The mostly intact bullet, CE399, is not consistent with the number of bullet fragments found in Governor Connally (some fragments were removed from his wrist while he died with other fragments never being removed).
David Belin, “November 22, 1963: You Are The Jury”, pages 317-318:
There was much comment after the assassination about whether the nearly whole bullet could have caused all the damage to Governor Connally, because X-rays showed metallic fragments in the wrist, whereas the bullet itself, Exhibit 399, weighed only one and one-half to three grains less than an ordinary bullet. Dr Gregory put such speculation to rest with the following testimony:
Mr. Spector. Will you describe as specifically as you can what those metallic fragments are by way of size and shape, sir?
Dr. Gregory. I would identify these fragments as varying from five-tenths of a millimeter in diameter to approximately 2 millimeters in diameter, and each fragment is no more than a half millimeter in thickness.
They would represent in lay terms flakes, flakes of metal.
Mr. Spector. What would your estimate be as to their weight in total?
Dr. Gregory. I would estimate that they would be weighed in micrograms which is very small amount of weight. I don’t know how to reduce it to ordinary equivalents for you. It is the kind of weighing that requires a micro adjustable scale, which means that it is something less than the weight of a postage stamp.
I googled to find the average weight of a postage stamp and here is what I found:
A used average size US commemorative weighs 1.1 grains.
From the same Belin Book, page 322 (Dr. Shires is referring to Connally’s thigh wound):
Mr. Spector. What would your best estimate be as to the size of that fragment?
Dr Shires. One millimeter in diameter - one to two.
Mr. Spector. Would you have any estimate as to how much that might weigh in grains?
Dr. Shires. In grains - a fraction of a grain, maybe, a tenth of a grain - very small.
David Belin, “November 22, 1963: You Are The Jury”, page324:
Most important of all, the testimony of Dr. Gregory and Dr. Shires was unequivocal on the amount of bullet fragments that remained in Governor Connally’s wrist and in his thigh. The amount was infinitesimally small - a measurement in “micrograms,” which are thousandths of a grain - there are 7,000 grains in an ounce. However, to a third party inspecting X-rays, such as Dr. Shaw, the opaque showing on the X-rays would give the impression of a substantially larger amount of fragments. This is of crucial importance in determining whether the nearly whole bullet found at Parkland Memorial Hospital caused all the damage.It appears to me that the two doctors tell us that the estimated total weight of all of the metallic fragments seen in Connally is something less than 1.2 grains. Whereas CE 399 lost an estimated total of 1.5 to 3 grains.