recoil reduction ?

robchar

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So I have 40 cal major loads with 180 gr. Berry bullets with 6.2 gr. of long shot to make major with a velocity about 1000 fps. I switched to x-metal coated 180 gr. bullets and found I got the same velocity with only 5.5 gr of long shot. What are your thought id this would reduct recoil ?
 
If you already have loads with both, why not try and see for yourself? I can't see how the same bullet weight and MV can result in different recoil in the same gun, but maybe I'm not a experienced enough shooter yet.
 
X-Metal projectiles have a polymer coating. (I shoot JTT projectiles - very similar to the X-Metal brand)

These coatings are relatively new and there isn't a ton of load data available. My experience with them (starting in January of this year) has been very similar - you need to download the powder by around 5% (YMMV) to get the same velocity as jacketed or plated.

As far a recoil reduction goes - just reduce the powder until you achieve the desired velocity. For my part, I've gone from 5.2 to 4.9 grains of VV N320 to keep my velocity at about 980 fps with 180 gr. JTTs (originally I was using Berry or Speer).
 
Yes you would think that with the same weight and velocity it would be the same but it is actually the shell that pushes back the slide and with less powder it pushes back less because it takes less energy to push a coated bullet thru. Any physics profs out there ?
I did a double blind test with three friends and they all said it had somewhat less recoil.
 
+1. The laws of physics don't care how much powder you use, just bullet weight and muzzle velocity matter.


Mark

Mark while I agree the recoil should be the sane the felt recoil might be different. The formula to calculate recoil does take into account the weight of the powder incidentally. All that said, I would think the difference would be small and any testing very subjective.

If reducing felt recoil is the objective going to a heavier bullet to make the same PF will have more of an effect on felt recoil than small changes in powder. There is a price you pay though as the slide recovery will be slightly slower. I have always found the 40 at major to be snappy mostly because I do not have Bob Vogel strength in my arms. Folks who carry extra weight around with them seem to manage recoil better than guys with slimmer arms. Just saying.

Take Care

Bob
 
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The formula to calculate recoil does take into account the weight of the powder incidentally.

True enough, the weight of the powder is added to the bullet to get the total mass that is being accelerated. But changing 0.7gr on the powder charge makes a very small difference in the recoil impulse (~1%) and free recoil energy (~2.7%). I can't imagine that those would be perceptible to most of us compared to changing the bullet weight.


Mark
 
At first glance we might think that same weight, same velocity gives same recoil. But it's not really the velocity but instead the acceleration curve of the bullet that gives us the recoil.

If that new coating lets the bullet slip out of the casing and down the barrel a little sooner than the other then we may not see the same peak chamber pressure. Instead the pressure may be lower but with a longer and broader peak. So the muzzle velocity is the same but the "hit" to get the bullet there was lower and longer. This can result in a lower impact felt recoil.

It's much like how a 9mm can feel snappier than the "push" of a .45acp. A more or less typical 9mm round with a 124gn bullet has a peak pressure of roughly 30K PSI. A 200gn .45acp bullet is about half of that pressure. So it feels like it has less bite to it.

So getting back to our miracle product coated bullets if this allows them to exit the case mouth more easily and move a touch further down the bore as the powder burns the increase in volume will work to lower but broaden the peak pressure curve. So the recoil might feel a touch more mild to the shooter. Yet because the bullet is pushed for longer by the lower pressure it still has the same muzzle velocity.

But will it? That depends on if the new coating allows this sort of earlier movement down the bore. If the difference is only around 5% that's not much. At that point I doubt the shooter would feel such a small amount. But a 5% smaller charge coupled with a softer and longer pressure peak could add up to a noticeable amount.
 
While I know Ganderite is very seasoned reloader and I have followed many his advices on reloading, I have to respectfully disagree with him on this one for the reason BCRider stated above.

When we are talking about physics, not only just bullet weight and velocity count, but also we have consider the aerodynamics. In this case, as OP stated, the new bullet with new coating achieved same velocity with less powder charge, the coating obviously reduced the air resistance.

With this in mind, all others being equal, I would say less powder means less recoil because it generates less pressure that is required to push the bullet to the same velocity. A simple analogy would be to compare pushing a small rock on dry concrete vs on ice. you will need more force, feel more resistance and the rock moves slower than it's on ice. and when it's on ice.

I use longshot exclusively for my 40S&W and have tried from 5.1 to 6.x with 0.2gr increment. While 6.3gr is the listed minimum on Hodgdon site for 180gr, my favor target load is 5.5gr. for me, the 5.5gr is much less recoil than 6.3 and still dead accurate @ 25 meters. I shot 44mag regularly. so, it's not that I am over sensitive to recoil.





At first glance we might think that same weight, same velocity gives same recoil. But it's not really the velocity but instead the acceleration curve of the bullet that gives us the recoil.

If that new coating lets the bullet slip out of the casing and down the barrel a little sooner than the other then we may not see the same peak chamber pressure. Instead the pressure may be lower but with a longer and broader peak. So the muzzle velocity is the same but the "hit" to get the bullet there was lower and longer. This can result in a lower impact felt recoil.

It's much like how a 9mm can feel snappier than the "push" of a .45acp. A more or less typical 9mm round with a 124gn bullet has a peak pressure of roughly 30K PSI. A 200gn .45acp bullet is about half of that pressure. So it feels like it has less bite to it.

So getting back to our miracle product coated bullets if this allows them to exit the case mouth more easily and move a touch further down the bore as the powder burns the increase in volume will work to lower but broaden the peak pressure curve. So the recoil might feel a touch more mild to the shooter. Yet because the bullet is pushed for longer by the lower pressure it still has the same muzzle velocity.

But will it? That depends on if the new coating allows this sort of earlier movement down the bore. If the difference is only around 5% that's not much. At that point I doubt the shooter would feel such a small amount. But a 5% smaller charge coupled with a softer and longer pressure peak could add up to a noticeable amount.
 
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luckey I think you missed the point. The calculation to determine the amount of recoil is no secret. Recoil and what shooters describe as felt recoil are not the same thing.

I would suggest the biggest factor in felt recoil is the weight of the gun. The same loading shot in a J Frame revolver is going to have more felt recoil than it would if it were shot out of N Frame revolver with the same barrel length even though the amount of recoil is the same. The N Frame weighs more. When comparing identical bullets using different powders, the longer the bullet remains in the barrel to achieve a certain velocity will have an effect how how much felt recoil the shooter feels. I would suggest most could not tell the difference as we are talking variances of micro seconds. Remember the word "subjective". What you believe is what you will feel.

The while discussion involving felt recoil is very subjective. The amount of recoil is not. The amount of recoil generated by any load can be calculated by using simple physics. You can google the formula. Get a decent scale and a chrongraph and you will be on your way.

A heavy bullet can reach a certain power factor (bullet weight x velocity) with less felt recoil than a lighter bullet. Check out the formula for recoil and you will see why.

Take Care

Bob
 
Hi Bob, I agreed with all you said. However, if you paid attention to OP's post, you will find you are the one off topic here.

OP is asking if there is difference between 5.5gr and 6gr longshot when he switched to a different bullet with the same weight, but different coating when he got same velocity between the two charges. So, we have to assume all other conditions, like the weight of the gun or the personal physical strength etc., all being equal. Under that context, I said 5.5gr should have less recoil than 6gr.

luckey I think you missed the point. The calculation to determine the amount of recoil is no secret. Recoil and what shooters describe as felt recoil are not the same thing.

I would suggest the biggest factor in felt recoil is the weight of the gun. The same loading shot in a J Frame revolver is going to have more felt recoil than it would if it were shot out of N Frame revolver with the same barrel length even though the amount of recoil is the same. The N Frame weighs more. When comparing identical bullets using different powders, the longer the bullet remains in the barrel to achieve a certain velocity will have an effect how how much felt recoil the shooter feels. I would suggest most could not tell the difference as we are talking variances of micro seconds. Remember the word "subjective". What you believe is what you will feel.

The while discussion involving felt recoil is very subjective. The amount of recoil is not. The amount of recoil generated by any load can be calculated by using simple physics. You can google the formula. Get a decent scale and a chrongraph and you will be on your way.

A heavy bullet can reach a certain power factor (bullet weight x velocity) with less felt recoil than a lighter bullet. Check out the formula for recoil and you will see why.

Take Care

Bob
 
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