Hmm... I might have to look into one for my next GI clone build. From what I can see, the sights, hammer, safety, mainspring housing, and magazine (at a minimum) would have to be replaced. Does it have a Series 80 firing pin safety?
ETA: I see Tisas offers other models that might be a better starting point. And they have Series 70 internals. Biggest hangup is the lowered ejection port.
The Tisas, my RIA, my Charles Daly, and my ATI are all series 70 actions.
I did replace the "Commander" type hammer with a "GI" type hammer.
I am not a cocked and locked type. The original pistol was designed by John Browning with the "safety position" being the half cock. I think lowering any hammer by thumb alone, which is what John Browning intended, to be so risky as to be insane. Many users lost control of the hammer when they used the thumb. The Army first intended carry mode was round in the chamber, hammer down. The thumb safety was there at the instance of the Cavalry, to make the pistol safe with one hand, as the other hand was controlling the horsey. When horsey issues were settled, troopers were supposed to unload, or, make safe by lowering the hammer all the way down, before putting the pistol into the flap holster.
I use the middle finger of the support hand as a hammer block, and the forefinger fits into the hammer spur, when lowering the hammer
I use the forefinger to block the downward movement of the hammer, and I get the trigger finger off the trigger to ensure the half cock engages the hammer. I pull out the middle finger slowly, get that hammer on the half cock, and re position my hand. At half cock there is no space left for a blocking finger, so I have to control the hammer with the forefinger in the hammer spur. With the hammer on the half cock, I lift it gently till I feel the sear clear the half cock notch, pull the trigger, and slowly lower the hammer with the fore finger.
This is something that cannot be rushed when there is a round in the chamber!
The Commander type hammer does not provide enough of a rest to be controlled by the forefinger. So I removed it. I much prefer the wider, early GI type hammer on a 1911 as it was designed to be easy to thumb cock.
Pistols with beavertails block access to the hammer and it is positively dangerous to attempt to lower the hammer on a loaded round no matter how many hands and fingers you use. I have played with my beavertail 1911's and the only one beavertail that allows condition two carry is the old Clark beavertail.
This arrangement of hammer and grip safety preclude any carry mode but Condition 1 or Condition 3. And the long thumb safety has to be ridden by the thumb.
Personally, I consider the Tisas ready to go with the GI hammer. If you want an arched mainspring housing, go for it. I find shooting with one hand, the arched housing has its benefits by making a tighter grip.
I have short fingers so the trigger is the right length. The GI grip safety will wear on the web of your hand, but it is easy to get around and thumb cock the action. Beavertail grip safeties made access to the hammer difficult to impossible, though they are very comfortable to use.
I don't ride the safety, the GI configuration pushes the hand down, and the GI safety is small enough that your thumb has to be way out of position to bump, and it is only bumped out of position if the spring is very weak. However, if you plan to have an extended safety, riding the safety is imperative as the length of an extended safety over powers the spring/indent and makes rotation of the safety very easy. And you would need to go to a higher grip safety to get your hand up and in position for thumb riding the extended safety.
The sights are fine on the Tisas and ATI.
They are all regulated for a 230 grain bullet going 800 fps. Which is fine for me. I have shot 185 JHP's and the difference in point of impact is trivial at 7 yards. Assuming there is a way to figure out the group center.
The RIA and Charles Daly have short rear sights and thin blade front sights, which are closer to the WW1 era sights. Those sights are great for twentysome's shooting against bullseye targets, but horrible otherwise. If you have ever shot Bullseye Pistol with irons, being able to get a precise 6 OC hold will get you better, tighter groups. Fat front sights, which I consider better in all other circumstances, are blobby when pushed into the bull. This is an example where training simulations resulted in sub optimal sights in the real world. The tiny M1903 front sight is another period example. Great in a 6OC hold at the bottom of a 5V bull in bright sunlight, but horrible every where else. What is now NRA Highpower and Bullseye, and are fun precision games, was considered combat training between WW1 and WW2. And what you see as sighting systems in the weapons of the period reflect what is necessary to shoot high scores on contrasting paper targets with round, black bulls. And there were those who defended the tiny sights, because they really and truly believed paper punching represented combat conditions.
RIA rear sight, short, small notch. Front is a thin short blade.
The Charles Daly front and rear are similarly thin and short.
in good light conditions, you can still group at an acceptable distance with the things, but I consider the original WW1 sights to be sub optimal.
All of these inexpensive 1911's are tighter than any Colt Series 80 I own. And they are tighter than the average new Colt I have handled. There was one new Colt I handled that was as tight, but three to four times more expensive.
If you get one, ask the guy behind the counter to let you pick the best out of three. And take an oil bottle and drip oil on the slide rails, muzzle at barrel bushings, barrel hood in slide, and trigger sear. That way you can feel the smoothness of the slide rack, and get a realistic appreciation of the trigger pull. Dried oil will give a false trigger creep and may create lock up issues on a new piece. I lubed the ATI, the Charles Daly, and the Tisas to bring the pistol to the level of lubrication I use them, and then cycled them, pulled the trigger, checked the muzzle to barrel bushing fit, the barrel hood/link tightness, and slide to frame fit.
I am amazed how modern machining has made these inexpensive pistols tighter than the Colt NM pistols of the 60's, 70's, 80's, 90's. And the materials are outstanding. Tisas Customer service said their pistol is M4065 steel. Could not find that but did find
MIM4065 and the material properties were very good.
The Charpy impact of MIM 4065 is very good, this is a good tough steel, which is desirable for a high fatigue life in an impact loading environment. The RIA, ATI, and Charles Daly are all 4140 steel, which is also greatly superior to the original GI SAE 1035 of the frame, and 1050 of the slide. The only GI heat treatment was for the first two inches on the slide. A bud suggested slide noses broke off before the heat treatment was phased in. I have no idea if the slide and frame were surface hardened by a salt bath, or gas nitriding. I doubt it, they are probably dead soft. The GI 1911 choice of materials and heat treatments were the minimum necessary for a 6000 round lifetime. They were not built for the ages.