Zambini in the 30-06 -- this was an attempt to combine a lube comparison with ongoing load development. I hadn't shot the 30-06 since May. At that time, sometimes it would do 2 MOA with WW760 powder, but sometimes it wouldn't. Also, the pressure had been a little too high and there were some questions about the optimal nose diameter.
To deal with the pressure, I dropped the powder charge half a grain. However, I also had to switch to a new jug of powder.
I sized the noses in a tapered nose die so that the top band was 0.308" and the band below that was 0.309". This created a very snug fit in the freebore cone. However, despite carefully nose-sizing each bullet, a few rounds were very difficult to chamber at the range.
Two shots were fired with the validation load to make sure the strain gage was working OK. Pressure was a little lower than loadbook, but so was velocity, so the strain gage got a passing grade.
Here\'s the traces for felix lube. 180 gr. loverin, 0.314", HTWW, 55.2 gr. WW760, 2.935" COL. Pressures and velocities were much higher
than expected. At every shot, the felix lube created a huge cloud of smoke that obliterated the range. It was kind of embarrassing.
Here's the traces for Zambini. There was no unusual amount of smoke. On T5, the funny looking trace, the bolt had to be pounded closed with my fist because the bullet was a too-tight fit in the throat. However, that 5-shot string turned in the best group of the day, 2.1".
Here's HVR. Again, no unusual amount of smoke. I'm not sure what caused the dud. The dud was not included in the statistics, but I left it in the trace because it's interesting.
Here's a summary of the data. There are only 10 shots for each lube, which isn't enough to prove anything. I had loaded 15 rounds but only used 10 because a couple of rounds refused to chamber.
[mrow]lube [col] avg. fps [col] fps SD [col] avg ksi [col] ksi SD [col] 5 shot MOA
[row] felix [col]2762 [col] 0.69% [col] 67.3 [col] 2.09% [col] 5.95
[row] zambini [col]2770 [col] 0.14% [col] 65.7 [col] 3.60% [col] 4.40
[row] hvr [col]2773 [col] 0.50% [col] 67.1 [col] 2.94% [col] 2.90
For the benefit of those who think Quickload always errs on the conservative side, QL predicted 2696 fps and 54.5 ksi for this load. I like Quickload, but I like my chronograph and strain gage more.
For the benefit of those who think they can judge whether a load is safe by looking for so-called pressure signs, take note that there were absolutely no pressures signs -- primers were rounded and the bolt opened with one finger.
Next time I'll drop the powder charge and hopefully get the pressure right. Then I'll do the lube tests all over again. So far it doesn't appear that lube makes a hoot of difference with this load, except that felix lube smokes a lot. I'm guessing the loverin bullet with its many lube grooves and long bearing length creates a superior gas seal that does not depend on the lube to form a gas seal. That's good -- that's the way it should be.
Also I will either size the noses a little more or else seat the bullets a little deeper, so they will chamber reliably. Maybe try it both ways.
All in all, I felt OK about today's results. After all, if a cast bullet will do 2 - 3 MOA at 67,000 psi, it might do better at sane pressures.