kinda off topic 9mm question

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garredondojr
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kinda off topic 9mm question

Post by garredondojr » Fri Jun 14, 2019 5:06 pm

So I was goofing around yesterday at lunch and decided to stuff one of my homemade cast bullets into a 9mm case just for kicks....then I got to playing with QL and was surprised of what I found. This monster 354gr bullet can actually get semi respectable speeds according to QL ~880-950 FT/sec from standard to +P+ loads.

So I checked berger to see if it had any chance to be stable at said velocities and to my surprise it would be very stable in a 10 twist barrel even as low as 700 ft/sec.

My largest suppressor is 9mm so these things could be a riot and It looks like I could use my de-ribbed 20 round mag with no issues from an AR. I could easily order up a blank from GM and chamber it, open up the bolt face and make as straight pull AR with this bad boy on my SBR lower.

It would require some serious throating or since I made my cutter for this and cut my own mold I could cut a new mold and make this bullet a "bore riding" bullet then just ream the section of the bullet that would remain in the case to .358" then PC and size (did my figures with 1/2 caliber diameter so .180")

Anyone see any fault to this? I think it could be fun to lob a 300+gr of lead a few hundred yards for less than the cost of 22lr yet hit with a lot more authority :D
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:shock: 8)
oh yeah that's just the bullet barely in the case mouth. I would seat it ~.180"

ECCO Machine
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Re: kinda off topic 9mm question

Post by ECCO Machine » Sat Jun 15, 2019 12:35 pm

I guess if you don't mind a literal rainbow trajectory. You won't get anywhere near 900 FPS without having nuclear chamber pressures. 950 with a 158 gr. is fairly spicy. I think you'd be lucky to see 500 FPS without pressure signs. Remember, it's not just weight increasing resistance, but also bearing surface, and that bullet has a ton of it.

Secondly, staying subsonic only eliminates sonic crack; a hot load pushing a heavy bullet at low speeds will still be loud. Look at the American Eagle 147 ammo; subsonic, but pretty warm and almost as loud as supers. If you want max quiet, you need to tailor hand loads and accept that the quietest ammo is not gonna put down the kind of energy associated with a cartridge. .45 ACP 230 gr. is always subsonic, but you have to drop down into the 700 FPS range for it to really start sounding good.
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garredondojr
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Re: kinda off topic 9mm question

Post by garredondojr » Sun Jun 16, 2019 9:36 pm

ECCO Machine wrote:
Sat Jun 15, 2019 12:35 pm
I guess if you don't mind a literal rainbow trajectory. You won't get anywhere near 900 FPS without having nuclear chamber pressures. 950 with a 158 gr. is fairly spicy. I think you'd be lucky to see 500 FPS without pressure signs. Remember, it's not just weight increasing resistance, but also bearing surface, and that bullet has a ton of it.

Secondly, staying subsonic only eliminates sonic crack; a hot load pushing a heavy bullet at low speeds will still be loud. Look at the American Eagle 147 ammo; subsonic, but pretty warm and almost as loud as supers. If you want max quiet, you need to tailor hand loads and accept that the quietest ammo is not gonna put down the kind of energy associated with a cartridge. .45 ACP 230 gr. is always subsonic, but you have to drop down into the 700 FPS range for it to really start sounding good.

Yeah I figure the trajectory would be pretty exaggerated. I was quite surprised what QL predicted for velocity but you are correct in it being a full pressure load and with slow powder no less (in the h110-lil gun range) so I didn't consider that into the sound signature. my figures are however with a 8" barrel so not sure how much that would help.

I considered cutting a new mold to make the bullet bore riding (so minimal bearing surface) I could also reduce the length thus further lowering weight.
I also have a 200gr bore riding mold already from my 35 remington days.

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Re: kinda off topic 9mm question

Post by Capt. Link. » Tue Jun 18, 2019 4:24 pm

The Navy used a +P+ 170gr 9mm in the MP5SD that was very quiet though the barrel is a ported design.I use a .38special load called the 200 police positive from the Lyman cast bullet book.The pressure is not even +P and it hits like a ton of bricks out of a two inch snubby.It is remarkably quiet from a 10" suppressed pistol.You might be able to duplicate this load in the 9mm using the 35 Remington bullet.If you can't find the load data I'll dig it up.
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garredondojr
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Re: kinda off topic 9mm question

Post by garredondojr » Tue Jun 18, 2019 8:04 pm

that just might be the way to go. I used to shoot 158 swc's (which were 162gr lubed and sized) and they were quiet and hit hard from my old hi-point 9mm (pre suppressor days)

May have to order up a blank and give it a try with those 200's.

I have QL so I can use that to find a starting load. I remember reading about the 38-200 british loads (different than your 38spl) and that they would tumble and cause all kinds of damage despite how slow they were going. (want to say they were under 600 ft /sec)

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