Case head stamps

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  • Last Post 07 January 2025
JeffinNZ posted this 01 January 2025

Bit of a long story.  Brace yourself.

We all know the old rule of running brass by manufacturer in order to minimize variations in internal volume and subsequent ballistics.  Basically, every manufacturer forms their brass slightly differently allowing for variances of case weight and internal volume between brands.  I have been running a batch of 25 Hornady Hornet brass.

Lately I have been working with my old pattern Lyman 225415 mold running linotype.  I felt my WW loads were topping out on pressure and wanted to try linotype as 1) it is stronger/harder and 2) casts the most perfect little bullets.  Fitted with Lyman brass GCs and powder coated with final sizing of 0.2255 the bullets were loaded over three different powders (Lil Gun, H4227, H4198) and three different primers (CCI small pistol, Win small rifle, Murom small rifle).  

Results were awful.  Patterns rather than groups and ES of velocity of 130fps.  Frustratingly 2-3 shots would land close then the remaining 3-2 shots (to make 5) would go 'west'.  

ES spread occurred over all primers so I ruled primers out as the issue but considered poor ignition due to firing pin strike issues.  On stripping the bolt however there were no issues; it looked like new.

Powder charges were consistent and weighed and much like the primers all powders were turning in poor results.

I began to doubt the bullet as the 225415 is 0.550 long and borderline for the 1-16 Hornet twist.  This is the reason I was chasing velocities of 2300fps plus to ensure stability.  

THEN, last evening I was loading some more test rounds and had 1 x Nosler case I wanted to use as a fouler.  Out of interested I weighed it then likewise weighed the Hornady brass to compare.  To my surprise the Hornady brass dropped 15/25 at 48gr and 10/25 at 56gr.  That's 16% variance!!!  All of the sudden the penny dropped.  The heavier brass has a smaller internal volume and was causing the velocity spread issues due to higher pressures/velocities.  This in turn was tossing bullets on the target.

Today I shot the same combos again with batched brass by weight and was rewarded with tight little groups.

The Hornady brass on close inspection displays two slightly different headstamps.  One is a little more bold than the other.  Obviously difference batches or third party manufacturing.

Live and learn.

Cheers from New Zealand

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Aaron posted this 01 January 2025

Anyone who runs a progressive press and uses scrounged range brass in 9mm, with 30 different head-stamps, can vouch for the “pattern” on the target. One can feel the differing force needed to size the cases among the varying cases.

I would have never thought to weigh the cases in the same head-stamp group. Great catch.

Today while loading 9mm on the Dillon, I did discriminate on those rascal cases with the thicker bases which have that visible step in the base of the case. That’s about a 5% reduction in case volume. That’s very dangerous in an “intense” cartridge like a 9mm.

Fortunately these loads are plinking loads, not match loads, hence the mixed brass.

For groups, I never mix brass and now will be sure to weigh scrounged brass with the same head-stamp.

With rifle in hand, I confidently go forth into the darkness.

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Ed Harris posted this 01 January 2025

For my match loads I always weighed and sorted brass after trimming to length and annealing. If this was done and rifle cases lotted up into +/- 1 grain batches, then headstamp didn't matter.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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BJung posted this 01 January 2025

Case head stamps make a difference. Not only are you dealing with a different volume, you are dealing with a different case wall that translates into a different neck tension. If the wall is not concentric, the bullet will release slightly differently.

I did a test over a year ago comparing .38 Special cases. The cases were the only variable. The result was that Remington brass grouped the best for that bullet and load. The other brass has varying sized groups. And, a test load using one of each brass had a group the size of all the other groups combined. 

 

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JeffinNZ posted this 01 January 2025

I would have never thought to weigh the cases in the same head-stamp group. Great catch. 

I wish I had thought of it sooner! Ed, as always, is on the money.

Cheers from New Zealand

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Carl Pegg posted this 02 January 2025

My son and I had a similar experience a while back working up loads for his .243 H&R handi-rifle. We had worked up to a mid range load of Varget with a Hornady 75 grain jacketed bullet using Hornady brass that was given to him by a friend. I looked over this brass by sight and measured lengths, but didn't think to weigh them. My mentality at the time was "we're not going to use max loads anyway, so why bother weighing cases, hell, this is a handi-rifle, not a bench gun!" Starting loads gave us no issues so we worked up to a mid range load and suddenly a case is stuck in the chamber. (This is an early handi-rifle with the ejector and they are known to be problematic. I have since converted this and several others to positive extractors.) I dropped a brass cleaning jag down the barrel which knocked out the case no problem but noticed the primer was noticeably flatter than the others we had fired, so we stopped shooting and pulled the bullets from the remainder of the loads and weighed the powder charges. All were OK. Then I noticed the headstamp; they were all Hornady, but there were two cases that had a slightly different font, one of them being the stuck case in question, so we weighed the cases and discovered those two with the "slightly different font" were about 20 grains heavier!!! In a bolt gun we probably wouldn't have noticed except with a chronograph, but the weak ejector spring gave it away. Lesson learned: when dealing with brass of unknown age, weigh it! I still don't think splitting hairs with case weight makes much difference in a sporting rifle, but it'll save your butt if you have cases that are grossly variable like these, and with Jeff's 22 Hornet that tiny case is really finicky!

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Brodie posted this 02 January 2025

Years ago, I was shooting a lot of off-hand with a 30/06 and I began wondering about the different capacities of the brass I was using, it was all old  WW2 and Korean war manufacture.  Once I weighed and sorted the brass by weight my groups shrank by about 2 inches.  It pointed out to me just how variable the capacity of different cases could be.  Now, when I want best accuracy I only load one brand of brass that I have weighed and sorted. 

B.E.Brickey

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JeffinNZ posted this 02 January 2025

Carl - So Hornady is the offender it would seem.

Cheers from New Zealand

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mhice posted this 02 January 2025

Carl - So Hornady is the offender it would seem.

No. All manufacturers are subject to case die and punch wear. It is about their acceptable tolerance at any given time/manufacturer location. Lot numbers are important but not the end all be all. Range pickup brass exponentially magnifies the issue due to being fired in different cambers, fluted HK cambers being one. Weight sorting is one way to manage brass. Case volume can be measured but it is a labor of love.

For the 22 Hornet, I know of only 2 manufacturers that still make the brass. Hornady and PPU. Hornady is way more consistent than PPU and lasts longer in my K Hornet. Besides, the 22 Hornet, K Hornet, and 17 caliber variants are obscure calibers least days. The masses should not base their choices of case manufacturer on a caliber of nostalgia, but I do love my K Hornet.

That being said, if I can get Lapua, Alpha, or Peterson brass for the caliber, I will. They are basically load and go! Hornaday brass always takes some work.

 

-Michael

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Bud Hyett posted this 02 January 2025

My uncle shooting 600 and 1,000 yard competition always weighed his cases and his results got me interested in doing the same. He claimed 6 grains of brass occupied the same case volume as one grain of powder. That weight difference could raise or lower pressure significantly causing vertical stringing. At 1,000 yards, the lower velocity could get you a nine or even an eight. I found this to be true, especially with the lower volume cases such as .22 Hornet and .30 Carbine.

The difference in the format of head stamps within a brand of cases I've noticed over the years, especially with the older cases manufactured in the first half of the twentieth century. Sorting cases first by brand and then again by the format of the stamp has helped reduce flyers.

My source of mixed headstamps was when I lived in Southern California and shot at the San Bernadino range, I traded Linotype lead for pick-up cases with the range master. There was a varying collection of cases, mostly .308 Winchester, .243 Winchester, and .30-'06. That was thirty years ago and I'm now starting to run low on .30-'06 cases. 

Farm boy from Illinois, living in the magical Pacific Northwest

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Wilderness posted this 02 January 2025

My sensitivity to case weights began with a .308. Bud's number for .308 is 6 gns of brass equals one grain of powder. Somewhere I'd picked up a figure of 10 gns. Either way, case weight counts, especially for something like .308 which has extremes between commercial and military. The lightest brass was early Winchester (WW Super), so data for this tended to be really problematic for military brass.

Fast forward to a few years ago and I was at first a bit indiscriminate with .30-30 brass, using whatever I could pick up. This was for LAS. That changed when I found, as I recall, about 100 fps difference in velocity between my lightest (RP) brass and my heaviest (PPU) using the same load in both. This was for the heavier Ram loads. In my Marlin 336A a 100 fps difference translates into a 2" difference in POI at 50 metres, or 8" at 200 - possibly more at 200 considering that the high shots are the faster ones. The first step in reducing the vertical stringing was to settle on one headstamp (RP) for that rifle. Weighing the cases and taking the tails off the distribution got into the act also. This certainly helped round the groups.

You are only as good as your library.

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Carl Pegg posted this 02 January 2025

No. All manufacturers are subject to case die and punch wear. It is about their acceptable tolerance at any given time/manufacturer location. 

mhice nailed it. I should've added that I think the fact that I had a similar experience with Hornady brass was purely coincidental. The real issue is that the two heavier cases had a headstamp that was obviously struck with a different die therefore indicating a different production run from who knows when. The lesson I learned was when somebody gives you a big ol' bag of brass, inspect it carefully (done), sort it by headstamp (done), and then weigh it for any outliers (Not done. Will do it from now on!)

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John Alexander posted this 03 January 2025

     There is no doubt that major variation in case volume can cause larger groups and even unsafe pressures.  Recently a friend, I was shooting with, blew the extractor off his Savage 30-06. The load was a maximum load recommended by major powder manufacturer which he had been shooting without obvious pressure signs.  When we poked out the case, it was a military case he had used to replace a lost case in the box of Winchester cases. He was relatively new to handloading and hadn’t realized that military brass is usually significantly heavier and thus smaller volume.

     However, for cases currently being produced by most manufactures, the variation in case volume WITHIN A LOT is less than one percent which is too little to affect group size.  

     Additionally, unlike case weights that vary 5% and up, trying to sort cases by weighing which vary in volume by only 1% and under is a waste of time because a lot of the weight variation seems to be in the base of the case which doesn’t affect volume.  This causes some of the heavy cases to have more volume than the average, and some of the lighter cases to have less volume than the average, the opposite of what one would think.  In other words, there is a very poor inverse correlation between weight and volume for cases from one lot.

     The theory supporting the claim that one percent is too small to matter depends on two things. One, Boyles Law says that a one percent change in volume will produce a 1% change in pressure. And two, chamber pressures vary about 10% from shot to shot and there is nothing we can do about it.  Fortunately, this apparently has little effect on precision shooting since Jacketed benchrest shooters often shoot aggregates under 0.2 MOA with chamber pressures varying 10%.  Thus, it is almost inconceivable that 1% variation in pressure caused by variation in case volume causes bigger groups. 

      The results of a study of case volume vs. shooting results supporting this theory were published in The Fouling Shot #276 March/April 2022.  The study involved measuring the weights AND THE VOLUMES of 12 lots of cases with 9 different head stamps in seven different calibers from 223 to 338.

 

Findings, 

     Recently manufactured cases from a wide variety of manufactures varied less than one percent in volume within a lot. Some lots older than 40 years varied much more.

     Two sets of cases were selected from a lot of 200 with one set having 1% more capacity than the other.  Twenty, shots were fired with each set using the same load and rifle on the same day. There was no significant difference in the average MV of the two sets. 

 

 John

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MP1886 posted this 04 January 2025

     There is no doubt that major variation in case volume can cause larger groups and even unsafe pressures.  Recently a friend, I was shooting with, blew the extractor off his Savage 30-06. The load was a maximum load recommended by major powder manufacturer which he had been shooting without obvious pressure signs.  When we poked out the case, it was a military case he had used to replace a lost case in the box of Winchester cases. He was relatively new to handloading and hadn’t realized that military brass is usually significantly heavier and thus smaller volume.

     However, for cases currently being produced by most manufactures, the variation in case volume WITHIN A LOT is less than one percent which is too little to affect group size.  

     Additionally, unlike case weights that vary 5% and up, trying to sort cases by weighing which vary in volume by only 1% and under is a waste of time because a lot of the weight variation seems to be in the base of the case which doesn’t affect volume.  This causes some of the heavy cases to have more volume than the average, and some of the lighter cases to have less volume than the average, the opposite of what one would think.  In other words, there is a very poor inverse correlation between weight and volume for cases from one lot.

     The theory supporting the claim that one percent is too small to matter depends on two things. One, Boyles Law says that a one percent change in volume will produce a 1% change in pressure. And two, chamber pressures vary about 10% from shot to shot and there is nothing we can do about it.  Fortunately, this apparently has little effect on precision shooting since Jacketed benchrest shooters often shoot aggregates under 0.2 MOA with chamber pressures varying 10%.  Thus, it is almost inconceivable that 1% variation in pressure caused by variation in case volume causes bigger groups. 

      The results of a study of case volume vs. shooting results supporting this theory were published in The Fouling Shot #276 March/April 2022.  The study involved measuring the weights AND THE VOLUMES of 12 lots of cases with 9 different head stamps in seven different calibers from 223 to 338.

 

Findings, 

     Recently manufactured cases from a wide variety of manufactures varied less than one percent in volume within a lot. Some lots older than 40 years varied much more.

     Two sets of cases were selected from a lot of 200 with one set having 1% more capacity than the other.  Twenty, shots were fired with each set using the same load and rifle on the same day. There was no significant difference in the average MV of the two sets. 

 

 John

 

John I couldn't agree with you more. An analogy. Take an automobile engine.  Which do you think would run better, one where all the cylinders have the exact same volume or another there they are mixed match? Again which would run better, one where the compression ration is same among the cylinders or the other where they are mixed?  We know the answer to that.  

 

I remember an article where a write visited Hornady's case making plant.  The Hornady representive took a case that was finished, except for stamping the head and cutting the extractor groove, off the line. They weighed them and the variance was only .3.  Then they proceeded to the end of the line where the cases were completely finished and weighed a few. They were far on the left of the decimal point. The representative said "That's the problem we've been trying to solve and eliminate".   

 

In my opinion placing weighing cases over measuring internal volume for accuracy is foolish. You explanation was very good. Military cases have thicker case walls. The brass is also softer initially, but age and repeated shooting and reloading them will make them harder.  I've sectioned enough of them to find the thicker walls.  I will say that wall thickness on military 5.56 and commercial 223 are much closer then 7.62 NATO and 308 commercial, and WW2 30-06 and commercial 30-06.  For years they wrote in reloading manuals to reduce loads for military cases when using them over commercial cases. 

 

I know a friend of a friend that is a match shooter for accuracy. He has more money in his rifle rest then the rifle. He's was stuck in a certain bracket of accuracy until he started measuring case volume. He made a tool, which he was going sell and never did, to measure the volume. He used alcohol for the measuring fluid. I asked him why alcohol. He said you don't have to deal with drying the cases when using water.  Anyway his groups dropped dramatically. 

 

I know that measure volume is as boring and slow as turning necks. Most of us don't do it. I certainly don't do it for loading regular plinking ammo.  Then again look at how many of us weigh our cast bullets.

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M1fuzz posted this 07 January 2025

Nothing wrong with HK brass. The brass does not “melt” into the chamber fluting. Clean it resize it and go. Have done it in 9mm, .223, and .308. It is carbon scoring anyway. My PPU brass has been very consistent and very long lasting. In fact the only rifle brass I use for my military rifles in the cast bullet game is PPU and Starline.

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MP1886 posted this 07 January 2025

Nothing wrong with HK brass. The brass does not “melt” into the chamber fluting. Clean it resize it and go. Have done it in 9mm, .223, and .308. It is carbon scoring anyway. My PPU brass has been very consistent and very long lasting. In fact the only rifle brass I use for my military rifles in the cast bullet game is PPU and Starline.
Sellier Bellot brass is damn good stuff too.  I would prefer it over PPU, but PPU is more available and pretty decent.
The HK fluted chambers don't ruin the cases, just not pretty and they are dirty. 

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