Supersonic Lee 200gr Load Data for 300 Whisper

[thehouseproduct]

C309-200-R
Does any one have supersonic load data for this boolit in a 300 Whisper? I want to seat it to the crimp groove and shoot cheap. I have to go super sonic because I have a carbine gas system and can't get it to cycle sub sonic. What would my max load be?

[Nobade]

You don't say what powder you want to use, so just to see what would happen I told Quickload you're seating the bullet .308" deep and 16.0gr. IMR4198 (101% load) would give 1570 fps at 36KSI from a 16 inch barrel. If you give more details you can get more results.

[thehouseproduct]

Sorry. the barrel is actually closer to 13.5" with the brake pinned on. I have the following powders that might be applicable.

Unique
IMR-4895
IMR-4227
Xterminator
H4198
H110
H335
Varget

[Nobade]

Unique - no way.
4895 - 17.5gr, 25KSI, 1300 fps
4227 - 14gr, 33KSI, 1450 fps
Xterminator - 19gr, 37.7KSI, 1570 fps
H4198 - 16gr, 36.5KSI, 1480 fps
H110 - 14.5gr, 35.7KSI, 1500 fps
H335 - 19.5gr, 35.7KSI, 1525 fps
Varget - 18.0 gr, 26KSI, 1300 fps

Note the high pressures most of these operate at. Likely you will find they are not terribly accurate at full loads, but these are the max loads. Start lower, normally add just enough powder to function the action every time. I'd be looking at 4895 and Varget for best accuracy if it were me. Keep in mind I specified a .308" seating depth. More or less will change the loads. Hope this gets you going in the right direction.

[thehouseproduct]

Good info, thanks. The bullet is actually seated 0.445" into the case but the 0.0103in^3 difference in case volume shouldn't be significant enough to over come the 55kpsi limit on an AR15.

[Artful]

I'm not using cast because I have a can on my whisper but for lighter bullets am using 5744 and 1680 for heavier (220 smk) - of course I'm limiting myself to under 1100 fps to stay away from transonic/supersonic noise. - do you have gas port in pistol position or carbine?

[thehouseproduct]

Mine is in the carbine position. It makes getting subsonic a tricky matter.

[rufracer]

1680 and h116 works in my ar with the same boolit down to about 900fps. I used some data 68 to but had some un-burnt powder. I am using a carbine length tube adj. gas block. I use a cavalry arms lower with a heavily greased buffer tube, which makes for the quietest ar action Ive ever heard. The buffer spring seems to be a bit lighter on these lowers too. I cant remember what my excact loads are off hand, but I remember it was substantially less than what I found here http://www.quarterbore.com/300whisper/subsonic.html for similar weights.

I know of another guy here locally that couldnt ever get his ar cycling with the right powder burn rates and ended up getting a pistol lenght tube installed. If you dont find a load that works well I would start by removing the weight from your buffer, and then maybe a lighter spring or cut the one you have down a bit. You could also check if you gas port is .125 which is as big as is affective, and see if your gas block is lined up just right with it by looking for fouling around the edges of the gas port hole on the ID of your gas block. I wouldnt write all this but getting a 300 to cycle sub-sonic round can be a bit of a balancing act.

Oh yeah, if your gas port hole is .125 and you are going to run full power loads, I would definately get an adj. gas block or tube.

[Artful]

or have your gunsmith get creative

Dual port (pistol and carbine) selective 300 whisper set up
I keep looking at it and have to decide if it's worth it to be able to use fast pistol powders.

[rufracer]

nice!!

[rufracer]

Of course after that long technical post I re-read the title and realized you wanted super-sonic loads.

Still 1680, 4227 though.

[Artful]

OK, I have not had any use for a heavy supersonic but found some data by googlage

http://www.quarterbore.com/300whisper/supersonic.html

http://www.loaddata.com/loads/300caliberloads.html

http://www.accuratereloading.com/300whisper.html

http://www.lasc.us/RangingShotLongWhisper.htm

http://www.reloadersnest.com/frontpa...?CaliberID=135

looks like some are getting 1100 to 1200 with 1680 or 5744 and 220 SMK
200 grainer with RL7 going 1600 fps
1700 fps with 190 grainer and RL7 (bet that's hot one)

may have to pick up some RL7 to try out

[thehouseproduct]

Finally got out and shot some 200gr supersonic loads. For poorly cast boolits shot offhand with an Eotech, I am happy with the results.
200gr wheel weight C309-200-R 5 shot group at 25 yards:

[redneckdan]

I used mostly 4227 in mine. I found H335 to be way too slow, lots of unburned kernels in the barrel. Be careful with the published data out there. Some if it is HOTTT!!! I turned one case into a belted magnum with a load that was 1 gr below the published max.

[thehouseproduct]

I had 17gr of Xterminator.