Is this possible 4.5gr BE smoother than 4.1gr BE

yesterday I shot a match and used 185 Nosler JHP over 4.5gr of bullseye (first time) and also Zero 185 SWC-HP over 4.1gr bullseye. What surprised me is the nosler felt a lot smoother (less felt recoil) than the lighter load with the Zero. Is this possible or did I do something different

Anything is possible but maybe not probable.  

I load Bullseye at 4.1, 4.3, and 4.6 grains to push both 185 grain Zero and Nosler JHP bullets.  
In my iron sighted and optic sighted 1911 Accuracy X guns the recoil increases with each additional grain of BE.

My optic gun sports a 12 ounce Aimpoint 9000 SC mounted to the slide.  The 4.1 gr load will cycle the action only if i do everything correctly.  If however I do not keep an absolutely stiff grip, wrist, and elbow, I will have a malfunction.  The iron sight gun always functions with 4.1 grains.  

Because I have a tendency of loosening my grip and wrist with a lighter load in timed and rapid fire, I am adding light load practice to refine my consistent opposition to recoil.

Crimp?  Tighter crimp would create more pressure.
- Dave

It seems very unlikely that the total recoil, as measured in momentum or energy, is less, but the perceived recoil might be different. 

Lead bullets and jacketed bullets will move down the barrel at different rates. The pressure needed to push the bullet into the rifling will be different. 

My guess, and that's all it is, is that the jacketed bullet takes more pressure to start down the barrel and the larger charge volume ignites and burns faster so the pressure rises faster, the bullets exits the barrel faster and the recoil is more of a sharp crack, kicking a bit harder, but finished faster. Less powder and a lead bullet means the pressure rises slower and the bullet takes longer to exit so the recoil is more of a long whoosh with a lower peak momentum, but throwing the gun further off target.

The main reason I prefer frame mounts over slide mounted scopes it the recoil is over very quickly. With a big dot sight and/or heavy rib on the slide it seems to take forever to recoil and the gun gets thrown much farther off target. This takes me longer to get back on target for the next shot.

If it was a slower powder I might guess that the larger charge wasn't burning completely, but that isn't likely with a fast powder like bullseye.

You're talking about two totally different bullets. It's​ possible that the lead bullet load has higher velocity than the jacketed. I've chronographed a swaged lead bullet with 4.1gr of bullseye at 775, and a jhp with 4.6gr at 770.

And since its two different bullets, you're talking about 2 totally different internal case capacities as well.  The remaining internal volume after each bullet is seated is a variable that affects pressure and therefore velocity (and the resulting recoil) just like the amount of powder used.   

For example I shoot 200 gr and 180 gr Oregon Trail bullets with exactly the same charge of 3.85 gr. of VV310.  At my seating depth (controlled by the shoulder of the bullet) the 200 gr bullet has a slightly higher velocity than the 180 gr. bullet due to the smaller internal capacity after the 2 bullets are seated.  

Do not underestimate the effect of interal capacity when switching bullets, even the same type or weights due to bullet design.

CR10X wrote:And since its two different bullets, you're talking about 2 totally different internal case capacities as well.  The remaining internal volume after each bullet is seated is a variable that affects pressure and therefore velocity (and the resulting recoil) just like the amount of powder used.   

For example I shoot 200 gr and 180 gr Oregon Trail bullets with exactly the same charge of 3.85 gr. of VV310.  At my seating depth (controlled by the shoulder of the bullet) the 200 gr bullet has a slightly higher velocity than the 180 gr. bullet due to the smaller internal capacity after the 2 bullets are seated.  

Do not underestimate the effect of interal capacity when switching bullets, even the same type or weights due to bullet design.

I learned this yesterday. 

Side note: Loaded the same lot of brass,powder,primer and bullet. Identical loads done on my Star vs my 550. I can't get the star load to cycle in my wadgun while the 550 does with the same recoil spring. Need to take some measurements of cases after sizing but so far the expander is the only noticeable difference. The star expander expands .018 deeper into the case also has a .003 greater diameter than the Dillon. Using 185jhp I believe the star is expands greater than the jhp bearing surface.

I love your New NRA classification Chris. They said by 2032 they will actually put you in Master. They are waiting for you to get out of collegiate