Coated shoot softer than jacketed at equal MV?

[MilkMyDuds]

I am doing an experiment with Bayou coated 147 FP vs. Precision Delta 147 FMJ TC. I load them with Titegorup and both to OAL of 1.135''.

What's interesting is, when both are loaded to reach the same MV, 880fps, in my case, the coated feels softer shooting, and I can feel the difference and tell exactly which round is loaded with coated vs. FMJ when randomly mix matching them into the same magazine.

I then looked at the video taken during the shooting, and noticed the brass were being ejected further with the FMJ.

Did anyone else notice this? Is there an explanation for this? Maybe because Bayou, being coated, requires less powder to reach the PF floor, than the PD which is FMJ? So less powder = less recoil = closer brass ejection, even though the bullets reach the same MV?

[rdinga]

Coated typically shoot a whisker faster with the same powder charge. I have noticed the same thing.

[mgrs]

<snip>

Did anyone else notice this? Is there an explanation for this? Maybe because Bayou, being coated, requires less powder to reach the PF floor, than the PD which is FMJ? So less powder = less recoil = closer brass ejection, even though the bullets reach the same MV?

Yes, or "C: All of the above."

I find that plated fall somewhere in the middle.

Edited May 18, 2015 by mgrs

[Sarge]

I am doing an experiment with Bayou coated 147 FP vs. Precision Delta 147 FMJ TC. I load them with Titegorup and both to OAL of 1.135''.

What's interesting is, when both are loaded to reach the same MV, 880fps, in my case, the coated feels softer shooting, and I can feel the difference and tell exactly which round is loaded with coated vs. FMJ when randomly mix matching them into the same magazine.

I then looked at the video taken during the shooting, and noticed the brass were being ejected further with the FMJ.

Did anyone else notice this? Is there an explanation for this? Maybe because Bayou, being coated, requires less powder to reach the PF floor, than the PD which is FMJ? So less powder = less recoil = closer brass ejection, even though the bullets reach the same MV?

If MV Is velocity then you used more powder on the jacketed bullets as coated or lead are faster in general. Of course ejection will change with powder charges

[MilkMyDuds]

This does sound interesting, because according to the laws of physics, the same mass (147gr) reaching the same velocity meaning these bullets carry the same kinetic energy when they are out of the barrel.

Since coated require less powder to burn, it implies coated has less energy source to start with. What I am getting out of this is that the jacketed bullets must have transformed some of the original energy into something else other than velocity. Could it be more friction turning into heat energy while they travel through the barrel?

[jstagn]

Softer bullets such as lead/lead coated seal better going down the barrel, hence more speed for the same powder charge. FMJ are also slower than plated.

[techj]

I believe that it's a combination of better seal and less friction that allows lead/coated bullets to achieve the same MV with a lower powder charge.

Less powder charge means less energy being generated and therefore the recoil will be less.

More important to me, less powder - and a cheaper bullet - means less $$$ to shoot the same number of rounds.

[MilkMyDuds]

I believe that it's a combination of better seal and less friction that allows lead/coated bullets to achieve the same MV with a lower powder charge.

Less powder charge means less energy being generated and therefore the recoil will be less.

More important to me, less powder - and a cheaper bullet - means less $$$ to shoot the same number of rounds.

Right on.

For me, coated would be the perfect choice only if I could stop the endless shaving of lead on my SDB... I even upgraded to use the MBF/DAA funnels...

[Frank48]

This does sound interesting, because according to the laws of physics, the same mass (147gr) reaching the same velocity meaning these bullets carry the same kinetic energy when they are out of the barrel.

Since coated require less powder to burn, it implies coated has less energy source to start with. What I am getting out of this is that the jacketed bullets must have transformed some of the original energy into something else other than velocity. Could it be more friction turning into heat energy while they travel through the barrel?

Higher powder charge equals more powder flying out of the barrel, in a handgun not all of the powder is burned. The additional powder equals more mass exiting at the same velocity. This results in slightly more energy or momentum. This might account for a very slight difference.

[Yeti]

I believe that it's a combination of better seal and less friction that allows lead/coated bullets to achieve the same MV with a lower powder charge.

Less powder charge means less energy being generated and therefore the recoil will be less.

More important to me, less powder - and a cheaper bullet - means less $$$ to shoot the same number of rounds.

Yup.

Lead/coated lead bullets do not require as much charge weight per grain...providing properly sized.

Plated and especially jacketed do not form to the bore as readily and require higher charge weights to accomplish the same velocity.

I honestly think most shooters could tell the difference in recoil impulse on midrange or less lead/coated lead loads. I can.

Once driven above moderate muzzle velocities it is harder (for me) to distinguish a difference in recoil between lead and plated or jacketed.

[Aric]

You have to look at it from a work stand point. The same amount of work is done, with more or less powder depending on the bullet seal in the barrel.

[Steve RA]

You really don't want to "crimp" when loading coated. Back off on the crimp portion of the die until the sides of the case are straight after loading, no curve in at top. This should maintain the integrity of the coating, not cut it at the top of the case. Some experimentation may be required to achieve this.

[Postal Bob]

This does sound interesting, because according to the laws of physics, the same mass (147gr) reaching the same velocity meaning these bullets carry the same kinetic energy when they are out of the barrel.

Since coated require less powder to burn, it implies coated has less energy source to start with. What I am getting out of this is that the jacketed bullets must have transformed some of the original energy into something else other than velocity. Could it be more friction turning into heat energy while they travel through the barrel?

You're forgetting the laws of physics regarding resistance. The less resistance of an object, the less energy needed to move it. Not only are coated bullets softer than jacketed, they are also more slicker. My ibejiheads bullets are so slick, they are hard to hold in my fingertips.

All else being equal, powder charge, bullet weight, etc., I average 35-40 fps faster using coated bullets over jacketed. So I can reduce my powder charges about .2-.3 gr for similar velocities as jacketed.

[mjmagee67]

IMHO defiantly yes. Coated bullets are a win win win. Cheaper, use less powder, and shoot softer.