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+--- Thread: Anyone come up with a action Cycling Subsonic Load yet (/showthread.php?tid=2239)
Anyone come up with a action Cycling Subsonic Load yet - JASmith - 11-30-2012
Apologies in advance for two major thoughts in a single post:
First, I know from my own experience with lead bullets in pistols that getting expansion at 1000 ft/sec and below is a challenge. 44 cal bullets cast from wheel weights did not when I shot a lot of jackrabbits as a young gentleman.
A good thing to try is a soft cast bullet at the lower velocity. The caliber doesn't absolutely have to be .264 and the firearm could even be a pistol. The important thing is to determine whether you can get the bullet to expand.
I am reasonably sure that commercial cast bullets will not expand since they use alloys that have yield strengths on the order of 15,000 psi. You, a buddy, or one of our forum participants might need to cast a few with either pure lead or the minimum practicable alloy to get the strength down.
I would start with water as the medium and use gel to verify your findings.
******
If the cast bullet expands at your velocities, I would then suspect the jacket is be too thick in the nose region. Getting thinner jackets might be problematic.
The easiest solution is to ask Hawk to start with shorter jackets with the thinnest available walls so you get more lead exposed at the nose. Too much exposed lead, of course, might lead to dinged noses.
I wonder if Hawk would be able to work with you and arrange for scoring or slitting the jacket over the first 25% of the jacket length.
I can visualize a die to do that with probably one added step in the swaging process.
Another alternative would be to ask them to apply a chamfer to the inside of the jacket so the wall is about 20% of the original thickness where the exposed lead starts and gets to full thickness just behind where the ogive starts. This is more labor intensive and possibly not a better solution.
******
Other, more complicated, solutions like deep hollowpoints or large diameter plastic tips can be tried but...
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 11-30-2012
I did discuss a few options with Hawk for custom designs including some heavier bullets. These are his standard design and have soft annealed pure copper jackets. I plan to call him again and discuss the next step when I have time.
I have also considered soft cast lead bullets but have some concerns with how they will function in this rifle. Plus I don't have any casting equipment or any experience casting. I'm willing to give it a try if someone is willing to partner up.
Anyone come up with a action Cycling Subsonic Load yet - robk0000 - 02-05-2013
I have been shooting mostly super through my grendel. Just lately ive been toying with sub's and have gotten some very interesting results. I am starting to toy with this because my 300aac just isnt capable past 200 yd without dropping 36 or so inches.
I have been casting my own 168 hard lead, 2% solder and 98%lead. 12 on the bhs. After 200 rounds casted, i have successfully fired and extracted 90%. The rest dont feed. This was without the cyclone suppressor.
With i managed to get 99% cycle, until my gas port jammed. That was 50 or so round in. I dont just spray down the range, i take my time i might add. I am currently down with my 6.5 setup as i play with the trigger. I do have load data available that i will share.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 06-10-2013
Small update for those who may have been following this. The Hawk bullets did not expand either. While they have a softer jacket it is much thicker than the Hornady bullets. I have some other ideas but time has been short for a while.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 06-10-2013
I thought I would bump this up. I haven't had time to do any more testing but I did shoot some last weekend with a suppressor.
http://www.65grendel.com/forum/showthread.php?6425-Suppressed-sub-sonic-short-video&p=64234#post64234
Anyone come up with a action Cycling Subsonic Load yet - tcte - 09-10-2013
have any more news on this? think im gonna start trying with my 10.5" grendel with AAC can
Anyone come up with a action Cycling Subsonic Load yet - Nukes - 09-10-2013
Depending on the intended quarry, I would expect that yaw and tumbling would obviate any need for expansion of subsonic 6.5 projectiles.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 09-28-2013
Nukes Wrote:Depending on the intended quarry, I would expect that yaw and tumbling would obviate any need for expansion of subsonic 6.5 projectiles.
This is what I saw in my "redneck" testing. I don't think expansion is possible without some type of exotic material. Maybe a fracturing bullet like Lehigh makes is possible but it would be difficult with the relatively small diameter.
Anyone come up with a action Cycling Subsonic Load yet - Nukes - 09-28-2013
Fragmentation is a bet against one's own marksmanship. If one selects and hits the correct target, there is no need for fragmentation. In fact, fragmentation lessens penetration—a net negative. Fragmenting a subsonic projectile guarantees a superficial wound (think of the Glaser Safety Slug), ugly but relatively ineffectual. Peppering a superficial area with metal dust is far less effective than a yawing and tumbling projectile penetrating into the vital zone that the shooter selected. Small arms projectiles are not "area weapons." [laughing]
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 09-28-2013
I'm not talking about frangible projectiles like shot filled jackets (Glaser) or sintered copper. Controlled fracturing is very different. RE: http://lehighbullets.com/products.asp?cat=26
Anyone come up with a action Cycling Subsonic Load yet - joker31 - 09-28-2013
the lehigh works well in 300 AAC. I know its not a Grendel but I think if you could get the bullet to come out at about 1080 and maintain the numbers for a good distance then the round would be very effective against a given target, and even more than the 300. I'm relatively new to the Grendel and have only used subsonic rounds against two legged targets but I think it would be nice for hunting if we could get a heavier bullet and it maintains velocity. Expansion is overrated at subsonic speeds btw.... subsonics that are used with cans are effective because you can fire multiple rounds quickly without recoil or excessive flash and the heavier bullet with more frontal area displace a lot of tissue very rapidly. Headshots with high amounts of hydraulic pressure do the job very well. occular displacement is very good indication of this, (not to be too graphic)...pressure in with no place to go, takes the path of least displacement. it either results in occular blowout or extreme rapid expansion (Think Gallager in a watermelon patch.) Its not pretty an def not PETA safe but then again we are more HUMANe to animals than people.
Anyone come up with a action Cycling Subsonic Load yet - Klem - 09-28-2013
I agree with Gunner...If using SS on flesh you definitely need the bullet to do something when it hits. Essentially you have turned your Grendel into a handgun; 160gn projectiles impacting the target at sub-sonic speeds.
I have done some testing SS with a .300 Blackout, enough to know that your usual hunting bullets designed for supersonic impact act like monoliths when subsonic. I've tried ballistic tips, soft noses, Barnes TSX and FMJ Match projies. They all act like big lumps of metal that neither fragment or expand, more like crumple and bend. Impressive penetration, however that means in one side, out the other taking a whole lot of valuable energy with them.
I am now testing 220gn hunting rds designed by Outlaw State Bullets in the Blackout. Outlaw State and LeHigh are the only two companies that I am aware manufacturing jacketed dedicated SS hunting projies. Neither produce them in 6.5mm. The Outlaw State has the jacket cut all the way to the base in four petals with a severe hollow point to aid expansion at low speeds.
The majority of Whisper/Blackout shooters (see other forum) load normal supersonic projies for subsonic shooting and either shoot holes in paper at the range or those few that use them hunting hope the bullet will tumble on hitting flesh.
6.8gn Trail Boss (TB) behind a 220gn in a Blackout gives 900fps but it does not cycle. It is as quiet as an 9mm H&K MP5SD, however as it is single shot only the relative value is questionable.
SS Loads that do cycle the action in a Blackout are noticeably louder than TB. i.e. louder than an H&K MP5 SD which is useful to compare against as it shoots pretty much the same weight; 147gn SS.
The conclusion of all this;
1. The Grendel will be similar the .300 Blackout in an AR. To reach cycling pressures of over 5,000lbs at the gas port means higher muzzle pressures at the suppressor. That means cycling subsonic will be louder than a 9mm suppresed SMG... The upside however is that by changing mags you can shoot supersonic to 1,000M which is something the SMG cannot do.
2. Unless the Subsonic 6.5 projectile does something more than act like a solid blob of metal when it hits flesh then you are worse off than a 9mm hollow point; which is designed to open-up subsonic. If you can get it to do something then it will be the same lethality as a 9mm handgun.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 09-28-2013
Klem Wrote:The upside however is that by changing mags you can shoot supersonic to 1,000M which is something the SMG cannot do..
This is exactly my reason for doing this.
I think the key will be a bullet that destabilizes and tumbles in a short distance. In the water jug and ballistic gel tests I have done the bullets that yawed created very large wound channels. Problem was they didn't turn over until the were 12" or more into the gel. I have an idea of a bullet similar to the Lehighs but with petals cut only on one side. Anyone have a CNC lathe that can crank out a few hundred?
Anyone come up with a action Cycling Subsonic Load yet - joker31 - 09-28-2013
I'm not seeing any application for Civies, even LEO's. Might be a novelty but novelties hardly make money or have the customer base to make it commercially. I guess a custom setup for hog hunting would be a stretch because there are already viable options out there. 300 for close in subsonic then swap upper to grendel for long distance. I have carried 2 uppers in the past in my pack. Its not that bad if one is a very short barrel and if the ammo count is low (Less than 100 each) I carried 2 rifles and a pistol downrange and I'll tell you that sucks when one is an M14 platform and the other is a mk18 uppered M4A1. I did end up swapping the M14 for a M16A4 upper later and it was nicer because you can do cave work with the 10.5" then swap out for A 20" in Mountains.
Anyone come up with a action Cycling Subsonic Load yet - Klem - 09-28-2013
I agree, the Blackout is more suited to this dual supersonic/subsonic capability than the Grendel.
The .30 cal Blackout has less space to fill with powder than the Grendel; 25grains H20 space compared to the Grendel's 35gns. The bullet choice is also heavier; up to 240 grns in .30cal compared to 160gn in 6.5mm. Both of these make loading for subsonic easier and less dangerous. There is less chance of flash-over or secondary-explosion-effect (SEE) from partially filled cases.
Taking the earlier stated Grendel load of 13.3gns of A2015 with a 160gn projectile and running the numbers, even pushing the bullet back as far as is reasonable (say, 2.12" OAL) you still get only 57% case capacity filled. Anything less than 80% and you have to start worrying about it being dangerous. Trail Boss is about the only powder I know designed to be high-bulk, low-pressure. But you fill the case and get safety at the expense of cycling and perhaps even low subsonic speeds.
As for low subsonic, given the supersonic crack starts at about 90fps below the sound barrier and gradually builds to its loudest about 100fps beyond the sound barrier a round travelling at 800-900fps would be quieter than the same round at 1,000fps, even though they are both subsonic. Plus there's not much difference in drop between 900fps and 1000fps at 100M, and let's face it, that is about as far as subsonic is practical.
Hornady's subsonic Blackout load is their 208gn AMax bullet. They've taken an off-the-shelf supersonic match bullet which was never designed for flesh, no doubt because it saves them money, it is the right weight, and the most reliable feeding (pointy tip). Perfect for punching paper.
Again, I have to agree, it is all about supply and demand. There's just not enough demand for the real thing in the civilian market. And when Hornady's SS paper-punching ammo is half the price of LeHigh's SS specialised flesh ammo which one are the majority of civilians going to choose?
One more edit... A typical supersonic Blackout projectile is 110-125gns whereas a subsonic is 200-240grains. You are doubling your ammunition weight for no more ability to kill (probably less). The only benefit subsonic ammo gives you over supersonic is sound. It has to be a real specialised need to use subsonic before it offsets the downsides; the extra weight, and the severely compromised effective range, and the cost. This assumes you've solved the potential danger of flash-over and you believe a subsonic round is no less deadly than a supersonic rd...but it is quiet! Well, not 'Hollywood' quiet but you know what I mean, quieter.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 10-01-2013
All valid points. Trail boss didn't work at all for me. Even a compressed load gave only 700 to 800 fps with very high extreme spreads. If I remember correctly my 8208 load density is somewhere around 70% and velocity ES#s are consistently very low. I feel comfortable saying SEE has a low probability of occurring with this load.
My reasons for doing this-
I wanted to carry 1 rifle and change loads only by changing magazines.
I wanted to have 400+ yard lethal range. Blackout doesn't cut it in this area.
I wanted the ability to dispatch critters (racoons, hogs, etc.) without blasting everything out of the area.
It's definitely not the end all/be all load but it works for me.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 08-31-2014
Time to bring this thread back from the archives.
Just got my new 12.5" upper together and running. Initial test look good. With my old load of 13.7 grains of 8208 behind a 160 Hornady I get full cycling (3 rapid shots) but not reliable lock back on an empty mag. 14 grains locks the mag back but might be too hot. Hopefully tomorrow I can put some over a chrono.
More to come...
Anyone come up with a action Cycling Subsonic Load yet - Variable - 09-01-2014
Sounds great man.
An idea what your gas port diameter is on the new barrel?
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 09-01-2014
Not sure exactly. I'll have to ask Mark.
Anyone come up with a action Cycling Subsonic Load yet - Sgt45 - 12-06-2014
I'm shooting a 20" barrel but interested in sub-sonic. Has anyone tried 140 gr bullets and IMR 4198? I've found 4198 works very well in my short 300 BLK, just wondering about the Grendel? I haven't found a source yet for the 160 gr bullets and was curious about the 140.