Nothing on this page is provided as legal advice. If you need legal advice, contact a qualified attorney.
If you are involved in a use of force event, you can be sure that your weapon will be scrutinized as part of the investigation.
Did you legally acquire it?
Colorado has laws regarding the sale of firearms and while the state does not require the registration of firearms, there is usually a paper work trail for a legally purchased firearm.
As of 2013, virtually all sales must go thru an FFL dealer because of the state law requiring a background check. That check required you to fill out a form 4473. If you acquired the gun after the background check law went into effect, you can be sure investigators will check with the FFL. The serial number of the firearm can be used to determine its date of manufacture, the retailer who sold it and subsequently if you could have possessed it prior to the law going into effect.
Is my magazine capacity legal?
As of 2013, all magazines sold in the state must have a capacity of 15 rounds or less. Magazines don't have date stamps, but if you purchased the gun after the law went into effect and possess an over size magazine, you are in violation of the law.
The ONLY way you can have a large capacity magazine legally is that you owned it BEFORE the law went into effect. There are a few other exceptions, but they don't really apply for most of us.
Is my ammunition legal?
If you purchased your ammunition for a retail source (in person or on line), then you're very unlikely to have your ammunition legality questioned. Generally speaking, your reloads will be fine as well. There are specific material types that cannot be used when making ammunition. As long as you avoid those, you should be fine.
What about the caliber?
There are no constraints on caliber if it's .50 or under. Over .50 is classified as a "dangerous device" and should be avoided as a carry weapon. Seriously, the danger of collateral injury to others because of over penetration is just too great. Never mind how hard it is to access, draw, aim, fire, and take a follow up shot. Likewise small calibers become ineffective due to a lack of stopping power.
Stick to a .30, .40, .45, 9mm, 10mm and you'll have no caliber related issues.
What about hollow points?
Use only hollow point ammunition!!!! Standard ball ammunition risks over penetration. You want to stop the bad guy without having your shots go thru and thru. Recently, composite ammunition has started to become widely available. Certainly consider using this instead of, or in combination with, hollow points.
A load of two composite rounds with the balance being hollow points gives you a good defense load. The composite offers two shots with minimal risk of penetration. After that, the risk goes up but so does the potential stopping power.
What about modifications?
People like to accessorize and perform other modifications to improve their handgun. These, generally speaking, fall into two categories. Non-operational and operational. Non-operational modifications would be things like grips, sights, lasers, etc. Operational modifications are those that change how the fire control group works. Trigger modifications, spring changes, adjustments to the sear, etc. Basically, anything that plays a roll in the process of causing the primer cap to be struck.
Modifications that do not violate the law are normally not going to be an issue.
However, if you have made modifications to the fire control group and then say something like "...I didn't mean to shoot" or "...it just went off"... well you're going to have problems. You are supposed to be able to control your weapon at all times and as a consequence, be in control of it at all times.
Indicating that you were not in control could open you up to charges of negligent homicide. Combine that with a modified control group and you can see the slippery slope you'll be on.