OK, I was finally able to put my 'new' 1979 Armi San Marco to the test. The results were both good, and disappointing in some respects. But mostly good.
To begin with, just to make sure the thing shoots straight so I could safely shoot it through the chronograph, I tried it on the nearest target, which on this particular range was 21 yards. I know, terrible small group, but in my defense, this is the very first time I fired this gun, and the target is smaller than man size:
By the way, I only had about 12 #10 caps left, so I only allowed myself 3 shots.
Then, I prepared the chronograph, and loaded up 4 paper cartridges of .454, with 30 grains of BP. Very surprisingly, I found that the .454's were way too small-- no shave ring, and I could tell that they could rather easily move and shift inside the chambers. This worried me (chain fires) so I applied generous amounts of bore butter to the chambers. So, this gun takes at least .457's, if not larger calibers.
My results for the 30grain shots were:
700.9 FPS, 713.8 FPS, 606.3 FPS, and 704.0 FPS. I believe the low number is due to a possibly different or defective chamber (for reasons you'll see below), so I disregarded it. The average works out to 706.2 FPS.
As I was really hoping the 30 grains would put it over the 800 FPS mark (which in my mind is minimum for a self-defense weapon), this was a bit disappointing at first.
I then loaded up a few 32 grain cartridges, and fired those through the chrono:
778.4, 716.4, 712.6, and 609.0 I did not check , but I suspect the low number in this batch was through the same chamber as the low one above. I don't know why the one 778.4 number is so high, but it's possible I measured out too much powder on that one. Throwing out the 609.0 and the 778.4, the average is 714.5. Barely a difference from the 30 grain loads.
On the good side, I found how excellent this gun is-- it's VERY solidly built, VERY strong hammer spring-- there was not a single cap jam, not even close. In fact, the caps were so tightly smashed onto the cones that I had to use a plastic knife to try to scrape them off the cones when I was done. Look how tight this cap was crushed around the cone, not going anywhere:
And even better-- I realized just how much powder this smaller cylinder can hold. As I mentioned in an earlier post, this gun has a considerably shorter cylinder than my new Pietta Navy in .44, so I was worried that I'd barely be able to fit more than 30 grains in the chambers, but look how much space is left over the ball, even with 32 grains:
So I don't think I'll have any problem whatsoever with loading cartridges with 35 grains, or possibly more. I believe that when I do this next time, I will achieve 800 FPS velocities, no problem.
Next, I tested my new Pietta .44 with 32 grains, so see if I got comparable velocities. Sure enough, I got 716.2 and 701.9, pretty much the same as through the ASM. So it's not the gun that's to blame.
So, now that I am completely out of #10 caps, and they are completely impossible to find, I ordered #11 cones from Track of the Wolf (as well as .457 balls)-- I have plenty of #11 caps saved up. Next time I go to the range I'll test the ASM with 35 grains of BP to see if I can achieve the vaunted 800 FPS. May also test with 27 grains or so of 777, which should achieve about the same results. If I still can't get 800 FPS, will probably sell her.
There is something else I'd like to point out-- apparently, the open top ASM and the Pietta Navy achieve FAR lower velocities than "top strapped" guns like the Remington NMA and the Ruger OA. I use for evidence for example Paul Harrell, who consistently (judging from his videos) gets velocities averaging in the 840s or even 980s with only 30 grains of BP with his Ruger OA. I will be testing my own Pietta Remington NMA with 30 grains the next time I go to the range. I would wager that she'll get considerably higher velocities than the ASM or the Pietta Navy. Of course, the Remingtons also have 8" barrels, so 1/2" more twist than the Navys.
Also-- I can't stress enough how much better the ASM Navy feels than the new Pietta Navy. So much better built-- the Pietta feels so loose and "rattly" in comparison. Much weaker hammer spring. Terribly shaped grip. Just lesser workmanship-- even though the ASM is decades older. This was surprising, as I would have expected the older guns to be shoddier.
Thanks for reading.