Home Forums Reloading Big Game Rifles How does Different brass affect accuracy ?

When switching from one brand of brass to another, all other load components/measurements the same, how does/can it affect group size,etc..?

Different case capacities = diferent pressures!
Neck runout and tension will change accuracy!

I have solved a couple of shooters grouping problem by sorting their reloads by brass mfr. Suddenly a real shooter appeared.
jmho
Tim

hmmm...guess i better hold off loading anymore til i find out how these PMCs are gonna work compared to RPs

I have a Ruger MKII 30-06 that WILL NOT group worth a damn using R-P cases; switch same load but Win cases: sweet! From 2.5"-3.0" to .75"-1.25" Go figure.But there it is.

I have a .223 bolt gun that strongly prefers Winchester cases, but other rifle that I can't detect a difference between brands. You won't know till you try.

deg967, which PMC case do you have? I have a lot of them myself.

If you are mixing brass or working up loads with one brand then switch to another, expect different results within certain accurcy and pressure standards.

Your rifle may shoot very good with one brand of brass, switch to another and it may be like you are shooting someone else's rifle.

Shooting the same load between commercial brass then using the same load in military brass may spike pressures for sure.

You don't know, till you know.

Generally Winchester brass has the thinnest hardest necks so if you have a tight necked gun it may work better, if loose Remington or Federal may be the winner.

If you want to get anal, do a chamber cast and match the brass to it.

In general Norma, Nosler, Lapua and US Natl Match Brass is superior to regular factory stuff.

Unless you're shooting small varmints at long range, almost any factory ammo is accurate enough for big game.

$14.00 a box ammo in a Ruger #1 with a 2-7 Leupold. Would kill anything it is suitable for.

Kieth,
I worked up a load that shoots 1/2 - 3/4 inch using range brass I picked up(RP). I got 120 PMC Silver FACTORY rounds in a trade and pulled 20, dumped the powder and loaded with what I worked up. NOT sure of primers used in the factory stuff and Dont know the safe way to remove them to replace with the Winchester primers I used..This could be QUITE a different trip to the range than the last..all I can do is see.
If things dont work out I'll have 5 Factory boxes of The Silver PMC with 130 GameKings up for sale..(I am using 110grain TTSXs)

I havent aquired the knowledge or tools to measure chambers and such...I suppose measuring the case neck before and after would do it though huh?..(duh) funny how things just come to my feeble mind

I have done some testing with different brass cases of different manufacturers, all other components were the same. If you change the case you are going to change the pressures and the harmonics of your rifle with said load. I don't necessarily believe that one brass is that much more accurate than another,but I saw that a couple of different cases would group about the same. The only reason I was checking was to find out if any of them were interchangeable. I has some Lapua that did not group well with the charges used, that does not make that brass inaccurate, it just meant that I would have to change some components.

I learnt the hard with my 260rem a little while back. I had been shooting Lapua brass and it did shoot wonderfully well, however given the pain in the ass it was to neck up from 243 I switched to RP cases for a hunting trip. Turned out the new remington brass had the same bullet shooting four inches high and three inches to the right. I should've known better, I certainly do now.

I am a self confessed doofus sometimes.

Oh, the R-P brass mentioned earlier? Works just fine in my No.1B
30-06. Geez, damn rifles are like horses sometimes; can't figure 'em out.

I suspect that how accurate a particular brand of brass is in a given rilfe has a lot to do with how the rifle's chamber and the neck thickness of the brass matches the die you're using. I have a .308 that dotes on WW brass sized in a garden-variety RCBS FL die. Just so happens that I get the perfect amount of shoulder bump (zero) with the die just touching the shellholder, and the neck thickness is such that the expander ball just barely kisses the inside of the neck on the way up.

This gives me very straight cases and close to zero runout on loaded rounds, with no shoulder bump.

Lapua brass is another story with that combination. The expander ball is a much harder pull and runout is not nearly as good as with the WW brass. And it's not as accurate as WW. No way WW brass is "better" though.

Of course, it could be the difference in case volume too.

It's both. Been there and checked that.


BTW, how do you lube the inside of the case necks?

Spray one-shot from 4 directions, angled down in, and hit the expander ball and one in 10 necks with Imperial.

Maybe I need to try something new.

When I FL size with a ball in place, I use the water soluble RCBS lube. I lube the inside of the necks with a cotton swab, being sure to coat a bit of the shoulder just below its junction with the neck. Where will the ball make first contact on its way out, right?

They size straight and smooth, even though there is more resistance with thicker necked brass. A hot soapy water bath with neck brushing, hot water rinse, a shot of compressed air and a short ride in a 250 degree oven and they're ready.

I've found that when I've gotta run a ball with more than a thousandth or two interference, short cuts and "no remove wonder lubes" don't get it done for me.


BTW, how do you get the Imperial out of the necks? Besides, if I treat one neck a given way, then they all get the same treatment. I want consistent seating and bullet release.

mathman,

What you're describing is exactly how I do it. Steaming hot water and Dawn dishing liquid desolves all traces of lube.

I've also found it helps prevent the brass from tarnishing during long term storage by getting it squeaky clean.

I blow it down the barrel when I shoot the round. Seriously, I just run a brush in/out, which is not good for removing stuff, I know.

Maybe I'll have to give your method a try. With Redding Bushing dies, it's not hard to get the right interference, but they don't make 'em for everything in the safe.

On mixing brass or changing cases: the group size may mean nothing if your point of impact changes to an appreciable degree.

Its akin to having a 1/4 min shooter after three fouling shots...