Reloading--What cases have to do with it?

[usmc69]

A friend of mine thinks that some rifles like certain manufacturers cases over others. We are testing this theory in my rifle. Using a load and bullet that the rifle shoots extremely will, we are using batches of different cases as our variable. So far our best groups are with PMC cases. Hornaday is a close second.

[charlie b]

A common issue. Usually related to how different mfg cases are different volumes and some do not have consistent volumes.

My experience shows that sometimes it means a lot and sometimes not so much. When shooting for absolute accuracy I will only use cases from the same mfg. Some will go to the trouble of measuring the volume and weight of the cases as well. Just depends on how accurate you are trying to be.

FYI, using the same load with different cases will give slightly different velocities as well. If one setup happens to be at the vibration node of the barrel and the others are not you will have a more accurate load, not because those cases are 'better' but because the load and volume matched up. The other cases might do as well if you varied the powder charge to get the same velocity.

That is why it might seem that a rifle will "like" a certain brand of case better than another.

[6mmBR_Shooter]

Some competitors sort cases by weight because in theory it should be a good predictor of internal case volume (which as mentioned above will cause pressures to differ, thereby affecting velocity among other things). While you are testing your theory, I would offer up to take a few cases from one manufacturer that are very close together in weight. Run those on target through a chronograph and see those results.

For my F- Class loads I don't weight sort because I use the same headstamp, fired the same amount of times, from an already known good brass manufacturer (Lapua, Norma, Starline, etc). The gun may shoot well with mixed brass, but until you work to eliminate variables you are not reaching the full accuracy potential of the load and rifle.

[Stumpkiller]

Different capacity[pressure], different neck tension, different neck thickness [which can alter bore alignment], different manufacturing consistency.

Some rifles definitely will favor some cases over others.

[usmc69]

Thanks for the info.

[Coyote_Hunter]

usmc69 -

Be VERY careful switching cases on max or near max loads without working the loads up for the new case. "Very careful" as in "don't do it". Internal volumes can vary enough to make a load that is safe in one brand unsafe in another.

[jim_k]

Here are the two most useful test results I got. I loaded 10 Hornady 6.5 Creedmoor cases with a load that was on a node, using QuickLoad and barrel time. I also loaded 10 Lake City .308 cases that I resized to 6.5 Creedmoor, likewise on a node per QL and barrel time. Both loads used the same bullet at the same node with the same powder, although the powder charge was slightly different, so as to be on the node. No case volume measurements were made. One group was 0.69" and the other was 0.70". Next test was 9 cases of the same brand (Lake City .308 Win). I measured the capacity of 60 cases, and found the median capacity and the extremes of capacity. There were only 9 cases at the extremes (4 of the lightest and 5 of the heaviest by water capacity), so I only loaded 9 of the ones that were in the dead center, and which were all the exact same measured capacity. Both 9-round samples were loaded with the same proven good load in the test rifle. The groups were fired indoors on the same trip to the range, and the barrel was fouled before shooting the test. Time was allowed between 9-shot strings for adequate barrel cooling. One group was 0.706" and the other was 0.712".

[mikeinco]

pretty much a useless test.
your VARIABLE has variations
you need to develop a load in EACH make of case.
same bullet type of powder and primer..but case volume will vary so powder must be adjusted.
so without testing, yes you will get different results

[usmc69]

We are loading H335 25.4 grains with a Sierra 52 gr HPBT.

[bigedp51]

We are loading H335 25.4 grains with a Sierra 52 gr HPBT.

What cartridge are you testing? I'm guessing a .223/5.56

[usmc69]

Savage M11 in .223. Wish it was a 5.56.............

[bigedp51]

I buy once fired Lake City 5.56 and 7.62 brass, it is very uniform and made of harder brass in the base. My Savage .223 has a 1in9 twist and has a longer throat than my AR15 rifles.

https://i.imgur.com/4kXrGuI.png

https://i.imgur.com/LjAQ7L9.jpg

https://i.imgur.com/PExmCCk.jpg

[charlie b]

Savage M11 in .223. Wish it was a 5.56.............

You might check and see but my Axis in .223 chambers 5.56 just fine. Still plenty of bullet jump to the lands.

[charlie b]

pretty much a useless test.
your VARIABLE has variations
you need to develop a load in EACH make of case.
same bullet type of powder and primer..but case volume will vary so powder must be adjusted.
so without testing, yes you will get different results

Not quite. He demonstrated that different mfg cases had basically same group size with same load. Maybe he got lucky and the Hornady cases happened to have same volume as the Lake City resized cases, but, it is not a useless test.

[yobuck]

We are loading H335 25.4 grains with a Sierra 52 gr HPBT.

What are you loading for Stick Marsh? Lol

[bsekf]

Read about the Houston Warehouse, in the interview, Virgil's last comment "the secret is in case preparation".

[usmc69]

No, just punching holes in paper.

And at the moment all is on hold. Small thing called Dorian messing up things.

[eddiesindian]

I buy once fired Lake City 5.56 and 7.62 brass, it is very uniform and made of harder brass in the base. My Savage .223 has a 1in9 twist and has a longer throat than my AR15 rifles.

https://i.imgur.com/4kXrGuI.png

https://i.imgur.com/LjAQ7L9.jpg

https://i.imgur.com/PExmCCk.jpg
Plus 10 on lake city brass. Turning necks and annealing once fired brass has been my go to brass for years. Consistency and longevity

[nksmfamjp]

Just my opinion, I think you take your current proven load and recreate in 5 increments....ex. Proven load =45.0 gr so, load 44.4, 44.7, 45, 45.3, 45.7...you choose the logical increment.

Then buy 25 or more new brass of each type/brand and your current brand.

Load 5 of each to your current load. Pay special attention to setting up your dies to give you the same CBTD and CBTD. Also, it is worth trimming and chamfer/demurring. If you can, confirm your neck runout and bullet runout while loading. When shooting, it is best to capture each string of 25.

[Three44s]

While I most certainly group my head stamps and keep them separate I am a firm believer in case prep.

I trim with a Wilson trimmer on the initial pass.

I also cut primer pockets and debur the insides of my flash holes. On occasion I also outside neck turn.

I will select a particular batch of brass and run with that in working a particular load for a rifle. After I have tried a few combinations and if things are not coming along well I generally switch to another batch of brass and start over.

Now life and shooting are rarely in a vacuum and so along the (generally with a new to me rifle) I start looking at changes to the gun. Granted I change one thing at a time but we are still “spinning plates” here.

If I find something aggregious with the rifle I will revisit load ranges that previously held some promise after the gun issue is fixed.

Three44s