gunDriller
13th February 2016, 06:40 AM
http://gold-silver.us/forum/attachment.php?attachmentid=8084&d=1455369558
http://gold-silver.us/forum/attachment.php?attachmentid=8085&stc=1&d=1455369570
I was shooting yesterday and a few days ago, and had bullets that went over-pressure both days. 300 Blackout on Wednesday, 5.56 Friday.
I saved and labelled them and took pictures of everything. So far only the 300 Blackout pictures are decent, but it shows what happened with 5.56 (same bolt, 300 Blackout was derived using 5.56 brass.)
The picture with the 2 brass'es ... that's the difference between 1.350 grams and 1.300 grams. 1.250 grams was the right amount. This is in 300 Blackout with a 125 grain bullet.
Yeterday Friday I was all ready to shoot at 200 yards and had 6 targets lined up. 4 targets for re-loads, 2 targets for factory ammo.
Halfway through, I had 4198 powder (faster burning end of the rifle powder spectrum) with 2 different bullets, 75 grains (1.500 grams powder) and 55 grains(1.550 grams powder).
The 75 grain takes up more volume, and got a little less powder.
The bottom of the 5.56 brass look very similar to the 300 Blackout brass.
1.550 grams of 4198 yielded a more deformed brass - and a stuck and possibly damaged bolt. Nowhere near as bad as previous bolts, I think this one may not have been deformed.
Anyway, like they say ... you start LOW, and work your way up.
It was a busy Friday afternoon at the range, and someone else wanted to do a target change right when I was trying the bolt on factory ammo, after shooting the over-loaded 4198 bullets. It wasn't looking promising, so I used it as a chance to retrieve all my targets.
BUT - when we were all back at the firing line, I took a shot at the plywood target using factory ammo, and the bolt cycled AOK.
http://gold-silver.us/forum/attachment.php?attachmentid=8085&stc=1&d=1455369570
I was shooting yesterday and a few days ago, and had bullets that went over-pressure both days. 300 Blackout on Wednesday, 5.56 Friday.
I saved and labelled them and took pictures of everything. So far only the 300 Blackout pictures are decent, but it shows what happened with 5.56 (same bolt, 300 Blackout was derived using 5.56 brass.)
The picture with the 2 brass'es ... that's the difference between 1.350 grams and 1.300 grams. 1.250 grams was the right amount. This is in 300 Blackout with a 125 grain bullet.
Yeterday Friday I was all ready to shoot at 200 yards and had 6 targets lined up. 4 targets for re-loads, 2 targets for factory ammo.
Halfway through, I had 4198 powder (faster burning end of the rifle powder spectrum) with 2 different bullets, 75 grains (1.500 grams powder) and 55 grains(1.550 grams powder).
The 75 grain takes up more volume, and got a little less powder.
The bottom of the 5.56 brass look very similar to the 300 Blackout brass.
1.550 grams of 4198 yielded a more deformed brass - and a stuck and possibly damaged bolt. Nowhere near as bad as previous bolts, I think this one may not have been deformed.
Anyway, like they say ... you start LOW, and work your way up.
It was a busy Friday afternoon at the range, and someone else wanted to do a target change right when I was trying the bolt on factory ammo, after shooting the over-loaded 4198 bullets. It wasn't looking promising, so I used it as a chance to retrieve all my targets.
BUT - when we were all back at the firing line, I took a shot at the plywood target using factory ammo, and the bolt cycled AOK.