rcw3 said:
Chris
Initially there was a problem with the barrel for the 6mm Rem and it shot poorly no matter what I shot out of it. I just had another 1.5" cut off the muzzle to get rid of the problem,i.e. very rough tooling marks in the bore and not lapped or badly lapped at the muzzle end and picked up huge amounts of copper). Yesterday I did some accuracy testing with the Sierra 107's and DTAC 115's to see if the barrel issue was resolved, and it appears to be resolved, but now I am down to a 28.5" barrel instead of the 30" barrel it was to finish at.
I am also currently not confident with the DTAC 117's,boron nitride coated) as I went to a 1000 yard match a little over a week ago,with a different 6mm cartridge) and I had two of them vanish into thin air for no apparent reason,only going 2950-2980 fps). At this point I will try other bullets.
Robert Whitley
Robert the following is my recent experience with the 117DTACS b/n coated. two rifles both Surgeon single shot actions
Schneider 30 " 5P 7.5 twist hv 8
243 AI
pillar and skim bedded
Ammo : 117 Dtacs b/n
Lapua cases
RL 25 46.3 grs for rifle 1 and 47.2 grs. for rifle two
FED 210 GM
seated long ,bolt closing sets final seat depth
Velocity /es rifle one : 3044 avg /18
rifle two : 3007 avg / 11 es Oehler 35p with 8 foot bar
group sizes rifle one and two : 3tenths at 100 with many going in the mid twos, 5 shot groups ) .750 at 300 3 shot groups
Rifle one seems to have a tighter bore , note the velocity difference and powder weight difference between the two rifles . Also when first cleaning session occurred the same jag and patch for rifle two could not be pushed through rifle ones bore . Had to buff jag down and is still extremely tight . This condition persists at current round count .
Rifle one has 350 rounds through it and two has 210 rounds . Both rifles received same breakin treatment , i.e. shot one /clean for 5 round s , shoot two and clean for 5 sets, and shoot 10 then clean . The last step was not necessary as the bore was not copper fouling any more .
At the Camp Robinson 1000 yd f class and palma shoot in June rifle one was the only one of the two shooting . elevation comeup was determined by using Exbal and the first sighter was around .5 moa low and centered .Oily bbl on that shot so sighter two was fired without any changes and was slightly high and centered . Down .5 moa , fire third sighter for a x slightly left .Record firing began at this point and the shots were 10, 9, 10 , X, 8, 9, X , M . Calling for the target to be rescored we were told by the pit crew that the bullet did not " Crack " down range at the pits , they only heard the boom of the rifle from the firing line . Next round sent down range for a 10 , then two shots later two " nonarrivals " in a row . The remainder of the string same as the first part .
The second 20 round string was without mishap , score was 193 5x, we are complete novices at the long range game and wind reading skills amount to comments like " yup ! its blowing ", hence the avg score ) and the third string had two nonarrivals . The vertical component of all shots fired was approx .3 moa .
Lots of head scratching and research reading went on between the June match and the just completed July match at Camp Robinson . No changes were made to Rifle ones load as it is not near the pressure max and did not think lowering the velocity was any fix . Rifle one was tested up 48 grs of RL 25 with resultant velocity avg of 3212 fps . This was a primer pocket killer however so we went back down to the next node of 3100 and then to 3044 as it had the best es .
Rifle two was ready for the July match and it was shooting the 47.2 gr charge of RL 25 . Both rifles were shot for confirmation of velocities the day before the match , 10 rounds ) and left with a fouled bore .
rifle one had a " nonarrival " the middle of the first string , by this time the pit crew had a clue and was quick to report no " crack " at the target . There were two more that string so we cleaned the rifle between strings .
In the meantime rifle one fired a mediocre 20 round string , that wind thing again ) of 180 3x . The vertical component was practically nonexistent . This was repeated with its second string with a slight improvement , 187 5x . The final string of the day for rifle two the day had warmed quite a bit and the string was being fired rapidly, read barrel was smoking hot ) when the first " nonarrival " for rifle two occurred . After a pause to drop the bbl temp a bit the firing resumed and the string was completed without mishap . Rifle two had around 70 or so rounds down the bore and was extremely hot before it suffered a bullet loss .
