We are talking normal pressures not overpressures. We all agree all guns can blow up.
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Lug setback? What am I missing?
- Thread starter Mram10us
- Start date
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bigngreen
Well-Known Member
No you did not ask about recoil you asked about what the lugs feel which is bolt thrust!!
And I am saying they are related. I asked about both multiple times
bigngreen
Well-Known Member
I have not built direct com
But the world of physics says they are not.
Not true. We can get 65k psi with a 100gr or 300gr. We will get different recoil, thus added bolt thrust. Its all in a line and connected. You cannot increased Pressure or increased mass (bullet) without recoil being affected
Let's start from scratch to see if there is a misunderstanding:
is it possible to get a 100gr and a 300gr upto 65k psi chamber pressure in a lapua and edge?
Is bolt lug setback related more to psi or projectile?
is it possible to get a 100gr and a 300gr upto 65k psi chamber pressure in a lapua and edge?
Is bolt lug setback related more to psi or projectile?
bigngreen
Well-Known Member
You can plug your RUM vs Lapua question into a recoil calculator and you will see the difference in recoil will come down to the difference in the weight of the powder charge to hit the same pressures.
You can put the internal case dimensions and pressure into the bolt thrust calculation and see the RUM has less thrust too.
You can put the internal case dimensions and pressure into the bolt thrust calculation and see the RUM has less thrust too.
Can you point me to the recoil calculator please? I'd like to see how weight and speed are related to recoil.
bigngreen
Well-Known Member
JBM has one, Google will bring up several.
Alex Wheeler
Well-Known Member
It doesnt matter.
Internal case pressure x internal case head area is what the lugs see.
Recoil is not related directly to pressure or case head size. I see why you could see it that way, but think of the rifle as a rocket propelling itself off of something. The heavier bullet gives the rifle more to push off of. Both the rifle and bullet want to remain stationary.
I checked out jbm and shooters calculator and neither have bolt face size as a variable When determining recoil. Is bolt thrust prior to, during or after recoil?
Can you give me an extreme example to make it easy to understand?
bigngreen
Well-Known Member
They don't have it because its not part of recoil!!
Bolt thrust peaks about 6 milli seconds after ignition from what I've seen from pressure transducers, changing powders move it a couple milli seconds either way. It peaks well before recoil peaks.
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Exactly. Because the bolt lugs feel every bit of the energy produced to push that projectile out of the barrel at x FPS, because everything is in a straight line behind the projectile ending with your shoulder. Including the bolt lugs and abatements
