COAL – Something doesn’t seem correct.

[orar750]

Rem 700 SPS .308
168 gr AMAX
Hornady Match brass

So after doing some reading it seems like my COAL is way too long. I am trying to work up a load for a new rifle and I am using the method described in “Hand Loading for Long Range 3: finding start OAL”. I found my COAL for this rifle to be 2.949 in. from the back of the brass to the meplat when just touching the lands and grooves. I understand that the meplat will vary from bullet to bullet so I sorted them to +- 0.001 in.

So my question is why does my COAL seem so long? I would have to jump 0.100 to get close to what I have read others are using as a COAL. This doesn’t seem right to me.

Compared to most I am new to reloading, so no big words and please type slowly so I can keep up (haha), thanks.

 

[jr81452]

Re: COAL – Something doesn’t seem correct.

Factory Remmy barrels generally have long throats, some worse then others. Most guys with factory barrels load to mag length so they can put more than 1 round in the rifle. If you plan to use your rifle as a single shot, you can use the lands to determine OAL; but you'll likely need more powder to reach standard velocities, and will want to ensure that you have a sufficient amount of bullet in the case for proper tension. Or you could get a new barrel

 

[Ratbert]

Re: COAL – Something doesn’t seem correct.

The AMAX doesn't mind the jump, just set it back until it will fit into your mag box. Remingtons come throated like an Amsterdam hooker, just a fact of life.

Also, most guys loading 308's around here probably aren't running AMAX's, so your COAL is going to appear a bit longer than what they get simply because of that plastic tip. Consider getting a stoney-point or sinclair intl or some other gauge that will let you measure to the bullet's ogeive instead of the COAL. That will give you a much better idea of consistency and your relationship to the lands.

The RCBS Precision MIC is easy to use but doesn't measure off the ogeive but rather some other arbitrary (near as I can tell) diameter so I've given up using it simply because it's results can't be collated with measurements from anything else.

 

[jakermeister]

Re: COAL – Something doesn’t seem correct.

What ratbert said. The A-max is not a picky projectile

 

[Fuzzball]

Re: COAL – Something doesn’t seem correct.

"I found my COAL for this rifle to be 2.949 in. from the back of the brass to the meplat when just touching the lands and grooves."

There can be and often is a significant difference between the max possible OAL and best OAL. Experiment.


"I understand that the meplat will vary from bullet to bullet so I sorted them to +- 0.001 in."

Not only will most bullets vary considerably more than that, so will the OAL of the very same bullet from round to round unless your seating skills are VERY good.

I ignore OAL. IME, I've found well chosen seating depths can tolerate an ogive length variation of as much as +/-5 thou (sometimes even a bit more) without effect. The rifle couldn't care less about OAL and where the meplat hangs in space, all it cares about is the jump to rifling contact.