Seating depth

[RonnieHelmo]

All,

Good afternoon. This post is both an introduction and a question. I screwed a 6br barrel,Shilen 26" 8-twist no-neck-turn) onto my Savage and have been having fun. Problem that I am facing is that the conventional wisdom seems not to work for me - let me explain. My intention from the beginning has been to use the 105gr A-max bullets. I bought a mess of them to tinker with but got terrible results,I mean really terrible, average groups close to 1" at 100yds). I tried different powders, different primers - no improvements. The one thing that I did not change was that I was jamming the bullet into the lands. Well, this afternoon I took my father to the range with me, it was cold and windy and I had just loaded 25 Lapua brass with 30gr of Varget with CCI BR4 primers,they are what I had in the priming tool) under 105gr A-max bullets seated 7mils OFF the lands. WHAMMO - groups dropped in half! What gives? Everyone knows that you should seat the bullets into the lands for accuracy - right? I am confused. Any input? Thanks in advance.

-Dr. Dave

 

[treeman]

dave sierras don't usualy like to be jambed either tho there exceptions. barnes bullets recomends seating off.050" or more and it works real. i have a savage 260 rem. that puts 5 120gr XLCs close enough that you could cover all five with a dime. UYou just have to find what each bullet likes.____treeman

 

[30xs]

Dave treeman is right some guns don't like to be jammed. I am shooting a factory Stevens 200 .223 with Sierra bullets. I loaded mine up .015 off lands, the result was a four shot group that was under a 1/4". I pulled the fifth shot and it ended up beind a five shot .442 group.

 

[billmo]

In my 6mmAR the A-max tends to shoot better off the lands about .010. I have not tried them in my 6 X 47 Shehane yet. Bill

 

[RonnieHelmo]

Fellas,

Thanks for all the input!

-Dr. Dave

 

[BigJim]

Dr Dave

When you pull that trigger and in a split second the primer sets off the powder you are building up tens of thousands of pounds of pressure. The case starts to melt and the lead in the bullet gets soft. When you are jammed up against the lands the pressure builds higher in expanding the case and more energy is placed on the back and sides of the chamber.

When you give your bullet a little jump there is less resistance as it enters the rifle tube,barrel) and is more accurately formed to the barrel. Less resistance more fps easier to stabilize more accurate on target hits.

 

[Preacher]

My 22/250 AI 9 twist don't like the 75 grain Amax into the lands either, seat em .010 off and the fun starts.........