Anyone come up with a action Cycling Subsonic Load yet

Anyone come up with a action Cycling Subsonic Load yet - Printable Version

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Anyone come up with a action Cycling Subsonic Load yet - Smoke - 02-18-2012

Its been a little while since anyone posted on this so i thought I would ask again

Anyone come up with a action cycling 6.5 Grendel Subsonic Load yet ?

I itching to shoot some coyotes with the grendel QUIETLY Smile

Thanks

Smoke

Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 02-18-2012

I'm very close with 13.3 grains of AA2015 behind 160 grain Hornady round noses. I'm using fired formed IMI brass and Rem 9 1/2 primers.

There was another member here that said a similar load was cycling his upper but I believe he was running a 18" mid length gas system. I'm running a 20" rifle length and the load throws the bolt enough to eject about 50% of the time but not enough to pick up the next round. I might bump the charge again but I'm already averaging 1050 fps. Once the paperwork for my 30 cal. can clears I hope the increased pressure through the gas system will be enough to cycle it reliably. Unfortunately I have about 6 months to wait to find out. If anyone in the Austin area has a 30 cal or 6.8 can and is wiling to let me try it maybe I can test the load sooner.

Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 02-18-2012

FYI- at 100 yds, point of impact for the SS loads is 18" lower than the point of aim of my full power loads.

Anyone come up with a action Cycling Subsonic Load yet - Smoke - 02-18-2012

TXgunner
Thanks for the heads up .. i have a 18" mid length AA Barrel and a 30 cal can .. So i will try your load .. And get back to you .. may take me a few days to get the projectiles

Have you done any accurecy testing with this load?

Anyone come up with a action Cycling Subsonic Load yet - Smoke - 02-18-2012

I will try Lapua and Hornady 6.5 brass and CCI std primers and mag primers ..

Thanks
Smoke

Anyone come up with a action Cycling Subsonic Load yet - Smoke - 02-18-2012

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

Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 02-19-2012

I have not tried H322. I don't know why you shouldn't be able to use it. With sub-sonic loads you need to start at a mild to weak standard load and work down. If you start low and work up, you risk getting bullets stuck- don't ask me how I know this. Smile

I use 7.62 x 39 brass because the reduced capacity increases load density thus helping burn consistency. If you don't have any you should still be OK with the 160 grn projs as they extend deep into the case. I've actually started using non-fireformed 7.62 brass recently. Not only does it improve load density even further but it also fire forms the brass for other loads I use for hunting.

If you use Grendel brass I would consider drilling the flash hole out and dedicating that brass to subs. This is another advantage to 7.62 brass as it uses a LR primer and has a much larger flash hole.

Accuracy has been decent- 1-2 inches at 100.

Good luck!

Anyone come up with a action Cycling Subsonic Load yet - Smoke - 02-19-2012

Thanks for the Tips especially the Flash hole Idea..
So far I have developed Subs for 308, 458 and 338 lapua and in all I use cases dedicated to those Sub loads only..
So far trailboss has been the answer for All them but all were bolt guns so not need to up the pressures to cycle

Thinking about trying H335 as well.. Will keep you posted

Thanks
Smoke

Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 02-20-2012

I use Trailboss on .223 but it didn't work for me in the Grendel. Couldn't get over 800 fps even with a compressed load.

Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 02-20-2012

http://www.65grendel.com/forum/showthread.php?266-SUB-SONIC-Grendel-loads&highlight=sonic

Here's a thread I started a while back. Good info from other members.

Anyone come up with a action Cycling Subsonic Load yet - Kikn - 02-20-2012

I'm just thinking out loud here a bit. But has anyone tried using a lighter buffer and a loser spring?

Anyone come up with a action Cycling Subsonic Load yet - Smoke - 02-20-2012

Thanks for the heads up on the old Thread .. confirms some of my thinking

Ok I have 160 Grainers arriving wed.. I will try H335 13.4 grns using a 30 cal Can ..
That should give more back pressure ..to the load
again I have an 18" AA barrel and Mid length gas system

Thanks

Smoke

Anyone come up with a action Cycling Subsonic Load yet - samalama76 - 02-20-2012

What twist rate are you guys using with the 160 grainers and are they stabilizing them?

Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 02-20-2012

Smoke Wrote:Thanks for the heads up on the old Thread .. confirms some of my thinking

Ok I have 160 Grainers arriving wed.. I will try H335 13.4 grns using a 30 cal Can ..
That should give more back pressure ..to the load
again I have an 18" AA barrel and Mid length gas system

Thanks

Smoke

It will be interesting to see if it works. SS loads that will cycle a gas gun require a fine balance between enough pressure to throw the bolt reliably but not too much to push the bullet over the speed of sound. Timing is everything and each rifle is different. To be successful you have to match the pressure curve to the gas port location, gas port size, buffer weight, buffer spring tension, etc, etc. This is why you typically need faster burning powders for SS loads. Don't get discouraged of you have to make several attempts.

Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 02-20-2012

samalama76 Wrote:What twist rate are you guys using with the 160 grainers and are they stabilizing them?

My barrel is 1:8.75.

Anyone come up with a action Cycling Subsonic Load yet - Variable - 02-21-2012

samalama76 Wrote:What twist rate are you guys using with the 160 grainers and are they stabilizing them?

I have a 1:7.5" twist in my 10.5" barrel. It stabilizes fine with the Hornady 160 grain bullet. I just couldn't find any load that would cycle in my upper at subsonic velocity. I'm pretty sure my problem is lack of dwell time. If I could do it over again I would wish that someone would make a 10.5" chromed bore with a pistol length gas system (instead of the carbine length on the AA Tactical upper.

My dream upper would probably be a 10.5"-12.5" chromed barrel with either a pistol length gas system or (preferably) a Noveske style switched gas block sitting over a larger gas port. If it was feasible then the switchable gas block would have a folding front site and three orifice sizes. One regular sized for conventional ammunition, one oversize to cycle subs with a can, and one "off" setting for maximum sound suppression while cycled manually. I can dream... Smile

Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 02-21-2012

Variable Wrote:I have a 1:7.5" twist in my 10.5" barrel. It stabilizes fine with the Hornady 160 grain bullet. I just couldn't find any load that would cycle in my upper at subsonic velocity. I'm pretty sure my problem is lack of dwell time. If I could do it over again I would wish that someone would make a 10.5" chromed bore with a pistol length gas system (instead of the carbine length on the AA Tactical upper.

My dream upper would probably be a 10.5"-12.5" chromed barrel with either a pistol length gas system or (preferably) a Noveske style switched gas block sitting over a larger gas port. If it was feasible then the switchable gas block would have a folding front site and three orifice sizes. One regular sized for conventional ammunition, one oversize to cycle subs with a can, and one "off" setting for maximum sound suppression while cycled manually. I can dream...

You dream has come true- almost. Paladin Machine will make a switchable gas block to your specs. I'm not sure about the front site though.

Anyone come up with a action Cycling Subsonic Load yet - Variable - 02-21-2012

txgunner00 Wrote:My barrel is 1:8.75.

I was surprised to read that "Trail Boss" didn't get you enough velocity. It worked great (except for cycling) in my 10.5" upper. I guess those long 160 gr. telephone poles have too much friction for that powder in barrels as long as yours.

I haven't had time to tinker with mine for a while, but I might give it another whirl this year when the weather gets better. I should probably just give up and start over with my 14.5" upper instead, but I'd much rather get the shorty running.

Anyone come up with a action Cycling Subsonic Load yet - txgunner00 - 02-23-2012

Kind of surprised me too. My first attempt with TB actually got the bullet stuck about 2" from the end. Even with compressed loads I couldn't get much velocity. I even tried the other end of the spectrum with US869. It actually cycled but not all the powder burned even with Federal LR magnum primers. I would have unburnt grains of powder stuck to the neck of the ejected case. I wish I had a picture of it.

I also tried Unique at 7.4 grains. 1050 avg, 57 es, good groups but no cycle.

Anyone come up with a action Cycling Subsonic Load yet - Retooferab - 02-23-2012

Keep in mind I know nothing about subsonics in a Grendel. I have had a lot of experience with subs in a 300 Whisper. I have had excellent results using N110 and AA9 with subs in my Whisper. 1680 worked well also but took more powder and was loud! Has anyone tried any of these?