# Bullet Seating



## Huntoholic (Sep 17, 2008)

Okay here is the other.....

What kind of changes in depth are we talking about?


----------



## DallanC (Jan 13, 2009)

How deep into the case the bullet is pressed. This depth increases, or decreases the distance from the nose of the bullet to the start of the riflings. Some rifles are picky about the amount of freebore they have (the area where there are no riflings). Weatherbys have a huge amount of freebore to get the bullet moving, before it engages the riflings. Other barrels have relatively little freebore... you will have to measure your own rifles to see how their barrels are.


-DallanC


----------



## Huntoholic (Sep 17, 2008)

DallanC

What I want to know is how much of a change do you do in your incremental change. A .010, .001.........


----------



## sagebrush (Sep 8, 2007)

how much you change is really dependent upon your self, I might start out somewhere around .0005 at a time. start with the recommended oal length or your cartridge then find your actual case oal and go from there.

here is a link for further info on the subject
http://www.6mmbr.com/catalog/item/1433308/977259.htm


----------



## Huntoholic (Sep 17, 2008)

sagebrush said:


> how much you change is really dependent upon your self, I might start out somewhere around .0005 at a time. start with the recommended oal length or your cartridge then find your actual case oal and go from there.
> 
> here is a link for further info on the subject
> http://www.6mmbr.com/catalog/item/1433308/977259.htm


The incremental change is what I am trying to get a handle on. It is an area of reloading, to be honest, that I have not focused on.

This past year I have been looking closer and one of the things that I have noticed is the difference in the bullets themselves, both in weight and dimensionally. Trying to understand if the changes that I see are significant or not. A .0005 change is not much and I see that much change in the bullets themself.


----------



## sagebrush (Sep 8, 2007)

If its the bullets then you should look at that also. They all have different specs try choosing them for what you want to do.


----------



## DallanC (Jan 13, 2009)

First off, you need to measure the COL of a each bullet according to its type and olgive. Generally people do this by inserting a bullet into a empty but sized case, and forcing the bolt closed, which in turn pushes the bullet against the lands until it stops, which in turn pushes the bullet into the case. Now carefully extract the bolt without pulling the bullet back out of the case (sometimes I use a wood dowel and tapped lightly to loosen a stuck bullet).

Now measure the COL of that case... that is your max. From this measurement I'd recommend starting testing at the published official cartridge COL, and a halfway point between the official COL and the max. If you see improvement you can go halfway between the last test col and max. So on and so forth. Final adjustment increments are up to you.

Every bullet type has a different olgive, so you need to remeasure this every time you change bullet types or weights!

Do note however, that with alot of freebore, some bullets can be seated out so far they wont fit in your magazine. My 7STW is that way... there is no way I can get near the lands and still fit in the magazine... so I just shrug it off and trust in Roy Weatherby  (actually the gun shoots fantastically with proper bullets even with a ton of freebore, remington greenbox 140s shoot .75"!!!)

-DallanC


----------



## Huntoholic (Sep 17, 2008)

sagebrush said:


> If its the bullets then you should look at that also. They all have different specs try choosing them for what you want to do.


Well one of the things that I did this past summer was take a box of bullets and separated them by weight and OAL of the bullet. With out thinking to deep, I expected that my loaded rounds would all be the same OAL. They were not. Since I seat the bullets based on shoulder contact in the seating die, that got me to thinking about how this might affect accuracy (bullet to lands).


----------



## sagebrush (Sep 8, 2007)

I would say that you are thinking to hard, look at your equipment they are not all the same. yes they do the same function but how well they do it?
if you want bench rest accuracy you will need equipment upgrades but is it really worth the hassle, this can be only answered by you. 

take for instance a seating die see how consistent the one that you have is verse a competition one which has a sleeve to keep the bullet aligned in the case ( bullet run out) then you have neck trimming, annealing cases it goes on and on. like you know already all bullets are not the same. stop pulling out your hair quit trying to get bench rest accuracy.


----------



## Huntoholic (Sep 17, 2008)

sagebrush said:


> I would say that you are thinking to hard, look at your equipment they are not all the same. yes they do the same function but how well they do it?
> if you want bench rest accuracy you will need equipment upgrades but is it really worth the hassle, this can be only answered by you.
> 
> take for instance a seating die see how consistent the one that you have is verse a competition one which has a sleeve to keep the bullet aligned in the case ( bullet run out) then you have neck trimming, annealing cases it goes on and on. like you know already all bullets are not the same. stop pulling out your hair quit trying to get bench rest accuracy.


The only thing that has me pulling my hair out is trying to find components.


----------



## Lonetree (Dec 4, 2010)

DallanC said:


> First off, you need to measure the COL of a each bullet according to its type and olgive. Generally people do this by inserting a bullet into a empty but sized case, and forcing the bolt closed, which in turn pushes the bullet against the lands until it stops, which in turn pushes the bullet into the case. Now carefully extract the bolt without pulling the bullet back out of the case (sometimes I use a wood dowel and tapped lightly to loosen a stuck bullet).
> 
> Now measure the COL of that case... that is your max. From this measurement I'd recommend starting testing at the published official cartridge COL, and a halfway point between the official COL and the max. If you see improvement you can go halfway between the last test col and max. So on and so forth. Final adjustment increments are up to you.
> 
> ...


Very good info.

Not only can you have issues with cartridges in the magazine if the bullet hangs too far out of the case, it can also set up a situation, for intermittent accuracy problems. As mentioned, every bullet has its own geometry, and part of this geometry, is the portion of the bullet, that makes contact with the case. If the bullet is making insufficient contact with the case in this area, then the possibility of the bullet getting pushed, or angled off center increases. This will cause an accuracy issue, in an otherwise very accurate round.

Weatherby's tend to have long chamber throats, because it is thought that with heavier bullets, and magnums in particular, that a longer, smoother transition into full contact with the lands and grooves, will stabilize and center the bullet more accurately. I'm not a big magnum guy, but the inverse seems to hold true with very light hollow points, so it would make sense.


----------



## Lonetree (Dec 4, 2010)

Huntoholic said:


> Okay here is the other.....
> 
> What kind of changes in depth are we talking about?


If the contact between the bullet and the case is sufficient, I like to start with the bullet seated about .015" shy of making contact with the riflings. This is one of those things you get set early on, and then only revisit, if you can't get good results. Or if you have a round that shoots good, but you know the rifle can maybe do better based on the performance of other rounds. Then this is another variable that you can play with to fine tune that round. One of the reasons I like to start close to the riflings, is that in theory this is optimal(distance to rifling, and case volume), and when it comes to any adjustment of this, there is only one direction to go. It keeps it simple. As for incriments, .020" is probably good, but this depend on the bullet. Some have more range than others.


----------



## Huntoholic (Sep 17, 2008)

Thank You....


----------



## Cooky (Apr 25, 2011)

In my experience seating depth makes a lot more difference in accuracy than any other variable in reloading. Here is a dicussion we had a while back.

http://utahwildlife.net/forum/18-firearms-reloading/29341-off-lands.html


----------



## fishreaper (Jan 2, 2014)

I dealt with my seating first,
And it made a huge difference to pushing the minimum load into about 1 in groups. Accuracy maxed out at about half load but hunting velocities are a slightly larger.


----------



## Stickboy (Oct 28, 2010)

Next to a charge weight ladder exersie (in search of an accuracy node), the biggest bang for your buck is spending time on seating depth. Well worth the effort.

-c


----------

