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Here's some vids from a couple weekends ago. The first is an unmodified bullet, the second is a bullet I drilled a small hole eccentrically on the tip. It seems to have caused the bullet to yaw sooner but it's hard to be sure.
[video=youtube;w5mru3PWN4I]http://www.youtube.com/watch?v=w5mru3PWN4I[/video]
[video=youtube;DG3EPYPFl3o]http://www.youtube.com/watch?v=DG3EPYPFl3o[/video]
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Posts: 2,075
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Posts: 2,412
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txgunner00 Wrote:Try this.
http://www.youtube.com/watch?v=w5mru3PWN4I
http://www.youtube.com/watch?v=DG3EPYPFl3o Thank you Sir! 
Yeah, looking at the vids, it does look to me like you are getting your energy dump earlier in the stack. It's hard to tell definitively from just a youtube vid, but I'd say you are right.
Pics of modified bullet?
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Variable Wrote:Thank you Sir!
Yeah, looking at the vids, it does look to me like you are getting your energy dump earlier in the stack. It's hard to tell definitively from just a youtube vid, but I'd say you are right.
Pics of modified bullet?
Forgot to get pics of that- I'll get some next time. It was just a 3/32" x 1/8" deep hole drilled off center in the lead tip.
Thanks for all the hard work TXgunner and Rapier. This will be good info for many to start from in developing SS loads for their rifle. From working with 2400 in the 8x58RD and 190gr GC bullets I thought maybe you would be able to get that powder to work well in the Grendel as it is not position sensitive and ignites well. Have you noticed any powder position issues with the IMR 8208XBR since you lengthened your COAL?
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No problem.
The longer COL seems to actually burn more efficiently as the cases come out cleaner.
2400 may work in some rifles. It's all about matching peak pressure to the gas port position.
For another data point........I loaded up some Hornady 160gr RN bullets with 14.0gr of IMR 8208 in NEW AA cases and CCI 450 mag primers. Seated the bullet around 2.4" and fired away. All 5 rounds cycled the action in my 16 inch chrome lined Saber AA upper. Velocity was a bit high at around 1200 fps so I need to back the load off a bit but it was fun and accurate. Looking forward to the next experiment.
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Good to hear it's working for you.
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Smokepole50 Wrote:For another data point........I loaded up some Hornady 160gr RN bullets with 14.0gr of IMR 8208 in NEW AA cases and CCI 450 mag primers. Seated the bullet around 2.4" and fired away. All 5 rounds cycled the action in my 16 inch chrome lined Saber AA upper. Velocity was a bit high at around 1200 fps so I need to back the load off a bit but it was fun and accurate. Looking forward to the next experiment.
2.4? Really? 2.24?
You seek escape from pain. We seek the achievement of happiness. You exist for the sake of avoiding punishment. We exist for the sake of earning rewards. Threats will not make us function; fear is not our incentive. It is not death that we wish to avoid, but life that we wish to live. - John Galt
Yes Bill you are correct. I was in a hurry when I typed that or at least that's my story.....:o)
The actual OAL was 2.238"
Thanks for catching that slip.
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I hope to get back to my ballistic gel testing soon. I've been busy with work, fishing and other projects (mostly fishing related ).
I can't say how appreciative we are of you guys being willing to share your hard work.
I just put my can on order Wednesday, so its time for me to start down this path. I'm shooting a 16" mid-length set up. This should be fun.
Lead Chucker
Unregistered
This is good stuff, I have been running my cyclone can on my grendel with 95 gn v-max's and love it. I would love to have a subsonic load for it. Then I would have a hard time choosing between it and my blackout for sub work. Thanks
Well, I made it out the range this morning. I started with TxGunner's loads. Every round successfully ejected the empty. But it never successfully loaded the next round or locked back on an empty magazine.
First, my hardware:
16" AA barrel, mid-length gas system
1:8" twist rate
"Standard" carbine buffer, tube and spring
I do have another lower with a rifle tube, buffer and spring. I have fired the Grendel upper on both lowers, and they function interchangeably with full power loads. I did not think to try the rifle lower today. Maybe next time.
All loads were 8208 powder under the 160 grain Hornady RN (0.264).
I had some Wolf (PPU) brass with large rifle mag primers.
I also shot some out of Hornady brass using small rifle magnums. Surprisingly, the hornady brass was giving 200-300 fps faster for the same charge.
Brass / Charge / Avg Vel / StdDev / ES
Wolf / 13.9 / 1110 / 56 / 109
Wolf / 13.7 / 1086 / 19 / 27 - 2-shot group
Wolf / 13.5 / 1182 / 66 / 131
Horn / 13.9 / 1417 / 109 / 154 - 2-shot
Horn / 13.7 / 1371 / 67 / 95 - 2-shot
Horn / 13.5 / 1265 / 142 / 201 - 2-shot
Point of impact is about 3" below my full power loads at 50 yards.
My 1:8 barrel is not stabilizing the 160s. All of the sub 1200 fps rounds were keyholing.
An interesting side note: the 160 grain round nose want to fall into the hornady cases once they get a little past the cannelure. Someone on here commented they noticed that, but I can't remember who. In order to get them to hold, I put the hornady's back through the sizer just enough to increase the neck tension. I had no problems with the Wolf brass holding the bullets.
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Aggie,
Do you have or do you plan on using a suppressor with the subsonics?...My 300BLK has intermittent issues with cycling/locking back if I don't use the suppressor (and is acknowledged as a potential issue by AAC/Noveske). The suppressor will increase back pressure and may solve your issue (if you aren't using one).
I'm not using a suppressor...yet. I have one on order. I'm just trying to get a jump on it.
How much do you find the suppressor affects the velocity? Or will it be in the noise, considering the spread we're getting anyway?
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Honestly, I don't know how much the velocity is affected (I haven't chrono'd the subsonics). The suppressor basically prolongs the amount of time pressure is present in gas tube (and possibly increases pressure some) which helps with cycling. Theoretically, the suppressor should increase the velocity due to "free bore" while passing through the suppressor (no friction of rifling; pressure still present behind the bullet pushing it along). Maybe someone who has a good chrono who has done this comparison can chime in.
You will definitely hear the difference...I love the suppressed sound of subsonics!
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Aggie,
BTW, the 1200 fps rounds will not be sub-sonic...at 100F, speed of sound is approx 1160 fps; at 20 F, it is approx 1075 fps (air pressure doesn't matter, temperature dictates with a little input from humidity).
You will suppress the detonation sound, but still get a sonic crack with 1200+ fps...but it still sounds cool! 
Yeah, i'm pretty close to the limit already. Given the spread, I need to shoot more to see if the loads will all remain subsonic. If the can increases the speed, i'll be over.
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