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Anyone come up with a action Cycling Subsonic Load yet - Rambozo - 03-22-2012
Smoke Wrote:TXgunner
have you tryed H322 .. According to the hodgdon burn rate chart its next to
AA2015.. Just curious as I have alot of H322
any reason not to try it like heat sensitive or not good for reduced loads?
Thanks
Smoke
H322 is a great powder. It's my favorite, but it's fairly fast burning, and you will likely run into load density problems and port pressure problems. In my experience, the powder isn't very temp sensitive. It's a Hodgdon "extreme" powder.
Personally, I would look at slower burning powders, maybe even something that would be used in a heavy magnum cartridge. I'm sure you can find something that offers a good fill, low velocity, and slow enough burning for port pressure. at the same time though, I have heard of secondary pressure spikes due to using too slow of a powder relative to projectile weight. I don't know how much of an issue that would be with lapua 144s and the 6.5 bore volume of the grendel though.
anyway, just some thoughts.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 03-22-2012
Rambozo Wrote:H322 is a great powder. It's my favorite, but it's fairly fast burning, and you will likely run into load density problems and port pressure problems. In my experience, the powder isn't very temp sensitive. It's a Hodgdon "extreme" powder.
Personally, I would look at slower burning powders, maybe even something that would be used in a heavy magnum cartridge. I'm sure you can find something that offers a good fill, low velocity, and slow enough burning for port pressure. at the same time though, I have heard of secondary pressure spikes due to using too slow of a powder relative to projectile weight. I don't know how much of an issue that would be with lapua 144s and the 6.5 bore volume of the grendel though.
anyway, just some thoughts.
I have tried few slower powders and they were definitely not the way to go in this application. They would not produce enough pressure to burn all the granules and I had unburnt powder stuck to the neck and shoulders of the case. Even a Federal large rifle magnum match primer couldn't light them off quick enough.
I can't remember which powders I tried exactly but I think they were US869 and H4831
Anyone come up with a action Cycling Subsonic Load yet - Rapier - 03-23-2012
Ok Guys,
I am back from Vegas. Saw some interesting things while in the metro Vegas area with a 2 mil population, seems like they have a bit of everything you could want or not want, rolled into a ball. :o For us, I saw a new Polymer AR lower and bought one for $100 complete. Also found a new AR 5.56 upper with 1-9 twist, 16 inch, flat top with low gas block and a four rail free float for $298. So I got myself can gun #2 for $400. My Glock nuts buddy calls it a Glock AR.:p
The two powders I did get to work my action were AA #9 and 2015 BR. Now when I say work, I mean the entire show, sub sonic, lock back, strip 5 rounds, etc. #9 had the widest variances so I turned to 2015. But remember, I am using .267 bullets seated all the way down in the case as I must get clear of the throat which is .264 So my pressures have to be up, at least for a very short span of time, as I am swaging the bullets to .264 and with the 16 inch barrel it may well be all that is needed. I note in reading J. D. Jones notes on the Whisper that he was working a lot with short barrels, to make up for the can's length. One thing I found quickly is that the function is a matter of timing not just pressure period. The powder must reach a peak pressure point just prior to the gas port or that is what appears to be the case.
In silhouette shooting from a single shot, the barrel length for the Unlimited class is restricted to 14 inches so to obtain peak velocity you must burn the powder in under 14 inches. 2015 and #9 will burn in 14 inches and apparently delivers some push left over for the gas system at least in the 16. If the gas port position is relative then a 20 gas port should be aprox 4 inches further out the barrel towards the muzzle. If what I think is happening, is correct, then the next slower burning powder on the scale might be the place to look with a 20, if 2015 is just a tad fast. R #7 is the next powder on my scale with 3031 after that. But #9 and 2015 are not even real close on the scale, so.....
I will try to get up to the farm this weekend while getting ready to go tripping again, this time to Tulsa. We go to the big show every year at least once.
Ed
Anyone come up with a action Cycling Subsonic Load yet - Rapier - 03-25-2012
I did get out to my range yesterday with the 12.2 gr load and suprise, suprise when you seat the bullet a tad lower it increases the velocity a tad higher and at the fringe, a tad is to much, so about 90% of my loads were just over sonic. I will drop back to 12 gr of 2015 with the bullet seated to an OAL of 1.808 this should put me back to the velocity were I was with 12.2 gr at the prior OAL setting befor the change, that had all subsonic velocities. Only thing is the 12.2 gr load this time had an ES of 100 fps with the lowest at 1063 and the highest at 1163, exactly 100 fps off. You know, to do this right, you might need to adopt a bench rerst load process, press, scales and powder to the bench and shoot as you adjust.
In my post above I said #9 functioned, that is true to one extent, the first load at 8.5gr did function, however the higher charges did not function, odd that. But I went back and reread my notes. It was H-335 that functioned through its entire range of loads in my gun but had extreame spreads of numbers like 176 fps. However 13.4gr gave me a highest velocity of 1101 with a SD of 31. So 13.2 to 13.3 might well work well at the reduced OAL in my gun.
One thing is obvious, you must fiddle with the load to get the velocity, function and accuracy into one package and it helps a lot to have some experiance in reloading otherwise you can spin your wheels for a long time on this.
Well I am off to Tulsa for the show, so it will be a while before I post again. Oh, the AR upper I bought in Vegas shot 3/4 with some scrapped up loads for the Mini-14's testing I did when I rebuilt it, so with loads built for new upper, it should shoot OK. Not to bad for $298.
Ed
Anyone come up with a action Cycling Subsonic Load yet - Gswamp - 03-26-2012
txgunner00 Wrote:Originally Posted by txgunner00
AA#9 is actually in the ball park of the next powder I want to try. Unique was too fast, AA2012 too slow, hopefully in the middle is just right.
What length barrel and gas system to you have?
I have an 18in Satern with a mid length gas system and a JP Enterprises adjustable gas block.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 03-27-2012
I would think you could get a mid length to run. I'm chasing other possibilities in mine. I'm not giving up yet.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 03-28-2012
I tried some 8208 tonight. I was able to run 3 consecutive rounds from a magazine with a 14 grain charge. I just need to get to the range and run them over a chronograph.
Anyone come up with a action Cycling Subsonic Load yet - Grimmy - 03-28-2012
I have ran reloader 7 in my 300aac and it is very quiet. Don't know what that would be in the Grendel as far as case load density but it is really quiet. My load was 10.3 grains. Like stated start high and reduce!!! Also remember what is quiet on a cool day may go trans sonic on a warm to hot day. My target velocity is between 1000fps to 1025fps max. Up here in Pa we have a large temp swing and I want a loading that works in any temp I encounter. L had loads go super sonic just from setting in the chamber and absorbing heat from previous fired rounds.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 04-01-2012
FINALLY!!! I have a sub sonic load that cycles my action. Data is below.
20" Satern barrel, AR-15 carrier, 3.0 OZ buffer, gas port diameter .098"
Powder: IMR 8208
Case: IMI 7.62x39, necked down but NOT fire formed.
Primer: Rem 9 1/2
Bullet: 160 Hornady RN
COL: 2.220
Charges: 5 shot strings
14.5 gr, 1187 avg, 36 ES, 13 SD
14.0 gr, 1129 avg, 55 ES, 23 SD
13.5 gr, 1079 avg, 56 ES, 26 SD
All 5 shot strings were fired from a magazine, cycled properly and locked back on the last round. Temperature was 90 deg. (in March :p) so the speed of sound was around 1150 fps. I still intend to do some more testing and fine tuning but these results are encouraging.
Cases were only slightly sooty and I'm hoping magnum LR primers will help with this. Most of the soot blow by could be due to the fact these are not fire formed cases so I'll load some rounds with FF cases to test this theory. I'm using non-fire formed cases specifically for the purposes of increasing load density and fire forming the cases for full power loads.
More to follow as I can get to it...
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 04-01-2012
Grimmy Wrote:I have ran reloader 7 in my 300aac and it is very quiet. Don't know what that would be in the Grendel as far as case load density but it is really quiet. My load was 10.3 grains. Like stated start high and reduce!!! Also remember what is quiet on a cool day may go trans sonic on a warm to hot day. My target velocity is between 1000fps to 1025fps max. Up here in Pa we have a large temp swing and I want a loading that works in any temp I encounter. L had loads go super sonic just from setting in the chamber and absorbing heat from previous fired rounds.
If your loads are breaking over on a hot day it's probably due to the powder burning faster, not the atmospheric conditions the bullet is traveling through. Here's a link that helped me to understand more on the speed of sound. It also has a speed of sound calculator.
http://www.sengpielaudio.com/calculator-speedsound.htm
The higher the temperature is, the higher the speed of sound threshold is. As I understand it, an object can travel faster on hot day and not create a sonic boom than it can on a cold day. You might consider trying a powder that's less sensitive to temperature swings.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 04-11-2012
Here's a pic of the brass from the 8208 loads.
[ATTACH=CONFIG]1172[/ATTACH]
13.5 gr charge on top, 14.5 gr charge on bottom. Not too bad in terms of soot, at least not nearly as bad as some of the other powders I've tried.
You can also see how they form. The corners are not nice and sharp they do square up a bit more when they are full length re-sized. I measured the internal capacity and compared to full power fire formed brass and difference is nearly immeasurable.
Anyone come up with a action Cycling Subsonic Load yet - Variable - 04-11-2012
Is that with the can on? My factory supersonic loads look way worse than that with the can on. Your brass looks really clean to me!
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 04-12-2012
No- unfortunately I only have a .223 can now. My brass fired suppressed is much dirtier than this also. One of my main concerns with the cleanliness of the case was to get an indication of how well of a seal it was making. I had some of my earlier test loads that came out with unburnt powder stuck to the neck and shoulder. That was a PITA to get out of my chamber.
Anyone come up with a action Cycling Subsonic Load yet - Rapier - 04-15-2012
After many attempts to get full function from the Grendel, with 100% function while maintaining 100% sub sonic performance, I accieved the feat on 4-14 by seating the .267 bullet further down in the converted (fireformed) 7.62x39 WW case to an OAL of 1.794 with 12gr of AA-2015 BR. I reduced the buffer to 3oz and used a full rifle stock spring in a rifle stock. Temprature on this day 82 degrees. The barrel is 16 inches with a CAR gas tube. The load shoots .5 inches at 50 yards. It shoots 1.5 inches at 100 in a fair wind. At 100 with my 1-9 twist gun, the bullets are starting to get unstable and show signs of striking the target just off center, with round holes, but with ΒΌ moon black on one edge of the holes. I sighted in my gun for the load and feel confident in making a neck shot on a hog out to 100. Remember this is a night gun, not a day gun so any day shooting will be with full power loads.
The following is based on a five shot string, the AA-2015 load of 12 gr at 1.794 OAL, deliveres an average velocity of 1054 fps, a SD of 31 fps, a high of 1100.7 fps (my SS break is at 1116 fps), a low of 1024 fps with an ES of 77 fps with a MHD of 22.7 There was no failure to function in my 16 inch barrel with the suppressor attached. All shots were with the can. It was very nice to hear the whap as each bullet hit the cardboard at 100.
As we have gone through this process it has become obvious to me that the subsonic loads are going to have a high ES number regardless of what is done, so the figure you shoul be looking at in your testing is that one shot, that gives you the highest velocity reading. Could you reduce the high fluctiation, yes, and I have done this with bolt guns using spherical buffer. But in a gas gun, in my opinion, based on many years experiance with the use of various buffers, using something that does not burn is a recipe for disaster in the future as whatever you use, will build up in the tube/carrier key. An experiment for another day might be to use a very, very slow burning powder as a buffer.
Regards the soot build up, the neck of the 12gr loaded cartridges seals fairly well, leaving the body of the case only moderately dirty.
ERH
4-15-12
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 04-15-2012
Nice work.
I've been thinking about terminal effectiveness of these rounds and the fact that your bullets are on the borderline of stability may help you. I don't think these bullets will expand much at SS velocities but they may tumble. That would be much more effective as a 1"+ bullet turned sideways will create a heck if a would channel.
I have also considered a duplex load with a slow burning powder but I'm afraid based on my previous experiences with US869 in a SS load that many of the grains will not burn. This could cause the same problems in a gas system as an inert filler would.
Anyone come up with a action Cycling Subsonic Load yet - Variable - 04-15-2012
I'd look to "Trailboss" for any kind of duplex load.... That'll get your volume up, and without too much extra pressure.
Anyone come up with a action Cycling Subsonic Load yet - sneaky one - 04-15-2012
TX.,, are you shooting those 160's -as-is , no swaging or tweaks.-at the .268 diam.? Also, have you recovered any-by h2o jugs-to see the marks,, and expansion -if any on the unit? Would be a nice pic to see,, as my package of those 160's are missing-I was set to load some, and was curious as what to expect. Great work-between you and Rapier BTW.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 04-16-2012
Variable Wrote:I'd look to "Trailboss" for any kind of duplex load.... That'll get your volume up, and without too much extra pressure.
I have considered TB but I'm not really keen on duplex loads in general. Too many variables, especially in a gas gun. For me at the moment, extreme spreads of 50 or less are OK for my intended use of these loads. As long as they stay within a 3" group at 100 I'm good for now. Maybe one day I'll venture down the duplex load road.
Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 04-16-2012
sneaky one Wrote:TX.,, are you shooting those 160's -as-is , no swaging or tweaks.-at the .268 diam.? Also, have you recovered any-by h2o jugs-to see the marks,, and expansion -if any on the unit? Would be a nice pic to see,, as my package of those 160's are missing-I was set to load some, and was curious as what to expect. Great work-between you and Rapier BTW.
Thanks. I'm using .264 projectiles, Rapier is using the .268s. I have not had the opportunity to shoot water jugs yet but that is in the plan. I'm going to try to work it in next weekend.
Anyone come up with a action Cycling Subsonic Load yet - sneaky one - 04-17-2012
Thanks TX.