C.O.A.L In .308

[mb3]

Ok,
I made a gauge today out of a FGM casing and a SMK 168 gr bullet. I sized and chamfered the casing then split the neck across the axis, and placed the bullet in the neck. It holds good tension, while still allowing me to adjust the length. Placed the gauge in my rifle to find out what my max COAL is for my LTR (bullet setback by contact with rifiling). My Rifling appears to start around 2.8975 and 2.901; at least that’s what I came up with. Does that sound about right for those of you who have measured your Rem 700's? I figure I will set my COAL at about 2.805 and make adjustments on future loads. How would that compare to what you guys have experienced?

 

[scissorhands]

I do the same thing, except I'm taking my measurement from the ogive and adjusting accordingly. I feel you will get more accurate measurements from the ogive vs. the tip of the bullet.

 

[normbal]

I do the same thing, except I'm taking my measurement from the ogive and adjusting accordingly. I feel you will get more accurate measurements from the ogive vs. the tip of the bullet.

Yeah, that seems to be the most effective answer. The tips get beaten up and shortened during transport and reloading. But the sources I've read and spoken with say that the Meplat of the bullet effects the ballistics the least compared to the other features of the bullet (secant/tangent ogive, bearing length, taper on base).

But all things being more or less equal, you can pretty much get away with an OAL of roughly 2.800 - 2.810.

Look for a Hornady (formerly Stony Point) bullet comparator and measure from the ogive. Then every round will come within about 0.001" of the same OAL to that point.

 

[mb3]

Thank you for the info. I'll use the measurements from the bullets ogive.

 

[JGorski]

Ok,
I made a gauge today out of a FGM casing and a SMK 168 gr bullet. I sized and chamfered the casing then split the neck across the axis, and placed the bullet in the neck. It holds good tension, while still allowing me to adjust the length. Placed the gauge in my rifle to find out what my max COAL is for my LTR (bullet setback by contact with rifiling). My Rifling appears to start around 2.8975 and 2.901; at least that’s what I came up with. Does that sound about right for those of you who have measured your Rem 700's? I figure I will set my COAL at about 2.805 and make adjustments on future loads. How would that compare to what you guys have experienced?

In both of my Rem 308s & 168MKs, the oal is 2.940" with the bullet just kissing the lands, I load 168AMAXs at 2.825"oal. Id set lour MKs about the same. From past experience they dont shoot very well closer to the lands.