200 grn XTP + 13 gr Accurate #9 = compressed load?

[tilefish]

Seating 200 gr XTP to a COL of 1.260 and a little under book max for Accurate #9, it looks like it will be a compressed (or damn close to it) load.

I have triple checked my measure and scale. 12.9 gr of #9 takes up a lot of case capacity. Any insights? Hornady book max is 13.2

[tilefish]

I am going to go back this down to 12.5 and see what that looks like.

[tilefish]

Ok, so I loaded 12.5 gr Accurate #9 under 200 gr XTPs in brand new Star Line brass, S&B primers with COL @ 1.260

This load is definitely compressed. Compressed to the point where the petals of the hollow point are slightly pushed in/smaller opening in tip.

I quadruple checked everything but something does not seem right. I am .7 gr UNDER Horandy book max for this projectile and powder with the correct COL... How do they figure another .7 gr of #9 could possible fit in there? Even if I tried it, I would turn hollow points into round nose FMJs lol.

The particular jug of Accurate #9 says Made in Belgium on the side. I am not sure if that means anything but I know I have come across threads discussing #9 regard Made in USA vs Belgium.

So what is next? Kevlar gloves and a Lexan face shield?

[Geeman]

10.6 is the 100% fill point (not compressed) at 1.26".

That's the thing with AA-9 in a 10mm.  You generally run out of room before you can get into trouble

Greg

[tilefish]

So Hornady's published MAX is 13.2 gr #9

I am at 12.5 gr, compressed.  I am thinking I might have a bunch of bullets to pull....

However what really confuses me is the actual #9 MAX for the 200 gr XTP, 13.2 gr. There is no way possible to load 13.2 gr AND have a 1.260 COL, yet Hornady specifies it. What gives? Could it be a book error?


Shoot 'em or pull 'em? Honestly, I am kinda scared to pull them...

[The_Shadow]

Accurate #9 has changed it used to be micro beads now it is a flattened ball powder...I have seen where the powder will push the bullet back out on compressed loads.

[tilefish]

Accurate #9 has changed it used to be micro beads now it is a flattened ball powder...I have seen where the powder will push the bullet back out on compressed loads.

The batch I have is Made in Belgium and it looks likes little spheres.

What do you think Shadow, is 12.5 too much even though its .7 grn less than published MAX for same bullet?

[Pinsnscrews]

i would contact www.westernpowders.com who is the importer of Accurate and see if they have correct load data for that older version of the powder

[The_Shadow]

The Accurate data I have shows the Hornady XTP using No.9 12.5 grains (max load) @ 1170 fps producing 37,000 psi with a COL of 1.2500".
SAMMI pressure was set at 37,500 psi...

[tilefish]

So I grabbed 5 of the Accurate #9 rounds I was not sure about, 5 stout Longshot loads, my G20 (had back for a couple hours, see here....) and my G19 loaded with Hornady Critical defense and headed for the canyon.

See last post here: http://10mm-firearms.com/gunsmithing/how's-this-for-a-theory/msg35994/#msg35994


Target: A big 'ole brick of an ancient laptop sandwiched between 8 layers of heavy denim in front and a 1/2' catalog on the back. Backstop was a steep hill (canyon wall) of soft-ish dirt, with the target propped up by a sage bush. Close range, about 15 feet.

All 5 9mm Critical Defense rounds, complete penetration

All 10 200 grn XTPs also passed right through. I was not at all surprised the 10's went through but I was surprised that the Critical Defense made complete penetration with equal ease. I figured they would stop in the catalog.

I recovered minimal brass with no signs of over pressure. I even recovered one bullet in the dirt. It was not a 9 though, it was one of the 200 grn XTPs..base of the bullet was completely in tact and retained its shape. Inf fact in fit snug right back into the brass case.

As for expansion, it expanded but it looked like a big knob or something. The entire bullet itself looked like a lead mushroom, not an expanded hollow point.

Most of all I find it strange that the bullet I recovered was a heavy loaded, heavy bullet. All the 9's were deep into the dirt.

[The Earl o Sammich]

I found a way to check to see how close you are to crushing your load.  A 9mm case nests pretty nicely into a 10mm.  Load your powder and drop a 9mm case in on top.  Scribe a mark at the top of the 10mm onto the 9mm case.  The length from the bottom of the 9mm case to the scribe mark is available volume.  Measure that with a machinist ruler.   

Then measure the over all length of a bullet, the over all length of a case and the over all length of a finished round.  Bullets are not too consistent so do half a dozen or so to see what the max is.  The overall length of an average bullet plus the over all length of a case, minus the over all length of a finished round is how far down into the case the bullet is seated.  How does that compare to your 9mm case?

Kind of going out on  a limb here but I don't think a little bit of crush should be cause for much concern.  As long as you've been working your loads up and see no signs of high pressure, a negative volume of 10 to 20 thou isn't going to yield unexpected results. 

Of course I could be all full of bullshit and it's your gun, your hands that are at risk here. The views an opinions presented here in no way reflect the views of Sammich Inc.  Your mileage may very. License, title and dealer preparation fees are extra.  Should you experience an erection that lasts for more than four hours seek immediate medical attention.