Ram-O-Meter

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SteveD
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Re: Ram-O-Meter

Post by SteveD »

Ferret Master wrote: The only new bullets in my thinking that need to be tested are the solid copper bullets.
Cutting Edge 50 cal recovered after striking gong at 2000 meters.jpg
It is too early this morning for me to do the math but the velocity and energy of these bullets when striking the gong is comparable to that of the 90 gr, 6mm solid copper version of this bullet striking a Ram at 500 meters. I would not be surprised to see similar results.

This is the focus of my investigation.
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w30wcf
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Re: Ram-O-Meter

Post by w30wcf »

Interesting topic. :D
In the early days of NRA High Power Rifle silhouette it was felt by the competitors in the know that 1,000 ft lbs of energy was needed to reliably take down the 500 meter rams.

Later, Black Powder Silhouette proved that the ft lbs theory was all wet when they had no problems at all knocking them down with bullets arriving at 500M with around 600-700 ft. lbs. of energy. What they did have was plenty of momentum and Keith's Lbs. Ft.

Back around 1980, American Rifleman Ballistics Editor William C. Davis, Jr. ran a test using a steel ballistic pendulum.
After shooting a number of different cartridges and bullets he concluded that as the momentum impulse increased, the ballistic pendulum movement increased. He also stated, that based on his observations, it did not matter what a bullet was made of, if it weighed the same and hit with the same velocity, the pendulum moved the same amount.

Here is an interesting picture. A 500 gr. bullet has impacted a 300M steel Javelina, disintegrated with the remaining small part of the bullet rebounding back and the javelina has barely moved. Anybody that has seen a steel javelina hit with a 500 gr. lead bullet knows that it pretty much disappears in the "blink of an eye". It sure looks like momentum impulse is at work here.

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Steve, it will be very interesting to see how your testing works out.

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Varn
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Re: Ram-O-Meter

Post by Varn »

Jason,
I have also seen the change on the 139 Scenar. And I tested the 143 ELD-x on Rams out of a 6.5 TCU at 2400. They work well. Shockingly well.
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Re: Ram-O-Meter

Post by cslcAl »

If you can try some of the new Sierra 6.5 130 Gr. TMK's I have been shooting them in a 260 and a 6.5 X 55. In 2 matches at 2 different clubs I haven't lost a ram yet. The accuracy with these bullets is outstanding.

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SteveD
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Re: Ram-O-Meter

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cslcAl wrote:If you can try some of the new Sierra 6.5 130 Gr. TMK's I have been shooting them in a 260 and a 6.5 X 55. In 2 matches at 2 different clubs I haven't lost a ram yet. The accuracy with these bullets is outstanding.

Al Foust
I am sure that someone will give them a go. I might try some of the 95 gr 6mm TMK's if I had some to try.

Everyone is welcome to try any Silhouette legal cartridge/bullet combination.
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Re: Ram-O-Meter

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I have been cogitating on the design, how to fit everything, keep it simple and still get everything accounted for and strong enough to last a long time. An engineer I knew had a simple rule, if you are building a one off, figure out what you might need to make it strong enough and then increase it by 100%. Not that you necessarily need it but why mess with fixing of improving it later, just over engineer it by 100% and be done with it.

So I have been working through ideas in my head and finally got to a point where I think I am ready to go, at least for the base so I ordered the wheels today. They are 3.5" diameter by 1.25" wide and are of a very high durometer, 98 Shore A, and have ball bearings.
Grainger ball bearing wheels 1KA91_AS01 reduced.jpg
https://www.grainger.com/product/GRAING ... heel-1KA91
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SteveD
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Re: Ram-O-Meter

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I went to Grainger to pick up the wheel and they were crap. The bearings in first one sounded like ground walnut shells and the second one had a .25" wobble. I told the guy to take them back.

I am looking for some better wheels.
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Re: Ram-O-Meter

Post by Ferret Master »

SteveD
What was used last time this was done were Thompson Linear Motion Bearings and precision ground shafts: Here is the link to their website: http://www.thomsonlinear.com/website/co ... oCUw7w_wcB

They were mounted on a 2" angle iron frame with a 1/4" steel top plate. With the Regulation size Ram mounted on the ends of the shafts it glided effortlessly. That is one reason I added a slight spring loading to make sure that if the wind blew against the ram it would not move to the rear on its own. It would also reset to the front after a hit had been recorded.

The bottom line was that the Sierra 140 6.5 bullet that left the barrel at 2550 yield about 1100 FT-LB gave the greatest shove to the rear on the regulation ram. The chronographed velocity at 500 was an average of the 5 shots of 1885fps. This is only one small part of the equation.

What a shooter really needs to do is study the rams at the range or ranges they are shooting on. You would be amazed at how much difference a small difference in angular displacement makes in what it takes to knock a ram over. What I means is that many rams do not have their feet welded at a perfect right angle to the body of the ram. The true pivot point of the ram is the back edge of its foot. Some target stands are not perfectly strait. A small lean to the front or back makes a big difference. If the stands are loose in the ground it will absorb a great deal of the energy. If the rams are set so that the back edge of the foot hangs over the stand it will make those rams much easier to knock down. There can be a difference in the weight of rams.
Over the years I have taken my sling and scale set and weighed rams a the different ranges at which I compete, usually 7-8 ranges in any given year. I record the weight, the angle of the feet using a small square, type of stand and any angle from plum. I record all this in my shooting diary. Once you have recorded all this data you will see quite a difference from range to range. This data will allow you to develop a match and shot plan for the rams at each range. If you are shooting on a range that has hard set rams that heave a slight lean forward or that will have wind behind them during the match you will have to make sure that your shots are high on the ram for example. If you don't think set makes a difference just read rule 4.2 in the NRA Silhouette rule book. You can't assume that all rams are made, set or are exposed to the same wind.
I believe that if you study the leverage of each shot you will generally find that any shot higher up on the animal away from the pivot point will give your bullet more leverage on the animal and a greater chance of knocking it down. I believe that the physics of what is required to know a ram down is poorly understood. I hear folks complain about hitting a ram in the lower part of the front leg without the ram going down and getting very upset and wanting to blame the bullet or it's velocity. The don't realize how much of the rams weight is bearing down on the foot and how little leverage they have with that low of a shot. Cupped rams can be a problem as well especially if you have BPCR matches at your range. Most ranges should have a rotation plan to avoid this problem.
A few more things to add to the pot are the weather and local politics. As for the weather mud can make a big difference in the amount of the energy needed to take down a ram if it coats the top of the stand and the foot of the ram. Local politics comes in to the picture, you want to make sure your rams are set the same as the local hero. A really good spotting scope and or a good pair of binoculars are a must. ( Mostly the spotters job) I have unfortunatly run into this twice in the last 30 years.
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Re: Ram-O-Meter

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I am taking a different approach. I will stipulate that the force required to knock over different Rams at a given range and Rams in general at differing ranges is not uniform. I am not intending to quantify the amount of force required to knock over Rams in general or any Ram in particular. It is what it is and we can not likely know and can less likely change it.

What I am quantifying is the amount of force that a particular bullet launched at a particular muzzle velocity from a particular rifle has when striking a 55 pound moving mass at 500 meters. Once we have that we have a means to compare the force of that bullet to the amount of force delivered by another.

For example take a 139 Scenar and a 142 Sierra MK, both launched from the same rifle at the same muzzle velocity. We will measure them both and will then know which delivers more force to the Ram-O-Meter.

Now launch a 308 cal 175 gr Sierra MK and a 168 gr Sierra MK. How do they compare to the 6.5 mm's? Now try various bullets from other manufactures and other construction methods. Add in 6 and 7 mm bullets. Add in different cartridges and with it a greater range of velocities. I am sure that there will be barrels that have faster and slower twists.

For each specific combination of caliber, bullet weight, bullet, cartridge and muzzle velocity will will get a specific number. Once we have enough data, a pattern will likely emerge. The variables of the Ram and of subjective observation will be eliminated and we will be able to draw objective conclusions. Regardless of the reluctance of a particular Ram to go over, we will know which combination has the best chance.
Last edited by SteveD on Sun Sep 11, 2016 9:31 pm, edited 1 time in total.
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Re: Ram-O-Meter

Post by Jerry G »

As a sidelight, The sil director at one club has told me that the heavy, slow moving bullets from the black powder rifles do a lot more damage to the targets than the modern HPs do.

Back in the 80s a friend of mine was shooting 100 gr partition bullets at just a little over 3000 fps and all you saw with a ram hit was grey powder splash on the ram and they didn't go over. The bullet has to hold together for the ram to go over. High velocity is NOT the answer.
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Re: Ram-O-Meter

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Dupe, sorry
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Re: Ram-O-Meter

Post by Bob259 »

Jerry G wrote:As a sidelight, The sil director at one club has told me that the heavy, slow moving bullets from the black powder rifles do a lot more damage to the targets than the modern HPs do.
That is 100% correct. We see it here and I know they see the same at Ridgway.
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Re: Ram-O-Meter

Post by cslcAl »

At Ridgway they turn the targets every match.

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Re: Ram-O-Meter

Post by SteveD »

Project on hold.

I have accepted a work position in China that is expected to last at least a few months so the Ram-O-Meter project is on hold until I return.

At least I will have a rifle by then. LOL I got the stock from McMillan and the Action from Stiller.
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Re: Ram-O-Meter

Post by Ken Green »

Steve: Good luck on your new job.
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