I built a 223 Ackley the other day, on a Sako S491 action, with a Hart barrel.

Yesterday I had a visit from a friend, and he started looking for loading data for this one, but could not find any in the two books we had open on the table.

One from Vihtavuori and one from Hodgdon.

Hi next question was how do I determine what is the maximum loaded round should be.

I told him I have been following a rule for many years.

That is to seat the bullet one caliber down in the case, and then take it from there.

I loaded one round to show him.

I took a prepared case, measured its length, then measured the length of a bullet I was going to use, added these two together, and subtracted 0.224 from the total.

I told him that is where I am going to start.

You can then adjust the over all length as you see fits best in your chamber.

Makes sense to me.

Saeed,
I presume you tailored the desired throat length in your rifle build.
I just did a quick calculation using your formula for one of my 30.06 rifles. The length I came up with would mean the projectile would jam into the lands and I wouldn't be able to close the bolt.
My own approach to finding OAL to start with is to seat a projectile, long, into an empty, unprimed case then chamber this to force the projectile back into the case as it is pushed against the lands. Then extracting carefully to ensure the case holds the projectile. I then measure to use this as absolute max length then experiment with following loads to find the ideal OAL for best accuracy. Sometimes however, in commercial rifles, actual magazine length dictates the maximum OAL one can start with or work back from.
Would you have any advice on how I might improve my system ?

brass rod with 2 drill stops on it. rod down barrel to face of closed bolt, then tighten outside drill stop (the one away from barrel)
place boolit into throat, just touching lands (pushes rod out of barrel) tighten drill stop touching barrel
measure distance between drill stops, that is maximum overall length for that bullet touching lands

or use a wooden dowel and a pen for "rough estimate"

Or..........

Buy a Sinclair Bullet Seating Depth Guage.

Kevin

quote:

Originally posted by aephilli:
brass rod with 2 drill stops on it. rod down barrel to face of closed bolt, then tighten outside drill stop (the one away from barrel)
place boolit into throat, just touching lands (pushes rod out of barrel) tighten drill stop touching barrel
measure distance between drill stops, that is maximum overall length for that bullet touching lands

or use a wooden dowel and a pen for "rough estimate"

That's basically how I do it, but with a few appropriately sized drill rods. Often compromises have to
Be made to fit the mag-box, or keep enough bullet in the neck.

I use a Hornady OAL gauge and usually start OAL @ .010 off the lands if the mag box will allow it, or at max mag box length if not. I start with minimum loads and work up, finding pressure, then start seating bullets off lands incrementally to find accuracy. I do not like starting loads way off lands, only to adjust seating depths longer, as pressure will increase accordingly as you do that.

I would run a wood dowell in my barrel from crown to bolt face, mark the wood. then ever so lightly tap the intended bullet into the throat of the rifle (bullet only not a live round) and push the rod back in from the crown until it makes contact with the bullet.and mark the rod,...then measure between the two marks and log the OAL. set the bullet back a thousands or two and be good to go....If you change bullets you must repeat this methond and log the OAL..If you want to play with the gap (bullet jump) that's up to you..I have done it and never made any difference..