Neck Separation w/ 6.6 grains VV 3N38

[Kiran04]

I found 3N38 off a letter someone published by Vihtavuori concerning reloading the 5.7 cartridge. They gave a list of powders, including N105 and 3N38. I settled on 3N38 because it was listed as for small, fast projectiles and it was what I could find on the shelf. Any load data I found using 3N38 was with the 40 grain V-max, and people had their max loads set at 7.5 grains. I chose a healthy amount under that, started at 6.1 and working my up to 6.9 to find what was most accurate. 6.6 was that load. I also chose the 40 grain Nosler ballistic tip over the V-max because I found it to be more accurate. Note that all of my testing was done from my 16" AR57.

Well, I got around to testing the load out in the FiveSeveN and it worked great for the first 10 rounds, then the gun seemed to jam. I cycled it again and the slide wouldn't go into battery. I sorted through the brass and found a casing missing the neck. With the mystery solved, I returned home and extracted the separated neck with my bore brush without issue.

So my question is, given that I was using once fired brass from 197SR, did I do anything wrong loading the round or did I just fail to miss a case in the early stages of failure? From what I've read here, some people have had to cull casings after just one firing. Was it just a fluke then and I missed the early signs? Or did I load the round too hot? Specs are:

Trim Length: 1.131"
COAL: 1.591"
Powder: VV 3N38
Charge: 6.6 grains
Bullet: Nosler 40 grain ballistic tip

My other questions would be, is there any other way to check for signs of neck separation other than the gold ring of death? How many loads can you get out of a 5.7 casing before you should chuck it? Why did I get neck separation in the pistol, but not the rifle? I've probably put a good 200 or so reloads through that rifle, not one of which resulted in case failure. I want to extend the life of my brass as much as possible, but not at the expense of my gun and safety.

[DoubleJ]

I've got no experience with your bullet or powder, but I can tell you that a friend of mine gets 6 loads from some cases. A failure on a once fired could just be a fluke. I'd also say you could shorten up your COAL a bit, I generally run 1.580". How about some pictures for us as well of the other brass that ejected. Primers, shoulders and necks would give us some visual cues.

[Rapier1772]

What other indicators of pressure did you have? Shoulder movement? Primer condition?
I too use a COAL of 1.58" on almost all my loads.

I have used 3N38 before but it was for subsonic loads, I don't think I have tried it for full power loads. I agree with DoubleJ, if you're working that far under a max it was probably a fluke. However, backing down & rechecking is an option.
There's no set number of reloads before failure, there are too many variables which can effect failures. I've had a few loads where I tossed the case after the first reload & I have some which I am still reloading after 7 reloads.

[Kiran04]

I'm pretty sure the mouths are dinged up from bouncing off of the shooting stalls at the indoor range. 5.7 cartridges really seem to fly after ejection. I often find them 10 yards down range when I go to pick them up.

Also, I load them to 1.591" because the Nosler 40 grains are longer than the Hornady V-max. Should I just load the Nosler to 1.580" anyways?

[DoubleJ]

Yeah, your neck dents don't look to be caused by the pistol, they're too rough, maybe the walls or the concrete floor.

I do see a little more shoulder movement than I'd like, but you'll have to compare that to factory loads to be sure. My new barrel does it to even the lightest loads, so I've lost one of my pressure indicators. Fire a couple 197s and show us a side by side.

Your primers look ok, but your ejector marks might be a little mean. Hard to tell in a picture though, they may be ok.

Have you chronographed this load? If not, that's a must. I've seen chrono numbers go out of whack a couple tenths before my brass indicated pressure.

Might not hurt to try a ladder at 1.580, as long as your ogive doesn't get into your neck. Back off another 6% or so to start though.

[Kiran04]

Any idea why the extractor beats up the back of the casings? It's even done that to factory ammo.

[panzermk2]

Any idea why the extractor beats up the back of the casings? It's even done that to factory ammo.

MIM Seam, one of the reasons I polish it when we perform Accurizing.

[GONRA]

Maybe GONRA missed it, but wonders the brand / type of primers you used.
Small Pistol? Small pistol MAGNUM? Small Rifle? Brand/nomenclature:

[Kiran04]

Maybe GONRA missed it, but wonders the brand / type of primers you used.
Small Pistol? Small pistol MAGNUM? Small Rifle? Brand/nomenclature:

CCI 400, small rifle.

[Kiran04]

Yeah, your neck dents don't look to be caused by the pistol, they're too rough, maybe the walls or the concrete floor.

I do see a little more shoulder movement than I'd like, but you'll have to compare that to factory loads to be sure. My new barrel does it to even the lightest loads, so I've lost one of my pressure indicators. Fire a couple 197s and show us a side by side.

Your primers look ok, but your ejector marks might be a little mean. Hard to tell in a picture though, they may be ok.

Have you chronographed this load? If not, that's a must. I've seen chrono numbers go out of whack a couple tenths before my brass indicated pressure.

Might not hurt to try a ladder at 1.580, as long as your ogive doesn't get into your neck. Back off another 6% or so to start though.

So you think I should try 6.2 grains at 1.580"? I'll welcome any change that saves me powder. How will that affect the velocity?

[DoubleJ]

Yeah, run a ladder from 6.2 to 6.6. I missed the part where you worked up in the rifle and then just moved over to the pistol That usually shouldn't be a problem, as it's my understanding that rifles will get smokey and start spitting mags out as pressures get high, while those same pressures are still way safe in the FsN. I've never played with an AR57, but I did work up a load for a guys 90, and it got smokey but never spit it's mag.

Any chance you can test outdoors, with a chrony, and watch your ejection patterns? I've found with some powders that pressures are getting high right about the time your brass is moving forward more than right.

[Kiran04]

Outdoor yes, chrono no. I do not currently own one. I can check for smoke at least. I'll run them through the pistol too, see if they eject more forward than right. Might have to have someone else watch.

[DoubleJ]

I'd put one on your short list, big help when reloading. Think I got my CE for like a hundo new, I bet they're on ebay for half that.

Let us know how the ladder goes, pop a couple 197s as well for a shoulder comparo.

[CPTKILLER]

Do inspect your cases as you reload. Any question about the case, toss it!

I generally had good case life with reloads in various calibers with Metallic Silhouette Shooting. I probably had a few issues with 30-30 cases that had been renecked to 7 mm with a 7mm International load.

http://www.reloadersnest.com/frontpage_ ... liberID=85" onclick="window.open(this.href);return false;

It was a great load for what it did.

[panzermk2]

Have you seen this thread?


http://www.fivesevenforum.com/viewtopic ... hilit=ring" onclick="window.open(this.href);return false;

[Kiran04]

Have you seen this thread?


http://www.fivesevenforum.com/viewtopic ... hilit=ring" onclick="window.open(this.href);return false;

Most of the loads there were using True Blue, so the charge data isn't really useful to me. None were using 3N38. I've seen your postings on neck separation, but other than looking for the gold ring of death and checking over the cases visually, I haven't seen any other way to inspect the casings for possible separation issues.

[GONRA]

GONRA's not sure this applies for the small 5.7x28FN cartridge - but pretty sure it does - so here goes One Way or Another:
Methinks you SHOULD be able to use the commercial INTERNAL wall thickness gauge / dial indicator gizmos
to detect STRETCH RINGS / dangeous brass.
Home made LARGER VERSIONS (based on ENCO "granit cheks", Home Depot / Lowes extrusion stock
and some tricky home machine shop efforts) verk perfectly for detecting "stretch rings"
in .50 BMG "scrap dealer brass" fired from BMG's.

[panzermk2]

Have you seen this thread?


http://www.fivesevenforum.com/viewtopic ... hilit=ring" onclick="window.open(this.href);return false;

Most of the loads there were using True Blue, so the charge data isn't really useful to me. None were using 3N38. I've seen your postings on neck separation, but other than looking for the gold ring of death and checking over the cases visually, I haven't seen any other way to inspect the casings for possible separation issues.

I did not post the link up for the load data, just the case information.

Also the dented case mouths are from hitting the slide cover not the range wall.

GONRA's not sure this applies for the small 5.7x28FN cartridge - but pretty sure it does - so here goes One Way or Another:
Methinks you SHOULD be able to use the commercial INTERNAL wall thickness gauge / dial indicator gizmos
to detect STRETCH RINGS / dangeous brass.
Home made LARGER VERSIONS (based on ENCO "granit cheks", Home Depot / Lowes extrusion stock
and some tricky home machine shop efforts) verk perfectly for detecting "stretch rings"
in .50 BMG "scrap dealer brass" fired from BMG's.

The ring is so small in the 5.7 brass is would have to be some sort of micrometer.



Check out the scale of the grid in this pic. Short of cutting the case is would take some costly equipment.

[Kiran04]

I did not post the link up for the load data, just the case information.

Also the dented case mouths are from hitting the slide cover not the range wall.

So you think I should cool the load off more?

[panzermk2]

Hard to see how much of a ring, slice a case open and check.

But if you're getting separations is might be a really good idea to back off a little.

Kinda a bitch when you get one, don't catch it and then shoot the next round through the piece of neck in the chamber.

It's hard on the gun and harder on your hand.

[Kiran04]

Hard to see how much of a ring, slice a case open and check.

But if you're getting separations is might be a really good idea to back off a little.

Kinda a bitch when you get one, don't catch it and then shoot the next round through the piece of neck in the chamber.

It's hard on the gun and harder on your hand.

Mine didn't even chamber. The piece of neck kept the next round from going into battery. That's why I couldn't figure out what was wrong right away until I checked out the brass.

[Kiran04]

Ok, so I finished off that batch of 6.6 grainers at 1.591" and the rounds were a little on the smokey side. The shoulder movement looked about the same as the American Eagle 40 grain FMJs, but someone else must have been shooting 5.7 at the outdoor range. I found myself standing in a pool of it with way more brass than I started with, so I was only able to track down a few from my reload batch that I could definitively say were mine. The rest got lost in all the other brass at the range, which was fine with me, since I just picked it all up and walked off with it. The case heads didn't look anymore or less dented than the American Eagle stuff either. Given that the rounds gave off some smoke, I'm gonna go ahead and run a ladder from 6.0 - 6.4 at 1.580". I already have a batch loaded up, just need to shoot it. I am going to put it through the rifle first.

[Kiran04]

Alright, so I got my shiny new chronograph and a ladder of rounds from 6.0 grains 3N38 VV to 6.4 grains at a new length of 1.580". I reneged on my promise to shoot it from the rifle first and went straight to the FSN, since that is sort of the benchmark for the round anyways. I took my first shot string and... everything went perfect! Not only was the ammunition accurate, but the shots were super smooth and not a puff of smoke in site. The ejection at 6.0 was a tad on erratic side, but the ejection consistently improved as the load got hotter all the way up to 6.4, when everything including velocity, seemed to taper off. I only loaded 5 rounds at 6.4 grains and 10 at every other load because I suspected 6.4 would be on the hot side and didn't want to have to pull bullets if it was too hot. Here are my results:

6.0 grains, VV 3N38, Nosler 40 grain Ballistic Tip, CCI 400 Small Rifle, Trim 1.131" OAL 1.580"
1857
1775
1814
1787
1752
1754
1763
1761
1773
Avg 1781, Extreme Spread 105, Standard Deviation: 34

6.1 grains
1796
1792
1799
1804
1777
1777
1740
1849
1828
1839
Avg 1800, Extreme Spread 109, Standard Deviation: 32

6.2 grains
1821
1821
1811
1862
1819
1809
1823
1821
1854
Avg 1826, Extreme Spread 53, Standard Deviation: 18

6.3 grains
1826
1841
1834
1851
1859
1844
1831
1839
1854
Avg 1842, Extreme Spread 33, Standard Deviation: 11

6.4 grains
1851
1834
1841
1834
1851
Avg 1842, Extreme Spread 17, Standard Deviation: 11

A few strings had one shot that failed to register on the chrono, but with 10 shot groups it wasn't a big deal. 6.0 grains had one shot register at 4321, which I was pretty sure was wrong, so I deleted it. Ejection consistency continued to improve until 6.4 grains when it seemed to be the same as 6.3. I also stopped noticing quantifiable velocity gains at that load, but I did only load 5 rounds. 6.3 also had the most consistent velocity and the lowest standard deviation from the mean. All casings were extremely clean when I recovered them, although I was unable to locate 1 out of the 45 I fired and was extremely irked. All primer pockets looked fine. No signs of excessive shoulder movement even at 6.4 grains. I suspect going hotter is possible, but I don't see any potential for round improvement other than some very minor velocity gains, which I don't find to be worth it. I am very pleased with rounds consistently over the the 1800 FPS mark at 40 grains of bullet. They shoot very accurately, feel smooth as silk, eject well, and don't wreck the casing. Even my mean ejection marks aren't as noticeable in this grain range. I think I'm going to stick with 6.3 grains because it was the lowest standard deviation and most consistent cartridge performance. I've essentially just come up with a faster, straighter SS197SR, which was more or less the goal, but at ~$.28 a round as opposed to >$.40 a round. VV 3N38 seems to be quite amazing stuff. I will move on the 30 grain varmint grenade and try to break the 2100 fps mark, so stay tuned. I'm also going to put a few of my SS197YK(Yagami Kiran) into some ballistics gel and see what kinds of gooey goodness I can destroy. Reloading the 5.7x28 FN cartridge sure is tricky, but this is the most fun I've had reloading since ever!

[DoubleJ]

Good on ya for getting a chrono. As you can see in your avg velocities, you gained ~20 fps with each increase in charge weight, until 6.4 where you gained zero. You only shot 5, but it gives you an idea of where you're at. I'd call 6.3 your top load, and even consider 6.2 depending on temperature and such. If it was 100 out today, then you can pretty safely call 6.3 tops, but if it was a mild day, dropping another tenth to account for hotter days, shells in the sun, mag dumps ect probably wouldn't hurt. Something else I see there is a consistent drop in ES as your charge gets heavier, making me think maybe your VV powder is a bit slower and harder to ignite. Is it a ball powder? I don't recall what primer you're using, but maybe another ladder with something hotter like a 450, BR-4, 7.5, or the mil one that escapes my memory right now (39?) and stop at 6.3. See if your ES numbers drop and velocity comes up.

[Kiran04]

CCI 400 Small Rifle. Temperature was about 84 F. I think 6.3 is the way to go. The gun was pretty clean too after firing all 45 rounds. I can try some other primer types. CCI was just really easy to get a hold of. I'll try 450. The powder is really light and flaky. It's not large and round like ball powder. My auto-charger kinda hates 3N38. It acts like it's dying when the powder is that light, but it still gets the job done and gives me a consistent charge.

[panzermk2]

You where at the max when the velocities leveled off. Instead of pushing the bullet faster you where stretching the case instead.

Do not fire a load like this in your PS90, it won't like it and it will end poorly.

[DoubleJ]

Flake powder should ignite just fine from a normal primer. Hell, a pistol primer would probably do it. It's certainly on the slower end of suitable powders for the 5.7, but it's not mad slow. At this point I'm over my head and I don't want to steer you in the wrong direction. Hotter primer will light it up a bit faster, but it may get your bullet moving before the powder is burning properly and cause a SEE. I'd assume you've also got good case fill with it, like Blue Dot? If it was me, I'd settle at 6.2 for a little safety margin, or maybe lower if you want a load that runs your carbine as well. You've outrun factory loads and saved money doing it, that's a win.

[Kiran04]

According to the burn rate chart, 3N38 is #48 while True Blue is #40. 3N38 is slower than True Blue, but faster than Longshot. It's also faster than Accurate #7, but slower than Accurate #5. I can try a few 450s and see how they work out. I'm just anxious to finalize this load so I can start mass producing. I'm also working on a 30 grain varmint grenade load and plan to try the Lehigh 45 grain bullets, though I'll probably have to change powders for the heavier bullet since 3N38 is listed for smaller, faster projectiles.

[Oldbindlestiff]

Hotter primer? :huh: :skep: Not in my pistol or hand. You may value yours less. IMHO, quit while you still have all the pieces and parts intact.

[Kiran04]

SUCCESS!

Using 6.9 grains of VV3N38, an OAL of 1.525", CCI 400 small rifle primers, and a Lee Factory Crimp on a 30 grain Varmint Grenade yielded a result of 2140 FPS avg. Data is as follows:

2129
2140
2123
2150
2160
2140 avg, 37 ES, 15 Std Dev

I put a Lee Factory Crimp on the rounds and those little buggers were screaming. I think I might like these the best. A shame they're flat based. At least the 35 grain NTXs are boat tailed. I haven't lost faith in them though, if I can reliably get them up over the 2k mark.

[panzermk2]

FYI I have over 10 burncharts one with over 500 powders, and none of them agree.

[DoubleJ]

If you get bored, re-run them without the crimp, curious how much a difference it makes. I know you'd have to run hundreds for a scientific test, but even 10 might give us an idea.