Help with 9mm load

[chamber143]

I am working up a 90 gr 9mm bullet and was stumped by something. It is a Hornady 90 gr xtp and according to Hornady the max charge is 7.2 with hs6 at 1250 fps. Sierra has a listing for a 90 gr bullet at a max of 8.2 gr of hs6 at 1400 fps. Whats strange is the most of the other powders match pretty well with charges and velocity between the two manuals but Sierra pushes about another 150 fps for a 90 gr bullet. Is it fair to say I can work up to close to the 8.2 gr with the Hornady bullet? What sorts of pressure signs should I be looking for?

[mRad]

Two different bullets. Data cannot be used interchangeably.


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[chamber143]

Two different bullets. Data cannot be used interchangeably.


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Right I get that they are two different bullets but I am wondering why if I check all the different powders for both bullets the data for all the powders are almost identical for charge and velocity as well as pressure except for the hs6.


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[markm]

Is there standard bbl lengths for pistol velocity data?

I really think you need to work your own load up with a chrono. Using your barrel, your lot of powder and your bullets. Mileage varies greatly between powder lots and actual loading.

[223to45]

Well Hodgdon shows a 90gr Gold Dot at 8.2, at 1413 ft/s. With HS-6. .



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[gaijin]

HS6 is Relatively slow compared to a lot of pistol powders.
Look at a burn rate chart and compare it to other common pistol powders.
It is frequently used in “Major 9” loads in USPSA competition that are way over SAAMI pressures for 9mm.

[wil]

I am working up a 90 gr 9mm bullet and was stumped by something. It is a Hornady 90 gr xtp and according to Hornady the max charge is 7.2 with hs6 at 1250 fps. Sierra has a listing for a 90 gr bullet at a max of 8.2 gr of hs6 at 1400 fps. Whats strange is the most of the other powders match pretty well with charges and velocity between the two manuals but Sierra pushes about another 150 fps for a 90 gr bullet. Is it fair to say I can work up to close to the 8.2 gr with the Hornady bullet? What sorts of pressure signs should I be looking for?

watch the primer for extrusion and firing pin cratering. Also check the extractor ring for a claw mark. If the extractor claw is starting to deform the extractor ring, it's an indication of extremely high pressure.

If you see extrusion on the primer, the round shoulder flattens out and starts flowing over the edge of the primer cup in the brass........STOP, the load is too hot.

my hornady book has hs-6 at 7.7 grains on a 90 grain bullet gives 1300 fps. (4th edition book)

Speer book has hs-6 at 8.2 max on a 115 gr gives 1316 fps. I have run this load in a BHP and Sten Mkll on full-auto and neither gun had any complaints.

I'd start at 6.5 grains and come up very slowly and keep an eye on things. Come up a 1/4 grain at a time and see how things look.

[DG23]

watch the primer for extrusion and firing pin cratering. Also check the extractor ring for a claw mark. If the extractor claw is starting to deform the extractor ring, it's an indication of extremely high pressure.

If you see extrusion on the primer, the round shoulder flattens out and starts flowing over the edge of the primer cup in the brass........STOP, the load is too hot.

Straight wall pistol brass does not 'read' like rifle brass will. You are better off reading tea leaves to determine over pressure.

Want to prove it to yourself? Trim a piece of 9mm brass a tiny bit short and then fire it with a known to be 'safe' loading and inspect the primer / brass. Compare to the same loading fired with brass that actually fits the chamber properly and chime back in...

Mouse fart loadings will flatten the hell out of primers in my 460 Rowland chamber IF the brass is short. (Think 45ACP brass fired in a longer 460 chamber)

Seeing as how most 9mm brass is going to be a tiny bit 'short' anyway and mixed brass will likely be all over the map in length - Visual 'signs' of pressure are very unlikely to be the same from one piece of brass to the next even if the loading / charge weight remains exactly the same.

Don't just take my word for it - Trim you down a few pieces of brass and give it a go for yourself.

[gaijin]

^^ 9mm is a tapered case.
Don’t disagree with your statement of difficulty in reading pressure sign with pistol ammo, at least until you reach primer flow/crater pressures.

[mRad]

It’s silly to want to run up your 9mm loads to pressure anyway.


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