrier.

I am getting some unreasonably long readings. Readings that would basically not even leave enough of the bullet to seat it sufficiently, much less fit it in the mag.

Is this common in AR's? Is there an issue with using the bolt version of the tool?

 

[mrawesome22-250]

The 5.56NATO chamber has an extremely long throat compared to the 223Rem chamber.

What you're seeing seems normal.

The 223Wylde chamber sort of splits the difference.

 

[Shooterbob]

Check magazine length no need to chase lands on an ar15 .

 

[Bfh_auto]

Good luck finding a bullet that fits both the mag and find the lands on a 5.56.
Even my modded mags were far from reaching the lands.
I found 55 SP and 77 SMK seated to the cannelure make as accurate of ammo as I got from the notched magazines.

 

[crackleback]

OK thanks. Good to know it's not me or my rifles.

 

[redcon1]

I've tried measuring several AR15's with the Hornady OAL gauge to determine where the bullet contacts the lands. I don't have the curved version for semi-autos, but I am using the straight version, the one for bolt rifles, and simply removing the bolt carrier.

I am getting some unreasonably long readings. Readings that would basically not even leave enough of the bullet to seat it sufficiently, much less fit it in the mag.

Is this common in AR's? Is there an issue with using the bolt version of the tool?

It's a fruitless exercise. Just load for your magazine length and maintain good control over the other aspects of your reloading and your rounds should shoot well. Reloading for semi-autos is a different game than bolt action rifles but AR15s are still capable of delivering bolt action like accuracy with properly tuned ammunition.

 

[crackleback]

It's a fruitless exercise. Just load for your magazine length and maintain good control over the other aspects of your reloading and your rounds should shoot well. Reloading for semi-autos is a different game than bolt action rifles but AR15s are still capable of delivering bolt action like accuracy with properly tuned ammunition.

So then tuning comes down to bullet weight and powder? I guess you do have some variations in OAL to play with, and stay within mag length.

 

[redcon1]

So then tuning comes down to bullet weight and powder? I guess you do have some variations in OAL to play with, and stay within mag length.

In my experience, neck tension, concentricity and overall uniformity are probably aspects of the tuning process as well for semi autos. Bullet weight and powder do seem to be pretty important however. I like my ammo to be as accurate as I can make it but since most of my time is spent shooting semi automatic MBRs, reliability comes before accuracy. Safety comes before reliability. Accuracy is probably #3 then.