Bipods ~ What's The Craic, Please?

[macberran 2]

I would like too thank you all for a very informative thread, idon't use a bipod but have been considering for somtime piles of info too di-gest . And Docter M that was amazing....after I had picked my jaw off the flaw Feck me

[Deker 3,478]

The topic of bipods is probably well exhausted by this stage. This post is not so much intended to extend the discussion as address and explain the issues raised by Snap Shot's failure to understand my angle on bipod mounting and his over simplification of the forces involved in firing a rifle from such a piece of apparatus (Feb 09th).

Snap Shot appears to have focused primarily on the force applied to rifle at rest and without firing. His statement that this is 9.81N is not exactly correct. The force of gravity is the force with which the earth or other massively large object attracts another object towards itself. By definition, this is the weight of the object. All objects upon earth experience a force of gravity. This force on earth is always equal to the weight of the object as found by the equation Fgrav = m * g where g is acceleration due to free fall or 9.8 m/s2 and m = mass (in kg). Oh well, you were nearly right, Snap Shot.

 

However, the intention is to actually fire the rifle, not merely take it for a romantic walk in the countryside. One might expect that firing would be a repeated activity over the life of the firearm. What has been overlooked almost completely in Snap Shot’s consideration is this fact, and also the undeniable and proven concept of conservation of momentum (blame Newton not me) and free recoil. The forces involved are not inconsiderable. Consider this scenario:

 

Firearm: Mauser 98 chambered in 7 × 57mm weighing 4.54 kilograms (10 pounds).

 

Projectile: spitzer type weighing 9.1 grams (140 grains) with a muzzle velocity of 823 meters per second (2700 feet per second).

 

Powder charge: single base nitrocellulose weighing 2.75 grams (42.5 grains) with a powder charge velocity of 1585 meters per second (5200 feet per second).

 

The momentum short form:

 

Etgu = 0.5 • [{( mp • vp) + (mc • vc)} / 1000]² / (mgu)

Etgu = 0.5 • [{(9.1 g • 823 m/s) + ( 3.63 g • 1585 m/s)}/1000]²/4.54 kg =

Etgu = 0.5 • [{(7489.3) + ( 5753.55)}/1000]² / 4.54 kg =

Etgu = 0.5 • [{13242.85}/1000]²/ 4.54 kg =

Etgu = 0.5•[13.243]²/4.54 kg =

Etgu = .5 • 175.377 /4.54 kg =

Etgu = 85.6885 /4.54 kg =

Etgu = 19.14 J of free recoil

 

This converts directly to 19.14 Newton Meters of energy (Newtons appearing to the unit of measurement so beloved of Snap Shot). This is instantaneous or 'shock' force. This force is being transferred to the bipod in the first instance and latterly to the shoulder of the firer. The bipod is a relatively rigid affair; the shoulder is not. In those cases where the bipod is attached in the end of the forestock (or some other odd place) there can occur flexing at, and of, the point of attachment. Given the minimal surrounding material in this area, occasionally, this can be detrimental to the mounting arrangement and to firearm in general, particularly where natural materials are used as in the very nice walnut stock of my friends Sauer. Damage can and does happen for the reason I’ve explained. My words of caution are based on clear science and personal experience. This post is not intended to antagonize or embarrass – merely to correct misconception.

 

In latin I think the phrase is “quod erat demonstrandum". For those with limited latin this means “that which was is demonstrated".

 

My thoughts on seeking assistance from a competent smith are based on the fact that over the years I’ve seen some very pretty rifles damaged by bodged DIY jobs. I read one of the guys recommending measuring 10 times and drilling once. If you’ve to do that, trust me, you are categorically incompetent and likely to make a problem rather than cure one.

 

Thanks for listening. Mauser Man, (Dr) Lecturer in Applied Physics…seriously.

 

 

 

 

Ok...I'm old enough to have done proper "O" and "A" levels (when they were hard) and I've got a Degree (admittedly not in physics), I have considerable ballistics experience and knowledge .....enough, enough. I'm getting lost, put this in simple terms, are you suggesting that attaching the Monopod/Bipod/Tripod/Poles/ Whatever to the front swivel stud is a problem?

 

In addition, and whilst it is obvious many forces come into play when firing "ANY" type of gun, what is the problem with attaching a bipod to a (sturdy) barrel?

 

I still struggle to understand why making an attachement to "almost" any part of a gun, excepting the very obviously flimsy areas is going to cause a destructive problem! Help me out, I know, I know a lot, but I also know I still have a lot to learn!!!!

 

I understand the principle of what you are suggesting but I fail to grasp the detail/reality. Put simply, did this post require this sort of response which is way above the heads of many and is therefore virtualy meaningless! You are obviously trying to make the suggestion that you are quite clever so put it in terms "the man on top of the number 10 Clapham Omnibus can understand!"

 

Thank you.

 

Deker

[Squirrel_Basher 17,100]

Just for reference -Anybody thinking of fitting a bipod on a standard forend would do well to fit a full threaded stud that has its own locking nut on the inside of the forend.

.

Theres nothing high tec about fitting a bipod ,just a bit of commen sence .IMO the screw in studs arnt man enough for a bipod .

[Mauser Man 0]

Forgive the indulgence of yesterday. All I'm saying is make sure you have an adequate point of attachment for the bi pod. Avoid the tip of the forestock and any place were material surrounding the stud is minimal. Damage is a likely result. Never attach the apparatus directly to the barrel. Anything which could conceivably affect the oscillation of the barrel on firing must certainly affect point of impact.

Edited February 13, 2008 by Mauser Man

[Deker 3,478]

Forgive the indulgence of yesterday. All I'm saying is make sure you have an adequate point of attachment for the bi pod. Avoid the tip of the forestock and any place were material surrounding the stud is minimal. Damage is a likely result. Never attach the apparatus directly to the barrel. Anything which could conceivably affect the oscillation of the barrel on firing must certainly affect point of impact

 

 

Me again...help clarify the one in red please. Fixing a Bipod etc to many guns effects the POI. If we assume the ammo remains constant and the surface the bipod is resting on remains constant and the gun is zeroed to this point why will the POI not remain constant as the oscillation should remain constant, or am I missing something?

 

Thanks

 

Deker

[Mr_Logic 5]

Forgive the indulgence of yesterday. All I'm saying is make sure you have an adequate point of attachment for the bi pod. Avoid the tip of the forestock and any place were material surrounding the stud is minimal. Damage is a likely result. Never attach the apparatus directly to the barrel. Anything which could conceivably affect the oscillation of the barrel on firing must certainly affect point of impact

 

 

Me again...help clarify the one in red please. Fixing a Bipod etc to many guns effects the POI. If we assume the ammo remains constant and the surface the bipod is resting on remains constant and the gun is zeroed to this point why will the POI not remain constant as the oscillation should remain constant, or am I missing something?

 

Thanks

 

Deker

Don't ask me the physics, but it's the same reason as free-floating barrels are good. If they oscillate freely it's better, but I don't know why because I am only a humble archaeologist and don't speak physics beyond GCSE Bipod always affects zero anyway because it affects recoil, but it's usually pretty minor.

[Guest JohnGalway]

http://en.wikipedia.org/wiki/Old_Moore's_Almanack

 

I'd also like to predict that Ditch will buy a Lightforce lamp, most likely a scope mounted 170 Striker with dimmer switch AND a Dell Lappy sometime in the future. This Oracle is now taking bets

[dickyboy 1]

yep as said, it is the free floating arguement which has been proven by many shooters worldwide......the reason most guns have freefloating barrels

 

Deker you are correct saying that if the forces were the same on the barrel then it would not affect POI but while hunting the surfaces the bipod etc will rest on will differ, adversly affecting the oscilation of the barrel, likewise you would have to apply the exact same force down or up on the barrel to avoid altering the POI, therefore attaching to the barrel will always make shooting next to impossible..............as an example i had the legs folded forward on a bipod the screws of the bipod were lightly touching a neoprene cover on the silencer, this changed my grouping from sub 1" @100 to well over 2" with one round missing the target.......only alteration, took it back off and shot fine again!!

[Deker 3,478]

Guys...thanks for all that which I knew anyway...the term used was "Never attach the apparatus directly to the barrel"

 

Answer is, for general hunting its not a good idea, but if you are a useless shot it will probably be better anyway, in controlled environment where all else remains equal its not a problem!

 

Its just the term NEVER is very final and I recall a film......"Never say never again"

 

I still don't understand all the formulas quoted earlier so just attach the Bipods etc to the stud!

 

Took an awful long time to get here didn't it!

[snapper5 0]

Just had a new 27" Harris swivel bipod delivered - an early birthday pressie to myself. I already have the 23" cheaper Rockmount versions but having now got the two side by side I would say the Harris is definately worth the little bit extra. The construction looks more robust and all the movements are smoother. Cost me £87.99 inc delivery from Sportsman Gun Centre. I wear glasses when shooting and kept finding myself trying to look through the top of the glasses frame as the 23" bipods were not quite tall enough. Just fitted it and it feels far more comfortable.

 

I find the taller bipods offer quite a few advantages over the shorter ones. Namely, I don't have to lie down in the mud and muck the cattle left behind, I can pan and easily spin round to provide a wider firing arc, I can clear low vegetation and from a safety point of view, I am always shooting down at the quarry so giving myself a better backstop. And as the largest thing I shoot are foxes, if I find myself looking up at it, it's going to be a bloody big fox.

[SNAP SHOT 194]

http://www.thehuntinglife.com/forums/index...&pid=380901

 

 

 

i don't think he missed the target, check to see where the greater force is, in the fore-end or the barrel and base, action, scope and barrel flex,

[Ratman2 2]

I'm more in favour of a mono-pod, I use a fishing rod rest, it's telescopic and very light, doubles up as a walking stick too. I prefer to rest my forehand on the rest and hold the gun as if shooting free hand.

Bargain at £6.