Pressure signs ???

[Metal god]

I worked up a few loads of 308Win recently to stockpile. Yesterday I went and shot them in my other rifles of the same cartridge to be sure they function and are safe.

All these cases were fired in different rifles than the one I worked the load up with. I'll add the three cases on right are fired in a different rifle than the ones on the left.




The cases with red marks are the same different rifle as above.




Not sure if you can see it but the primers in red or the three on the right above have waves in them as if there was metal flow but no cratering. The others look OK but have a crater here and there. These primers are new-ish to me and I don't have a good idea to there hardness. I've loaded for years and rarely see cratering but I've almost exclusively used Win LR primers. I'm seeing cratering with these CCI's much more often than the Win. To be fair to each, I don't think I've overlapped loads, meaning all my Win primer loads are different than my CCI primer loads so it could just be I'm loading the CCI's too hot ???

[Marco Califo]

My understanding is that the CCI #250 and #450 have thicker cups (and are magnum primers). You don't "need" magnum primers with extruded powders, but I don't think they hurt anything.
I do not think the pictures show anything out of normal. But, after peircing a few #400 in 5.56/223 I will only buy magnum 223 and 308 primers, and use them in semi-auto and bolt guns.

[Metal god]

I should add that the two rifle used in the above tests were a Ruger American Rifle and a PA-10 semi auto . I'm bringing this up because the PA-10 did have a few ejector smears , not all cases but there were a couple I saw . I'll add for what ever reason the PA-10 "seem" to leave ejector smears with charges I know shouldn't be over pressured while I was doing other load workups with that rifle . Not sure how important that is but thought I'd mention it .

[HiBC]

H-335 shines with 55 gr 5.56 loads. Without looking it up,intuitively I'd guess it to be too quick for 150 gr 308 loads.

I don't put much stock in reading primers.But I do look at them.

On your h-335 loads I notice that corner radius is squared off.That may indicate pressure....

On your 8208 loads the only thing of note is the crater ring on the one upper left case.I might look into why that happened, Why just that one? Might it have cooked too long in a hot chamber? I'd try to figure that out.
I can't look at pics of primers and pronounce your load safe.Besides the one ring,I saw nothing alarming Note the corner radius at the OD of the primer is still pronounced.
Its more flattened on the H335 loads.

I'm not proclaiming anything. Reading primers is not a reliable pressure indicator.

[tango1niner]

Military brass is thicker and has less internal volume. I remember reading that max loads should be reduced by 1 full grain when using military brass.

I notice some " ejector smears " and as HiBC mentioned, the radii on the edge of the primers is changing a bit which could imply the pressure is getting up there.

[mkl]

You might try measuring the case rim with a micrometer before and after the shot. Before better methods were available Speer increased the powder charge until they got .001 inch rim expansion, and then reduced the load by six percent and called that maximum in their manual.

[Unclenick]

That's probably how Speer's older data came to be known for including some hotter loads than were reasonable in some guns.

Both primer and case head expansion as pressure signs tell you for sure only that the pressure got too high for that primer or that case. And by "that case" I mean, that individual case. Denton Bramwell measured case head expansion in same-lot, same-load-history pieces of 7.62×54R and has one case expanding only about 0.0001" at 65 kpsi while another did the same expansion at 48 kpsi and still another expanded 0.0004" at 58,000 kpsi. I don't know a reason to think primers are any more consistent than cases are in this regard.

7.62 military brass is often lower in capacity than some commercial brass is, but not all. The new (relatively) ADG commercial cases are made with extra thick brass and extra-hard double-struck heads for reloading durability, and the maker cautions you the internal capacity is low for that reason. In .308 W, ADG measures about 54 grains water capacity for the ones I have, matching the findings in the review on their site. Military 7.62 brass seems to run 55 or 56 grains a lot of the time. I have some older (15-20 years), Winchester, with 59-60 grains water capacity. That may give you some sense of the common range (but watch for outliers in the less common headstamps). Because head dimensional differences (diameter, rim thickness, extractor groove dimensions, extractor forward relief angle tolerance) can bring up to 7 grains of weight difference in cases without affecting the internal volume, case weight alone is not a precise indicator of internal volume. You just have to measure a case's water overflow capacity to see.

Other military brass is not as different from commercial as 7.62 is from .308. Most .30-06 commercial brass is within half a grain of water capacity compared to the LC I have, excepting some Winchester (especially older Winchester) which is more like one grain more capacious. In 5.56 vs. .223, it is the other way around, and Lake City has to greatest volume, as shown in the third table about 1/3 of the way down in this article.


MG,

The lower photos make the primer look a bit unhappy. Knock 5% off and change to a magnum primer and work back up to see what happens.

I'll point out that H335 is canister grade WC-844. BL-(C)2 is canister grade WC-846. WC-846 was developed during WWII for loading .303 British for our the Allies using it, and was later adopted by the U.S. for M-80 Ball ammo that became 7.62 NATO. WC-844 is the same powder but with a lower surface deterrent concentration. Depending on whose history of the development of 5.56 you read, WC-846 was tried in the AR design and proved too slow for it, but a faster burn rate version of the same powder (less deterrent) proved successful in 5.56 and was designated WC-844 to prevent confusing the two burn rate versions. But the bottom line is that BL-(C)2 is the version normally used in .308/7.62 with 147-grain bullets and, up to a point, heavier. BL-(C)2 does like a magnum primer, so you can make both adjustments and be reasonably sure it will work out.

[Metal god]

Not sure if I can find mag LR primers locally. Are they on the whole thicker cupped ? Why are you suggesting the magnum primers ? Is it that they will handle the pressure better or they will ignite the powder more consistent resulting in less likelihood of pressure spikes ?

Is BL-C2 the same as H-335 just harder to ignite or is the harder to ignite part slow it’s burn rate . Sorry I had Some trouble fully following that paragraph .

When I looked at H-335’s burn rate it looks to be in a good spot for 308 fit mid weight bullets . I don’t consider 150gr heavy for 308 but rather pretty much dead center weight wise for the cartridge??? It’s the lightest bullet I shoot in 308 and I go as high as 200gr with 175 through 190 being my sweet spot . I wouldn’t likely try H-335 with anything heavier then 168gr .

[Marco Califo]

They handle pressure better.
In fact I have lost confidence in CCI regular rifle primers of either size for 5.56 and 7.62. The #41 and #34 CCI primers are magnum primers.

[Metal god]

I did some case volume tests because the cases I used were different than the ones I work the loads up with. As far as I can tell the new Lake City 17 cases have an average larger case volume of .7 grains . Well that negates my thinking that I had higher pressures because of the case change.

[jmr40]

According to my sources you're almost 1 full grain over a max load with the 178 gr bullets and about 1/2 gr below a max load with 150's. I don't use a lot of military brass, but when I do I stay with mid level loads.

Over pressure signs don't show up until you're significantly over loaded.

This is where I like a chronograph. I'd expect about 2750 fps with the 150 gr load. Anything over that is probably overloaded.

You should be around 2500 fps with the 178 gr bullet.

[Unclenick]

Originally Posted by mg

Is BL-C2 the same as H-335 just harder to ignite or is the harder to ignite part slow it’s burn rate

In spherical propellants, the burn rate is controlled by the deterrent concentration and penetration, so H335, with less of it, burns faster than BL-(C)2, even though it is otherwise made by the same process.

One source of load history for 5.56/223 I read (I've forgotten which one, but I didn't find the same description in others) claimed that when the military made the move from stick to ball powder in 5.56, they tried WC-846 (I don't recall the year given, but through much of the '60s the military kept messing with chamber dimensions and powders to improve functional reliability in the M16, which is how the cartridge came to diverge a little from the 223 that Remington submitted it to SAAMI in 1962—the year before the 5.56 mm Ball designation was adopted by the military). At the time, it said, the military had a particular lot number of WC-846 they had set aside because it was too fast for M80 ball in the M14. That lot was tested and proved to work better than normal burn rate WC-846 in the 5.56 Ball load, so more was ordered from Olin to be earmarked as WC-846 for 5.56 Ball. But Olin didn't like the idea of producing two different powder burn rates with the same name, so they decided to name the faster version WC-844. I don't know, in their numbering system, how they decide what digits to use. Sometimes it increments, as in WC-750 superseding WC-748 (still made in canister grade as Winchester 748) as a military powder, but in this case it was decremented two digits.

Keep in mind that M14 loads have to meet a ±30 fps velocity range, not exceed the rated peak pressure, and also produce gas port pressure inside a narrow enough window that apparently the powder that became WC-844 couldn't do all three simultaneously. That simultaneous requirement and narrow velocity range make military load specs tighter than commercial standards. SAAMI suggests a three-times wider ±90 fps velocity target for standard rifle loads. SAAMI also has peak pressure parameters, but no gas port pressure spec.

The bottom line is, you can make the H335 (WC-844) burn rate work in guns that are not based on NATO spec gas gun actions. You can probably make it work in them, too, if you don't insist on matching NATO exterior ballistics. But if you want to copy or approximate military specs for M1A's and other NATO-type 7.62 actions, then you probably want to go to BL-(C)2 and use magnum primers, as you can match military parameters more closely that way so they both function reliably and have their sight systems track at longer ranges.

[Metal god]

According to my sources you're almost 1 full grain over a max load with the 178 gr bullets

My hornady manual says I'm a couple tenths below max and Hodgdon says I'm right around max . They don't have data for 178gr bullet but the 175 I'm a tad under and the 180 I'm a few tenths over so I concluded I'm likely right at there max for the weight of the bullet .

The bottom line is, you can make the H335 (WC-844) burn rate work in guns that are not based on NATO spec gas gun actions. You can probably make it work in them, too, if you don't insist on matching NATO exterior ballistics.

I don't know if the AR-10 has the same limitations as lets say the M1 garand as far as pressures needed at gas port . Mine seems to operate with a multitude of bullets and powder combos . Mine is a 18" with a mid length gas system which IMO is over gassed no mater what I use . Adding a heavier buffer is in the future for this one . Not sure if it's that easy to tune the M1 garand or M14 if your gas port pressure is not optimal .

As for matching NATO spec , I was not trying in any way to match any spec when I worked up that load . I not only have never shot M80 ball in any firearm I own , I have zero knowledge of it's specs . I used H-335 because it's the powder I use the most in my AR-15 loads , it is in my manuals for 308 , it meters great and I have 20+ pounds of it . All that adds up to the perfect plinking AR-10 powder . Why 43gr ? it shot the smallest group , I think I went to 43.4 or .5 which had more cratered primers . I don't see me adding a new powder but can see me reducing the load .5gr to give me a little wiggle room .

[Howland]

Originally Posted by Metal god

My hornady manual says I'm a couple tenths below max and Hodgdon says I'm right around max . They don't have data for 178gr bullet but the 175 I'm a tad under and the 180 I'm a few tenths over so I concluded I'm likely right at there max for the weight of the bullet .



I don't know if the AR-10 has the same limitations as lets say the M1 garand as far as pressures needed at gas port . Mine seems to operate with a multitude of bullets and powder combos . Mine is a 18" with a mid length gas system which IMO is over gassed no mater what I use . Adding a heavier buffer is in the future for this one . Not sure if it's that easy to tune the M1 garand or M14 if your gas port pressure is not optimal .

As for matching NATO spec , I was not trying in any way to match any spec when I worked up that load . I not only have never shot M80 ball in any firearm I own , I have zero knowledge of it's specs . I used H-335 because it's the powder I use the most in my AR-15 loads , it is in my manuals for 308 , it meters great and I have 20+ pounds of it . All that adds up to the perfect plinking AR-10 powder . Why 43gr ? it shot the smallest group , I think I went to 43.4 or .5 which had more cratered primers . I don't see me adding a new powder but can see me reducing the load .5gr to give me a little wiggle room .

I also tried working up a 178 gr. load in a PA10 and came to the same conclusion - way overgassed. Even mid range loads left cratered primers and swipe marks and a few had rims ripped off by the extractor. IMR 4064 & 4895 with IMI Match brass.

Another project put this on the back burner so I don't know if the solution is buffer or adjustable gas block. Probably both.

[Bart B.]

Ball powders are rarely, if ever, used in center fire rifle matches producing best results.

Smallest groups don't best define real accuracy because they typically indicate what happens when all the variables cancel each other out. Near impossible to repeat time after time after time.

Shoot a 30 shot group and compare its extreme spread and center to that of the first few.

[zeke]

Perhaps i read through too fast, but did not find any mention of measured velocity? Reading primers can be indication of increasing pressure over lighter load, but not a reliable indicator of max/safe pressure. Case head swipe can be related to the powder speed/gas port size/spring rate in AR-10 style rifles, especially with heavier bullets. Playing with springs may help, adjustable gas block be better.

Have had extremely good accuracy with W748 ball powder in 308, but temp sensitive.

[Metal god]

Perhaps i read through too fast, but did not find any mention of measured velocity?

Correct , I've not ran them over my chrono but considering doing that on Monday before I make any final decisions . Also going to call up a local reloading supply store and see if they have LR mag primers . When I look around on line they seem to still be available , maybe they'll have some .

[thallub]

Been re-loading .308 since about 1965. Decades ago i ran into over pressure problems when using Lake City cases. After weighing Federal, Lake City, Remington, and Winchester cases, i much prefer Winchester cases for my maximum loads. Ditto for Winchester primers.

Winchester cases weigh 20-25 grains less than Lake City cases. Additionally, there is too much variance in the weights of Lake City cases, even Match cases, from lot to lot.

i have not used Lake City brass made after about 2000.

Some of my .308 re-loads were tweaked after being checked out by a friend using his Pressure Trace system.

[Metal god]

I almost exclusively use LC-brass I literally have several thousand of them . I have a minimum of 500 LC-09 , 10(1k) , 12 , 14 (1k+) , 15 , 17 and that's just my 308 brass and I've done water volume test and batches of all of them . I don't weigh my brass after doing all this water volume testing . I can't tell you how many times cases in the same lot weigh 3+ grains different and yet still have the same water volume . I've found weighing brass only becomes helpful if there is a 10+gr difference and if your working with the same headstamp or year I rarely see that big a variance . I worked these loads up in LC brass so and pretty much all my loads in LC brass since I started reloading last week just kidding lol I believe I've got a pretty good grasp of the brass .

You don't even want to know how much LC 5.56 brass I have . I have a very good local source for once fired LC brass .

[zeke]

Am using mag primers (CCI 34) for 748 in 308 loads. Getting better accuracy than the standard primers tried. The ball powder load gives about a perfect fill of the case, and is extremely consistent . Unless comparing velocities due to temp extremes. Am not outside in the extreme heat/sun anyway.

[Bart B.]

Originally Posted by Metal god

I can't tell you how many times cases in the same lot weigh 3+ grains different and yet still have the same water volume.

Any case has the most volume when its outside is perfectly round.

The more that case is out of round oval shaped, the less volume it has. That's why it's best to measure case volumes with the case full into a full length sizing die.

Some people sort by weight. If all the same weight, they will take up the same space in the chamber at peak pressure.

[Metal god]

Am not outside in the extreme heat/sun anyway.

Interesting you point that out . The loads were worked up at about 78* but when I tested them in the other guns the temp was 98* . I had picked maybe 10 days ahead of time when I was going and that day we had record heat throughout the county . Monday is expected to be 22* less then that or 8* hotter then the temp I originally worked them up in . I'll take the same guns out and shoot over the chrono on Monday and see what I get . FWIW not one of my 4-308's has the same length barrel so that should put an interesting spin on things haha

The IMR 8208xbr load should not care about heat but that H-335 may show some differences .

FWIW I just checked that reloading store and they have Remington 9-1/2 are those magnum ?

[zeke]

Am not real familiar with Rem primers, except the 7 1/2. Google would know.

[Marco Califo]

No. But 9 1/2 M are.

[Metal god]

No. But 9 1/2 M are.

yeah I was just looking at that , The guy on the phone said they were mag , I asked twice to confirm FWTW .

I also found during my search that the cup thickness is not any thicker then CCI standard primers or the Remington standard primers and also came across an article saying the Remington mag primers are the weakest/least powerful mag primer on the market ???? Which might be a good thing in this case ???