The following has been taken from the Offical IDPA Rule Book regarding equipment. Please be sure to read the entire rule book as this is only one section of it http://www.idpa.com/rulebook5-2-01/Rulebook.pdf

All equipment used in Defensive Pistol matches must meet the following simple guidelines: equipment must be practical for self-defense use, concealable, suitable for all-day continuous wear, and must be worn in a manner that would be appropriate for all-day continuous wear. The match director will be REQUIRED to disallow any equipment that does not meet these simple criteria.

If you wouldn't carry it to defend yourself, you can't shoot or use it in Defensive Pistol competition. If you are caught using equipment that is not in the guidelines set forth, not in the spirit of Defensive Pistol “PURPOSE”, and the Match Director is convinced you did so to gain competitive advantage, you will be disqualified from the entire match.

STOCK SERVICE PISTOL DIVISION

Handguns permitted for STOCK SERVICE PISTOL division must be Double Action, Double Action ONLY, or Safe Action and be of 9mm (9x19) or larger
caliber, be readily available on dealers’ shelves, have a minimum annual production of 2000 units (discontinued models must have had a total
production of 20,000 units) and meet the following criteria: Pistol including magazine must fit in a box measuring 8 3/4" x 6 " x 1 5/8". No external
modifications other than changing sights and grips will be permitted. To reduce cost and provide a level playing field for all pistols permitted, the
maximum number of rounds that may be loaded in a magazine is ten (10).

NON-INCLUSIVE list of pistols permitted: (These are just examples of pistols 10 that meet STOCK SERVICE PISTOL DIVISION requirements and is NOT meant to be a definitive list of approved pistols.) Astra A-75, A-100, Beretta 92FS, 92 Elite, 96, Cougar, Browning, BDA, CZ 75, 85, 100, Daewoo DP-51, DH-40, Desert Eagle Baby Eagle, EAA Witness, FEG PJK-9HP, Glock 19, 17, 20, 21, 22, 23, 26, 27, 29, 30, 31, 34, 35, H&K USP, Kahr K9, K40, Para-Ordnance LDA, Ruger P89, KP89, KP90, KP93,KP94, P95, P97, Sig 220, 225, 226, 228 & 229, Smith and Wesson 908, 909, 910, 1006, 3913, 3953, 4506, 4516, 4566, 4586, 6904, 6906, 6946, 4013, 4053, 4046, 410, 4006, 4043, 5903, 5904, 5906, 5946 & Sigma, Smith & Wesson Performance Center Shorty 9, 40 & 45, model 5906 Tactical, Taurus PT92, PT908, PT99, PT100, PT940, PT101, PT945, PT911, Walther P88, P-99

NOTE: Selective DA/SA pistols MUST begin hammer down.

INCLUSIVE list of permitted modifications: (If it's not on this list, it can't be used in Defensive Pistol competition.)
• Change of sights to another conventional notch and post type
• Change of grips to another style or material that is similar to factory configuration (no weighted grips)
• Slip-on grip sock and/or skateboard tape
• Action work to enhance trigger pull as long as safety is maintained
• Reliability work to enhance feeding and ejection
• Internal accuracy work to include replacement of barrel with one of factory configuration
• Custom finishes

NON-INCLUSIVE list of EXCLUDED modifications:
• Externally visible modifications other than grips or sights
• Heavy barrels and/or barrel sleeves (factory or aftermarket)
• Guide rods made of a material different than the factory part it replaces
• Add on weights of any type, weighted magazines
• Sights of non-standard notch and post type
• Porting of barrels (factory or aftermarket)
• Compensators

ENHANCED SERVICE PISTOL DIVISION

Handguns permitted for ENHANCED SERVICE PISTOL division must be Single Action or selective SA/DA and be of 9mm (9x19), (9x21), (9x23), .38 Super, .357 Sig, .40 S&W, .41 AE, 10mm Norma, .400 Cor-Bon and meet the following criteria: Pistol including empty magazine must fit in a box measuring 8 3/4" x 6" x 1 5/8" and have a maximum unloaded weight of 43 oz. To reduce cost and provide a 11 level playing field for all pistols permitted, the maximum number of rounds that may be loaded in a magazine is ten (10).

NON-INCLUSIVE list of pistols permitted: (These are just examples of pistols that meet ENHANCED SERVICE PISTOL DIVISION requirements and is NOT meant to be a definitive list of approved pistols.) Browning HP, CZ-75, EAA Witness, Colt Govt., Commander, Glock 17, 19, 22, 23, 26, 27, 31, 34, 35, H&K P7, Springfield 1911A1, Military 1911 and 1911A1, AMT Hardballer, Auto Ordnance 1911A1, STI/SVI, Para Ordnance.38 super/.40 S&W pistols, Smith & Wesson Performance Center 9mm, 356TSW & 40 Limited, PPC. NOTE: Pistols approved for SSP may also be used in ESP and CDP depending upon caliber.

INCLUSIVE list of permitted modifications: (If it's not on this list, it can't be used in Defensive Pistol competition.)
• Change of sights to another notch and post type
• Change of grips (no weighted grips)
• Internal accuracy work to include replacement of the barrel with one of factory configuration
• Internal reliability work
• Checker frontstrap and backstrap
• Checker or square and checker trigger guard
• Cosmetic checkering/serrating
• Extended thumb (may be ambidextrous) and grip safeties
• Full length guide rod manufactured of material that is no heavier than common steel
• Change of hammer and other trigger action parts to enhance trigger pull
• Beveled magazine well and add-on well extensions
• Custom finishes

NON-INCLUSIVE list of EXCLUDED modifications:
• Heavy barrels, cone barrels and/or barrel sleeves (factory or
aftermarket)
• Porting of barrels
• Compensators
• Add on weights, weighted magazines, tungsten guide rods, extended
dust covers
• Sights of non-standard notch and post configuration
• Extended oversize magazine release buttons
• Trigger shoes

CUSTOM DEFENSIVE PISTOL DIVISION

Handguns permitted for the CUSTOM DEFENSIVE PISTOL division must be .45 ACP caliber and meet the following criteria: Pistol including empty magazine must fit in a box measuring 8 3/4" x 6" x 1 5/8" and have a maximum unloaded weight of 41 ounces. To reduce cost and provide a level playing field for all pistols permitted, the maximum number of rounds that may be loaded in a magazine is eight (8).

NON-INCLUSIVE list of pistols permitted: (These are just examples of pistols that meet CUSTOM DEFENSIVE PISTOL DIVISION requirements and is NOT meant to be a definitive list of approved pistols.) Colt Government model, Gold Cup, 1991A1, Officers Model, Springfield Armory 1911A1, Auto Ordnance 1911A1, Les Baer Premier II, Custom Carry, Prowler IV, SRP, Wilson Combat all 1911 style models except Tactical Elite, Stealth, Kimber 1911A1, Para-Ordnance P10, P12, P13, P14, Glock 21, 30, 36 EAA Witness, S&W 4506, Smith & Wesson Performance Center model 845, 45 Limited, Sig 220 and other 1911 style pistols built on aftermarket frames and slides such as Springfield Armory, Caspian, CMC, Wilson Combat, Baer, STI, SVI and Nowlin if 5" or shorter conventional bushing type standard weight barrels are used and all other stipulated criteria is met. Factory installed cone style barrels are permitted on pistols with a barrel length of 4.2” or less. NOTE: Pistols approved for SSP may also be used in ESP and CDP depending upon caliber.

INCLUSIVE list of permitted modifications: (If it's not on this list, it can't be used in Defensive Pistol competition.)
• Change of sights to another notch and post type
• Change of grips (no weighted grips)
• Internal accuracy work to include replacement of the barrel with one of factory configuration.
• Factory installed cone style barrels are permitted on pistols with a barrel length of 4.2” or less.
• Internal reliability work
• Checker frontstrap and backstrap
• Checker or square and checker trigger guard
• Cosmetic checkering/serrating
• Extended thumb (may be ambidextrous) and grip safeties
• Full length guide rod manufactured of material that is no heavier than common steel
• Change of hammer and other trigger action parts to enhance trigger pull
• Beveled magazine well and add-on well extensions
• Custom finishes 13
NON-INCLUSIVE list of EXCLUDED modifications:
• Heavy barrels, cone barrels (over 4.2”) and/or barrel sleeves (factory or aftermarket)
• Porting of barrels
• Compensators
• Add-on weights, weighted magazines, tungsten guide rods, extended dust covers
• Sights of non-standard notch and post configuration
• Extended oversize magazine release buttons
• Trigger shoes

STOCK SERVICE REVOLVER DIVISION
Any revolver of 9mm/.38 Special Caliber or larger with a barrel length of 5" or less. NOTE: Effective 10-26-02 the maximum barrel length will be reduced to 4” (7 & 8 shot revolvers are permitted, but may only load six (6) rounds). No external modifications other than changing sights, grips, shortening of factory barrels, and changing the finish will be permitted.

NON-INCLUSIVE list of pistols permitted: (These are just examples of pistols that meet STOCK SERVICE REVOLVER DIVISION requirements and is NOT meant to be a definitive list of approved revolvers.) Smith & Wesson model 10, 13, 15, 19, 29, 64, 65, 66, 67, 586, 629, 625, 686 and 657, Ruger Security-six and GP-100, Colt Python, Trooper, King Cobra and Anaconda, Taurus 82, 85, 83, 65, 66, 669, 689, 608 and 44, Rossi 971 and 851
INCLUSIVE list of permitted modifications: (If it's not on this list, it can't be used in Defensive Pistol competition.)
• Change of sights to another conventional notch and post type
• Action work to enhance trigger pull as long as safety is maintained (smoothing the trigger face and removing the hammer spur are considered action work and are permitted)
• Change of grips to another style or material that is similar to factory configuration (no weighted grips)
• Chamfer the rear of the chambers
• Shortening of factory barrels
• Custom finishes

BACK-UP GUN DIVISION
Handguns permitted in BACK-UP GUN division may be single or double action and either pistol or revolver and be of .32 auto, .380 ACP, 9x19mm, .38
14 Special, .357 Magnum, .40 S&W, 10mm, .45 ACP and meet the following criteria: Pistols must have a barrel length of 3.8” or less (factory installed cone style barrels with or without a barrel bushing are permitted), revolvers a barrel length of 3” or less. Maximum (total) number of rounds that may be loaded into the handgun is five (5).

NON-INCLUSIVE list of handguns permitted: (These are just examples of handguns that meet BACK-UP GUN division requirements and is NOT meant to be a definitive list of approved handguns.) ACCU-TEK AT-32, AT-380, CP 9/40/45, HC-380, BL-9, AMT .380 & .45 Backup, Beretta 3032 Tomcat, 84/85/86 Cheetah, Browning BDA 380, Colt Detective Spl, DS-11, Pony, Pocketlite, Mustang, Officers Model, Defender, CZ CZ-83, EAA Witness European, Witness Polymer, Windicator, Glock 26, 27, 29, 30, Heritage Stealth, Kahr K9, K40, MK9, Para Ordnance P10, P12, Rossi 877/677, 68/88, Ruger SP101, Sig P230, P232, P239, Smith & Wesson 10, 19, 66, 36, 37, 38, 60, 442, 637, 638, 639, 640, 642, 3913, 3953, 4513, 4553, 457, 6906, 6946, SW380, SW9M, Springfield Armory Ultra Compact, Taurus 85, 605, 606, PT938, PT111, Walther PP, PPK, PPK/S, Wilson Sentinel

INCLUSIVE list of permitted modifications: (If it’s not on this list, it can’t be used in Defensive Pistol competition.)

Revolvers:
• Change of sights to another conventional notch and post type
• Change of grips to another style or material that is similar to factory configuration (no weighted grips)
• Action work to enhance trigger pull as long as safety is maintained
• Bob hammer spur
• Chamfer cylinder
• Custom finishes Pistols:
• Change of sights to another conventional notch and post type
• Change of grips to another style or material that is similar to factory configuration (no weighted grips)
• Slip-on grip sock and/or skateboard tape
• Action work to enhance trigger pull as long as safety is maintained
• Reliability work to enhance feeding and ejection
• Internal accuracy work to include replacement of barrel with one of
factory configuration (factory installed cone style barrels are permitted)
• Custom finishes

15. This division is intended for club level matches ONLY and will not be recognized at the annual Championship. All courses of fire for the Back-Up
Gun Division must be limited to 5 rounds maximum per string to allow autos and revolver shooters to compete equally. Sample Back-Up Gun Division
courses of fire are available from IDPA HQ.

The following modifications are SPECIFICALLY DISALLOWED IN ALL
DIVISIONS (unless otherwise specifically approved above):

compensators of any type including Hybrid or ported barrels, add-on weights for a competitive advantage, heavy and/or cone style barrels without a barrel bushing and sights of non-standard configuration (i.e. ghost rings, etc.).

HOLSTER and AMMUNITION CARRIER RULES

Holsters and ammunition carriers permitted for Defensive Pistol competition must be specifically designed and marketed for concealed carry/duty use and NOT for range or competition use and must be suitable for continuous all-day concealed carry wear, unless you are a full-time law enforcement patrol officer, and then your duty gear is acceptable. All holsters/ammunition carriers must be worn in a manner consistent with everyday concealed carry use. A maximum of two (2) spare magazines carried in 2 single pouches or 1 double pouch or three (3) speedloaders may be worn at any time. One additional magazine may be carried on the person for “charging” purposes only. Up to two (2) speedloaders may be worn immediately in front of the holster. If a holster or ammunition carrier is listed in the competition section of a manufacturer’s catalog, it’s probably NOT suited for IDPA use. If a holster or ammunition carrier is listed in the law enforcement or concealed carry section of a manufacturer’s catalog and can be worn behind the centerline of a shooter’s body, it is probably appropriate for IDPA use. A three-man holster committee will review and decide which holsters best meet IDPA criteria. Additional holsters will be added to the list as the holster committee approves them and rule books are re-ordered. The web site is your best source for an up-to-date listing. ALL retention features of the holster MUST be used. All holsters must fully cover the trigger when the pistol is holstered. The front of holsters for autos may be cut no lower than ¼" below the ejection port. Revolver holsters may be cut no lower than half way down the cylinder. Holster and pouches must be worn on a belt that passes through regular pants loops. The holster must position the pistol so the center of the trigger pad is behind the centerline of the body from a side view and all magazines and magazine carriers for pistols must be positioned behind the centerline. Revolver ammunition carriers may be worn directly in front of the holster on the strong side. The seam on the side of a shooter’s pants may or may not indicate where the centerline of a shooter’s body is located. If you can conceal your pistol/holster/ammunition carriers with a light windbreaker and comfortably draw your pistol while seated in an automobile with bucket seats, your equipment is probably
okay. Exception – Police/military officers may use their duty rig, but ALL retention features of the holster MUST be used.

HOLSTERS AND AMMUNITION CARRIERS MAY NOT BE MODIFIED ANDTHEY MUST BE USED IN THEIR
ORIGINAL FACTORY CONDITION FOR IDPA COMPETITION.