Brands of brass

[treebranch86]

I just started reloading within the last month and I observed when shooting my .270 reloads that the group I shot with Hornady brass was about an inch higher than the group i shot with Federal brass. Both groups were under 1/2 moa at 100 yards with the Federal brass group being slightly better. The powder charge was the same. I also noticed that the Federal brass was significantly heavier than the Hornady brass when weighed. I am curious if the brand of brass was the reason for the different point of impacts or should I be looking in a different direction?

 

[jonbearman]

The heavier the brass equates higher pressure.Putting the same amount of powder in a smaller space makes higher pressure.

 

[treebranch86]

Okay I understand. So this higher pressure would result in a higher velocity correct? If so why would the federal brass group be the group that shot lower?

 

[fullersson]

If the different groups were shot on the same day, at the same time, and in the same conditions it is safe to say that the poi difference came from the brass (assuming same powder, primer, charge weight, and bullet). The case capacity does affect pressure which affects velocity, but in my opinion what happened to you has to do with barrel harmonics more than velocity changes. POI changes at short range with minimum pressure and velocity changes can be caused by barrel harmonics. This is just my opinion and it could be that you just had different neck tension for the different types of brass. Hope this helps.

 

[LRPV]

The brass I use for 22-250 hunting differs 100fps +or- with the same load using Remington or Winchester brass. Both shoot good groups but different POI especially past 100yd. For what it's worth. Jason

 

[RonAKA]

You could fill a few of the cases for each brand with a fine powder level to the top of the neck and weigh it to see if there is a difference in case volume. Some sort their brass based on volume.

 

[treebranch86]

Thanks guys, it makes sense. I was shooting a factory steyr sbs with a light sporter barrel so I imagine harmonics would create a larger variance in the lighter barrel. I also realized that with one brand bullets seat easier than the other, so neck tension could also be a variable.

 

[wapiti25]

You can find that brands of brass made at different times can make more change than you think. Light weight barrels are more sensitive to EVERYTHING. As mentioned before hardness can change things, Keep your brass in groups or lots and you will be happier.

 

[Larryh128]

Everything being equal, neck tension is a big deal & I've never seen 2 brands of brass have the same amount. On hunting rifles I use only 1 brand of brass per caliber, makes life easier.