Accuracy Issues When Switching Brass?

[PredatorDown]

Has anyone had any issues when switching between brands of brass? All of my old Hornady brass is starting to drop off quickly (loose primer pockets after 10-12 reloads), so I recently ordered a couple hundred Lapua since it's supposed to be a lot longer lasting. My old pet load with my Hornady brass is 30gr of BL-C(2) pushing 123gr Amax's at 2490fps.

Yesterday I went out to test the Lapua against the Hornady side by side, and was quite surprised at the results. I shot two 5 shot groups with each brand of brass, and the old Hornady grouped noticeably better than the Lapua. Hornady was 1.25" and 1.5" at 225 yards, while the Lapua brass shot 2.5" and 3". Everything was the exact same except for the brass. Same case length, same primers, powder, and pills.

Ok, I decided maybe it was something with shooting virgin brass. I had heard that your best accuracy will come after it's been fired and reloaded, even though I full length sized them before the initial loading. Today I loaded up 15 rounds with each respective brand of brass and went out to another location to try my hand at 1000 yards.

I set up my 16" gong and fired the Hornady brass first. I finally made contact on shot 5 (top left), missed 6-7, hit 8 9 and 10 in the nice little group on the lower right, then the last hit was 13 on the top right. All of my misses after my first two sighters looked to be within a couple inches of a hit.


I drove down and painted the target, then set up with the once-fired Lapua brass. I hadn't dialed the scope at all since shooting the Hornady, but I figured I should still be pretty close. My first shot was about 10' to the right and 5' low. Ok, there was a variable 8-12mph wind, so I thought that could have caused it. I dialed in, and the next shot was a foot to the left and elevation looked good. I was only able to hit the dang thing on shots 9 and 13, with several flyers throwing me way off.


I'm completely at a loss as to what is going on. I didn't think that the brass would have that big of an impact, but that is the only thing I can figure. They were all loaded in the same session, powder weighed to within .02gr...I'm just not sure what it is.

I'm signed up for a 1000yd Milk Jug Challenge hosted by the Long Range Shooters of Utah on the 11th, so I'm trying to get as much practice in as I can before then. I'll have 10 shots to hit a milk jug at 1000 yards. Nobody in that group has done it with an AR-15 to date, and I'm hoping to be the first. They've had one do it with an AR-10 in 260Rem, but that's the only non bolt-action to do it. I've hit several at 1000-1200, just not at one of their "sponsored" shoots.

Any and all help is appreciated!

[LR1955]

PD:

Paint a milk jug on that steel with the background being that which you will be shooting.

Get a good observer with a decent spotting scope who knows what he is doing so can record your shots verses your calls and the wind.

Load twenty rounds with each brass.

For the first ten rounds of each brass, let your observer load your rifle so you don't know what type of brass you are firing.

Let him give you a wind call and you give him a good call on your shot. He will record where each round goes with the brass type.

Do this for ten rounds of each brass type and then look at his data card(s) to see if there really is a difference and if so, which load shoots tighter.

For the load that shot the best, fire ten rounds yourself without your observer giving you wind calls. Your observer will keep the log book and you tell him your hold and call so he can record what you did along with your shot and his own wind call. This way you can check your wind calls with his and also see if any hits on your milk jug target were simply random or were deliberate.

Sure, you did the best you could but you need to know if you are depending totally on luck or not to succeed.

LR1955

[Klem]

PD,

No doubt the different neck tension and case volume between manufacturers will influence velocity but my thoughts are that you may be coming to conclusions too soon.

You fired two 5-rd groups of new Lapua at 225yds at the same point of aim (yes?).
You then shot 13rds of once-fired FL sized Lapua at 1,000 adjusting for wind/impact each time (yes?).

When doing a comparison you need to eliminate as many variables as possible so that the only variable left is the difference in brass manufacturer. Your results at 1,000 must be discounted as you did not shoot at the same point of aim each time. 'Chasing the spotter', or in other words adjusting each shot according to where the last one impacted is what you have to do to get as many impacts on the gong but that string is not a group. You need a bigger target at 1,000 to compare both brass manufacturers and keep the same point of aim and same conditions. Probably better to stagger the shots; one Hornady, one Lapua, one Hornady (etc), so as to share variations in wind and barrel temperature (and therefore eliminate these variables as much as possible).

That leaves the 10rds each fired at 225yds. Not a lot of rounds to come to the conclusion that Hornady brass is better suited to your gun. It may well turn out to be true but worth shooting a few more rounds before being confident about it.

A couple of questions;

Is your full-length sizing back to SAAMI or do you size 'full length' back to less than SAAMI for your chamber?

Is there an opportunity to chronograph the difference in brass manufacturers?

Did you size the new Lapua's at 225yds or load them straight out of the box?

[wraith1516]

If you don't like them I'll be glad to take them off your hands mine loves lapua

[sneaky one]

Lots of issues can pop up on the 2 brass manufes. Neck tension, due to brass thickness, etc.

Hornady is basically the upgraded wolf crap brass. I bought a 50 pack years ago, when it first came out.,, 7 loads on each was the max.
Lap- AA -is Lapua brass= the best you can get -for now, it's awesome. 20 + reloads.
Yes, I noticed the accuracy was same as Lapua! What the ?

Nosler brass, will be determined soon, as per quality.

We all need to push against, And On to, the manufes on making more Grendel ammo-- reload components , etc.

It's GO time, before the next oops, public school type of shooting takes place. Let's get what we want, while we can. Spend a few extra bucks to line the safe with goodies. Don't hoard, tho.

[PredatorDown]

Great advice here guys! Glad to be a part of such a knowledgable group.

Unfortunately I won't be able to do much more testing before my challenge, but I will be sure to hit it hard afterwards to get things figured out. I Really need to meet more people around my area that shoot long range, nobody I currently shoot with does.

I also need to restock my supply of 123gr amax, I'm down to my last box of 100 right now. got plenty of powder and primers, just need to build up my supply of pills!

[Klem]

This is what I am talking about relating to one of my questions...Did you load straight from the box of new cases without sizing first?

Uncle Klem learned his lesson the hard way. Got lazy and thought that seeing they were all new and shiny and fit into the rifle gauge they must be sized, right?...WRONG!



Fired a few 4rd gps at 100yds and was wondering why the first round of every group was going 6 O'Clock low. 4rds per mag and it took me while (getting old). It's related to velocity and the only difference was that the first round was hand cranked into the chamber while the remaining 3 were getting more violently loaded by the self loading action. Bullets must be shifting forward and jamming in the lands...higher start pressures and hence the higher sub-group.

I did some measuring with the micrometer and confirmed as much.

Moral of the story...New Lapua brass out of the box does not have enough neck tension for our platforms.

If you did similar then it might not be so obvious and a vertical stretched group would make you think your Hornady's were better. Regardless we need to be mindful of neck tension with different brass. Lapua has pretty thick necks around 0.013". It also has a reputation for being very good quality.