Two manuals two C.O.A.L.'s same bullet

[5.56Geo]

Huh?!?! I have both Lymans 49th Edition and the Hornady manuals and on the same bullet one calls for the C.O.L. of 3.200" and the other 3.335". That is a difference of 0.135", that is a HUGE difference. Could that be correct? I first loaded the Lyman and the cannelure was fully exposed and sighted in my rifle, they shoot well then I bought the Hornady and that C.O.A.L. calls for the cannelure to be almost completely covered.

The bullet I am using is the Hornady .277 140gr BTSP (2735) Interlock with 56.5gr of H4831SC in my Howa 1500 .270Win with a 22" barrel.

Is a 0.135" a big deal in C.O.A.L.?? Thanks for the help.

[Whiterabbit]

I usually just use oal as a guideline. I always seat to the cannelure then doublecheck the length to sammi spec.

This is of course when working up loads, not just going to max then plunking the bullet in as deep as it goes.... as always common sense rules the day....

[FLIGHT762]

Most factory rifles have a long throat. In my Tikka T-3 in .270 Win., I can seat nearly all 130-150 gr. bullets out to the COL max of 3.340" and not be anywhere near the lands. I have one of the Hornady OAL gauges and have measured my contact to the lands and most of the measurements are out there.

It also depends on what rifle/barrel they used for testing.

Most of my 130 or 150 gr. loads, I load to 3.330".

[Fjold]

That's the length that the two companies did their pressure testing at.