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Not sure you will get just

May 15 2017 at 7:59 PM
Prouzy  (Login prouzy)
YF12


Response to Hi Guys. I need the exact BC of JSB .357 81 grain and BC

one answer, but thats ok. You have a few different variables, but Ill chime in with some of what I found, know and experienced. I was able to shoot JSB 34gr .22 in high 800s to test BC to 40yd and obtained just over 0.04 if I recall. This was greater than 25 gr .25 which came in just under 0.04 but the 34gr .25 did come out higher and approached 0.042 while 44gr .30 was anput the same. The 81gr was not measured via chrony and was estimated on drop at 75yd, 0.05. Certainly could be more and likely approaching 0.055 or better.

Different barrels, velocities, amd different distances measured will result in some variability in findings but there may be some consensus. Rsterne was doing a thread and collecting from different folks, over on GTA, if I recall. You are in the ball park with muzzle velocity comparisons between .257 and .357 both shooting around 80gr being around 150fpe at around 910-15fps. The difference will be the BC and whether you need that down range. My .257 Condor shooting only 55gr had the same down range energy as my .357 shooting JSB 81gr at 150yd. The JSB is more affected by drift and betond that, the 55gr wins in the fpe. Shooting the gold standard Lyman .257 you are looking at dramatic differences in energy retention and likely a BC exceeding 0.15.

I dont know that much about the RAW, but it takes a lotta air power to push a cast bullet 75-80gr over 900, hence the Airforce conversions. The .357 pellet shooter seems about closest to a .22lr, but cast bullet shooters can certainly surpass. My Extreme .308 could double it, and even my 3000psi PBBA shoots 220+ fpe with its favorite 120gr. Im currently working on a project to shoot cast 37gr .224 with a BC estimated 0.12+. I agree, cool times anead, and Im interested in what the Crown has to offer. Neilsen is working on some great ammo for pellet shooters, but is a solid with higher BC, might be an additional choice for your application. I really like the idea, as pellet shooters and smaller calibers can use air more sparingly per shot and with a quick change out of a hammer spring I cam shoot my .30 for 14+ shots (small reservoir) at around 60fpe to NSA slugs at 100fpe+ and suspected BC 0.07-8 (still testing). I like shooting big ol cast slugs, but shooting .35 pellets is just a hoot!

 
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