Reasonable R700 .308 COAL

[whubbard]

Just looking to make sure I didn't do anything wrong in my measurements. I'm measuring for a Remington 700 in .308

COAL for Pulled M2
2.910"

COAL for Sierra MK 168
2.912"

COAL for Sierra GK 150
2.920"

I made a dummy bullet with a pulled M2 and set a COAL of 2.900" and it chambered just fine and upon extraction the bullet was the exact same length. I'm good on these numbers right?

Also, do many of you developing accurate loads start .010" or .020" of the lands.

Thanks!

 

[PCCUSNRET]

There is really no way for us to tell if these correct for your gun as the lands on your gun are probably different than the ones in 700's. If the bullets aren't hitting the lands (and you could tell by the scrape marks on the bullet) and you have at least .308 of the bullet (not including the taper on BT bullets) contacting the neck of the case then you should be good to go.

I try to stay .010 off the lands in target rifles and .020 for hunting.

 

[blarby]

FWIW

Are you using a bullet comp on your mic ?

If not.... getting an accurate reading in the .010 range is gonna be tough.

 

[whubbard]

Blarby,

I am not. I'm also using digital calipers, so I guess my reading may be a bit off. Do you have a micrometer you can recommend? Also, what bullet comps are usable on a mic, I've only ever seen them on calipers?

 

[gamestalker]

I start at the lands and move back if necessary for accuracy reasons. Typically, most loads will have an accuracy edge when they are up close and personal to the lands. But some of the newer throats are designed accomodate this style of OAL.

Speaking of, I went to the range yesterday with some 110 gr. TNT's for my 7 mags. that are seated to the lands and only have .097" of neck, and they shot incredibly well. The thing about not getting a bullet diameter worth of bullet in the neck is only problematic if the round won't fit the magazine, or won't maintain it's OAL during feeding or firing. Other than that, neck tension is not an issue unless you can move the bullet with your fingers, in my opinion.

 

[blarby]

I have never seen one offered for a round end/flat mic.

If you have a blade end mic, the sinclair one can be made to work.

If you have calipers, investing in a decent blade end mic probably isn't worth the expense.

Once you get down into the .001's ( and occasionally the .010's, depending on brand) you start noticing the actual bullet length difference, tis why I brought it up. A comp is going to give you the measurement you are actually looking for

I'd get a comparator set of your choosing that will work on your existing tool