Anyone come up with a action Cycling Subsonic Load yet

[txgunner00]

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

I believe Rapier did. I have not as of yet because I don't want to switch any parts to shoot one or the other. One option is a switchable gas block with an oversize port for subs. It does come with some risk because shooting full power loads on an oversize port could cause damage.

[Smoke]

Just a heads up .. I loaded 3 rds 6.5 160 grn (.267) 13.5 grns H335 Seated at 1.850 (touching the rifling of my barrel ) WITHOUT a Suppressor Attached
2 in mag.. all 3 cycled the action no problem ..and Stripped the next round.. Thats on a 18" mid length AA barrel .. next I will load another 5 and chrono

again just a heads up looks promising on this gun anyway

Thanks
Smoke

[txgunner00]

Good deal. Looks like we have several known loads for a mid length. Rifle length is proving to be more of a challenge.

[Variable]

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.

Somehow I missed this post last time. I'm a goober. Anywhoo-- I looked at what pics I could find of his blocks, and they are interesting. They kind of look like they are milled out of that soft free machining stuff we used to use in machine shop class. They also kind of look homemade? I guess if they work well that's all that matters though. I'm going to try to keep my eye out to see what everybody else comes up with.

The dual switch blocks looked pretty neat in this thread on Arfcom: http://www.ar15.com/forums/t_3_121/474337_.html

[txgunner00]

I have had a set-up like that in my head since that was originally posted but the thing that has kept me from pursuing it is the fear I would forget to close the first port and fire a full powered load. I'm sure the gas system, extractor and brass would not like it at all.

Very cool solution though.

What someone needs to invent is a self regulating gas system for a rifle like whats on a shotgun.

[Rapier]

Just to let you guys know, I picked up my can yesterday. So this weekend with a little cooperation from Ma nature I should get up to the farm to run a few rounds. The proof is in the pudding and we shall see if the calculations prove true. I have 50 rounds loaded that function the gun with a 3 oz buffer and a carbine spring and should be sub sonic. I can shoot them without the can and hear the impact on every shot at 100 yards, which should be sub sonic.
Ed

PS: The can was made by Liberty and is their QC Torch can. They did the 5.56 to 6.5 mod for no additional fee although they quoted me an additional $100 to start with. It was $580 plus $20 shipping. Order to delivery yesterday on Corp paper was 42 weeks.

[txgunner00]

Sweet! Looking forward to your AAR.

[QuadCam]

Wouldn't using a light weight bolt carrier help out in this situation?

[txgunner00]

Yes, but I'm trying to find a load that doesn't require modifications to the rifle. I'm already using a standard carbine buffer and AR-15 carrier because that's what works the best for full power loads in my rifle.

[Rapier]

It was wet and windy this weekend, but I did get out with the new 6.5 can and the Grendel. Good news and bad news. The bad news is I got my reloads off a tad for some odd reason and had chamber feed problems due to the OAL being just off a tad. The bullets were seated out to far and were being jammed into the lands, on over half the bullets, to the point that the bolt was out of battery, which should be an easy fix.

Now the good news: Previously I had full function from 12 and 12.5 gr of AA-2015 using Hornady .267 bullets seated deep and using a carbine spring plus a 3 oz buffer from the carbine, in a full rifle stock. My estimated subsonic threshold was 1116 fps the 12.5 gr load was 1100 and the 12 gr load was 1024 so I decided to take 12.2 gr loads to my range at the farm. There was no failure to function with the 12.2 gr load using the 3 oz buffer and the carbine spring but the chamber problem was obviously exasperated by the light spring, so after 15 rounds I changed to the rifle stock's full length spring. The load with that longer spring functioned flawlessly as well, with the 3 oz buffer. The additional power helped feed the rounds better. But, this feeding issue was my fault to start with and had nothing to do with the load or its function. However I suspect it probably had to do with the velocity's extreme spread.

I have some work to do on the load, as the highs and lows were very wide for my taste, 974 fps for a low and 1098 fps for a high with two 5 shot averages between 1074 and 1076. But even at 974 fps the load still functioned the action with the rifle spring! I just want to snug up the extreme spread and I hope revising the bullet seating to a depth without contact with the lands will do the trick nicely. This load remained sub sonic at its highs through 40 rounds and the load still shot under 1 inch at 50 yards for 5 rounds in a high wind, over 25 mph.

I am running a Rock River lower with a White trigger, a rubber wedge, and a Model 1, 6.5 Sporter, upper with a 16 inch ER Shaw 1-9 twist Carbine barrel with a mid length tube, the bolt is a Model 1 matching bolt, lubed with white lithium grease. I removed the carbine stock and replaced it with a full rifle stock which I am used to. Scope is a 3x12x50 tactical with a lit red dot, topped by a laser. The can is a Liberty Torch QC 6.5mm, which is 8 inches long.

Full Function= Strips 5 rounds from 10 round mag without failure to cycle and locks the bolt back on last shot, every time. I made no effort to place the powder in the case before each shot, like raising the muzzle, etc.
Ed

[txgunner00]

Good news

[Variable]

Excellent! Thank you for sharing your results!

[Rapier]

Ok, got the crazy stuff figured out. My initial loads were done with an Alexander Seating Die (Lee) and I switched to a Redding. It turns out that both dies, even set down all the way would not reach my correct seating dept, remember I am using .267 bullets. The Lee looked OK but was using the body, not the plug to seat the bullet. So my easy fix turned into a project. I made a new seater plug for the Redding die that was longer by .250 or 1/4 inch. I used a stainless bolt that was cut down to the smooth shank with the head rounded to fit inside the body while the shank fit the body/collet tube and moved freely, worked like a champ. So now I have the chamber/bullet jamming issue solved. I am hoping this setup will give me more stable Standard Deviation and Extreme Spread readings.

Just to let you know the easy fix got a bit more complicated. But I do have 40 more 12.2 gr rounds loaded and ready to roll, when I get back from visiting the son in Vegas at the end of the week.
Ed

[txgunner00]

Waiting to hear your results. I'm planning a range trip one day this week and I hope to get my loads ironed out.

[Variable]

Looking forward to hearing you guy's results.

[txgunner00]

Well I'm having heck trying get a SS load to cycle my rifle length rifle. The last time I chronographed them I was getting and average 1017 fps with 13 grains of AA2015 but the bolt would only throw back about 3/4 of the way. I just shot a series of loads working up to 16 grains but the bolt still didn't lock back on a empty mag. I sure I'm over the threshold at this point so it's back to the drawing board.

Other pertinent info on the rifle:

20" Satern
Carbine spring
3 oz carbine buffer

I don't know what the gas port size is but I did try an H3 buffer at one time with full power loads and I had reliability problems. It seems the port may be on the small size or I have some other restriction in the gas system but the rifle functions flawlessly with a wide range of full power loads so I don't want to mess with that.

Opinions on where I should go next? Faster or slower powder?

[txgunner00]

Just tried X-terminator. Anything below 22 grs would eject the casing but not pick up the next round.

I should also mention I'm using IMI brass, sized but not fire formed and a CCI 250 large rifle magnum primer. Load densities are above 50% even with the sub-sonic AA2015 load and cases are not too sooty. No evidence of unburnt powder.

[Gswamp]

Too bad AA#9 won't work. I have 8lbs and nothing to shoot it in.

[txgunner00]

AA#9 is actually in the ball park of the next powder I want to try. Unique was too fast, AA2015 too slow, hopefully in the middle is just right.

[txgunner00]

Too bad AA#9 won't work. I have 8lbs and nothing to shoot it in.

What length barrel and gas system to you have?