Post by sevenfan on May 16, 2023 10:14:18 GMT -5
Off to a good start, then went downhill from there. Try as I might I couldn't put together consecutive good groups and was getting lead fouling with heat treated Lyman 2, Xlox 2500+ lube, and gas checked boolits at ~2200fps.
Kept asking myself why the same charge weights that initially produced respectable, good groups, were now erratic performers that might be sub 2moa. I switched to heat treated, gas checked, powder coat boolits and same thing. Why?
We all know when you microfocus on details, you miss the elephant in the room and I did. Add to that trying to learn QL so I don't have to burn powder and waste primers in my quest for solid performance.
I shot my 7BR at the first score match in Mar, my 5 shot agg was a dismal 1.62", 10 shot was 3.02" and score (which I typically do poorly) was bottom of the heap at 159. I was so dejected I considered bringing my 6.5CM to the next match because I know it shoots very well.
Frustrated and feeling beat, decided I wasn't ready to throw in towel yet.
I've been taking baby steps with QL, using extreme caution while learning to manipulate certain parameters so predicted velocity matched actual chronographed velocity as well as adjusting for temperature. Still no success so over the weekend I asked myself how is this better than picking a range of charge weights and seeing which ones shoot well and tweaking from there?
Saturday afternoon I sat down with all my targets and notes from each session. Poured over the targets and recorded data with the question what am I missing? Why did it shoot well initially and then go south?
The elephant in the room was velocity! I had fixated on the minutia and overlooked the one big glaring change, the barrel had sped UP.
Ok, that's not quite true, the barrel is simply breaking and even though it is a select match barrel that still happens. The best group I shot was 26gr N135 which produced a group that measured 1.034" with 4 into .548", those wewre rounds 45 - 50 down the tube. The difference was that group, shot Feb 12th, and a group shot last week at exact same charge weight (1.92") are now 100fps apart, 2120fps vs 2224fps.
The only good thing about last week's session showed I have refined my loading technique well, the SD/ES for the three groups were 9.1/27; 6.0/13; & 0/4.
Now I can utilize the tools to produce usable data and hopefully predict a good outcome!
I loaded 33rds yesterday afternoon, 3 sighters/foulers, plus 2 groups of 10ea that bracket predicted barrel exit times and nodes and 10ea that bracket a good group shot outside predicted exit times and nodes.
It's calm this morning, just waiting for the rain to stop before setting up. I'll need 'skeeter juice after the rain clears but hope to be smiling afterward.