Different brass strength between batches?

Hi team,

Bought 2x50 boxes of Hornady brass the other day for trying out 90gr eldx for my .243. Did a ladder test from 2gr under to 1 over ADI max loads, all ok to me, small crater around primer and slightly flattened, but it was doing the same from 2gr under max load. (Federal match primers and ar2209) All brass was FL resized from New. Settled on 44.5gr, as it should get me 3100fps.

Loaded 50 to sight in and give some turkey a hard time, in this 50 there was 20 bits of brass from the next box, a different batch.

While sighting in a round gave me a slightly stiff bolt, good extractor/ejector marks, indicating high pressure?? Trade another, fine, then pressure sign, primers all looked similar.

The only variable is the brass? I checked the boxes and they were definitely from different batches. Is it a case that I need to find a load safe for the soft brass? Or ditch the soft brass? How us/safe is it to shoot the soft brass?

Thanks Lars

Attachment 146035

I personally think the primers on both cases are ok as far a flattening goes, though there is small amount of primer extrusion on the middle case. The brass could be softer in some but I would also check case capacity (and weight) of the two batches. Small variations can have reasonably significant effects if you are close to max.

Quote:

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Originally Posted by Larrygoat

Settled on 44.5gr, as it should get me 3100fps.

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You might find it's a fair bit faster than that, depending on barrel length.

42.4gr of AR2209 gets me 3140fps. 90gr ELD-X, Federal 210 primer, Norma brass, 24 inch barrel.

Greetings Larry Goat,
Yes that one on the right is way too hot and I suspect the middle one is as well. The Hornady 90 grain ELDX is a long pointy projectile and the Hodgdon/ ADI data is worked up with the Speer 90 grain spitzer flat base and this is old CUP data not PSI. When the pressure measuring system was changed the .243 max pressure was lowered due to erratic pressures in the .243. Your ELDX projectiles are likely seated deeper due to the mag length so case capacity is less and pressure is higher. It is also possible, likely even, that your AR2209 is significantly faster than the batch used by Hodgdon to work up their loads. I found this in my 6.5 recently and Cigar above is matching book velocities with 2 grains less powder. This is exactly what I found. I don't think your cases are the problem, your loads are excessive. 42.4 grains matches the Hodgdon data for the 85 TTSX and the 95 grain Partition. A chronograph would have warned you that you were too hot. Sorry to give bad news.
Regards Grandpamac.

Greetings Again,
Just checked some of my old load data. The load of 44.5 grains of AR2209 for the 90 grain Speer for 3,185 fps appears in the November 2000 ADI Guide. This is before the increase in powder speed. Cigar is spot on and you need to cut your load by 2 grains to get back to safe pressures.
Regards Grandpamac.

Grandpamac, that load is also currently on ADI's website, so its possibly a case that the ELDX are harder to push down the barrel? Either way ill pull and reload lower, I'm not that set on blowing myself up.

Thanks Lars

Just saw yore first post grandpamac ignore my last.

Quote:

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Originally Posted by Larrygoat

Grandpamac, that load is also currently on ADI's website, so its possibly a case that the ELDX are harder to push down the barrel? Either way ill pull and reload lower, I'm not that set on blowing myself up.

Thanks Lars

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The load is also on the Hodgdons website. Hodgdons does all the testing and load development for the ADI powders. It is a bit remiss of Hodgdon in not updating the data when the powder speed has increased to that extent. I did a post a while back on my findings with different AR2209 lots and also an article on NZ guns. Others have found the same speed change. When you compare the data for the 85, 90 and 95 grain loads the 90 grain ones stick out like a shag on a rock. The 85 grain load for the TTSX was lower as expected for the hard Barnes projectile and the 95 grain load (also slower powder) was 2.5 grains less than the 90 grain load. There is an awful lot to learn about handloading and I am still learning after 50 years.
All the best,
Grandpamac.