Group size vs ES/SD?

[willie]

Maybe I missed it, but are you neck sizing fired cases or full length resizing them? This question may not reflect an issue. To eliminate a variable, I suggest neck sizing only. You may need to buy a neck sizing die. Another variable is neck tension. Lee makes a factory crimp die which uses a collet to crimp the bullet. The die will apply the same pressure on each case. This die and the handgun caliber factory crimp die operate differently. Anyway, I think changing powder will will provide desired results. 600 yards is a long way. That figure disqualifies me even from discussing the topic. However, I will show my ignorance and say you have the wrong rifle for 600 yard shooting.

[ccmdfd]

Maybe I missed it, but are you neck sizing fired cases or full length resizing them? This question may not reflect an issue. To eliminate a variable, I suggest neck sizing only. You may need to buy a neck sizing die. Another variable is neck tension. Lee makes a factory crimp die which uses a collet to crimp the bullet. The die will apply the same pressure on each case. This die and the handgun caliber factory crimp die operate differently. Anyway, I think changing powder will will provide desired results. 600 yards is a long way. That figure disqualifies me even from discussing the topic. However, I will show my ignorance and say you have the wrong rifle for 600 yard shooting.

So far only using brand new from the box brass from Nosler. Haven't had a chance to actually reload my once fired brass yet. Haven't been using any resizing dies on the new brass.

Agree 600 is hell of a long shot, and highly doubt I'd ever even try that. But for typical game around here, the 280AI with the LRX is certainly capable at that distance

Thanks

[willie]

So far only using brand new from the box brass from Nosler. Haven't had a chance to actually reload my once fired brass yet. Haven't been using any resizing dies on the new brass.

Agree 600 is hell of a long shot, and highly doubt I'd ever even try that. But for typical game around here, the 280AI with the LRX is certainly capable at that distance

Thanks

One consequence of not resizing new bottleneck cases is that the neck is not sized and hence neck tension is not created. I suggest not assuming that the new brass came to you with consistent neck tension. It might vary. If so, this situation will cause velocity variation. Remember to lube the new cases before sizing and also lube the inside of the case neck. Clean this area after when finished. Keep lube off case shoulder.

[Hambo]

I agree with willie on new brass. I've certainly shot new, unprepped brass, but not for what you're trying to do. I'd definitely size and trim them.

[SecondsCount]

70 FPS is going to be about 2" difference at 600 yards.

[TCFD273]

Only work up loads on once fired brass

Find powder and primer combo with chosen bullet using magneto speed or lab radar. Just shoot into berm

Find combo with largest node

Tune the load at 600 using seating depth

ES doesn’t matter much at 600yds


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[TOTS]

I agree. I’m still 3/4 moa at 400 with worse SDs/ ESs. Shoot and map it. The impacts don’t lie.