Anyone come up with a action Cycling Subsonic Load yet

[txgunner00]

Few more pics.

Projos from the backstop.



Brass from yesterday's testing. Not perfect forming but well enough for full power blasting / hunting loads.



CCI primed brass on the left, Rem 9 1/2 primed brass on the right.

[txgunner00]

Here's the data from my unsuccessful tests over the last year. If Rapier and the other's that have posted information don't mind, I'd like to add it to the list and separate it by what worked and what didn't.

[Rapier]

TX,
I do not mind at all. I did note that you had a conversation about neck tension and pre fire formed 7.62x39 cases.

It is worth a mention here as a result of your discussions that I had problems with the Lee dies so switched to the Redding die set. Then discovered the .267 bullets had to be seated deeper than either die would reach. The Lee die would work with a home made plug. So I made a long seater plug for the Lee seating die from a cut off bolt with a long unthreaded shank. I just cut off the threads and left the part that contacts the bullet flat. The .267 bullet is .267 right to the ogive of the round nose, just like a rod.

I to found that the 7.62x39 brass worked for my loads.

I think I came upon what was happening with the Lee dies. I understand that back last year in the spring, I believe, the 6.5 Grendel bolts were changed by Alexander to what is called a Type II bolt. The Type II bolt has .010 of bolt face clearance. Lee dies may well have changed their sizer to match because the Lee dies I bought were advertised as Alexander Arms dies. Now, the 6.5 Sporter by Model 1 and the 264 LBC both use a Type 1 bolt face with a standard .003 or close to that, bolt face clearance. I kept having chambering problems that made no sense until I went through buying a new barrel with a guy that just bought a new Black Hole barrel and ran into the question, do you want a Type I or a II.......

On my Sporter barrel with its matching bolt, the Redding dies solved my feed problem, but I did not know why. I think it goes like this: You reduce the spring and or buffer weight and the bolt does not slam home with enough force to create a crush fit if your sizer did a .010 bolt face sizing for you and you need .003.

You need a sizer that matches your bolt to chamber fit so all that happens is that the case slides home with the bolt right behind it and locks up. Make sense?
Ed

[mongoosesnipe]

I have a barrel on order from satern that should be able to cycle light loads with out issue I am getting a 21 inch barrel with a mid-length gas system and an adjustable gas block also the use of a suppressor will often provide and sufficient increase in pressure to cycle a lot of guns running subsonic though you often need to take the weights out of the buffer or get an extra buffer that is lighter for use with subsonic loads

[txgunner00]

21" with a mid length gas system? Did you order that for a specific reason? Please share.

The suppressor will absolutely help but I don't have one the correct size yet. I'm waiting on a form 1 so I can make my own.

[LRRPF52]

TX,


I think I came upon what was happening with the Lee dies. I understand that back last year in the spring, I believe, the 6.5 Grendel bolts were changed by Alexander to what is called a Type II bolt. The Type II bolt has .010 of bolt face clearance. Lee dies may well have changed their sizer to match because the Lee dies I bought were advertised as Alexander Arms dies. Now, the 6.5 Sporter by Model 1 and the 264 LBC both use a Type 1 bolt face with a standard .003 or close to that, bolt face clearance. I kept having chambering problems that made no sense until I went through buying a new barrel with a guy that just bought a new Black Hole barrel and ran into the question, do you want a Type I or a II.......


Ed

Alexander Arms has not changed the bolt design, unless there's something I missed. They have always used the original Colt 7.62x39 bolt design, which has a .135" bolt face depth.

Many after-market companies started making their own 7.62x39 bolts with the same depth as a 5.56 bolt, which is .124", hence the .011" difference.

BHW started out with their Type I bolt as a .124" face depth, and have now gone to a .135" depth for the Type II.

[sneaky one]

Nice vids., TX. Try h20 jugs --3 rows, 10 deep. Or increase the size of the jugs,( no pun intended)...... or add some thick rubber-etc around the edges. to capture- or bounce back-inward? the ones that exit the side.-they are real slow at that point. I used a wheelbarrow to haul 2 loads of 30 juggs last May to the range= phew ! Plus all the shooting stuff=4 trips.

[txgunner00]

I would have stacked them deeper but that's all I had. I'm doing research into doing my own ballistics gel test. That should be fun.

[txgunner00]

Though I'd share a I little data I collected late last night (I have a bullet trap in my garage) I put a heavy crimp with a Lee factory crimp die on a few loads to see the effect. Non-fire formed cases came out a little less dirty and slightly better formed compared to uncrimped non-fire formed brass. (bottom 3 in the pic)

I also loaded a few using Winchester fire formed brass and crimped (top 3 in the pic). The increased case capacity / decreased load density had an adverse affect as they did not cycle- ejected the spent case but didn't feed. I need to play with the seating depth a bit to see if that helps. These were seated an 2.220. They do come out slightly cleaner than non-fire formed brass but still do not get a complete seal as evidenced by the soot around the case rim.



The cleanliness of the case is really a matter of observation of how the round is performing in the chamber. As long as there isn't any unburnt powder present it doesn't concern me much because adding a suppressor will make them come out black.

[Variable]

Yeah, with a can they'll likely look like #2--#6 in this pic. The farther down the mag they are the dirtier they'll be as the blowback from the can will deposit crap on them before they're even fired.

[txgunner00]

Here's another vid from today shooting water jugs. Passed through 5. Still wasn't able to recover the bullet because it yawed upwards and went over the berm.

http://youtu.be/JOcpYX5DXMo

Summary of the 5 jugs
1st- pretty much straight through, exit hole a little oblong.
2nd- entrance slightly larger than round, exit hole about 3/4" long, jug ruptured
3rd- entrance 3/4", exit over 1", bullet appears to be rotated 90 deg., jug severely ruptured
4th - over 1", entrance side of jug split, 1" exit
5th - 1" entrance & exit at top of jug.

[txgunner00]

Just a quick clip of a SS triple tap.

Nevermind my fishing hat...

I have some more chrono data also. I'll get it up as soon as I can organize it.

http://youtu.be/dw0VA9axrt0

[Variable]

[whispers]Pssst... Us Safari browsin' iPad impaired folks can't see the embedded vids on this board... Got any links?[/whispers]

[mongoosesnipe]

21" with a mid length gas system? Did you order that for a specific reason? Please share.

The suppressor will absolutely help but I don't have one the correct size yet. I'm waiting on a form 1 so I can make my own.

I like to use mid length gas systems with low profile gas blocks and rifle length float tubes gives a nice clean profile on my ar builds mostly just a personal preference and the use of an adjustable gas block allows me to cycle just about any load a habit I picked up on my whisper build

[txgunner00]

I like to use mid length gas systems with low profile gas blocks and rifle length float tubes gives a nice clean profile on my ar builds mostly just a personal preference and the use of an adjustable gas block allows me to cycle just about any load a habit I picked up on my whisper build

You should have no problem developing a SS load then. Lots of dwell time on that gas system.