[GJinNY]

Sorry if this is addressed elsewhere........

I fell upon the website and this was some great info:

http://www.quarterbore.com/library/articles/2506.html

"*****CASE OVERALL LENGTH*****

To begin I always trim my brass to a consistent 2.484" and ligtly deburr them.
I also deburr the primer hole to ensure consistant ignition of the case upon firing.

I prefer to seat the bullets in my reloads to the point where the bullet is just off the rifling.

This Overall Length varies for each bullet as the shape of the bullet can affect how far the bullet can be extended
before the bullet will strike the rifling. The way I usually determine this dimension is to take an empty resized case
and seat a bullet to a long overall length. I take this cartridge and slowly try to push it into the chamber.
At the point where the bullet strikes the rifling you will feel pressure as you can force the bullet into the empty case
using you rifle’s bolt. Once the bolt is closed I remove the cartridge and set my seating die to the length of this cartridge.

From this point I seat a second bullet in an empty case to the same length as the previous cartridge.
I blacken this bullet using carbon from a candle (Obviously don’t do this near gunpowder!).
I again run this cartridge in the chamber looking for signs that the bullet strikes the rifling (There should be marks in the carbon).
Take a third cartridge and seat the bullet to a slightly shorter COL, blacken it and evaluate if it strikes the rifling.
You can use the same bullet and cartridge to repeat this process but I prefer to use at least two so that you always
have your "longer" cartridge as a reference.

Once you have a cartridge that doesn’t hit the rifling I would measure the overall length using a micrometer and record it for future reference. I keep some of these "Maximum Off Rifling" cartridges as samples until I have completed my load development for that particular bullet."

 

[K31Scout]

I've done it that way a few times. Now i use a skinny wooden dowel.

1. Close the bolt on an empty chamber. Run the dowel down the pipe till it seats against the bolt face. Mark the dowel with pencil just as it clears the muzzle.

2. Seat a bullet extra long into a resized case and chamber it, pushing the bullet into the lands. Run the dowel in until it hits the tip of the bullet. Mark the dowell exactly as you marked it the first time.

3. Use your calipers to measure the distance between the 2 marks and subtract how far you want to be off the lands...with that type of bullet.

I like this way because every bullet brand and type will be a little different due to the bullets shape and where it hits the lands on it's length. Less messy than the blackened bullet way and there is no chance of the bullet sticking in the lands and pulling out of the brass a little during extraction, giving a false reading.

 

[GJinNY]

Cool idea too. Thanks.

How far back from the lands do you want to be? 1mm?

I didn't realize how precise this all had to be to get consistency. No wonder factory ammo varies from gun to gun.

 

[BNC04]

Remember...., Use caution with this activity. I'm relatively new to reloading myself but have read alot about the subject of bullet seating etc and I do change the seating depth on my loads to see the impact on accuracy. Please note, If your measurements are off, you can load a cartridge that will be touching or in some cases inserted into the lans and this will result in increased chamber pressures over the same cartridge that is not touching the lans. Remember to work up to the loads with any change in the handloading formula. Your current max load that is not touching the lands will have more pressures if you load it so it is touching the lans..

I'm only posting this because some people may not understand that this, as in any handloading activity needs to be used with caution and understanding. Just read up on it before you try this.

Brett

 

[Pard]

I have both the straight and curved OAL gages. I gage each rifle 4 times a year. Good way to see if you have gunk build-up in the chamber too.

Some long throated chambers you can not bridge the total free bore. I have a Mauser like that. One of the reason I do not buy new factory made rifles.

The other factor you need to address is that the round fits the magazine. You may have to shorten the round to fit down inside the rifle.

My Bud has a 300 win mag that shoots real good with the bullet .010 off the lands. He his to single feed them in the rifle. His magazine is .030 shorter than his optimum OAL.
We had to take his barrel off, cut the shoulder down, and short chamber it until his round not only is .010 of the lands, but fits his magazine.

I have not bought a new store bought rifle in over 20 years.
I buy junk, and make them into super shooters.

 

[GJinNY]

Well I just inserted a dud overmax length, loosely seated 75 gr VMAX and chambered it. Popped it out and it measured 3.20" COL.
Is that what I should be loading this bullet COL as?

 

[sullivan]

From memory (mine is pretty bad now) not all bullets are sensitive to seating depth. Someone here will be able to tell sooner or later, or you could go to a benchrest site.
Also, not all bullets from the same box are the same length. Therefore, no matter how careful you are to get all COLs the same, it is conceiveable that a bullet from one cartridge will be In the rifling when you chamber it. The way I deal with this is to use the "stick-from the muzzle-method", posted by K31Scout but you need several new bullets, a lot of time and a bit of luck. That is, one of the bullet samples has to be of an ogive shape, such that the final COL measurement reads Shorter than the others. i.e. some ogives will be "blunter" than others. If you seated the blunt bullet to the same COL as the more streamlined samples, then the blunt bullet would be seated Further into the rifling.
All this assumes that you are using a bolt action as I understand from this forum that levergun ammo must be made to a standard COL, in order for it to feed. I don't own a lever yet. I have no experience with Pard's tools either. We did not have them when I started shooting but it is another option for you to consider.
If you are itching to go shooting, reduce that 3.20 COL by 1/16th. That way nothing will stick in your rifling.

 

[K31Scout]

I agree with everything said above. Use caution and check aol often and more than once with every different type of bullet.

I once had a long throated Swedish Mauser that I could not get close to the lands with. I used a Lee Factory Crimp die and got great results with accuracy even though I was far from the lands. The crimp gives every round the same starting pressure and consistency.

I would stay .010 off the lands at least to answer your question and start with the minimum charge and work up.

Also, some rifles like a long jump to the lands by the bullet, crimp or not. That's the fun part of reloading; figuring out what your gun likes best!

 

[dhbwa]

Noslers manual is a good basic reference. I used to get anal on this but it seems like most rifles shoot well regardless.

 

[Sub95]

just remember to check and see if they will load into you're magazine, i seated mine to what barnes calls for .030-.070 off the ring lands and they were to long. i guess for target shooting they would be fine, but for hunting nope.

my .308 oal with barnes 168gr tsx is 2.914 to be able to fit them in my magazine they ened up at 2.820 and shoot like crap now.