Springer Vibration-Richter or MMI Scale

[brihacharan]

"bennedose" wrote...
I suspect that the pellet itself leaves the barrel a split second before the piston hits the end of the chamber so the "reverse recoil" may just cause vibration but not affect the aim.

A very important ‘aspect’ to be considered!

Well Guys....Here’s some food for thought …Courtesy > forums.pigeonwatch.co.uk

Spring Guns have double recoil…
Newton’s 3rd law: For every action, there is an equal & opposite reaction.

•Piston moves forward so the gun moves rearward. Piston reaches the end of its travel & strikes the end of the compression chamber with the result that the gun moves away from the piston = forward.
•The pellet may well have left the barrel before the forward recoil occurs but can't have left the barrel before the rearwards recoil occurs because that's a direct reaction to the forward movement of the piston.
•The piston has to move a short distance before the pellet first moves as there needs to be a build-up of pressure in the compression chamber to overcome the initial inertia of the pellet & the friction of the barrel, before the pellet is expelled.

Here’s some more GYAN courtesy > http://www.blueline-studios.com/kuengai ... ndium.html

AIR-GUN TERMINOLOGY ALPHABETICALLY EXPLAINED:
A
ACCESSORY RAIL
A metal track for mounting hand stops or slings, installed in the fore-end of the stock

ACCURACY
The ability of an air-gun to consistently Group all its shots close together at a given distance under optimal conditions. Accuracy does not take into account human error or environment conditions.

B
BALLISTIC COEFFICIENT
A measure of how a projectile decelerates during its flight through the air due to drag. The ballistic coefficient is an important and useful concept that is used for ballistics calculations. Smaller the BC of a bullet / pellet greater its air resistance & Higher the BC, the more aerodynamic is the bullet.

BARREL TIME
The time elapsing between the bullet / pellet starting to leave its seat until exiting the muzzle. Barrel Time and Lock Time are significant, as they can greatly affect the Point Of Impact.

BEAD SIGHT
The cylindrical top part on some front sights

BEDDING
The fitting of the action with the stock

BENCH REST
A specifically designed support, eg. a table

BIPOD
A two-legged support attached to the fore-end of the stock

BLUING
The chemical treatment to color ferrous metal parts in various shades of blue or black

BREAKING IN
A process of initial use of a factory made barrel by firing a certain number of shots and cleaning frequently. Breaking In the barrel should be done before trying to attain good Groups. 500 to 800 pellets are usually sufficient.

BULLET / PELLET DROP
The measure of a projectile's drop after the projectile crosses the line of sight for the second time; beyond the zero or sighted-in range.

C
CALIBER / CAL
The numerical value of an approximation of the bullet diameter in inches or millimeters

CHECKERING
A diamond-like pattern for ornamentation or improved / better gripping

CHOKE
The slightly narrower bore diameter towards the muzzle (about 1 to 1.5 inches long) The pellet is sized down before it exits the barrel to ensure that each one does so in exactly the same way

CHEEK-PIECE
The raised part of the side of the stock of a shoulder-arm

CO2 (CARBON DIOXIDE)
Pre-charged pneumatic guns use a sear that hits a valve releasing pressurized CO2 into the barrel and propels the bullet. CO2 is in a fluid state when pressurized.

D
DEFLECTION
The change in the path of the projectile due to passing through a medium or caused by wind

DIESELING
A detonation inside the pressure chamber when lube evaporates and the resulting gases ignite, caused by the heating of the compressed air in conjunction with the heat the piston seal generates while moving along the chamber walls. The Diesel Effect is unpredictable and dreaded, as its resulting excess recoil can easily damage scopes, even those which are designed to take the Spring Piston-specific type of Recoil.

DRIFT
Lateral movement of a bullet away from the line of bore, caused by its rotation on its axis, in the direction of the rifling twist. With air-guns, drift is not a significant value.

DROP AT COMB
It’s the vertical distance from the line of sight to the comb, or Monte Carlo, of the stock. It is measured from an extension of a straight line drawn from the base of the front sight bead across the top surface of the open rear sight adjacent to the notch

DROP AT HEEL
The vertical distance from an extended line of sight to the heel of the stock

E
ENERGY
Kinetic energy of a projectile – expressed in Foot-Pounds and Joules

F
FEET PER SECOND (FPS)
Unit of measurement of the speed of a projectile also measured in Meters per Second and Velocity

FOOT POUND (FPE)
Unit of measurement for Energy, being the amount of energy required to lift a one pound weight one foot.

G
GIRTH
The smallest circumferential dimension at the pistol grip of a stock

GRAIN (GR.)
Measure of weight applied to bullets. 1 grain equals 0.0648 grams

GROOVES
Grooves and Lands make the Rifling of a barrel. The grooves are the lowered areas between two lands.

GROUP
A cluster of bullet / Pellet holes made by the same air-gun/pellet combination, formed from numerous shots fired at a target using the same point of aim, for checking accuracy. A 10-shot group provides useable statistics.

GROUP SIZE
Usually measured center-to-center, the maximum distance between the centers of the two farthest shots in a Group

H
HAND STOP
A device attached to the stock's fore-end to prevent the supporting hand from sliding forward.

J
JOULE (J)
Unit of measurement for Energy, being the amount of energy required to lift a one pound weight about nine inches.

L
LANDS
Lands and Grooves make the Rifling of a barrel. The lands are the raised areas between two grooves

LENGTH OF PULL
The distance from the vertical center of the trigger to the vertical center of the butt plate or Recoil Pad

LOCK TIME
The time elapsing between the trigger release and
1.On Pneumatic and CO2 air-guns > The release of pressurized gases into the barrel
2.Spring Piston air-guns > the piston reaching the fore end of the pressure chamber. Since no one can hold an air-gun absolutely steady while shooting, the longer the Lock Time, the higher the chances to inadvertently move the gun before the bullet has actually left the barrel. The Recoil can also greatly affect the Point Of Impact due to the Lock Time and Barrel Time. Spring Piston air-guns have the highest Lock Time, one of the reasons why they are excellent for training, as they force the shooter to pedantically apply the rules of marksmanship.
M
METERS PER SECOND (M/S)
Metrical unit of measurement of the speed of a projectile

MID-RANGE TRAJECTORY
It’s parabola-shaped path, the highest vertical distance reached by a bullet above the line of sight.

MIL
Angular unit of measurement used to estimate distance and size: 1 Milradian is 1/1,000 of the distance; 1 meter at 1,000 meters; 1 yard at 1000 yards. 360 degrees consist of 6,400 Mils by military definition, 6283.2 mathematically.

MINUTE of Angle (MOA)
Angular unit of measurement used to describe the Accuracy. One MOA equals 1/60th of a degree (21,600 minutes in a complete revolution) and subtends 1.0473 inches at 100 yards, or, as a rule of thumb, 1 inch at 100 yards. 1 Mil contains 3.44 MOA.

MONTE CARLO
A stock with a raised comb

O
OBJECTIVE
The optical lens in riflescopes that receives light and forms the primary image - The image is magnified by the Ocular.


OCULAR
Also known as the eyepiece - The magnifier lenses between the optical system and the eye

OFF-HAND POSITION
A position in which the shooter stands upright, not resting the rifle or his body on or against any supporting object.

Open Sight Rear sight of traditional open-topped V-notch or U-notch.

P
PARALLAX
It’s the apparent movement of the target in relation to the reticule when the shooter moves his eye in relation to the ocular lens. When the target's image is not focused on the same focal plane as the riflescope's reticule, a parallax error is the result. For varmint shooters, improper Parallax adjustment can easily make the difference between a hit and a miss.

PNEUMATIC
Pre-charged air tank system - The sear hits a valve that releases pressurized air into the breech and propels the bullet.

POINT BLANK
The shooting distance to which one can hit a specified target area without modifying the Point Of Aim The Mid-Range Trajectory and the Bullet / Pellet Drop will both fall within the specified area

POINT OF AIM (POA)
The point on a target on which the sights are optically aligned

POINT OF IMPACT (POI)
The point where the bullet hits - By adjusting the sights, the point of impact can be made to coincide with the Point Of Aim at a preselected distance; hence we say the rifle/sight/pellet combination is "zeroed" or "sighted in" at that range.

PROBABILITY OF HIT (POH)
Refers to the chance (0 to 100%) that a given round will hit the target at a given range, depending mainly on the gun's Accuracy

R
RATE OF TWIST OR RIFLING
Pitch is the distance the Rifling needs to spin down the barrel for it to complete a single revolution

RECOIL
The rearward thrust caused by the propulsion of the piston or the bullet. Spring piston air-guns have also a very aggressive and powerful forward kick, caused by the piston hitting the front end of the pressure chamber. It is this second forward snapping that can damage even high-quality riflescopes. The recoil can have be devastating to the system when the air-gun diesels

RECOIL PAD
A rubber or leather pad at the end of the butt to absorb the Recoil

RETICLE
In scopes, the element which is optically referred to the target, consisting of straight or tapered cross-hairs, dots, or other marks used to determine the Point Of Aim, size of, or range to the target.

RIFLE CANT
Any leaning of the rifle to one side from a vertical position during firing, increasing the potential for misses, especially at longer ranges.

RIFLING
Twisted Lands and Grooves are placed into a barrel to impart spin on the bullets that pass through it.

RIFLING PITCH OR RATE OF TWIST
It’s the distance the Rifling needs to spin down the barrel for it to complete a single revolution.

S
SCOPE CREEP
An unwanted effect where the Scope Mounts creep along the Scope Rail - During the firing cycle of Spring Piston powered gun, the piston bangs into the front end of the compression chamber, making the entire gun to snap forward violently. There are systems that eliminate scope creep for good.

SCOPE MOUNTS
Devices for mounting a scope to a rifle

SCOPE RAIL
Machined grooves or rail to which the scope mounts are attached.

SIGHT-IN
The sight adjustments to get the Point Of Aim to coincide with the Point Of Impact at a preselected distance - It is best done by firing 3 to 5 shot groups between each adjustment.

SILENCER
A device designed to muffle the sound of the discharging of pressurized gases exiting the muzzle. See also Suppressor and Sound Moderator.

SPRING PISTON
It’s the mechanical part within the pressure chamber that moves forward under steel spring or gas spring pressure, compressing the air in the chamber and pushing it into the barrel. The piston front consists of a sealing.

SUPPRESSOR
A device designed to nearly totally absorb the sound of the discharging of pressurized gases exiting the muzzle. It can also be an integral assembly with the barrel. See also Silencer and Sound Moderator.


SOUND MODERATOR
A device designed to moderate the sound of the discharging of pressurized gases exiting the muzzle. See also Suppressor and Silencer.

STIPPLING
A random pattern of stipples for improved gripping. See also Checkering.

SWIVEL
The attachment hook for the sling to the stock

T
TERMINAL VELOCITY
The speed of the projectile upon impact with the target

TRAJECTORY
The path of a projectile in flight - As gravity causes the bullet to drop from the moment it exits the muzzle, its trajectory is always curved in the shape of a parabola.

TRANSFER PORT
A port hole, an air-tight connection between the pressure chamber/air reservoir and the barrel, through which the gases travel prior to propelling the pellet

TRIGGER PULL
The force that must be applied to the trigger for it to release the sear - A good Trigger Pull must be appropriately light, and the release must be a clean, sharp snap.

TURRET
The housing for the adjustment of wind-age and elevation dials on riflescopes.

V
VELOCITY
The speed of a projectile, measured in either Feet per Second or Meters Per Second.

W
WIND-AGE
The adjustment on the scope or open sights to compensate for horizontal Deflection of the bullet

Z
ZERO
The range at which the Point Of Aim and the Point Of Impact are identical

Happy Shooting
Briha

[bennedose]

Brilliant Glossary Briha - and I think that list needs to be a separate thread which remains visible as a sticky. I am considering starting a YouTube channel with videos entitled something like "Safe Fun with your Air gun" emphasizing safety, the law and then something informative.

Incidentally your desription of "Rifle cant" reminded me of the way I used to hold my catapult decades ago when I was a crack shot with one. By holding it tilted (canted) 90 degrees, elevation and windage were more easily adjusted than by attempting to hold the catapult vertically or an an angle less than 90 degrees. But I digress. I am trying to figure out a way of checking barrel vibration alone - will post if I can think of something workable.

[brihacharan]

Brilliant Glossary Briha -
I think that list needs to be a separate thread which remains visible as a sticky. I am considering starting a YouTube channel with videos entitled something like "Safe Fun with your Air gun" emphasizing safety, the law and then something informative.

Incidentally your description of "Rifle cant" reminded me of the way I used to hold my catapult decades ago when I was a crack shot with one. By holding it tilted (canted) 90 degrees, elevation and wind-age were more easily adjusted than by attempting to hold the catapult vertically or an an angle less than 90 degrees. But I digress. I am trying to figure out a way of checking barrel vibration alone - will post if I can think of something workable.

Incidentally your description of "Rifle cant" reminded me of the way I used to hold my catapult decades ago when I was a crack shot with one.

Ah! We have something common there - I used to be a 'Crack Shot' with the Catapult too - Could bring down Mangoes & Guvavas at 20ft / 30ft one at a time by slicing the stem that held them with no damage to the fruit

Also used to hit Toy Pistol Caps stuck on a wall 10ft away & watch them go Bang

BTW - Rifle Canting is fairly common in shooters trying to adjust their cheek bone on the cheek rest of ARs -
What with the Cheek Rest being standard & Cheek Bones varying in shape & size
Briha

[Basu]

Dear benne,

You have conducted the testing a little differently then my method .
I wanted to calculate the vibration of the gun in artillery position for which, in order to allow its free movement, I kept the gun on two boxes of MSFH 0.177 .
Objective was to estimate the jerk/vibration that one experiences while firing with artillery hold.
Since your phone was directly attached with the setup ,so the vibration registered , is higher than my testing results.

I think the shooting comfort depends on following factors :
1) Smooth easy cocking – no scraping sound
2) Low jerk/Vibration
3) Easy trigger approx 1500 grms or less in 3.5 + kgs guns
4) Low sound
I am sure that your liking for SDB is due to the presence of above four factors only.
I am of the opinion the vibration occur after the pellet leaves the barrel so it does not affect the accuracy any way.

Dear Marcury,

I am very sure that the heavier pellets causes low vibration since the piston rams the dead end with less force but that analogy does not work for my Local 35 in 0.177.
My local 35 is loaded with hard spring for which the pellets ranging from 7.71- 10.4 grns does not witness any difference in vibration whatsoever.In other ward the piston rams the dead end every time with the same force, resulting in almost same vibration.
I need to once again repeat the test for my Local 35 to be completely sure that with 39 coil high power spring also can deliver so low vibration.

Basu

[brihacharan]

Hi Basu / Bennedose,
> From what I gather from your's & Bennedose's tests / observation / conclusions etc. is that there is no standardization in the equipment you are testing.
> Different ARs fitted with different spring kits & shooting different pellets - One keeping the AR on boxes while the other is held in a vise....
> As you see there is no common ground or parameter for testing...
> IMHO....
1. 0.177 & 0.22 should be tested seperately....
2. All ARs should be fitted with same type of spring kit (Spring, Rear Guide, Top Hat, Seal)
3. ARs should be held / rested / positioned etc. in a similar manner...
4. Pellets used should be of the same brand, size, shape & weight...
5. The recording instruments should be similar & placed in a uniform manner & location...
6. Firing should be done by pulling a string tied to the trigger rather than using finger...
> All of us, atleast those of us who are more than familiar with ARs only too well know (even the foreign experts swear & agree) that no two ARs even though they come from the same batch & having successive serial nos. behave similarly
> If we are engaging in the academics of 'vibration technology' for the heck of it... well fine... But the findings / outcome mean nothing - just a few numbers with shifting decimal points, that leaves one thoroughly confused...
> Any high school chemistry / physics lab that teach us testing procedures always do so by providing 'standard results / reading' against which our experiment's outcome is compared to find the element of deviation for quality, purity, perfomance etc.
> It would be very interesting if these tests are done such as....
1. Take two ARs of different make but of same caliber
2. Fit them with same brand of spring kit (Spring, rear guide, top hat, seal etc.)
3. Use same brand, type, weight of pellet
4. Place the ARs in identical rests
5. Place recording devices (same model, capacity & type) in same / similar positions
6. Release trigger in a similar fashion
7. Take atleast 10 readings for each AR - take an average... perhaps you'll get some semblence of a behaviour pattern...
> But then remember - the receivers in the ARs tested will be different - the barrel will be different - the size of the transfer port could be different...
> All this even after we use standards for the internals
> So where are we????
> After burning the wires I am yet to come across some experiment in this regard conducted by world's leading & acknowleged experts... the likes of Tom Gaylord, BB Pelletier, Charles d' Tuna, Theobalt, Benjamin etc.
> This debate / discussion can be taken to micro & even nano levels.... but then how educated & wiser we stand????
> As of now- I am taking a breather
Briha

[bennedose]

I think the shooting comfort depends on following factors :
1) Smooth easy cocking – no scraping sound
2) Low jerk/Vibration
3) Easy trigger approx 1500 grms or less in 3.5 + kgs guns
4) Low sound
I am sure that your liking for SDB is due to the presence of above four factors only.

I would add - it is consistently accurate. Having said that I am not particularly bothered by the vibration of either my IHP35 or Orion. But the relative quietness of the SDB is useful because of two reasons. It is not just the sound of the rifle - but the clack/clang of the target being hit. The IHP and Orion deliver more power and make a louder noise so - so I prefer the quieter rifle.

Another thing is that when I am shooting off 10-15 pellets 3 times a day the cocking effort makes a difference.

[brihacharan]

Another thing is that when I am shooting off 10-15 pellets 3 times a day the cocking effort makes a difference.

If you love & own springers & shoot on an avg of 45 pellets a day - You cannot accomplish this without COCKING your ARs
Probably the only answer to this is - Switch to PCPs
IMHO - Cocking an AR is a 'Macho' activity - And I love it
Briha

[bennedose]

As an indicator of how misleading "personal impressions" can be I tested my 3 air rifles for noise using the same AIMCO round head pellets and a standard distance from the phone/sound meter

IHP 35 - 73 to 74 decibels
SDB 50 - 72 to 73 decibels
Orion - 68 to 72 decibels

Hardly any difference but the Orion is actually quieter. Maybe I should measure the sound of target being hit which "seems" louder to me with the more powerful rifles. Also maybe I should do a sound frequency analysis for time-pass value. I suspect that the SDB seems quieter because it has a slightly lower pitched sound . I mean "Thock!" sounds less loud than the Orion's "Tlockk" and the IHPs "Thrunk"

Brihaji apart from cocking effort I must point out that the locking mechanism of my SDB has been used so much that it locks (and opens) with less effort than either the Orion or IHP. I can break the barrel, cock and load, and then lock the barrel for shooting by lifting the barrel with using one finger with the SDB. That one finger push is not possible with the Orion unless I jam it back fast making a loud clunk. But this is because the SDB has probably been used for over 10,000 shots over its life, while the Orion and IHP may have done a thousand apiece. So everything is more lax and smooth on the SDB. The other thing is familiarity which counts when I consider that the SDBs sights are still unsatisfactory after all my jugaad/hacking.

[brihacharan]

So Basu / Bennedose....
> Where does all this lead to
> Like Bennedose's SDB - My Samurai too behaves similarly...
> So one can with some element of authority conclude that "More than 5000 Pellets" have to be shot before one begins to establish the 'Vibro Coefficient" of an AR.
> It takes an AR (may be 2000/3000/4000) shots to settle down when all its moving parts have adjusted themselves to cohesively perfom smoothly.
> BTW - One out of the box idea has just struck me....
> Smoking Pipe manufacturerers abroad sell 'Pre Smoked Pipes' (the pre smoking is done through a machine)...
> This is a way of curing the wood which is used for making the pipe....
> So why not the AR fresh out of the factory be shot at least a 1000 times mechanically to make it operate smoothly (help the AR settle down)
> Its just a food for thought
Briha

[Basu]

I redid the testing of vibration with earlier method for my Local 35 High power 0.177 AR , where I wanted to be verify authenticity of my last reading .
Results did not differ much and it ranged from 4.2 to 4.6 richter with all three pellets earlier used.
I am of the opinion the vibration can be reduced by tuning even with hard springs and it also involves the basic design of AR or receiver.
I also did noise testing for all three guns that I have.
I used Sound Meter Lite application of android without any change in calibration.
The phone/ Meter was kept at approx 5 mtrs distance from muzzle because it can not capture more than 86 dbs . Had I kept it within a mtr, perhaps each figure would have reached 86 or maximum reading.

IHP National-25-------- 73 dbs
SDB 45 Classic.22------- 73 dbs
Local 35 .177 -----------79 dbs

The local 35 with only increase of 6 dbs , caused me huge irritation.
On the other hand 73 dbs found to be a pleasing sound.I am sure this acceptance of noise will very person to person.
The testing could have been better if I could keep the meter pretty close to the gun but this application/phone has its own limitations.

Basu

[brihacharan]

Basu,
> I suggest you mail your findings to M/S. Pelletier / Tom Gaylord & Charles d' Tuna to elicit their opinion etc....
> Should be very interesting to know their views....
> Worth an attempt
Briha

[Basu]

Hmm......