Ram-O-Meter

[SteveD]

This project has languished a bit a I am still waiting for McMillan to deliver a stock for my HP rifle but it will come eventually.

In anticipation of that I am intending to order the AR500 for the Ram-O-Meter this week. A fellow Silhouette shooter has agreed to do the welding and I am hoping to get another fellow Silhouette shooter to do the machining of the non AR500 steel.

Here is the original concept pic.

Moving mass fixture.jpg

I purchased a copy of Microsoft Visio so that I could refine the concept pic a bit.

I'd like to find someone shooting a Sierra 142 gr MKs in 260 Remington to use a baseline but any cartridge shooting them would suffice. Please let me know if you would be willing to participate at Ben Avery.

I am especially interested in Sierra 6.5 123 MKs, Lapua 139 and 123 Scenars. Also 6mm, Sierra 107 MKs, Lapua 105 Scenars and DTAC 115, both the old and the new versions.

Anyone shooting any Silhouette appropriate cartridge would be welcome to shoot their cartridge at the Ram-O-Meter to help collect data. I would really like to get some 7 BR, 7-08 and 308 data to improve the quality of the chart.

The collected data will used to develop a 'Ramentum' (if that is in fact what I am measuring, perhaps one of the ME's can jump in and help me sort that out) and 'Ramfficiency' (whatever I am measuring divided by recoil) table and will be posted here. Your data can be posted anonymously or with attribution, up to you.

[SteveD]

Placeholder for data and table.

[xpilot]

""Please let me know if you would be willing to participate at Ben Avery.""

I would participate, 7BR w/162 Amax

Let me know when you are ready

Jim

[SteveD]

Thanks Jim. It will be great to have data on a 7 BR.

I have ordered the AR500. It will be delivered tomorrow.

Next up is to improve the drawing a bit and select some wheels. After that, order some steel for the base and for the bracing of the moving mass.

I am still looking for schematics for the force gauge. I would like to integrate a wireless transceiver so that I can read the results and reset the zero from the firing line.

[Jerry G]

We are waiting Steve.

[SteveD]

Hey Jerry, Does that mean you are going to participate? I think you have like a 6.5 X 47L or something like that.

The AR500 plates arrived yesterday. I will work on the concept drawing a bit more and then get some steel for the base and the moving mass. I'm not a Mechanical Engineer so I just over-engineer it by 100% and call it good. LOL

I am not in a big rush as I don't presently have a HP rifle. I ordered a stock from McMillan in April. Another guy I know of who ordered one in February has still not received it.

[Jerry G]

I'll be back in AZ by the end of Sep. I have a 6.5x57 with 3 different loads to shoot at it. 107, 123, and 142.

[SteveD]

So you shoot the AZ Smallbore State Championships?

Did you mean 6.5 X 47 Lapua? That would be perfect.

[Jerry G]

I will be in Denver that weekend shooting the CO SB. I will be in AZ the following Tuesday.

[Ferret Master]

This was done back in about the year 2000. AR500 Ram mounted on precision ground tubes and Thompson Linear Motion Bearings mounted on angle iron frame set in concrete. As bullet struck ram the amount of energy provided to move ram to the rear was recorded by mechanical spring loaded pencil, length of movement to the rear . The ram was spring loaded to return to reset after shot. You did have to go down after each shot and replace the paper and sometimes the pencil lead. 2550 fps for Sierra 140 was the thicket, provided the most energy transfer by almost 2" of rearward motion. A faster bullet start just made a bigger splatter with less energy transfer to the ram. All this data was posted here long ago. Took a lot of abuse from the faster is better crowd but who cares, they just burnt out barrels faster had more recoil and knocked down fewer rams.
The bottom line is the bullet has to stay together long enough to transfer energy to the target. Many bullets and calibers were tried.
If you look you may find all the data in the archives if we still have them. It would be a shame to waste all the time and money to do it all over again.
If big and fast was the ticket my 7br with 162Amax at 2300fps would not have worked as well as it did on rams.
Remember simple is better.
Ferret Master

[SteveD]

Thanks for the post Ferret Master.

It is my thought as well that the self destruction of the bullet results in an insufficient transfer of energy to the Ram, resulting in Rams being rung. In fact I believe that more of the energy of the bullet is expended in its self destruction than is applied to the Ram. This makes sense as the bullet is being used in a manner that was not considered in it's design.

As long as there are Rams being rung on a regular basis I see the question as being still unresolved.

I don't know this directly but I heard the Cathy Winstead-Severin was abandoning the 6mm bullets due to excessive loss of Rams. Something on the order of 25% or more.

In addition to the 'generally accepted optimum' formulae and current favorite bullets/cartridges I will be testing bullets that were not available in 2000.

My goal is a 95%+ (One rung Ram out of 20) solution or to prove that a high quality solution is not possible.

If you can help me find links to the data you are talking about it would be greatly appreciated.

[Jason]

Speaking of bullets not available in the year 2000, it would be great if someone could include the new Hornady ELD-X bullets in this experiment, specifically the 143-grain 6.5mm ELD-X bullet.

http://www.hornady.com/store/ELD-X

If the marketing hype on that bullet is true, it might be the king of the rams, with a high BC (quoted G1 BC = .625) and construction allowing higher impact velocities without losing the majority of the momentum due to redirection during rapid structural integrity loss. (Sorry.. I've been writing engineering documents today. Can you tell? )

[SteveD]

I'd be glad to. If someone wants to load and shoot them I can arrange it. Everyone is welcome to shoot their fav bullet and get a score on the Ram-O-Meter.

It will help build the data table and who knows what the magic bullet might be?

[Ferret Master]

Jason
Higher impact velocity is not your friend. Much above the 2550 mark the bullet starts to break apart faster and transfers less energy to the animal. There are some videos out there that show what happens when a bullet strikes a plate. Here are some links:

https://www.youtube.com/watch?v=uYtPHRSZ3K8

https://www.youtube.com/watch?v=Fgn7MUp6UxA

The correct idea would be to find a light load that would produce 2550 fps at muzzle and produce less recoil and barrel wear and hammer the ram by allowing the bullet to stay together a little longer.
I'm not sure exactly what type of instrument is going to measure impact but it needs to be able to measure time on target. Even a fast bullet that flies apart instantly will give you misleading impulse readings. You get a tremendous spike with very little dwell time that translates into lost rams. I tried all that and abandoned it. Shoot your highest reading bullet on the impulse type meter then set up a ram and you probably see a spectacular spot maybe even 3" on a freshly painted ram and you may find that it will not fall on a center shot. Take the same bullet at started at 2550fps and get a 1" spot and watch the ram go down. Time on target, dwell time is where it's at not instant impulse. That is why I chose a mechanical measure so that you could see the driving power of the bullet. It takes dwell time to push the ram to the rear. A fast bullet turns to dust and looses most of it's energy to heat.
As for bullets the Lapua 139 OTM has been a top performer for me in 6.5 followed by 140 MK, 140 Amax and 142 MK. In 7mm the 162 Amax has worked really well. Most new bullets are designed to try and stay together in the flesh of an animal not striking a steel plate. Even the Nosler partition will vaporize if it strikes a steel plate going to fast. Many of the newer bullets use a fairly hard alloy of lead in order to try to stay together pushing through flesh. The hard lead tends to vaporize quicker than the softer lead. If energy on paper was a good measure my 38/55 320 grain bullet, 30-1 alloy, that starts out at 1120fps would not take rams down at 500 yards but it does with authority.
Also you need to use a regulation ram target of normal weight. If you don't have the same weight of target your readings are useless. It takes a set amount of energy/dwell time to push a fixed weight of animal. Also it you use your sensor you will need to shoot the same spot in front of the sensor each time to make comparisons. If you use a full size animal with a mechanical measure like we did you will be able to see the effect of off center shots.. A lot of folks shoot for the rump or the face of a ram to get maximum leverage. All of that can be measured by a mechanical measure.
The only new bullets in my thinking that need to be tested are the solid copper bullets. Once again alloy of the copper and bullet construction needs to be taken into account.
All of this lost data needs to become a pined topic "What does it take to knock a ram down" That way we can focus on wind reading and shooting technique and less on reinventing the wheel. Would save a new shooter a lot of time.
Ferret Master

[Jason]

Thanks, but I understand all of that already. That's why I want the new ELD-X bullet tested on steel to see if the design changes to make it better at holding together in flesh and bone improved its ability to transfer momentum on steel targets. It has been quite a long time since this type of experiment has been done, even since Dan Theodore did the bullet smashing. There are new bullets like the ELD-X bullets and existing bullets have changed, including the Lapua Scenars. I have seen the latter's results change myself, which is why I no longer use the 139-grain Scenars for rams.