Bullseye & Hornady

[357Shooter]

I've been shooting 4.5 with XTP's & Zero's 230g HP for years, works great for me and easy on the gun (Kimber CDP). I never saw the need to go full bonzo with a 45, it doesn't seem to gain you much.

 

[GaryL]

My 9mm reloading book says a Max of 4.9gr bullseye with a 124gr bullet. How can it be so close to a 45 round?

Well, ljnowell mentioned a couple things. But just for grins, lets do a little math and see what is happening. Typical 45acp pressures are in the range of 10K-20K psi, and 20K-35K psi for 9mm. A lot more pressure acting on 9mm, so people often think a lot more force on things. But force is the result of pressure acting on an area, so lets assume the 9mm and 45acp are both seeing 10K psi (at some point in the process they will).

f = area x psi
10K psi, 9mm = 0.355", 45acp = 0.451"

9mm, f = 989.80 lbs
45acp, f = 1597.51 lbs

So 61% more force acting on the 45acp bullet.

Now we need to consider friction holding back the bullet. This isn't quite as simple, so we'll make a couple of assumptions, which will be good enough to get us in the ballpark. We'll assume the bearing surface length for both is about the same, and the friction per unit area is also about the same. That means we can reduce relative friction to a comparison of the circumference of the bullet.

9mm, l = 1.12"
45acp, l = 1.42"

So 27% more holding force due to friction on the 45acp bullet.

Here is where the math and physics get interesting. Now, I don't know exactly how much force is required to push a bullet through a barrel, but lets assume 500lbs for the 9mm, which is quite a lot. The 45acp would be ~27% higher, or 635lbs. So the net force available to accelerate the bullet is as follows:

9mm, f = 989.8 - 500 = 489.8
45acp, f = 1597.5 - 635.2 = 962.3

So the net force on the 45acp is ~96% greater, given this scenario. So it should be obvious that the 45acp bullet is going to move farther for a given amount of pressure, causing the volume behind it to expand accordingly.

 

[arizona98tj]

Hornady doesn't list Bulleye for the 230grn bullet.

Just checked my old Hornady manual.....they have Bullseye listed for their 230 grn FMJ bullet. 3.6 to 5.5 gr with a COAL of 1.200".

 

[MikeS.]

I tried 4.8 and liked the results so I loaded 200 rounds that way.

Thanks for all the info guys.

 

[homatok]

"Boolet"----On the plus side, next time you are faced with some idiot PC co. that blocks access to any site reffering to firearms, type in Cast Boolets and likely be pleasently surprized! Also the distinction comes in handy when doing a post that deals with both jacketed and cast bullets!