308 subsonic

[Night Shooter]

I would be real interested in your load data for the 220 SMK in the 300 Whisper with Win 321. I'm new to the site, but my interests are sound suppresson and accurate out to two hunderd meters.

George at THG is a real profectionest and a great person. I met him at the last Sniper Shoot in Boise, ID.

TR

[rumlover]

ARTFUL, you were right on with the lubing the barrel. I'd push a CLP patch through followed by a dry patch and each first shot was withing 1 SD of the mean vel.

[Artful]

1/8/08 windy and cool


Powder—Clays—8.1gr Case------Remington
Primer---CCI 250 Bullet---Remington—170gr SPCL-RN
OAL----2.747 Crimp--.003
Test Rifle—FAL—Suppressed
Vel. fps
758.3
875.8
867.6
782.0
846.6
697.7
827.1
766.3
761.4
828.9
816.5
809.9
771.7
762.5
800.4

Notes: One round stuck in Barrel and one stopped in suppressor! :shock:
Cleaning and re-Oiling the barrel seemed to alleviate the problem.
also notice with .003 lee factory crimp velocities ran a little low

#13 A
Powder—Clays—8.1gr Case------Remington
Primer---CCI 250 Bullet---Hornady---168gr--BTHP
OAL----2.800 Crimp--None
Test Rifle—FAL—Suppressed

777.1 * note: first round slower probably due to long barrel cold steel
999.1
975.9
1035
1031
1024
1033
1036
1017

Only change was the bullet (less bearing surface) & crimp - note higher velocity and it grouped better as well.

hear a shot compare

http://www.youtube.com/watch?v=wMIomwkvyBQ

the big noise is someone's AR without a can

Photographic credits to Sparky007

[Artful]

2/22/2008 - about 55 to 60 deg F Beautiful Sunshine morning in AZ.

Loaded some more 168 Hornady 168 BTHP over 8.0 gr of CLAYS powder
First batch with cci #34 primers 2.800 OAL in Rem. cases NO Crimp

Ran bore snake thru with nitro solvent then followed with CLP patch
thru 21" FAL with AAC Cyclone attached - set on single shot (Grenade)

Ran two chrono's in Tandem


First batch of 9 out of the clean/oiled barrel

1st_______2nd
Chrony ... Chrony ___Dif
1134_____1143_____+ 9
1118_____1123_____+ 5
1109_____1122_____+13
1115_____1068_____(-47)
1105_____1068_____(-37)
1115_____1066_____(-49)
1102_____1047_____(-55)
1110_____1054_____(-56)
1105_____1055_____(-50)
1089_____1035_____(-54)



No clue why the differences but we recorded both

We had Loaded 168 Hornady 168 BTHP over 8.0 gr of clays
with CCI #250 Magnum primers 2.800 OAL in Rem. cases NO Crimp
this time we first tilted up the barrel before shooting.

Ran two chrono's in Tandem
1st_______2nd
Chrony ... Chrony ___Dif
845.0_____865.6 ___+20.6
1088_____1045_____(-43)
1099_____1045_____(-54)
1106_____1115_____+ 9
1124_____1141_____+17
1115_____1132_____+17
1120_____1133_____+13
1104_____1116_____+12
1117_____1059_____(-58 )


Next nine where keeping the barrel level and loaded thru ejection port to keep powder spread out. Same Load 168 Hornady 168 BTHP over 8.0 gr of clays with CCI #250 Magnum primers 2.800 OAL in Rem. cases NO Crimp.

Ran two chrono's in Tandem
1st_______2nd
Chrony ... Chrony ___Dif
1166_____1188_____+22
1133_____1155_____+22
1129_____1153_____+24
1133_____1156_____+23
1132_____1153_____+21
1127_____1155_____+28
1135_____1158_____+23
1124_____1146_____+22
1135_____1162_____+27



Loaded 168 Hornady 168 BTHP over 8.0 gr of clays
with CCIi #34 primers 2.800 OAL in Rem. cases NO Crimp
Same load as first batch but with Moly coating on the bullets

Ran two chrono's in Tandem
1st_______2nd
Chrony ... Chrony ___Dif
1032_____1050_____+18
1117_____1135_____+18
1133_____1150_____+17
1112_____1127_____+15
1123_____1140_____+17
1111_____1128_____+17
1103_____1110_____+ 7
1116_____1129_____+11
1110_____1092_____(-18 )

[pug]

As far as the variation in two chronys there is probably a slight difference in frequency between the two master clock signals that drive the counter logic. If you could tie power and master clock signals from one chrony to the other there would probably be little difference in readings and it would make a good proof system. Just thought I would throw that in .

[Artful]

Went up to northern Arizona today 5800 elevation - brisk 38-40 degree's in breezy conditions wtih slightly overcast skys. I shot 10 rounds thru the 21 inch barreled FAL with AAC Cyclone on it. Testing for accuracy at greater distance than last test, 100 paces today well call it 90 yards to be conservative.


Lowered powder charge by .1 to 7.9 grains of Clays, using same
168 gn Hornady BTHP with CCI 250 primer.

First 5 shots


Second 5 shots


Consistant Velocities but still a little fast.

[Foxfire]

Artful,

Are you still using reduced capacity cases?
Or have you gone back to using stock cases?

TIA, Foxfire

[Artful]

Back to stock cases as both the epoxy and the thermal polymer failed to hold up inside and broke up sending chunks down the bore into the suppressor.

If you want to use reduced capacity cases I'd suggest you either look at the aluminum ones from Canada or the brass ones from Europe but either way it's not cheap - I'm going back over my results trying to find my errors as at this point I should have found what I was looking for but may have to rethink my parameters for what I want out of my load.

[Foxfire]

Find out your errors???....
I thought you had a very good load (7.9 clays), that is why I was asking about the cases.
What are you trying to get out of it?

Fox

[Artful]

Foxfire 7.9 of clays isn't a bad load it just isn't always subsonic out of my gun
- I need a load that is always quiet and accurate - last test I did which I didn't really put out was loaded with clays in lessor amounts

7.9 gave
1149
1140
1168
1192
1189
1186
1134
1147

7.8 gave
1018
1129
1126
1129
1139
1153
1240
and one missed one of the screens?

7.7
971.8
1120
1115
1126
1149
1152
1127
1152

still too fast and I don't want to go below 7.7 due to volume concerns.

Now keep in mind these are thru a 21" barrel so any of these may work very well in your barrel. You just have to try it and see.