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Old March 26, 2011, 12:38 PM   #1
serf 'rett
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Join Date: June 25, 2009
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Accurate Pistol Bullet Config. - RN? HP? FN? SWC?

As a neophyte to reloading I was wondering if there was particular bullet configuration which gives higher accuracy. I’m currently working with Berry’s plated bullets, 115 grain & 124 grain in 9mm and 165 grain & 180 grain in 40S&W; therefore, I don’t have ballistic coefficient information.

Given that a certain weight bullet is used, say 124 grain 9mm, it stands to reason that the hollow point bullet will be longer. If the bullet is longer, I was thinking it would have more bearing surface on the barrel rifling. Will the longer bearing surface give the hollow point greater accuracy through better stabilization or decrease the accuracy due to friction losses?

To compare bullets, wouldn’t we need the same components with the COAL adjusted to produce comparable velocities?

Ya’ll have any thoughts on this one?

Maybe, I’m straining at gnats while swallowing camels since we’re talking pistol ammo.
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Old March 26, 2011, 01:23 PM   #2
BDS-THR
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My experience has been that for pistol velocities and caliber ranges (less than 100 yards), ballistic coefficient really don't matter that much. An example of this is the popularity of SWC or flat point bullet nose profiles. Aerodynamically, they should not be better than pointed round nose, but they make nice round holes on targets out to 25/50/75/100 yards - meaning they did not end up tumbling when they reached these distances (and make nice sharp round cut holes for better target scoring).

For me, the greater the bearing surface the bullet profile provides, the better it will ride the rifling and stabilize in flight. This is proven in the 45 caliber 200 gr SWC bullet profile that utilize the same amount of bearing surface compared to the 230 gr RN (see picture below for 45ACP bullet comparison). The 30 gr of bullet weight is removed from the nose tip of the bullet that does not ride the rifling of the barrel - which results in faster than 230 gr bullet velocities for even flatter and more accurate bullet trajectory.

As to Berry's Hollow Base bullets, what this does is provide a 115 gr RN bullet comparable amount of bearing surface as traditional 124 gr RN and provide for comparable stable bullet flight (see middle 40S&W bullet comparison and bottom picture source from THR thread).

Remember, we are talking about shorter pistol caliber velocities and distances. All of these factors may not make much difference on your overall target shot groups as there are other variables that will affect accuracy even more, such as variations in powder charge (I use less than .1 gr chart-to-charge variation as match grade) and bullet weight (I cluster bullets within 1 gr as match grade). FYI, 45 ACP 200 gr SWC bullet designs are capable of sub 1" shot groups at 25 yards, way more accurate than most shooters are able to shoot.



Attached Images
File Type: jpg 40S-W.jpg (43.7 KB, 185 views)
File Type: jpg Bullet Comp.jpg (33.3 KB, 185 views)

Last edited by BDS-THR; March 26, 2011 at 05:06 PM.
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