use 185 gr ammo and they work fine
This is wrong. 185 gr. ammo may function fine, but the 185 gr. loads are much less effective from a 3" barrel than they are from the 5" barrel they were designed to be fired from.
Lighter weight (200 and 185 gr.) .45 acp bullets LOSE velocity at a HIGHER RATE than the 230 gr. bullets do... so, a 230 gr. bullet will retain desired velocity a little better (due to momemtum) than the 185 gr. bullet will. Therefore, the 230 gr. bullet will stay a little closer to it's designed velocity (which is with the 5" barrel) than the 185 gr. bullet will. Simplified: the 185 gr. bullet suffers from a greater slow-down rate from the short 3" barrel than the 230 gr. bullet does. Stick with 230 gr. if you must shoot a 3" 1911. You will give up most if not all of your expansion, but you'll still have the 230 gr. weight for good penetration and.... don't forget, penetration is KING! (Assuming good placement.)
NOW, if you really want good penetration AND expansion, as well, with the short 3" barrel, there are only two good ways to do so that I know of: Corbon 165 gr. PowRBall and Corbon 185 gr. DPX. These are proven to penetrate deeply AND expand fully when fired from a 3" barrel. BUT, these are really expensive loads to shoot; and VERRRRY expensive if you want to practice with your carry load!
I'm sorry to be the bearer of bad news, but 1911's with 3" barrels are the worst possible choice for both the 1911 platform AND for the .45 acp caliber.
I can certainly see the attraction to the Defender... in fact I was so attracted to one, that I bought one for myself. But with time and use I began to realize that a LOT had to be given up/compromised by choosing the Defender (or any 3" barrel 1911) and a bobtailed Commander is a MUCH smarter choice for a carry gun.
The reason I sold my Defender and decided to stick with Commander 1911's for carry use is multi-fold:
• cost of the Corbon ammo (necessary for achieving excellent terminal ballistics from a 3" barrel) is so high and I wanted to be able to shoot a LOT of practice WITH my carry ammo - too costly for me to do with the Defender, but affordable with the Commander.
• cost and replacement frequency of recoil springs in the Defender is high. Recoil springs in a Defender should be replaced as early as 750 rounds, typically, and the compound springs are MUCH less readily available and much more expensive than springs for a Commander, a model who's recoil springs last a LOT longer, are much cheaper, and much more readily available all over the place.
• Capacity of the Defender is reduced due to the short butt... whereas a bobtailed Commander has a very easliy concealed butt, yet retains use of full size/full capacity Government magazines! Choose mags without the bumper at the bottom and the bobtailed Commander has a VERY easily concealed butt.
• The 4.25" barrel on the Commander provides much better terminal ballistics with a wide variety of ammo types than the 3" barrel does.
• The 4.25 " slide on the Commander gives a much better sighting radius, enabling more accuracy if you need to take a longer shot, than the 3" barrel does.
• The greater weight of the 4.25" slide on the Commander reduces felt recoil and muzzle rise such that follow up shots are quicker to get off than with the 3" barrel 1911.
• The slide length on the Commander lends generally greater overall reliability than is typically found with 3" 1911's.
• The Commander is a more enjoyable gun to shoot and practice with - over a high volume of shooting, than is a 3" 1911.
REALIZE that you have to compromise/give up a LOT when you choose a 3" 1911 for a carry gun!!!
Don't get me wrong, I think the Defender is a GREAT and fun little gun, very attractive indeed, but I finally figured out after owning one that I didn't NEED to go that small and didn't HAVE to put up with lackluster terminal ballistic performance and high maintenance... I found that I could carry a bobtailed Commander JUST as easily and would have a MUCH better performing 1911 which allowed use of full capacity mags as well. Even full capacity 1911 mags are on the low end of capacity as far as I'm concerned, so giving up even one round had to result in gaining a HECK of a lot more in something else in return. What I found is that 3" 1911's are all about "giving up" a lot and not so much about "getting back".
GO with a Defender over an Agent if you must have a .45 with such a short barrel, but seriously consider a bobtailed Commander as a very strong, less-compromised 1911 alternative. And, if your hands are large enough to handle one, look at the Glock 30 ... they're an awesome (11-round) .45 acp choice in a small package that doesn't give up much in terminal ballistics with it's 3.8" polygonal rifled barrel and has awesome capacity for a compact .45!
The Defender is a much better choice, IMHO, than the new Agent because of the sights on the Defender. But neither are as smart a choice, in my view, as the Glock 30 or a bobtailed Commander. That's my reasoning. Your mileage, and others, may certainly vary!
Why am I so big on capacity?
We've all heard the statistic dating back to the revolver days that a civilian is not likely to need more than 5 shots in a self-defense situation.
In today's world, that's not a smart statistic to base your gun choice on. With that mindset, statistics show that you will never need to shoot anyone in defense of your life, so why even carry a gun at all?
Let's face it... you could very easily (in about 4 seconds) empty a low capacity auto in a hot hurry and still not have STOPPED an assailant. Add another assailant or two and you're totally screwed. RELOAD? Yeah, right... odds are strong that you'll never even get half chance to do that. This is not to discount the importance of training, which I think it critically important, no matter what the capacity of your carry gun.
It makes a huge amount of sense to carry a gun with as much capacity as you can reasonably carry. In a 1911 that's gotta be a full size mag. But my preferred choice is a GLock 30 with 11 rounds of .45 or even better, a Glock 23 (14 rounds on tap) or a Glock 19 (16 rounds on tap) or for me. You can never have too many rounds on tap before a reload!
Sorry for the extremely long post, but these are matters of great importance and I have given considerable years and energy to these matters. Rant off. ;-)