In my previous post, it should be noted that when asked about failures to feed my recommendation to
slightly trim the front corners of the lips of the magazines that were giving trouble, I stipulated that the amount to be removed should be very small. It really amounts to "smoothing" because less than 1/32 of an inch removal followed by polishing with very fine grit wet-or-dry and rebluing will many times, on almost any semi-auto mag fresh from the armory or factory, benefit performance. Many, many seasoned shooters polish and trim various parts of their pistols to improve performance and reliability including the magazines.
Here's a shot of my P-64s and all 12 mags:
There are two 73s on the left and two 67s on the right. I got two mags each with the pistols, and then bought four extra mags when the opportunity availed itself on Gunbroker.com from a friend and seller there. Eight of the mags would feed the 115gr with no problem, and only four of the mags had to be smoothed.
I like the Silver Bear 115 grain, HP with the nickle-plated case and the HP bullet. I have good recoil springs on all my P-64s, never had any trouble with the slide beating the frame, the accuracy is astounding and the recoil doesn't bother me at all.
I don't think you can buy a better quality 9x18 round than that Silver Bear 115gr HP from LVE (Low Voltage Equipment) plant in Russia. The newly manufactured Silver Bear 94gr. from the Barnaul factory there is not as good a quality as the LVE 115gr nickle plated round. It has a zinc plated case, and is not sealed at the case mouth as is the LVE round. The Barnaul 94gr is very good ammo, though, and good for all your P-64s. I use it entirely at the range now and am saving the last of the LVE 115gr rounds for carrying now, both in my E.G. and Bulgy Maks and my CZ-82, and have no compunctions about carrying it in the P-64.
The LVE ammo was made in 2000 and 2002, and the Barnaul 94gr was manufactured in 2006.
Overall length is greater in all the FMJ rounds I have bought.

CCI Blazer 95gr

Sellier & Bellot and Mesko FMJs
There is little difference between the Silver Bear LVE 115gr and the Silver Bear LVE 120gr hollow point bullets in weight. One weighs 116.5 grains actual and the other 116.8 grains actual.

(115gr on right)

The OAL is less than all the FMJs on both Silver Bear 115gr and 120 gr, however, the mouth of the projectile is larger on the 120gr round. (In this image, the diameter of the cartridge on the right looks larger because of the shadow and the angle. Both are the same diameter and in every other way, except for the size of the hollow in the points.)
The Silver Bear 94gr HP is shorter than all the rest of the rounds:

I am willing to concede that, over the long run, the 94gr round might be perceivably easier on the action, extending the life of the pistol. I have certainly put my money behind that idea, in that I have purchased 1800 rounds of the Silver Bear 94gr HPs for the range and casual shooting. I would not be hesitant to carry it for personal defense if it happened to be conveniently loaded in the mags at a given time, when I needed to grab a pistol. I can shoot a 2-inch group, off-handed with any of the Silver Bear rounds at 36 feet with my P-64s (I mostly shoot the 73s now, as I am preserving the '67s, which I truly adore) on any given day at the range. I can shoot good groups with the Makarov pistols, maybe three or four inch, but the P-64 is unbeatable in the Makarov caliber for me. If someone were to push me into it, I'm sure I could shred the bridge of his nose with a clip full in the P-64. Of course, I'm old enough and experienced enough with person to person conflicts to stay cooler than the average young person, and I can and have used disarming language (pun intended), both body and verbal, to avoid shooting in such situations, which is far the wiser tact.
Opinions are like A______S, everybody's got one, but good advice is a treasure and there is some to be had here.
I am in the group that says forget spring changes to lessen the double-action pull. The pistol was made that way on purpose and is perfect and safer the way it was origionally designed. Trigger spring changes have too many negative effects on the functions performed by the action, and reduce reliability and safety. JUST DON'T SHOOT THE P-64 DOUBLE ACTION, unless you just have too. If you're in an incredible hurry to get a shot off to save your life, I promise you, you'll be able to squeeze that first round off without any trouble. Adrenalin makes it easy, and the added benefit is that you'll not shoot yourself trying to get it drawn for action. If you're new to the forum and undecided, please read "Bzinggg's Introductory Post" in the Modifications, Repairs and Fixes" section to further understand this side of the spring change argument.
The P-64 is a remarkably well-made handgun, in design, fit/finish and particularly, metallurgy. It is worth three P-63s. You couldn't get one as well-made today for less than $400.00. It is, by far, the most accurate, compact pistol available anywhere.
A final note: If you like to carry the P-64, get a couple of extra mags and give them this treatment and see if it doesn't improve the ease and strength of grip and ease of drawing from concealment:
God Bless and Good Shooting, Bzinggg.