O.K., the further I get into this reloading/accuracy game the more I learn what I don't know. Here are the facts. I have approximately 150 rounds of brass for my .300 Winchester Magnum, most likely from three (possibly more) lots.

I am trying to refine a load that I will be using for hunting in the future.

Question...should I go out and buy enough brass from one lot to load my rifle for quite some time on that brass and relegate the brass I already have to practice with later on, or in your expert opinions am I making a mountain out of a mole hill?

FWIW I am pleased as punch if my gun will shoot 1 m.o.a., which it is capable of. It is a stock Browning A-Bolt II in Stainless Stalker.

I'd go ahead and stick with one flavor of brass. If nothing else it's one less variable in the problem.

If they are from a different make (different headstamp), I would deffinitely start with different brass, buying at least a couple hundred if not 300 from the same lot. I personally use federal gold medal match brass for my 300WM, but if it were me buying new brass, I would buy hornady. Winchester can vary in neck thickness as much as .005" whereas hornady claims theirs varies only .002", and hornady stopped having winchester produce their brass due to this. I would strongly suggest getting new brass anyway if it has been fired more than three times or so since you will be working up a new load, and you certainly don't want to adjust your load again for a new lot later on, because you WILL have to. I have had to adjust powder charge by .5 grains for a different lot of brass, and at least in my 300WM, .5 grains made a pretty big difference at 100 yards.



I have also seen big differences in case weight and accuracy from one lot of 22-250 rem brass compared to another made a couple years before that. Also, your not paying much more for the hornady if you are worried about consistancy. If you don't want to pay more, buy several hundred winchester from the same lot.

I would at least stay with the same brand, I recently tried switching from Winchester to Hornady brass and it changed my POI by about 1 1/2".

Northsniper,

Have you checked neck thickness variation and weight variation of your hornady cases? I want to know if it is as consistant as people say it is. Someday my Fed GM match brass will be shot out and right now I would go with hornady over lapua due to cost. What do you think?

Don't jump on me gang, I know the stuff is expensive, but I am soooooo happy with my 300 Win Mag Lapua cases. Driving a ten year old truck allows me to indulge in this extravagance.

I use Winchester brass for my .300 Win. Mag. I usually buy 1,000 cases at a time of the same lot number.

But the truth is, I've tried different lots of Winchester brand .300 Win. Mag. brass at various times, and I can honestly say that I've never seen a difference in accuracy, velocity, consistency, or POI with the various lots. Maybe the next lot I tap into might contradict that experience, but so far so good.

All I do is neck-size the cases, trim to uniform length, chamfer, and deburr the flash holes. Nothing else....

AD

Allen,



In my 300 win mag I have only had 2 lots of winchester, and I didn't see differences between the 2. However, with my .270, I have seen a big difference in lots. With one lot I worked up to 58 grains of H4831 under a 140 grain BT with no pressure signs at all. With the other lot, my primers were flush with the botom of the case, there was an extractor mark, and the bolt was plenty sticky at 58 grains.



Yah, if you can get away with it, you certainly couldn't go wrong with lapua.

Sometimes manufacturers change their process and there are indeed noticable changes in weight. I noticed that with RWS brass in .222 (small vs. large lettered stamping) and with Norma in 30/06. Within one lot they seem to be very consistent.

Doesn�t hurt to check.

I think your approach is the correct one. Buy a bunch of new cases from the same lot for your "MUST WORK" ammo, and use the old cases for practice shooting.

If you use the same manufacturer, Weighing each case on a digital scale will help you gain consistency.


Good Luck!

Reloader

Allen,
Do you necksize right out of the gate? I was wondering about this and on some cases (new) I loaded a while back I decided to do just that. I figured the goal was to just round the necks out. However when I was seating the bullets (I loaded 15) I noticed a large difference in the amount of friction a was experiencing as I seated the bullets...felt like different neck tension. I am using the Lee Collet Die. Maybe I should have just run them up on the collet, but not all the way in .

Also, do you notice that you have to change your powder charge slightly between the brand new brass and the fired brass?

Thanks.

If you're truly getting into extreme accuracy, you should do several things.

First, with regard to the cases you have, you'll find that over time that brass can get brittle from pollution in the air. That may account for your perception of different tension on the necks. The older the brass the more likely it is a bit more brittle and less elastic than newer, protected brass. You can cure the disparity by annealing the brass.

As to the different lots, if you sort your cases by dry weight within about 1%, you'll never be able to tell the difference once you get the neck tension uniformed by annealing. You can then segregate what you do have by sorting them in different lots. You should likely do this anyway even with a new lot of brass, so use what you have.

With regards to the necks in new brass, you're always best of rounding them by running them at least partially into a die before you load them the first time.

If you are going for the extreme accuracy bit, you will want to do your trimming for case OAL after forming and before reloading the first time. After trimming you'll want to deburr flashholes which is easiest when all the cases are the same length. AFTER this is the time to weight sort the brass when you have them all uniform as to exterior dimensions.

I just faced the same problem with 170 7mmSTW cases a guy had collected through the years and who wanted them reloaded. They were good Federal cases. I did just as mentioned to you and he was able to get easy half inch groups when we were done.

. . . and, yes your velocity will vary between new brass and fireformed brass. You may have to adjust a slight amount, but seldom over .5g. New brass will be slower.

Follow Bob's advice to a tee and never look back. Those are the precise directions and counsel you should follow.

Thanks guys. It is nice to know I can get good answers that can be relied on.

Thanks again.

Bob338,
Thanks for the advice...I took it and have started but now I am kind of ticked off...not at anyone, but heres the deal. I started running my new brass (250 cases) through my Hornady full length sizing die. I get through about 50 of them and I notice they are scratching my cases something fierce . I dismantle the die, clean it and it has scratches all over in it. The first twenty or so cases don't show much for scratches but by case 50 (that is where I realized and stopped) they are scratched good.

I quit. Questions: Did I ruin the brass I scratched? Are the dies ruined? What did I do to cause this? Where should I go from here

Thanks.

The cases aren't ruined, they just won't look very good. You probably didn't clean them before sizing and some may have had dirt or other abrasive material. Take a bit of 0000 steel wool on the end of a wooden dowel rod and polish the die a bit, or take some 600 grit wet or dry paper in there. That should polish them back up, and next time clean your brass well before sizing.

Be very careful annealing your cases, unless you REALLY know what you are doing you will screw up more than you improve.