308 subsonic

[m21black]

Can you provide some loading data on the 300 Whisper using the Winchester 231 powder. I have been using the H 110 powder.

[Artful]

Originally Posted by Artful

Test date 7/21/07 time 8:00 am to 10:30 am
Temp 98-103 Humidity 36%
Sunny and clear Wind 4 knots
Far East Valley out of Phoenix AZ

Cases filled to bottom of neck with Plastic clay and baked at 300 degrees for 20 min to solidify.

Flash hole diameter drilled at 1/8”, 3/16” up from rim.

Powder cavity diameter drilled at 3/16”,
drilled down from neck to need extended flash hole.
Remington 150gr Bullet PSP - moly coated
Each case loaded with 3 gr of Red Dot

(this loaded filled the cavity 7/8” up from bottom of case. filling the case to the bottom of the neck holds 5.7gr of Red Dot with bullet seated you have room for 4.7 grains of Red Dot)

Case—Remington with primer hole drilled out.

Each of 7 rounds weighed in grains loaded, velocity in FPS, FAL with or without can, overall length

#-Weight..Feet Per second...Suppressed....OAL
1-372.4....486.6...................yes.............. ..2.705
2-374.0...605.1....................no............... ..2.700
3-372.6...525.8...................yes............... .2.700
4-370.8...438.6...................no................ ..2.700
5-374.1...573.2...................no................ ..2.702
6-371.6...372.1..................no................. ..2.699
7-374.0...511.3..................no................. ..2.695

Needless to say I'll be upping the charge to see if it improves the consistancy of velocity and trying to get closer to 1000 fps.

Next Test

Test date 9/22/07 time 9:00 am to 10:30 am
Temp 80-83 Humidity 25%
Sunny and clear Wind 1-2 knots
Far West Valley out of Phoenix AZ

Cases filled to bottom of neck with Plastic clay and baked at 300 degrees for 20 min to solidify.

Flash hole diameter drilled at 1/8”, 3/16” up from rim.

Powder cavity diameter drilled at 3/16”,
drilled down from neck to need extended flash hole.
Remington 150gr Bullet PSP - moly coated
Each case loaded with 4.2 gr of Red Dot

(this loaded filled the cavity 7/8” up from bottom of case. filling the case to the bottom of the neck holds 5.7gr of Red Dot with bullet seated you have room for 4.7 grains of Red Dot)

Case—Remington with primer hole drilled out.

Each of 7 rounds weighed in grains loaded, velocity in FPS, FAL with or without can, overall length

All were shot Suppressed

#-..Feet Per second.......OAL

1-..851.4......................2.701

2-..872.6......................2.700

3-..856.8......................2.700

4-..854.7......................2.701

5-..838.1......................2.701

6-..846.1......................2.700

7-..816.3......................2.699

Lost some of the filler upon firing

- found new direction

http://data.hodgdon.com/cartridge_load.asp

Cartridge: 308 Winchester
Load Type: Rifle
Starting Loads

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Maximum Loads

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Bullet Weight (Gr.) Order BW Powder Bullet Diam. C.O.L. Grs. Vel. (ft/s) Pressure Grs. Vel. (ft/s) Pressure

--------------------------------------------------------------------------------


168 GR. SIE HPBT 168 Titegroup .308" 2.800" 8.0 1080 25,000 CUP

168 GR. SIE HPBT 168 Clays .308" 2.800" 8.0 1060 26,800
CUP


Cartridge: 223 Remington Load Type: Rifle
Starting Loads

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Maximum Loads

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Bullet Weight (Gr.) Order BW Powder Bullet Diam. C.O.L. Grs. Vel. (ft/s) Pressure Grs. Vel. (ft/s) Pressure

--------------------------------------------------------------------------------

55 GR. HDY FMJ 55 Titegroup .224" 2.200" 3.1 1064 4,000 CUP

55 GR. HDY FMJ 55 Clays .224" 2.200" 3.2 1060 3,700 CUP

[Artful]

Test date 9/30/07 time 10:30 am to Noon
Temp 80's Humidity 25%
Sunny and clear Wind 1-2 knots
Cottonwood AZ

Flash hole diameter drilled at 1/8”.
Horny 168gr HPBT - moly coated

Case—Remington with primer CCI 250. 2.800 OAL

All were shot Suppressed out of 21 inch FAL barrel
info from http://data.hodgdon.com/cartridge_load.asp

Titegroup 8.0 grains Shots FPS 966 1220 953 1123 1263

Clays 8.0 grains FPS 1183 1215 1223 1213 1111

next tried lower powder charges - not recommended by website

Titegroup 7.9 grains FPS 1145 1142 831.5 707 1264

Clays 7.9 garins FPS 1133 1067 1566 1191 711

Lowered by .1 grains more

Titegroup 7.8 grains FPS 2207?!* 1063 1185 764 787 - *suspected fault of chrono read maybe due to reflection as sounded subsonic

Clays 7.8 grn FPS 1156 1174 1188 1168 - note one shot errored on chrono

Lowered again

Titegroup 7.7 grains FPS 1192 1238 1254 1215 1247

Clays 7.7 grains 1078 846.5 827.1 883.1 - note one shot errored on chrono

[Artful]

Shot 10/23/2007
changed to non-flashhole drilled WIN case with WIN Large Pistol primer.
Using Hornaday 168 BTHP

Powder___Load_____OAL____Velicity
Titegroup__8.0 gr 2.800____1163-1298-1280-1292-1282
Titegroup__7.8 gr__2.800____1009-1248-1254-1264-1267
Titegroup __7.6 gr_ 2.800____957.2-1208-1238-1227-1239

Clays_____ 8.0 gr__2.800___916.9-1207-1199-1212-1189
Clays_____ 7.8 gr__2.800___827.0-1148-1152-1160-1169
Clays_____ 7.6 gr__2.800___815.4-1078-1117-1113-1157

Note the first round shoot in each group had a significan velocity drop
for some reason - accuracte was reasonable - round holes at 80 yards
in the target - about 15 inches of drop over normal loadings.

Conclusion it appears that faster powders like pistol primers more - Will load up some more with different bullets of similar weight and retest for accuracy and try and find out what the first shot being lower velocity is all about.

[m21black]

looks like a lot of your 308 loads are not subsonic based on the velocities provided I like 1020 to 1060fps...

[Artful]

In sunny AZ you can get away with a little more speed

when it's in 90's here about 1140 it starts getting very noise - anything over 1150 your booming - I'm still just trying to get a good reliable non-position sensitive load going.

I was really hoping trailboss was going to be my answer

but we keep trying.

[m21black]

build a whisper is all I can say...

[Artful]

Got one, but I'm stubborn and want my 308 subsonic cheap as well, the prices the other guys are charging for "factory" ammo is a little much.

[jarhead1086]

Artful, you need some Blaylock brass. Dale Blaylock used to have a site and sell the stuff and suppressors too. There has to be some around. My Blaylock brass dosen't fit my chamber now that it was rechambered. I was getting great results in my 16" 1:12 boltgun using about 8.7 grains of AA#9 and 175 MK's. Maybe you should try the AA#9 in your filled cases? Blaylock brass has a small primer pocket and I was using rifle primers. Benchrest brass with the plastic clay would duplicate this I would think. Blaylock sold me a Leupold scope with dots for every 50 yards of drop for subsonic and a line for supersonic which I still use too, but he has disappeared. I still remember my first shot and being amazed that I watched the hole appear on the paper. Instant addiction and Hollywood quiet. The factory subsonic has all been disappointing except for the EBR.

[zooly22]

Try this link. I plan to order some of these for my 30-30 SS Handy on monday. www.stealthround.com


zooly22