I went out to the range on Sunday morning when it was still below 100 and did some load work ups with the Sierra 85 Game King bullet. I was lazy so rather than strike out in a new direction I just used my previous loads from the Hornady 87's and put the new bullet on top. I did add H4895 to the mix as I wanted to see how it stacked up.
No surprises this week as the pressures remained nice and sane with primers looking like they had barely been used. Function was good again with no failures.
Loading the cartridges up was done using a Redding Type S full length sizing die. This one uses bushings for the neck. I pushed the shoulders back 0.003 for clearance and used a 0.267 bushing for the necks. That gives me about 0.003 neck tension which was more than adequate for my needs. Brass was Silver State Armory with three firings previously. Pockets remain tight and case growth was still below max length.
I did notice that the 85 Sierras are much more blunt in the ogive area and that a bullet seated using the 87 Hornady level would result in a loaded COL of about 2.200. A bit short for my needs!! I adjusted the Hornady seater for a COL of 2.258 and a Hornady/Stoney Point comparator reading of 1.888. The Hornady 87's , BTW, at the same COL on the seater length gave a 1.817 so you can see the massive difference.
On to the range.
Temps were 90 to 100 with a mild variable switching breeze up to about 8 MPH coming from 0600 to 1200. Testing today was three powder charges for each with eight rounds/charge shot in three and five round groups. I did not have enough prepared brass for the H4895 so shot three shot groups for the bottom and top loading and the regular eight round mix for the mid-level charge.
I was interested in seeing how the TAC would do this week as it was the top performer on the 87's. Same charge weights and negligible temperature changes should be a good test.
The lowest charge weight gave me 3054 on the clock and a pair of nice ones at 0.712/3 and 0.958/5. Not bad but it could do better. Up a half grain and the velocity gave a nice smooth increase to 3098. Not excessive and what I would expect. This time I was looking at an 0.743/3 and 0.606/5. A tad of improvement but not a tiny one like I want to see. Up another half and I was tad shaky. I shot an 0.827 with five and decided it was time to bear down. My best three shot with the TAC turned in a group of 0.385. Now that was what I wanted and the five shot showed great promise. Plus I now had the velocity up to 3133 so I was in Magic Land for speed.
The RL15 was tried again and this one was an interesting batch at the bench. Like last week I found it shot pretty well. No screamers but consistently at a level that many shooters would be tickled to have. Prior to my Black Hole introduction I would have taken this powder to the bank.
Speeds were way up by about 40 FPS at the lowest charge weight. Up a half showed me an increase of 185 FPS and a nice three shot group of 0.497 at 3214 FPS. I was looking hard at the primers and the case head for ejector marks but the primers were round and the case head was pristine. So far so good. Bumped up another half grain and the 75's are screaming!! 3299 and still sub-MOA at 0.968/5 and 0.845/3. the velocity with just a bullet change had gone up 221 FPS!! That tells me bullet shape and pressures have changed to some degree. Primers were starting to look less rounded but the case head remained unmarked. Across the board I felt the RL15 did very well. Speed was right up there for medium sized game and the accuracy is more than adequate for normal usage on big game. Not a consistent PD killer but darn good for Texas white tails and hogs.
Once again the full RL15 spread.
I mentioned I wanted to try the H4895 as this powder is a pretty good one across the board in the small calibers. I had not shot this one previously so looking over the available DTI numbers and the 243 LBC data I went conservative and loaded some up. Speeds were not high but certainly in the area of applicability in the field. Not like you are throwing pumpkin balls or anything. I only had 14 pieces of brass for this one so, as mentioned earlier, I shot three, then eight and then the last three.
I found the lowest level gave me 2919 and a horizontal string of 1.025. Probably me cheeking the rifle. The mid level was very nice with a velocity of an even 3000. I like that as a basic level and would be happy if that was all I got but I know I can get more. The groups were very nice with a sterling 0.714/5 and a very disjointed 0.650 three shotter. Not bad and certainly a keeper. The last charge up was decent at a three shot spread of 0.778 at 3068. Not ultra fast but getting there. The primers were good and I have more case to use. This one will be chased some more.
Well the last powder I'll go over is the IMR 8208 XBR that appears to be the darling of the smaller cases lately. Never ultra-fast but adequate in speed and in presenting groups that are pretty good across the board. Being one of Hodgdons Extreme powders heat does not hit it much and from my experience that is very true. I shot this powder first to settle in but it did set the trend for the day.
Oddly enough I saw a seven FPS drop on the 85 vs the 87's but groups were a consistent 0.731/5 and 0.749/3 at a speed of 2928. Not bad but I wanted 3000 on the clock. Did I mention I love speed?
I settled down for my next pair and promptly lost my mind. I found out that three pounds of jerk on a six ounce trigger does not make for a nice group. The first shot landed kind of high compared to the previous load thanks to the "hammer" stroking the trigger. I hoped that it wasn't so but four more rounds in the tray said they gotta go. Four shots later I took a good look through the spotting scope. The group looked like it was HUGE and I knew it went a good 1 1/2" and I was NOT HAPPY!! Slamming the trigger and loosing follow through on that first shot did not give me the feedback I wanted. I was there to test ammo and not me. Later my calipers showed I was overly distraught as it went 1.353. The velocity of 3026 was nice but did not make up for this lapse.
I sat down and had long pull on the ice water jug and watched the mirage dancing through the scope. I was using purple, that's all Target had, 3/4" dots for a target and they were moving about 1/2" across and up and down as the heat and light had their ways with them. I've been getting some long distance coaching from Ritch and decided I would give it everything I had. I was already sweating so it LOOKED like I was working at it anyway!!
I got behind the gun and waited. I watched the dot bob and weave and then set solid. This went on for maybe three or four minutes and I was starting to see what Ritch said about running and boiling. I was ready now. I charged up and waited. The run kept going and when the dot stopped I put six ounces on it and we were off. A minute later the mirage gave in again and once more a Sierra headed West. I saw a bigger hole. This is where I traditionally get the shakes but I was gonna win this one!! It took well over a minute and a half before it got solid down at the 100 yard line and I tweaked it off. Third shot down and only a bigger hole!! At home I got the pay off for the effort. It read 0.138 CTC and I was now pleased.
What is interesting, to me, about this pair of groups, was that of all twenty two groups fired on Saturday only this one exceeded an MOA and I then backed out of it with the best three shot effort I had for the day!! Another thing that was extremely interesting is that last week, shooting the 87 grain Hornady BTHP, I had a three shot group of almost exactly the same size.
Moving up in charge on the 8208 gave me a nice 3084 and groups of 0.352/3 and 0.997/5. Not bad and overlaying the targets they would have all been under an inch for eight shots.
This was what I looked at at home on these. The good, the bad and the ugly.
Again, what did I learn?
I found that the bullet choice can make an effect on the velocity out of proportion to the variation in weight. I also found that I can deal with the mirage mentally but my ADD trigger finger finds it very hard. I also found that the 6X68 performs well with the heavy bullets and can actually be pressed into long range target shooting and will more than likely get that chance. I do want to test the pure target weight 95's and also some of the Nosler Partitions to see what my top end in will be.
I am finding that loading for the case is easy. It has a huge case capacity compared to my usual 223 based cartridges and that I have a big selection of bullets and powders at my disposal. I know that the parallel testing by Ritch and the gang, with the light and medium bullets is yielding similar, if not better, results. All told I believe the 6X68 is going to be a viable platform and I can't wait to continue with my testing.
Feel free to comment and I'm sure one of us will respond. Thanks for reading my long ramble and enjoy the day.
Black Hole makes it happen for me.
Greg
PS: One last thought. I posted up my powder charges on this batch. They APPEARED safe in my rifle. Nothing has been pressure tested and everyone that loads and uses this wildcat is responsible for their own choices. Look closely, research what you can and choose wisely.