Changing POI

[longwinters]

I just got rid of a 308 and purchased a 7m-08.  Since I had a couple hundred new 308 brass I figured ..."hey why dont I just resize it to 7m-08" .  So I full length resized the 308 to 7m-08, chamfered and reamed it and measured it.  Hmm, 308 resized measures 2.015 where min trim to length for 7m-08 brass is 2.025 :eek:  Well, it can still get fire formed etc... would think it is ok, after all I did the same thing with 30-06 brass to 280 cal and it worked great.

So with the same load in both resized 308 and store bought 7m-08 of the same brand name I goes out to shoot.  First I shoot the pure stuff, 3/4" groups at 100.  Next I shoot the resized . . . 1 1/4" at a hundred and 1 1/2" higher and 1" to the left.  Granted sometimes I  roll my shoulder into the butt stock too much when shooting off of the bench and I get higher grouping but I don't think this was the case in this instance.  Cuz when I went back to the store bought 7m-08 brass I was right back in the bullseye.

Any thoughts or ideas?  I realize I could just shoot the resized stuff and not mix them with the storebought, but what fun would that be?

Long

[ricciardelli]

Although the name on the box may be the same, you have used totally different brass when you resized the .308 brass.

You changed a major component.  And you are going to get different results.

[longwinters]

Do you think this will be a problem if I resite in etc... or is it not a great idea?

Long

[Val]

I would re;oad some of the now fireformed necked down brass and see if  fireformed to your chamber, you get a result thae same as the commercial ammo. You should also reload some of the storebought fireformed brass and compare it to the necked down fireformed brass reloads. If the fireformed necked down stuff is still different (POI) I would dump it and just buy some new brass.

[Steve P]

I took out my .243 WSSM two weeks ago and shot two different hand loads and factory ammo.   Factory ammo was 2" high at 100.  Nosler BT shot 1" left of dead center.  Sierra 100s shot 1" left and 1" high of center.
Three distinctly different groups with similar loads.

Different brass, different bullet, different primer, will likely put your load in a little different place on the paper.  You need to sight in with the load you are going to use.  You get lucky if different loads hit the same place on paper.

Steve  

[Tycer]

Yep, like Steve said. Changing the ingredients changes the pie. POI :grin:

I'm still fussing with different combinations as to have four different weight and shape bullets hit the same POI as my large game round I like.

Makes for frustrating fun!