reloading for accuracy (400 yards) question

[Bigeclipse]

All,
I am not new to reloading but I am new to reloading as far as accuracy is concerned. I know certain things can have an impact on the accuracy of your load. For example, a good scale, accurate bullet seating depth can make a pretty drastic change on your accuracy. My question is, how about new unfired brass? For example, I will be buying 100 pieces of lapua brass for my wife's 7mm-08. Let's say I use 30 pieces of that unfired brand new brass to do a OCW test, then there would still be 70 pieces of factory unfired brass left. Let's say I get a good shooting load in that OCW test. How likely are the remaining 70 pieces of unfired brass loaded exactly the same to the best OCW load to get the same MOA as the OCW test? (Yes I know the OCW test is to find a stable load, but lets say for arguments sake the most stable load is .75MOA), will the remaining 70 pieces also shoot around that .75MOA mark or because these are unfired pieces of factory brass, they could change? Do I REALLY need to fire form all of the pieces of brass? I know that once these 70 pieces are used up and I go to full length resize all the pieces, things can change and I will likely need to re-run the OCW test but it will be several years of hunting before that happens. Most all of her shots have been under 200 yards anyways. She will only shoot a handful of shots out of this rifle each year.

 

[jpd676]

I'd say if you are only shooting out to 400 yards, you won't see much of a difference. Loading gives better accuracy because it tailors the bullet to the specific rifle. Factory ammo can have varying powder charges as it is mass produced and this causes inaccuracy. If you load the same charge and seating depth to fit your rifle you will get consistent accuracy. I normally full size my new brass before loading anyway.

 

[Kansaswoodguy]

I dought you see to much difference

 

[el matador]

I've found that it depends mostly on your chamber. Factory rifles with roomy chambers will see a bigger difference than guns with match grade chambers. Your best bet is to chronograph your loads with the virgin brass. Then if it shoots a little different with fire formed brass you can adjust back to the same velocity.

 

[toasty]

My experience has been new brass will shoot a little different than fire formed unless you resize back to the same size. If you do, you will get more repeatable results, but less loadings with the brass. If you neck size, you may need +.1-.2 grain to get the same POI as factory new brass. Either way, it won't matter much IMO and would probably fall within you .75 moa range.

 

[Bigeclipse]

Thanks everyone. I kind of figured at 400 yards and trying to simply maintain MOA or less it wouldn't really be an issue.

 

[rootie3]

I think it is a given that fire-formed brass will shoot differently than non-fire-formed.
look at the differences... Larry

 

[Bigeclipse]

I think it is a given that fire-formed brass will shoot differently than non-fire-formed.
look at the differences... Larry

My question wasn't whether fire formed would be different. I know it would. My question is...is NOT fire forming brass ok? I will be buying 100 pieces lapua brass. Using 30 or so to develop a decent stable load and then loading the other 70 pieces to load that load.