Thread: New rifle, scope question

Originally Posted by TheJanitar

before i make a new thread.. posting this question here.

Is there anyone in the southern auckland region that may be able to help me sort my scope and sight in my rifle? Was gonna make a separate thread about sighting it in but i thought itll be a better idea to get that done and sort the scope at the same time with an an experienced hunter/shooter's help. (And dont worry, Only need to be shown this one time then im sorted ) Dont wanna "screw" things up, as i realized it can be an expensive mistake.. Will save me so much hassle with gun ranges and gunsmiths if someone on here who knows what theyre doing might be able to help. BIG PLEASE guys

And thanks for everyones input thus far! much appreciated

Yes, I'm in Sth Akl, and have a Wheeler Fat wrench, Torx bits, and a scope level.

Send me a PM

B

Originally Posted by shift14

Yes, I'm in Sth Akl, and have a Wheeler Fat wrench, Torx bits, and a scope level.

Send me a PM

B

Good old Uncle B.
Hurry up and sell me that range.....

Originally Posted by Nibblet

Good old Uncle B.
Hurry up and sell me that range.....

NFS.....

B

All sorted! Getting the scope sussed on monday and going to the range next saturday. Thanks Bevan!

this forum is a gold mine for new hunters, i must say.

cheers guys

Originally Posted by timattalon

Recoil is not determined by calibre. It is relatively simple physics (E=MC2) Energy forward equals energy rearwards. Energy is weight x velocity x velocity. If the bullet energy is the same out the muzzle then the recoil is the same if the rifle weight is the same. The only ways to reduce recoil is to reduce the energy going forward or increase the weight going rearwards.

This relativity only applies to light projectiles going 3x 10⁸ meters per second. For what we're dealing with we just go for 1/2 mv².

Originally Posted by gadgetman

This relativity only applies to light projectiles going 3x 10⁸ meters per second. For what we're dealing with we just go for 1/2 mv².

I was trying to say that the energy the bullet has leaving the muzzle is the main determinant of recoil going the other way. The reason the rifle is slower going rearwards is that it is 300 to 400 times heavier than the projectile thus reducing speed. If he wants lighter recoil then choosing between identical models of 308 vs 7mm08 (say a T3) then the weight difference between the rifles is negligible, and the energy of the bullet at the muzzle is close enough to identical between the calibres, thus there is almost no difference in recoil between the two. To make any significant drop in recoil, he would either have to sacrifice speed / energy by using lighter loads or make the rifle heavier to slow the recoil.

As a side note, I use the term slow the recoil because the actual amount of recoil in a heavier rifle scenario would actually be the same but the slower transfer of energy to the shoulder will make it feel like less recoil.

Short and sweet. Recoil difference between 7mm08 and 308 is close enough to not matter.

Originally Posted by timattalon

I was trying to say that the energy the bullet has leaving the muzzle is the main determinant of recoil going the other way. The reason the rifle is slower going rearwards is that it is 300 to 400 times heavier than the projectile thus reducing speed. If he wants lighter recoil then choosing between identical models of 308 vs 7mm08 (say a T3) then the weight difference between the rifles is negligible, and the energy of the bullet at the muzzle is close enough to identical between the calibres, thus there is almost no difference in recoil between the two. To make any significant drop in recoil, he would either have to sacrifice speed / energy by using lighter loads or make the rifle heavier to slow the recoil.

As a side note, I use the term slow the recoil because the actual amount of recoil in a heavier rifle scenario would actually be the same but the slower transfer of energy to the shoulder will make it feel like less recoil.

Short and sweet. Recoil difference between 7mm08 and 308 is close enough to not matter.

Mmmm so how does a big fat slow bullet vs a small fast bullet smack me around more or less in the same rifle?

Read what good old Chuck has to say on the topic and check out his table
Rifle Recoil Table

Originally Posted by Gibo

Mmmm so how does a big fat slow bullet vs a small fast bullet smack me around more or less in the same rifle?

The powder/primer charge gives the energy to the projectile according to 1/2mv². From this, very roughly, we get the velocity of the projectile. Then as the projectile leaves us on it's little journey the momentum, mass * velocity (mv), comes into play which imparts the velocity and energy back into the firearm, with roughly the same momentum. This energy is dissipated into the firearm and shooters shoulder. There are other things in play but these are the main bits.

Originally Posted by gadgetman

The powder/primer charge gives the energy to the projectile according to 1/2mv². From this, very roughly, we get the velocity of the projectile. Then as the projectile leaves us on it's little journey the momentum, mass * velocity (mv), comes into play which imparts the velocity and energy back into the firearm, with roughly the same momentum. This energy is dissipated into the firearm and shooters shoulder. There are other things in play but these are the main bits.

No I was asking Tim, based on his previous reasoning that I quoted.

Originally Posted by Gibo

No I was asking Tim, based on his previous reasoning that I quoted.

Multiply the mass by the velocity for both projectiles. The bigger result will give you the bigger slap. Divide the result by your rigs weight and that will give you the initial velocity of your rig that needs to be absorbed. 1/2 mv² of your rig will be the recoil energy that you need to absorb.

Don't worry Janitar, all you need to know is the gun goes bang and if you and uncle B have set it up correctly and you've pointed the sharp end in the right direction the deer SHOULD fall over.

Doesn't always work that way though.....

I'm talking exactly the same info as Tim. He just used Einstein's energy equation for particles travelling at the speed of light which is double what we expect normally and leads on to the theory of relativity. Yes, I'm a geek that has done post graduate level physics.

Originally Posted by Nibblet

Don't worry Janitar, all you need to know is the gun goes bang and if you and uncle B have set it up correctly and you've pointed the sharp end in the right direction the deer SHOULD fall over.

Doesn't always work that way though.....

No it doesn't does it mr lever

Originally Posted by Gibo

No it doesn't does it mr lever

No it doesn't.

But that's because I didn't set up my scope proper 😁



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