Originally Posted by Stormrider
I have 2 308's one is an M40A1 clone from Texas Brigade Armory with a 26" barrel, the other is a parts gun that I made up from spares and a takeoff Rem PSS barrel cut to 20".
A 300 Win Mag from TBA w/26" bbl.
A 300 RUM from TBA w/26" bbl.
And an AR15 in 300 Whisper.
Powder scale is a PACT electronic scale, no ogive tool, Scopes are IOR 3X18X42, 2 Leupold 4.5X14X50 and a US Optics 3.2X17.
No mirage shades.
Man, you have some nice stuff. You should/will have fun with these laser-like projectiles. They actually are consistent as if they were lathe-turned.
To really get serious and try to shoot bug holes with these projectiles, I recommend the following as these were the basic steps we used to test the bullets:
--We always shot with a mirage shade on the barrel to keep the heat rejected by the barrel from getting into the line of sight of the scope.
--We had Jewell triggers on our guns.
--We always indexed our cases. Specifically, we performed runout tests on each round and marked the high side and indexed them into the chamber with the high side up.
--We always seated our bullets with a micrometer seating die. Coupled with this is the ogive nose and base installed on dial calipers to ensure the ogive is in the exact same distance from the lands.
--We used a powder scale that was of lab quality and is accurate to .02 grains. This really helps when you are attempting to minimize the velocity spread. We weighed each charge to -.00 and + .02 grain for each charge.
--We always used bushing sizing dies to ensure that the neck is concentric and that the expander ball does not touch the neck. This controls neck tension to the highest degree.
--Along with the bushing die is turning the case necks. This ensures the case necks are the same thickness for the entire neck cricumference.
--When we sized the cases we did so in a manner and to an amount such that there was light resistance on the bolt the last 10 degrees of closing. This was checked without the firing pin installed and with a sized round without primers.
--We tuned the primer pockets so that the primer had some resistance on the last one or two degrees of motion on the priming tool.
--We uniformed the flash holes. This is a no brainer to ensure the ignition source and size is uniform from shot to shot.
--We sorted the brass into one grain weight groups and took the culls that were way outside the groups and used it for this published testing. So all this shooting is with brass that has a wide variance in its weight.
--We stuck our hand into the bag of bullets and pulled out what was needed. We did not sort bullets in any fashion.
--We always fouled the barrel with two shots prior to shooting for record.
--After each shot, we stabilized the barrel harmonics by grabbing it to supress any vibration.
--We shot all groups between 0600 and 0830 except for the last shooting session mentioned yesterday. This prevents any ground mirage from interferring with the sight picture.
--We also used Bald Eagle rests and Protektor bags and use a doughnut under the rear bag.
Other than what I mentioned above everything else is fairly standard.
Note: We purposefully left the two accuracy variables on the table due to limited numbers of test bullets and limited amounts of brass. For our long range hunting rounds those two variables will be removed as we will sort the bullets and use the sorted brass in our hunting rounds.
I think that is about it. If you need any clarification or help, let me know.