Does this COAL seam long !

[357shooter]

I'm trying to find the best COAL for my new 700 in 30-06. I'm using a rod
with to stops. First I check it with the bolt in and set the stop, then put a bullet
into the lands and set that stop, and I come up with an avg. of 3.412.

I'm using Hornady 168 bthp in the Hornady manual it shows a COAL with this
bullet at 3.220 that would be .192 off the lands I was going to try .20 off the lands but that would be over max col of 3.340.

So where would you start the COAL at any help is appreciated. Thanks.

[Witch Hunter]

Seat a bullet long enough to reach the lands and mark it with a sharpie. Close the bolt and look for rifling marks. Keep shortening it until they just disappear. That should be your zero.

[bsumoba]

700s are known to have long throats. this doesn't surprise me. that said, if you are magazine feeding, I would say to load at or just short of what you can feed in a magazine.

if you are single feeding, then COAL will not matter as much. Just make sure you have enough bearing surface holding the bullet in the case.

[M1NM]

COAL with this
bullet at 3.220 that would be .192 off the lands I was going to try .20 off the lands but that would be over max col of 3.340.

The difference between .192 and .20 is only .008 but your COAL variation of .120 is almost 1/8 of an inch. Also going further off the lands as in your example will make the COAL shorter not longer. Don't forget you need a little jump rather than loading right to the lands to avoid pressure spikes.

[Enfield47]

I measured for my K31 and load longer than the COL in the manuals with good results. The thing to do is load up an empty case and color the bullet with a black sharpie and look for signs of it hitting the lands. If there are marks on the bullet then reseat at a shorter COL and repeat until you find the right length.

[Whiterabbit]

Seeing as this is where I have to seat for the bullets to touch the lands of my 7x57:



No, no I do not think whatever you are working with is gonna be too long.

[ar15barrels]

I'm trying to find the best COAL for my new 700 in 30-06. I'm using a rod
with to stops. First I check it with the bolt in and set the stop, then put a bullet
into the lands and set that stop, and I come up with an avg. of 3.412.

I'm using Hornady 168 bthp in the Hornady manual it shows a COAL with this
bullet at 3.220 that would be .192 off the lands I was going to try .20 off the lands but that would be over max col of 3.340.

So where would you start the COAL at any help is appreciated. Thanks.

It's normal for factory throats to be too long to be able to seat bullets near the lands and have the cartridges fit in the magazine.
They call these "lawyer chambers" as the lawyers like that you can't seat near the lands where pressures will be high.
Load to fit in the magazine IF you want to feed cartridges from the magazine.
If you want a shorter throat so that you can seat near the lands, the barrel can be set back a few turns and rechambered or you could rebarrel with a whole new barrel.

[357shooter]

Thank you all for that great info. Appreciate it.

[Whiterabbit]

357, here's something neat to think about:

Calguns "experts" say you have to be on the lands, or within .05" to have any hope of accuracy.

Those particular bullets need to be seated so the second band from the front is floating under the case mouth. That's a HUGE jump to the lands! The accuracy is there with that seat depth. The accuracy is not there when seated out long.

That is my case. But I have learned that I'm not special, so if that works for me, it works for many other people too.

So the next time you hear that OAL tuning is dominated by distance to lands, you may consider that perhaps empty space in the case may play a bigger role....

[ar15barrels]

you have to be on the lands, or within .05" to have any hope of accuracy.

That depends on your chamber.
If the throat is oversized, it helps to seat near the lands.
If your throat is right at bullet diameter, it really won't matter if you are near the lands or not.
Factory barrel throats are commonly oversized and off-center.
That is why it's common for factory guns to shoot better with the bullets closer to the lands.
Long bore-riders cause a problem in a long and oversized factory chamber where there is nothing to hold the bullet centered in the barrel while they start.
That would explain why they shoot better seated farther away from the lands.

[rdfact]

700s are known to have long throats. this doesn't surprise me. that said, if you are magazine feeding, I would say to load at or just short of what you can feed in a magazine.

if you are single feeding, then COAL will not matter as much. Just make sure you have enough bearing surface holding the bullet in the case.

Is there a general rule as to how much bearing surface is needed? Is there a minimum seating depth?
When loading for my Swedish Mauser, in order to touch the lands the bullet is barely seated and you can easily pull it out by hand. This was a boat tail bullet.

[Whiterabbit]

Randy, please don't take my quote out of context.

I do not believe that accuracy depends universally and specifically in loading the bullet a specific distance off the lands!

But that notion is absolutely prevalent on Calguns. As if it should be the primary consideration regarding OAL (as opposed to factors such as casefill or others).

My point was specifically that data can show that distance from the lands is divorced from accuracy in many cases. Therefore not a universal constant.

[ar15barrels]

Is there a general rule as to how much bearing surface is needed? Is there a minimum seating depth?

3/4 of the caliber is a good general rule.
So, about 0.200" on a 6.5mm.

[ar15barrels]

I do not believe that accuracy depends universally and specifically in loading the bullet a specific distance off the lands!

I don't either.