Okay, before we start I do understand that things will vary from gun to gun. Even between guns that are the same make and model. With that out of the way though has it been anyones experience that one or the other just always seemed to be more consistantly accurate out of their own guns. I just went through 250 of Berry's 115gr RN bullets and was pretty pleased with how they shot. Loaded with 4.6gr of W231 at 25 yards they were grouping better than any of the factory ammo I've tried (to be fair I also just replaced my 16lb recoil spring with a 19lb spring). So now I want to order another 1000 and am wondering if I should try the 124gr RN bullets instead. I can always order 250 of the 124's but thought I'd see here first if there was a general preference in weights.

I have loaded both and like both. I find all of Berry's bullets shoot accurately under a moderate load but I prefer the heavier bullet as it tends to lessen "flip" particularly in a compact like an M&P9C. The recoil seems to go more "back" than "up" if that makes sense.
The point of impact of the heavier bullet will be higher so you will need to adjust your sight picture accordingly.

1Sailor, what overall length are you loading the 115gr Berry's plated at? I loaded up a batch of the same lead, with 4.5gr. of W231 at 1.165 OAL and was very disappointed with the performance. Shot through a 5906 they hit very low at 10 yards, like 6 inches low. Am thinking I need to seat the bullet deeper to increase pressure and raise POI. My 5906 normally shoots POA with factory WWB.

Really. The heavier bullet will print higher. I would have thought it would have been the other way around. I have 3 dot sights on my M&P and have always had to hold the sights so that the dots make a pyramid rather than align horizontaly. I wonder if the 124gr bullet would change that.

May I suggest using a COL of 1.14 or 1.15? This would be more in line with what I've found/measured WWB, Federal from WM, and Blazer Brass to be. These COL's using Berries RN bullets perform fine in the Ruger and the CZ. I use these same COL's even with the hollow base RN bullets, and really like them.

__________________
S&W15-22 RIA 1911
CZ75B SR9

Thanks john16443! I will try seating at 1.15" first, and see how it reacts with the same load of 4.5gr of W231. I arrived at the number I loaded my first batch with by measuring some WWB 115gr FMJ's I had. Measure about 5 of them and the length ranged from 1.163 to 1.167". Needless to say I was really shocked when I was shooting at one paper target and holes were showing up on the target below it. The rounds did feed and function well, just didn't hit where I was aiming.

The theory is this: Due to it's weight the heavier bullet takes longer than a lighter bullet to move along the barrel. Since recoil begins as soon as the round fires the muzzle is higher when the heavier bullet exits.
I find it's much more pronounced with the M&P9C than it is with the 5906 - which makes sense since the muzzle flip is wholly different.

I've loaded Berry's 115 gr RN plated bullets for the past 5~6 years. Set at length of 1.15" over 5 grs of Unique, I find they work very well in my regular range guns (3" and 4" Springfield XDs) and also my Kahr PM9. This gives combo gives me 1130 FPS out of my 4" XD. The same load out of my 3" PM9 yields 1017 FPS.

I've been so satisfied with this load that I've not bothered to look for anything else. Eventually, I'll switch over to Bullseye when my current supply of Unique is exhausted.

__________________
Stu

Yes sir. In a handgun, it works backwards to a rifle. It took me a while to wrap my head around that when I began shooting/loading for handguns, as the heavier the rifle bullet, the lower it shot.

I assume the handgun bullet is moving slowly enough to make muzzle flip more a factor than in a rifle. The heavier the bullet, the slower it leaves the barrel, and therefore the more pronounced the muzzle rise at the time the bullet exits the barrel. That's my theory anyway.

My favorite parts of the TV show Top Shots is the really high speed motion picture photography.
The first couple of times that I watched it I was really surprised that the muzzle on a gun doesn't move until the bullet is a way away from the gun.
Something different must be going on here..........

That being said - I've noticed that with fairly close shots on deer (say 50 - 75 yards) with a 270, I've seen the bullet hit the deer through the scope before the scope moved from the recoil.

__________________
In dog years I'm dead.

I've wondered if it is due to the shooter releasing the trigger and decreasing forward pressure on the top of the grip.

The muzzle movement is measured in thousandths of an inch, but the muzzle of a handgun DOES move before the bullet exits.
You can't cancel the laws of physics and have the bullet magically impart momentum to the gun only after the bullet is gone. It does take an extremely high speed camera to catch it.
I've done the calculations MV = MV (Newton's second law) for gun and bullet, and using the barrel dwell time of the bullet in the barrel allows several thousandths flip before the bullet exits. Take the radian measure of the thousandths of barrel rotation and multiply it by 20 yds range, and you get the heavier bullet landing an appreciable fraction of an inch higher.

By the way, I have 6 thousand of the Precision Delta 124gr FMJ 9mm bullets sitting on the floor to load, since I found they shoot to point of aim in my M&P Pros.

__________________
Science plus Art