SmallCaliberCentral

I got my Cooper Phoenix in just before my last pd trip in Sep. I worked up a load using Sierra 39 gr blitzkings, and using 24.7 grs of Benchmark. This load chroned at 3600 fps, which Sierra list as max for this load, except their load is using 25.7 grs of Benchmark.
This load is very accurate, even out to 500 yds. However, I was a little disappointed in the destruction and "air time" of the pd's, (as compared to 32 gr blitzkings).
Question: do I work up in small incriments toward max of 25.7, even though I'm running max, velocity wise?
I don't want to run max loads, especially in the quantity of rounds I shoot. I want the bbl to last as long as possible. Or, should I be happy with a tack driver load, getting max velocity, with a full grain less powder? Maybe I'm expecting too much from the 39 gr bullets? Suggestions?

I worked up the 32VMax in my 26"Encore and I am at
28.1 Benchmark with 3889 and it don't act like it want's to hit 4000
and so many list over 4000 with that bullet

I would go 24.8,24.9,25.0,25.1,25.2,25.3,25.4,25.5,25.6,25.7 and load like 3 rounds of each and shoot over a chrono and see how they group etc maybe you are at your best point now but at least you will know for sure if you test them.

Try H4895 with your 39 grain sierras.

Sure was hopeing to get some input/suggestions from Rick.

Keith in Ga wrote:However, I was a little disappointed in the destruction and "air time" of the pd's, (as compared to 32 gr blitzkings).

Doesn't the the air-time depend on where they are hit? I've shot ground squirrels right next to each other, some flipped and others didn't. I was using the same ammo.

Jim

Jim White wrote:

Keith in Ga wrote:However, I was a little disappointed in the destruction and "air time" of the pd's, (as compared to 32 gr blitzkings).

Doesn't the the air-time depend on where they are hit? I've shot ground squirrels right next to each other, some flipped and others didn't. I was using the same ammo.

Jim

Hitting them on the bottom 1/3 will give you the best "air time". Simple physics state that upward forces must equal downward forces. In this case, your downward force comes up against solid ground, which in turn becomes your "launch factor" for skippy.

Keith in Ga wrote:Sure was hopeing to get some input/suggestions from Rick.

Well, here's some input Keith, for whatever it's worth......

I'm using Benchmark in my new Kimber (it hates RL10X), but have not taken it afield yet for squirrels or even coyotes, so can't comment on it's use yet with the 39gr SBK. I plan on mainly shooting the 32's in that particular rifle, along with the 35gr Berger. I'm using RL10X in my Sako and custom 11 twist 204's with the 39gr SBK. My load is a bit over the Sierra max in both rifles, so I won't list it here in case a newbie does something foolish, but with both rifles and that bullet, I'm chrono'ing over 3800 fps, a tad over 3900 in the Sako, both rifles showing no excess signs of pressure in any regard. My Kimber however, is a bit more pressure sensitive.

You really won't notice much difference in barrel life by the slight increase you want should you decide to go there. I'll take accuracy over velocity any day too, as it matters not how fast the bullet is going if you start missing rats at 350 yards that you would have hit with a load 100 fps "slower". As for the "launch factor", Gube said it correctly; hit them low, and you WILL get launch!

The rat below was smacked with my M700 11 twist using a 39gr SBK right at 326 yards from my bench. He flew up about 10', twisted about in mid-flight as can still be seen by his hide, and lost some vital body parts. This rat was hit amidships, not close to the ground either, so even so hit, you should get some pretty impressive results with the 39gr Sierra.



If you're getting good accuracy now but still under 'book max' with max listed velocity, you may have what is known as a 'fast barrel', meaning that although you're not at book max powder charge wise, you could still increase your load incrementaly and see how the accuracy relates to the increased powder charge. If it deteriorates, just back off till you find the sweet spot in regard to the balance between veolcity and accuracy, and go have your way with Skippy.