SMK ogive dimension variations changing O.A.L

[leadbury]

Found an accuracy load for new rifle using older production (paper boxed-$14.00/100) 168 .30 cal Sierra match kings seated with redding die.Got a new forster bench rest seater to load a bunch up,the o.a.l. was varying by up to .035+ using newer production bulletts. Started adjusting die to hit my desired o.a.l. of 2.825,then got idea to measure bullets in a hex nut shaped comparator I,ve had and never used. Bullets measured all over the place ( bullet ogives must be varying where it touches comparator.) The bench die seater stem makes contact at the ogive,I think I should just leave it set at one o.a.l. setting and see if they still shoot dime sized groups. Checked Hornady A-max bullets in comparator,all within .001.Any thoughts best way to use the out of spec SMK's?

 

[Demi-human]

As practice...

I have humans poo-foo my use of Hornady bullets. My experience has been the same as yours, they are quite consistent.

 

[leadbury]

The original .308 loads were set at 2.825-about .025 of rifling according to hornady tool. Using new lot of bullets I did not recheck max o.a.l., figured bulletts were still made same dimension.They would not even chamber,tight into rifling.Testing new bullets with hornady tool showed max length average about 2.750. They ranged from 2.725 to 2.780. I set them at 2.725,got maybe a quarter group.I sure don,t want to start sorting out bulletts,got to work on an A-max load. I also need to redo do my o.a.l. tests of different type bullets using a couple different samples from the box to repeat testing to check consistency .

 

[Blue68f100]

I use a comparator (the hex looking nut) to set OAL when I change bullet lots. I record the comparator number with my load data so I can go back and check if needed. Since your using some real old bullets then switching to newer, there will/may be a change due to it being made on newer equipment. The main thing that needs to be the same is where it contacts the rifling. These are normally pretty close from lot to lot, the OAL will vary though.

 

[Slamfire]

The 168 SMK and the 175 SMK are very jump insensitive, so the exact ogive distance from the lands is not important. Just load them and shoot them.

 

[frankmako]

slamfire has answer your question. this is what i have found also.