Question about bullet drop, BC and velocity. 260 rem

[Turbo900rr]

So I've been working on a load for my 260 rem and it looks like I found a winning load. 42.0gr H4350, hornady 140gr amax, 2.800 oal. At 100 yards it shoots .35 moa. I was curious of my velocity since I don't have a chrono yet. I ran it out to 300 yards and tested bullet drop to get an idea of what it would do at distance. It dropped 9 inches from a 100 yard zero. I ran the listed BC and kept upping the velocity till the bullet drop from 100-300 matched and the muzzle velocity was 3200fps! Is this correct or is there an error in the program. FYI 140 amax BC is listed as .585
Thank you

 

[jr600yd]

I think there's a miscalculation in there somewhere. I'm running 45 grs of AA-4350 fired off by a federal 210 match primer pushing a 142 SMK moly bullet at right around 2775 fps. Another very accurate powder ( in my rifle) is H-4831. These are my go to loads for 600-1K matches. In my rifle the SMK's shoot best -020 off the lands. I have no experience with the A-Max bullets.

 

[loneranger04]

Yeah that can't be correct. I'm running 42.1 grs of H 4350 with 139 Scenars in a 26" barrel and getting 2800ish. I'm showing 10.4" drop at 300 yards in Shooters. The Scenars don't have as good of BC as the Amax but I'd doubt that you are running over 2800.

 

[Turbo900rr]

Ok. Good to know. I was sure the numbers were wrong. I need to get a chrono now to find out where I'm really at. Thanks again

 

[Dos XX]

What program did you run the listed BC in? Does it have an option for G1 and G7? If so, did you choose the correct one?

 

[Bryan Litz Ballistics]

You need to shoot at longer range to determine MV from drop, 300 yards is to close and your result is very error prone at that distance.
Try the same thing at 1000 yards where you have much more drop. Also be sure your scope is tracking so you know the actual bullet drop.

 

[wrongside]

I run 42.9 gr. H4350 with CCI BR2 primers pushing 140 gr. Berger Hybrids at 2820 fps. That's through a26 in. Criterion barrel. Hope this helps some. Bill

 

[JarheadAZ]

I have run the 142SMK with 43.8gr of H-4350 at an averaged 2856 from a L-W 28" 1:8". I shot in the low 190's for F Open at 1000yd in Bodines/Williamsport PA. My wind skills were the limiting factor, costing roughly 2-4 points per stage. Brass is Win 7-08 necked down; COAL is 2.910" with about .010" of jump; with the drop from 100yd to 1000yd being in the region of 28-30MOA. Under favorable conditions, the rifle was capable of strings of X's.

Start low, work up, this load works in my barrel, may not be (as ?) safe in yours.

Inconsistencies between my velocity data and yours depend on accurate input data, with scope optical axis height above the bore axis being the one most frequently inaccurate. Mine was the result of repeated chrono testing.

Greg Langelius