What am I missing?

[Black Jaque Janaviac]

The load data I'm basing this off of is:
Starting Hodgdon HS-6/ Sierra FMJ/ Overall Length
6.4 grains/ 125 grn/ 1.090"

The boolit I'm using is Lee's 356-125-2r. Lube is 50-50 beeswax deer tallow with blue crayons for color.

I started with the starting powder dose, and seated for an OAL of 1.115". Plus the Sierra 125 grain FMJ is longer than the Lee boolit, 0.575" and 0.565" respectively.

So I've got several things going for me that would indicate that this load should not have any overpressure problems: Using cast in lieu of jacketed, using the starting load, using a shorter boolit, and a longer OAL (both translating to shallower seating depth).

So I fired off a few magazines not thinking to check right away. When I gathered the brass, all the primers had the dents flattened out. Not cratered, but it almost looked like the primer was unfired - the dimple was pushed back out and flat.

Same load worked without difficulty in my brother's Ruger P-95.

[Walter Laich]

see post just below this for load data question


let's run through the checklist

have you shot other loads without problems

standard vs Magnum or Rifle primers

checked to see the diameter of the bullet to see it is what the mold says it should be

slugged your barrel

tried some of the load in your brother P-95

correct powder--did anything get mixed in it (like different powder)

have you used the brass before--sometimes you run into thicker walled brass which will cut down on volume and increase pressure

Pictures of your primers for us to see

let us know

[Walter Laich]

just checked hodgdon reloading data http://www.hodgdonreloading.com/data/pistol

and found this
9 mm
125 gr bullet
HS-6

starting load HS-6: 4.1 gr
maximum load HS-6: 5.1 gr

If I read this correctly you may be over max loads

[tazman]

just checked hodgdon reloading data http://www.hodgdonreloading.com/data/pistol

and found this
9 mm
125 gr bullet
HS-6

starting load HS-6: 4.1 gr
maximum load HS-6: 5.1 gr

If I read this correctly you may be over max loads

The load data you posted was for the Hornady HAP bullet. It always uses lower data.
The site also had data for the Sierra FMJ and a 125 grain cast boolit. The max loads for those were 6.8 and 6.6 grains respectively.
The load data the OP used should be fine.

I would suggest that the boolit, as a RN style, should be seated to a longer OAL. I use that boolit in 9mm and load it to 1.140. The boolit is designed to replicate standard FMJ round nose loads.

[chutesnreloads]

I have your same data for the 125g. Sierra.You ARE loading 9mm...RIGHT?.......None the less it IS a Different bullet.Look at data for the 125g.LCN.....Start loads for it are only 5.9 grain HS-6 with max load at 6.6.The Hornady HAP has a start load of only 4.5 grains with max atonly 5.1.Hmmmmmm.....what COULD you be missing?Suggest in future you shoot one shot at a time checking for over pressure with untried loads until you know it's a safe load.A few magazines before noticing a potential problem? eeek

[Black Jaque Janaviac]

The load is one we've been using for years - in my brother's 9mm. So the only change was a different gun. I think the HAP and LCN data were not around when we began using that formula for my brother's 9mm.

The mold is the same mold we've been using for years. Sized to .356" with a Lee sizer die.

...and yes it is for a 9mm - sorry that's a piece of important information.

[chutesnreloads]

Tried any factory ammo in it?
My Lyman manual lists 4 different cast bullets from 120-125 grains.....highest max load of HS-6 for any of them is 6.1 grains

[Black Jaque Janaviac]

Factory ammo - the primers look just fine.

Yeah - as I'm looking around a bit the 6.4 start to 6.8 max charge for HS-6 seems like it is one of the stouter recipes for HS-6 in the 9mm.

None-the-less I'll be dialing it back quite a lot.

[chutesnreloads]

Most any loading manual will tell you when you change a component in a load.... back off the powder charge and work back up looking for pressure signs.A different gun could be considered one of those components.Thankfully nobody got hurt and probably not even damaged the gun.Hope you get a lot of fun out of it from now on.

[RED BEAR]

As with people different strokes for different folks. Same can be true for guns. Have some loads that work great in one gun and in another complete different result. There are a lot of factors that influence pressure.

[Dusty Bannister]

If you are using range brass, check the primer flash holes. For some time there have been factory loads with larger flash holes and this might be what you are seeing.

[Black Jaque Janaviac]

Dusty,

It is mixed brass - so I don't think it's out-of-the-ordinary flash holes. If that were the situation, I would only had the problem with those of a certain headstamp. But these were all exhibiting the problem, Winchester, S&B, Federal, etc.

No. I think that for whatever reason, that load designed around the Sierra 125 grain FMJ is a little warm - also, and I don't know why I didn't do the math, the 6.4 grain starting point is more stout than the traditional 10% reduction from max. Max (6.8 grains) minus 10% would be 6.1 grains.

[sigep1764]

Starting loads in my Lyman 49th Edition for a 120 grain TC boolit is 5.0 of HS6 at 1.11 OAL. For a 120 grain round nose, it is 5.0 grains of HS6 at a 1.065 OAL. Since you are starting with a heavier boolit, I would back this off to 4 grains and work up ladder loads to 4.6 or 4.8 grains. Be happy, you might be able to save a little powder with this loading!

[Dusty Bannister]

Looking back through the thread I am not seeing anything to verify that the bullets are seated off the lands or against the lands when fired. If the bullet has firm contact against the lands, it might have to build enough pressure to force the bullet to begin moving down the barrel and that might give a little higher initial pressure. You only give the Cartridge OAL, and that only compares against published data and not specifically for your combination. That would be another point to consider in trying to find the issue. What is the alloy of your cast bullet and since you use tallow, is there any reason to think that there is a reaction between the tallow and the brass case?