30-06 oal

[CTPistol]

New to reloading rifles and was curious as to how critical OAL is?

IM reading min OAL of 3.34 in my Lee book with a max of 3.34 listed also...

My first few have come out as 3.25.

I am loading 180g Sierras with IMR 4350

any advice is appreciated.

 

[rcmodel]

OAL depends entirely on the bullet you are loading.

It can vary from 3.00" for a 110 grain JHP, up to the SAAMI max of 3.340" with a long heavy bullet.

Some folks load even longer then that to get to the rifling leade.

Your Lee manual is not very precise as it is just a collection of reprinted data from many different sources.

Your 180 Sierra boat-tail should probably be seated to 3.280" OAL according to Lyman #49 manual.

rc

 

[Ol` Joe]

The 3.340" figure is the SAAMI max lenght that will fit any SAAMI based chamber and magazine. It means nothing in real life as to your OAL. Find the distance to the lands of your chamber, load just under that lenght or to the max that will fit your magazine which ever is shorter, and consider that the MAX OAL for your rifle.
As noted the Lee book is generic and not real specific. Some manuals however give the lenght the data was developed at. Speer, and Hornady come to mind right off. That lenght is always under the SAAMI max and to copy the exact load at that lenght "should" give you a very close result to theirs. A bit longer or lower can alter pressure somewhat, but in bottle neck cartridges unless it`s a drastic reduction or you have the bullet jammed in the lands it will be moot.

 

[interlock]

when i started reloading i made sure that i had got my rounds a couple of thous off of the rifling in accordance with accepted best practise for accuracy. but i was using .30-06 and 150 gr bullet. this meant that not much bullet shank was in the neck. I took one out of my pocket and it was bent at the bullet to neck..... there was not enough shank in the neck. So i ran them all through the press again and shortenned them down by about 5 mm. i expected that they would not shoot straight. it had been a sub moa set up from an old parker hale rifle. However, there was no difference in the accuracy at all. This was not a high load so i didn't worry about the pressure. if you are near max then shortenning the round may increase pressure.

So really it makes no odds in my experience. However this is a hunting set up where MOA is very acceptable. Target shooting would be different