Bullet Seating Depth

[Clint.]

On the issue of bullet seating depth....do you folks try to seat your bullets as close as possible to the lands of the rifling?

Secondly, Do you find that seating bullets close to the rifling causes increased pressure and thus necessitates a slightly diminished powder charge?

Third, I know that some magazine lengths won't permit doing so....but, do you find that when the bullet is as close as possible to the rifling that accuracy is better?

Fourth, how do you determine your overall bullet length...and thus the proper seating depth? How do you go about measuring it?

Clint

[MOTurkeyTamer]

I believe a person reloading their own ammo for hunting purposes should not be concerned with loading out to the lands. Like you said, some guns magazines won't permit it anyway. It will not make enough difference in a hunting situation to worry yourself about it. Now if you are a benchrest competition shooter....then maybe it's a different story. I don't seat a bullet deep enough that the neck is onto the ogive of the bullet or exceed a loading manuals recommended cartridge OAL. That gives you plenty of room to experiment with most bullets. As far as a formula to figure seating depth in relation to bullet length.....someone else will have to answer that. Good luck!

[stubblejumper]

If the magazine will allow it ,and I get ample bullet length held in the case neck(at least one caliber)I start with the bullet about .020" from the lands and try different seating depths to test the effects on the accuracy of the load.I pay no attention to the lengths listed in the manuals as throat lengths vary greatly from gun to gun.With some guns accuracy is greatly effected by seating depths and in others it has little effect.Seating closer to the lands usually provides more pressure and therefore more velocity.

[gunsite]

When I set up a rifle. I always check the seating depht first. I try to set the bullet the same as the diameter of the bullet. which most of time is 40-50/1000 off the lands. you have to have enough case left to hold that bullet firm. If its a hunting rifle and you can achive 2moa at 200 yds by changing
powder and primer combinatons I would leave it alone. gunsite

[Mykey]

In my experience every rifle is different and while some may shoot great with the bullet next to the lands some don't. I think seating a bullet at .030 off the lands is a good place to start and .020 is really as close as you should seat for a sporting rifle to be safe. I have found that in most cases juggling components will get you the accuracy you desire and then if you want to experiment you can tweek it a little more by adjusting seating depth to see if it makes much difference in accuracy. I usually start at .030 off the lands and work on a load juggling components and if i find something that shoots really good and in most cases i do then i don't touch the seating depth at all. If i find a load that won't group very well with anything i've tried then and only then do i play around with the seating depth and sometimes accuracy gets better and sometimes it don't. When i do adjust seating depth i go out with the bullet .005 at a time shooting groups until i'm next to the lands just to see if it makes a difference. I don't think seating depth plays as big a role in accuracy or is as important as most people make it out to be because i've seen rifles shoot tight groups with the bullet seated .010 off the lands and the same rifle shoot the same load just as tight seated .040 off the lands.

[SnoBall57]

I set my overall length with a factory round. I always have a factory shell of the same bullet weight laying on the bench and I run it into the seating die and tighten everything down to that dimension.

[Clint.]

Thanks all.
One further question: Some of you wrote about seating the bullet at .030-.040 away from the lands.

How do you go about measuring that?

Do you deliberately seat a bullet in an uncharged case and then force it into the rifle so that the lands force the bullet to its maximun seating depth?
Do you then reduce that by measuring the resulting cartridge with calipers and seating .030-.040 deeper?

Or is there a better and easier way?

Clint

[stubblejumper]

I take a fired round, then press on one side of the neck to slightly flatten it so a bullet may be pushed into the case with your fingers with some resistance.I then start a bullet into the case purposely leaving it long enough to contact the lands.I place the cartridge into the chamber and close the bolt .I then open the action and carefully remove the cartridge and measure the overall length.I repeat this several times until I get consistant readings and this is the distance to the lands.This does take a little practise until you learn how much tension is needed to keep the bullet in place while loading and unloading the cartidge while still allowing the bullet to move in the case when the bolt is closed.Be aware that this distance varies from bullet to bullet so you must do this with every bullet weight and style that you intend to use in your gun.It also varies greatly from gun to gun even if the make and model are identical.

[Clint.]

Thank you stubblejumper. That is basically what I have been doing but someone was trying to show me a method using a cleaning rod and making pencil marks on it.
It all seemed a little funky to me though. I think I will keep on using the method you describe. If it ain't broke, I won't try to fix it!
Clint