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I was wondering how important it is to use all of the sight leaves on my 1911 Paradox gun. The gun has sights for 50yds, 100yds, and 150yds. I don't hunt dangerous game so, specifically, can I use the middle leaf for all my shooting within 100 yards?

To start to answer the question, I needed to figure out the ballistic coefficient of Holland's Fosbery bullet. So, I plugged bullet path data provided by H&H into a ballistic prediction program. The program calculated a BC of .330.

At first I thought the value seemed high. I would have guessed the BC was going to be around .175-.250 like some big pistol bullets. But, after some reconsideration, I now think .330 makes sense. Here is why:

1. If two bullets of different sizes have the same shape (form) then the larger one will exhibit less drag than the smaller one. Ballistic coefficient values of .175 to .250 are the norm for large pistol bullets but the Paradox bullets are definitely larger.

2. Ballistic coefficients are not static. Aside from other factors, the coefficient changes as velocity of the bullet changes. The result is nearly always that bullets demonstrate higher BC as velocity decreases. Sierra lists three, four, or five different BCs for their bullets to cover various velocity ranges.

For example, for their 300gr .458, hollow point, flat nose bullet Sierra lists five different ballistic coefficients:

.120 @ 2400 fps and above
.145 between 1900 and 2400 fps
.185 between 1400 and 1900 fps
.210 between 1150 and 1400 fps
.230 @ 1150 fps and below

If a 300gr .458cal hollow point can have a BC of .230 below 1150fps then it follows that a better shaped Paradox bullet could obtain a BC of .330 with a 740gr, .735cal solid, at 1050fps.

3. The ballistic coefficient was calculated using observed (H&H obtained) velocities at known distances, i.e. real world results. Observable and measured results trump any estimate.

I believe it fair to say that the table below shows a reasonable estimation of the flight of H&H's 740gr solid bullet in their factory Paradox ammo.

When you look at the chart you will also see that I calculated the "point blank range" for a 7.8 inch "vital zone". I arbitrarily chose that size because it matches the diameter of a target I shoot. Sierra's tables provide values for a 10 inch "vital zone" but I think my 7.8 inches is a more reasonable "vital zone" for deer, bear, and elk. No matter, it all helps support my conclusion that the 100yd leaf is good for any deer sized animal within 125yds.

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Edited by CptCurl (19/05/11 08:38 PM)