When should I stop? What's the temp effect?

[Jicko]

A couple of fundamental questions:

1) When should I stop?

I've got my 77gr Nosler CC out of my Mk12Mod1 SPR to about 1MOA, 0.9x" @ 100yds, for 5 rounds groups, are they good enough?

10 rounds average velocity (chrono @ 10ft, this past weekend, @ 50F) for 24.0gr RL15 is 2626fps.

10 rounds average velocity (chrono @ 10ft, this past weekend, @ 50F) for 24.5gr RL15 is 2716fps.


BHA (red/new) 77gr SMK, did a 1.33" (5 rounds), but 4 of the 5 rounds is 0.69".

5 rounds average velocity (chrono @ 10ft, this past weekend, @ 50F) is 2650fps.


2) What's the temperature effect?

If my rounds w/ 24.5gr RL15 are @ 2716fps now, what's vel can I *expect* when it is mid summer?

[Fjold]

1.) What are you trying to hit? If it's mansized target out to 600 yards you're fine right there.

2.) It varies with the powder charge as some powders are more affected by temperature that others.

[ocabj]

I lost my notes from when I developed my 200/300 yard loads, but I'm pretty sure my 77gr Noslers, 24.0gr RL15, CCI BR4, and LC brass clocked at around 2750 out of a 20" SR barrel in December 2006. I've had no pressure problems or zero changes in summer with the same load, but never clocked them.

Midsummer you'll probably see an increase of no greater than 50fps, and that's being pessimistic.

[eviioiive]

average velocity isnt as important as the average difference in velocity round to round... you want consistency

[Jicko]

average velocity isnt as important as the average difference in velocity round to round... you want consistency

True, I understood that.

Those
10 rounds average velocity (chrono @ 10ft, this past weekend, @ 50F) for 24.5gr RL15 is 2716fps.

lo: 2699
hi: 2733
ES: 34
SD: 12.4

[Pthfndr]

I lost my notes from when I developed my 200/300 yard loads, but I'm pretty sure my 77gr Noslers, 24.0gr RL15, CCI BR4, and LC brass clocked at around 2750 out of a 20" SR barrel in December 2006. I've had no pressure problems or zero changes in summer with the same load, but never clocked them.

Midsummer you'll probably see an increase of no greater than 50fps, and that's being pessimistic.

This mirrors my experience, except I was using the Sierra 77.

[ocabj]

The SMK and Nosler are pretty much interchangable. I was using 24.0gr with the SMK until Nosler started making their 77gr available under their website 'specials'. Then I simply swapped bullets.