Ransom rest rabbit hole

Nice, you do a lot of pistol testing? I only have 2 so I might be able to justify making one before buying one.

Nice work! I'm jealous of the machine shop as well!!!

At least its not a prairie dog hole like my bullet feeders became......a complicated maze.... I was wondering what your next focus was....you've been relatively quiet lately.
Interesting stuff.....and here I thought Ransom Rests were same point accurate.....

What does a Ransom cost now days? So, as is, are they not worth the money?

jmorris said:

I have owned a ransom rest for about a month and in my testing, even with low SD's I was getting different amounts of muzzle rise on different shots.

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How much difference?

Ruger 15151 said:

Nice work! I'm jealous of the machine shop as well!!!

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As am I. I Pa I had use of a high precision South Bend finishing lathe and an old Bridgeport mill at my disposal and I had to leave them behind when I move to NC. I'm still crying over that one.
I have nothing now for machining tools. You have no idea how much I miss them. To me they were as natural to have as a table saw or a drill press.
Looking back, I should have bought them and paid to have them shipped down here to NC. I feel like a fish out of water now.

I'm sure your rendition of the Ransom Rest will be better than anything Ransom produces because of your skills and the fact that your not trying to make a living selling them.

I like your improved version. It looks miles ahead as far as repeatability. Always enjoy your projects and the accompanying posts.

So.... how do I place my order for one?

Just an FYI, the MantisX 10 has a recoilmeter as part of the app. It displays recovery time, muzzle rise, recoil width, and recoil angle in the app.

jmorris said:

For me I think I will learn more when my shore 80A polyurethane gets here and I start making other grip molds.

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Back when my club had a Ransom Rest on long term loan from a member, my FLG had the idea of picking an accurized 1911 and making glass bedded aluminum inserts to fit it and it only for ammo testing. Never got 'round tuit and the new range does not have a Ransom emplacement.

This looks an interesting project JM. I did a fair bit of work with a Ransom rest back in the 80's testing loads with various good quality target pistols, mostly shooting .32 S&W Long full wadcutters through Walther, Hammerli, Pardini, FAS, Unique type pistols - some of these pistols, with only about 4-5" barrels shot extremely tight groups consistenly at 25 yards.

lordpaxman said:

So.... how do I place my order for one?

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Do you mean a RR? Do a Google search. They are available at lots of places.

fxvr5 said:

Do you mean a RR? Do a Google search. They are available at lots of places.

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No. I mean a JR.... @jmorris Rest.

jmorris said:

Of course it is load dependent but for two rounds that only had a 2 fps difference between them there was a 1/4” difference in ending muzzle position.

Lots of variables involved and none are going to really change anything for me as I know what loads I have are accurate and what ones will do the job at very low cost. It’s more of a learning experience and just trying to build a better mouse trap, so to speak.

For me I think I will learn more when my shore 80A polyurethane gets here and I start making other grip molds.

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I look forwards to seeing your grip forming process with the polyurethane, I hope you will post some pics of the process!

Just a thought... Do you think that the recoil force is changing shot to shot or do you think that the coefficient of static friction of your pivot is not very repeatable? I am going to venture a guess that the coefficient of static friction of the pivot is not staying uniform from shot to shot which is causing the 1/4" variance for only a 2fps change. I purpose that you might want to consider tweaking your design a bit and instead of relying on the static/kinetic friction of the pivot joint to provide the recoil measurement reading that you use a more linear force to counteract and measure the recoil force.
My first thought is to employ a spring and a maximum deflection pointer like a manual trigger pull gauge. Hooks law for determining a "springs constant" (http://labman.phys.utk.edu/phys221core/modules/m3/Hooke's law.html#:~:text=F = -kx.,direction towards its equilibrium position.) which would allow for more repeatable measurements.
A second idea is to use a large counter balance weight mounted below the pivot in a pendulum format to counter act the recoil force and use the same maximum deflection pointer again like a trigger pull scale. Both of these ideas are just derivations of common scales used to measure the force of gravity acting on an object (i.e. weight of an item).

Just a thought to spur some thinking, I know this isn't needed but you seem interested in the experimentation aspect of this project and the challenge of building your own better mouse trap so I thought it might be worth mentioning.

P.S. You could also measure the recoil force in real life meaningful units (ft-lbs or Nm [newton meters]) with a very simple ballistic pendulum setup and very basic math. By using a common unit of measurement you can actually compare your results to those of others. I would be more than happy to explain and provide references to the physics and math if you are interested?

I want to be you when I grow up.

MikeInOr said:

P.S. You could also measure the recoil force in real life meaningful units (ft-lbs or Nm [newton meters]) with a very simple ballistic pendulum setup and very basic math. By using a common unit of measurement you can actually compare your results to those of others. I would be more than happy to explain and provide references to the physics and math if you are interested?

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It's easy enough to measure recoil force with just knowing the bullet weight, bullet speed, powder charge weight, and some value for gun weight.

A Ransom Rest has been used to measure relative recoil, and rocker arm movement does a decent job reflecting calculated recoil.

https://www.shootingtimes.com/editorial/measure-relative-handgun-recoil/99442

fxvr5 said:

It's easy enough to measure recoil force with just knowing the bullet weight, bullet speed, powder charge weight, and some value for gun weight.

A Ransom Rest has been used to measure relative recoil, and rocker arm movement does a decent job reflecting calculated recoil.

https://www.shootingtimes.com/editorial/measure-relative-handgun-recoil/99442

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There are a LOT of ways to accomplish any particular task. Some of us don't mind a bit more round about approach in the interest of learning something along the way. Mounting a handgun on a ballistic pendulum and recording different weight bullets with a high speed camera might be very enlightening for differentiating between recoil force and recoil impulse period (speed).

Nothing wrong with working it out using the bullet weight and bullet speed though.

Do you have a way to check that your not getting any movement/slipping in the grip? I would think that would be one of the weakest points and most likely a change in accuracy, POI shift.

Really like what your doing.

Blue68f100 said:

Do you have a way to check that your not getting any movement/slipping in the grip? I would think that would be one of the weakest points and most likely a change in accuracy, POI shift.

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One can measure the gun's position at some stage early in the session, then check it over time. If properly settled, the guns won't move. Steel framed guns can usually be held very tight. Some polymer framed guns can't be held too tight because the frame flexes and the magazine won't be able to be inserted/removed. But, as noted, if properly settled, the guns won't move.

Id buy one.

FLG and I tested that.
A good tight 1911, good ammo (a brand of SWC no longer made) and the gun laid for each shot with a scope sight in V blocks on top of the slide. Groups were smaller than by depending on the Ransom Rest to return exactly to battery.

Jim Watson said:

FLG and I tested that.

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Who/what is FLG?

Friendly Local Gunsmith.