Reloading help

[Bigs28]

So I bought some 90g speer TNT and some PPV. According to Speer website max load is 33.2 and starting is 30.1g. So naturally I was a risk taker and started at 30.4g of PPV, 90g Speer TNT, CCI 450, COAL 2.195. This is Hornady Brass on its 5th load. Ive primarily used 110g Maker Trex and 110g Lehigh Defense Controlled Chaos previously in this brass with zero issues. Im shooting out of a 12" Krieger from precision firearms.

First 4 rounds 30.4g had velocities 2353,2311,2336,2385 about a 1.5 inch group and in the box picture they are the primers on the furthest left.

Second load 4 rounds, first round blew the brass apart at a chrono velocity of 2309. Primer looked fine. Velocity was noticeably less then the previous 4 rounds. I figured this was some sort of anomaly with the used brass being that it was such a low load and the velocities were as I expected them to be so I continued shooting. The remaining 3 loads chronoed at 2339,2361,2333.

Next load is 31.0. Second shot blew the brass apart again so day over for my Grendel. The first velocity was 2413 and the blown case was 2300.

Here are some pictures of the brass. The primer pockets were still tight when loaded and I have never loaded these hot. I use redding full length resizing dies.

[Bigs28]

When i uploaded my ammo box picture it rotated for some reason. First loads are at the bottom now.

[FLshooter]

When I reload I like to have my velocities as consistent as possible. I say within 20 of each other is pretty good. I strive to get them within 10 FPS of each other . It all has to do with consistency .Take your time and try to do every load the same.

[Bigs28]

I do every load the same with a beam scale. My es narrows closer to accuracy nodes. I have loads within 10fps with my 110g but during load development they vary.

[Lemonaid]

My first take on seeing the cases was case head separation. I would check the brass interior with a tool (sharpened straightened paper clip) and look for a shiny ring on the ouside of the brass in the same area where the decapitation occurred. If it was the brass, the load may be o.k.

[grayfox]

I can only think of a couple things.
1. case-head separation from worn brass, maybe you could try some new or 1-2x brass with those loads.
2. The other thing is well, maybe out of box, but could it be the loads were - for your gun - too light and so some kind of almost-over-kaboom? for me when I had my 12.5-er the 90 Tnt's were going at (factory Federals) 2628. I did load some up with AA2200, had one node at 2420 but wound up at 2529, with 29.2 grs (29.2 is book max).

[A5BLASTER]

So I bought some 90g speer TNT and some PPV. According to Speer website max load is 33.2 and starting is 30.1g. So naturally I was a risk taker and started at 30.4g of PPV, 90g Speer TNT, CCI 450, COAL 2.195. This is Hornady Brass on its 5th load. Ive primarily used 110g Maker Trex and 110g Lehigh Defense Controlled Chaos previously in this brass with zero issues. Im shooting out of a 12" Krieger from precision firearms.

First 4 rounds 30.4g had velocities 2353,2311,2336,2385 about a 1.5 inch group and in the box picture they are the primers on the furthest left.

Second load 4 rounds, first round blew the brass apart at a chrono velocity of 2309. Primer looked fine. Velocity was noticeably less then the previous 4 rounds. I figured this was some sort of anomaly with the used brass being that it was such a low load and the velocities were as I expected them to be so I continued shooting. The remaining 3 loads chronoed at 2339,2361,2333.

Next load is 31.0. Second shot blew the brass apart again so day over for my Grendel. The first velocity was 2413 and the blown case was 2300.

Here are some pictures of the brass. The primer pockets were still tight when loaded and I have never loaded these hot. I use redding full length resizing dies.

First question- what was the air temp when you shot these?

Second question- what's the jump? Any chance you was jamming the bullet?

Those velocity's seem very slow for that bullet and that powder. I'm getting over 2300 with the 120 gold dot and ar-comp with less powder.

So with ppv and the 90 tnt I would expect to see more speed at your starting load.

Any chance you made a mistake on the data you used?

[grayfox]

hey. one more thing, can you mic the brass on the separated brass, the non-caseweb piece, it doesn't look stretched to me but a mic could tell. Looks almost like a clean break, not a stretch-yield-then break type.

[A5BLASTER]

hey. one more thing, can you mic the brass on the separated brass, the non-caseweb piece, it doesn't look stretched to me but a mic could tell. Looks almost like a clean break, not a stretch-yield-then break type.

Agreed. The case on the right, if you zoom in on it. It looks like it was twisted off, like it was really over pressured and the bolt tryed to extract while it was hard against the chamber walls and the bolt snapped the case and ripped it out.

[Arkhangel5]

Bigs,

While I agree the velocities look a little low, I think you should redo the test with new or newer brass. If just to get rid of that variable.

You should be able to get more velocity before ripping up a case like that.

My 2c.

SY

[Klem]

This is a classic case of incipient case separation. Your sizing die is screwed in too far.

Incipient means gradual, so over the life of five shots the case has been squashed and stretched, squashed and stretched too much and it eventually splits in the weakest spot, which is just forward of the web. It has happened to me twice in my shooting career and incipient case separation splits the case in that exact spot every time.

It will have little to do with those cases being overloaded. Incipient will occur even if the loads are mild; it's more related to too much headspace.

Do you measure headspace when loading?

[Bigs28]

I don't know what "mic the brass" means. These are my first 90g loads. My 110s at close to max load are 2400ish so i was thinking starting loads around 2300ish might be accurate for 90s. But i have no clue. No clue what the jump is but when i make my first load at desired coal i send one into battery and pull it to check for marks or how hard it was to eject and everything was smooth and clean.

Temp today was high 70s, maybe low 80s.

[LR1955]

This is a classic case of incipient case separation. Your sizing die is screwed in too far.

Incipient means gradual, so over the life of five shots the case has been squashed and stretched, squashed and stretched too much and it eventually splits in the weakest spot, which is just forward of the web. It has happened to me twice in my shooting career and incipient case separation splits the case in that exact spot every time.

It will have little to do with those cases being overloaded. Incipient will occur even if the loads are mild; it's more related to too much headspace.

Do you measure headspace when loading?

What Klem said.

Headspace separation due to excessive headspace. Either the brass was sized down too much for a number of firings or the chamber has excessive headspace which weakened the brass over a few firings.

LR55

[Bigs28]

I have never measured headspace. Just size my brass to within spec. Usually bumping the shoulder back around .003 to get the case to chamber and fall out on its own.

[A5BLASTER]

This is a classic case of incipient case separation. Your sizing die is screwed in too far.

Incipient means gradual, so over the life of five shots the case has been squashed and stretched, squashed and stretched too much and it eventually splits in the weakest spot, which is just forward of the web. It has happened to me twice in my shooting career and incipient case separation splits the case in that exact spot every time.

It will have little to do with those cases being overloaded. Incipient will occur even if the loads are mild; it's more related to too much headspace.

Do you measure headspace when loading?

Thanks for dropping in Klem. I suspected some kind of over pressure situation. Never dealt with incipient case desperation before are seen a pic of it. So now I know what to look for if it should ever happen to me.