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Ballistic mystery, would like your thoughts.....

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Unread 07-10-2007, 05:17 PM
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Location: Fort Shaw, Montana
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Ballistic mystery, would like your thoughts.....

To all,

I have been testing the new 265 gr Al RBBT bullet from Wildcat Bullets in my lightweight 338 Allen Magnum. This is proving to be an amazing bullet but I have run into some issues getting my ballistic program to match up with actual real world trajectories.

Last two mornings I headed out really early to beat the wind and heat of the day heading out of the shop around 6:00 each morning.

The first morning by the time I got out to my shooting area, the wind had picked up and was causing some problems accuracy wise. Still I got the rifle set up close to where I wanted and did some test shooting at 927, 1915 and 2410 yards.

I got extremely good results at the two closer ranges but was getting some vertical fliers at the 2410 yard range but after a discussion with Shawn Carlock we both agreed it was more then likely just an issue of catching some life as the target I was shooting at was on the face of a very steep hill with the wind running straight up the face toward the target.

This morning was supposed to be even cooler and with less breeze so I packed up and got out early again. This time I set up and the shooting conditions were about as ideal as I had ever shot in in this area. There was simply no wind at all, it was around 60 degrees so there was no issues with mirage either, just perfect.

I had developed a rough drop chart from the results I had gotten the day before so I had a general idea where to dial up for the testing at different ranges.

Now I will admit, I have not checked the impact of this rifle with this scope zero at close range. 927 yards is the closest I have shot with it.

From the rough drop chart I had developed, which I selected a zero of 325 yards simply because that way I can go out to 500 yards on big game without ever touching the dials really and dial up from there on out.

The first range I tested at was the 1915 yard target. Now in all cases, the targets I was shooting at were rocks roughly the size of a basketball. I dialed in the recommended moas for this range and let one of the new Wildcat Bullets fly. Impact was roughly 4 moa higher then it should have been. Made a scope adjustment and hit the rock on the second shot needing 35 3/4 moa for a dead on hit at that range.

Next I set up for the 2410 yard target rock. The rough drop chart listed just shy of 59 moa needed to reach this rock from zero. Since the last impact was around 4 moa high, I cranked in the needed additional moas from the last adjustment to bring me up to 54 3/4 moa total.

The first shot landed roughly 8" to the right of the rock, right at the bottom edge of the rock. Took the same hold for the second shot and the shot landed between the first shot and the rock. Two shots at 4 to 5" ctc at 2410 yards.

I was not overly concerned about missing the rock that small amount. This was more a test of the drop chart then anything, fine tuning will come later, just trying to figure the details needed to get the drop chart accurate with bullet flight.

Next up I wanted to see where this new bullet would reach to. I had tested the 300 gr SMK out to 2800 yards loaded to 3400 fps. At that range, consistancy was not all that great because I was dropping out of super sonic velocity before this point and once that happens with the 300 gr SMK, it seems to really fall apart with consistancy.

I found another target rock, ranged it with my wilde range finder and ran the conversion to yards. 3008 yards was the range. Ran the measurement three more times and got within +/- 50 yards of this each time so I shot for 3010 yards.

This is the farthest I have ever shot my 338 Allen Magnum to and was a bit curious if it would prove consistant at this range as I had not had good luck with the 300 gr SMK much past 2600 to 2700 yards.

The drop chart listed I needed a total of 91 moa to reach this distance. Like the other yardages, I took some moa off this and decided to go with a dial up of 86 moa total from zero.

I cranked up the NF scope from the last setting and found she topped out at 84 moa. Instead of leaving the adjustments bottomed out I backed the turret off 2 moa and used the Np-R2 reticle for the extra 4 moa needed.

I let the barrel cool as I was getting a bit of mirage off the barrel as it was pretty warm. Once she cooled I sent a 265 gr pill down range. To my suprise she landed dead center of the target rock but roughly one foot low. Again, not being to worried about a hit at this point, just wanted to check if the bullets would remain consistant.

Cranked another round in and sent her down range. Best I could tell from the 22x NF scope, the second shot kicked up dust in the exact same spot as the first!!! I damn near fell off the shooting bench. I then shot a third shot and this time the shot landed roughly 2 feet higher then the first two.

This could have been because of several things, velocity spread, baring surface variation, pilot error..... Still, even with the flier the three shots were well under 1 moa at that range, far better then anything I had gotten with any bullet at that range. Well to be honest, roughly 300 to 400 yards farther with consistancy then any bullet I had ever tested before!!!

I was feeling about as good as a montana boy could at this point. This is when the mystery comes into play.

Just for S&G, I glassed a closer pile of rocks where its common to see an occasional rock chuck. Sure enough there was a big fat boar splade out sunning in the morning sun.

Ranged him at 930 yards with the Wilde and Swari rangefinder. I figured this big boy was going to be flipped hard!!!

Drop chart said I needed 10.5 moa up from zero for this range. Took two moa off this to compensate for what the bullet flight had been doing on the farther range tests.

Lined up on the old hog and let one rip. The impact of the aluminum tipped bullet at that range was deafening with the electronic head set on. Only problem, the shot landed 3 moa low!!!! I figured I pulled it and the chuck suprisingly just set up to see what was going on. Took the same hold figuring I pulled the shot and the second shot landed withing inches of the first???

The first shot had woke the chuck up, the second shot made him decide he was not to fond of what was going on.

I was baffles. I dialed up for a total of 13.5 moa and aimed at a very small rock for a target just to the left of where the chuck was. At the shot, the rock simply crumbled into gravel from a solid center hit, still baffled???

I dialed her back down to zero and then cranked in the 35 3/4 moa adjustment that had gotten me the center hit previously. First shot, chipped the bottom left edge of the rock, second shot dead centered it for a CTC pair of less then 8" at the most.

So here is the mystery, why is it the the ballistic model is consistant from ranges of 1900 out to past 3000 yards but take a 180 degree turn when dealing with a range of just over 900 yards??

By that I mean that for all the ranges past 1900 yards I only had to take off 4 to 5 moa from the recommended dial up for a near dead on hit but at the closer range, I actually had to add 3 moa to the adjustment????

Any ideas on why this is happening would be most interesting to hear about.

I would tell you the BC I am using to get the ballistic model to match up from 1900 to 3000 yards but that would probably just get someone kicked off LRH again.

Lets just say, it makes the 300 gr SMK look rather silly as far as BC is concerned.

Thanks for your time and input. I really do not care what I need to do to get the drop chart accurate but just curious as to why the actual trajectory dead on consistant at several long range test ranges but need a significant adjustment at closer ranges?????

All in all, these bullets are performing extremely well. There are some minor issues that need to be handled before the production bullets are ready but Richard is already working on that.

Kirby Allen(50)
Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

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Unread 07-10-2007, 06:25 PM
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Join Date: Jan 2004
Location: Blackfoot, Idaho
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Re: Ballistic mystery, would like your thoughts.....

What a nice problem to have. I'm sure you'll figure it out.

Maybe I ought to sneak up there and give a hand. [img]/ubbthreads/images/graemlins/wink.gif[/img]

It may have to something with the shift in position from the targets to the boar. Not much of anything else changed.

Guess I ought to get some of those 265s
I may be the slowest guy on the mountain . . . . but . . . . I'm on the mountain!
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Unread 07-10-2007, 06:41 PM
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Join Date: Jan 2003
Location: The rifle range, or archery range or behind the computer in Alaska
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Re: Ballistic mystery, would like your thoughts.....

I am no expert here in the field of beyond 1000 yard shooting so anything said here is merely a theory. That being said, could it be that it takes a significant amount of time for this long missle to go to sleep where its true BC can be realized while at shorter ranges it maybe restless and cause a major amount of BC loss or decay. Once she goes to sleep the BC and drag model would likely be off the chart.

That ought to get some people around here fired up!!
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.
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Unread 07-10-2007, 06:53 PM
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Join Date: Mar 2003
Location: Southern Wisconsin
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Re: Ballistic mystery, would like your thoughts.....


I was pondering the same thing, with the BC not being a constant number, perhaps the 265 is being pushed so fast that its simply not as aerodynamic as it is once it slows a bit.

That is also just theory and speculation cuz I aint no ballistic enganier [img]/ubbthreads/images/graemlins/grin.gif[/img]

Ignorance can be treated with education, sadly there is no cure for stupidity.
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Unread 07-10-2007, 06:59 PM
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Location: USA
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Re: Ballistic mystery, would like your thoughts.....

The BC may be getting higher with the reduced velocity.Maybe try a higher bc at the slower speeds.The Exbal will accept multiple bc's......see if this helps
range it,check the wind, dial in correction, aim and only one shot
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Unread 07-10-2007, 08:39 PM
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Re: Ballistic mystery, would like your thoughts.....

My bet is as several have said, the long aluminum tip is creating issues at close range that a hollowpoint design would not have. Once the bullet gets out a ways the precession of the tip settles down and it begins to actually help the BC.

Second possiblity is that the scope is not linear in its dial up. You can check this with a few bullets
The Smokin Fur Rifle Club
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Unread 07-10-2007, 09:05 PM
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Join Date: Aug 2003
Location: McKinney TX
Posts: 408
Re: Ballistic mystery, would like your thoughts.....

Iíve got a couple of ideas but at 2 to 3K who really knows. Ballistics is just math and physics. Are you using a G1 drag model as your basis? If so, I donít care whose ballistic program youíre using thatís going to screw up your results especially at those distances. Actually I wouldnít trust a G1 drag model beyond 500 yards but thatís just me. Using multiple BC's is a total waste of time and effort and doesn't accomplish a thing! Thatís a short coming of ballistic programs trying to message the G1 drag model for slightly more accurate results.

A good ballistic program should have CD models (coefficient drag models) such as G5 and G7 drag models. These programs are much more accurate at extreme ranges, but it all depends on what model your bullet fits into and using the proper BC for that model. You canít use the published G1 BC for those models. Your bullets BC should really be calculated to how itís performing from your gun and matched to the proper drag model. This is simple to accomplish with RSI ballistic program and a good chronograph.

If you can give me your average muzzle velocity as well as a 100 yard and even better a 200 yard velocity, I can match your bullet to the proper drag model and calculate the proper BC for your bullets, then we can re-run your numbers. Weíll need a bit more info to run the numbers but we can take that off line.

So my first thought is the ballistic model and BC youíre using?

My second thought could be the tracking of your scope. Does it truly track accurately through the full range of elevation? It may track differently as you increase elevation. Screwy as that sounds it happens.

Those are my thoughts. Must be nice to shoot at those ranges. Let me know if I can help.

Mathew 5:16

Distance is not an issue, but the wind will make it interesting!
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