Rules question that is not specifically covered in the rule book.

In the open division, is it against any rule to use a large magazine such as the Wilson Combat 1911 .45 ACP 10-Round Magazine With Finger Rest?

In either of the 2 cases below they are allowed:

1) If you are asking so you can load 10 rounds for slow fire here is the rule:
Under 10.7
Note: In slow fire events, which are scored after 10 shots, the command should be “10 SHOTS SLOW FIRE, 10 SHOTS IN 10 MINUTES, LOAD.” (The number of rounds to be loaded by the competitor in slow fire stages will be determined by the competitor.) 

2) If you are asking because you want to use it as part of your grip, it would probably fall under grips.  3.6 Grips - The grip, or any part of the firearm, may not be extended or constructed in any way which would give any support beyond the hand. The wrist must remain absolutely free and visible when the pistol is held in the firing position. No part of the grip or accessory may encircle the hand (see Fig A). Upward curvature of the heel of the grip may not exceed one inch as shown in Fig. A. Adjustable Grips are permitted as long as they conform to the dimensions as shown in Fig. A.

If you are going to actually grip the magazine you would have to make certain you did it the exact same way every time or the rounds may not feed consistently and your groups may open up.
- Dave

Thanks, Dave. When a string or stage consists of ten rounds, I didn't want to have to reload after seven or eight.

wesleytilson@gmail.com wrote:Thanks, Dave. When a string or stage consists of ten rounds, I didn't want to have to reload after seven or eight.

That would be slow fire only.
I don't know a lot of shooters that use a 10 round mag., maybe because of the difference in mag spring pressure on the first to last bullet.  There are quite a few that will drop a mag after 4 rounds with the 5th round in the chamber then insert a 2nd mag with last 5 rounds.  This allows them to keep their hand on the grip while reloading and only have to cycle the slide manually once.  Then there are those that have only one mag they use for the long line and reload it.
- Dave

CMP rules give the command to load 5

I found it in 10.7 by searching the entire pdf for "round".

"The Range Officer having made sure that the range is clear (in
timed and rapid fire the targets must be turned out of firing position)
then commands “WITH 5 ROUNDS LOAD.”

Note: In slow fire events, which are scored after 10 shots, the command
should be “10 SHOTS SLOW FIRE, 10 SHOTS IN 10 MINUTES,
LOAD.” (The number of rounds to be loaded by the competitor
in slow fire stages will be determined by the competitor.)"

Thanks.

Chris Miceli wrote:CMP rules give the command to load 5

Chris is correct the CMP rules are different and if you read the rules you must fire 5 rounds before reloading.  I haven't been doing this I load after 4 rounds have been fired.  I've never been called on it but it's good to know.

On page 86:
Turn targets to edge. 
THE PREPARATION PERIOD HAS ENDED. 
THIS STAGE WILL BE 10 SHOTS SLOW FIRE AT 50 YARDS IN A TIME LIMIT OF 10 MINUTES. 
WITH FIVE ROUNDS…LOAD 
AFTER FIRING FIVE SHOTS, RELOAD YOUR PISTOLS WITH A MAGAZINE AND FIVE SHOTS AND CONTINUE FIRING.

While it sounds like a good idea, I wouldn't do it. One fully loaded ten round magazine weighs a considerable amount and the pistol's weight will vary from round 1 through round 10.  

Loading five rounds each into two magazines minimizes the weight variation as you shoot.

Much better idea. Besides, there will be a command about how much to load. This makes things simpler for my military mind.

I think that there is an NRA rulebook and a CMP rulebook. If so, which one do we follow?

In Pistol and Revolver Shooting, by A L A Himmelwright, found here:

https://bookspublicdomain.com/Shooting/Pistol-and-Revolver-Shooting-by-A-L-A-Himmelwright.html#Page_72

Himmelwright states:

"Target-shooting with the pistol and revolver, as a sport, may be said to have originated at the annual meeting of the National Rifle Association at Creedmoor in 1886. During that meeting a revolver match was scheduled to be shot at 25 yards on the 200-yard Standard American Rifle Target. It was a reëntry match, with the three best scores of five shots each of any contestant to count. In this match three scores of 48 out of 50 were made, the highest individual aggregate of three scores being 143 out of a possible 150.

The rules are determined by which match you are shooting.  NRA, CMP or whatever group is sanctioning the match.   

Yes, you can use 10 round magazine for NRA matches.  

I would err on the side for caution for CMP.  (I thing they may not make the equipment check for CMP as they used to disallow magazine pads (but they seem to be OK now) so the extended magazine may not be allowed (as they are not the same as factory or standard issue). 

You can go to the CMP website and research the rules there.  Don't be surprised if nothing is mentioned specifically to 10 round magazines. So look for what is allowed or specifically excluded.  If it ain't allowed, then don't assume its OK. 

The match director should be giving the commands as associated with the specifically sponsored type of match (NRA, CMP, etc.)  If there is a limit on the number of rounds that can be loaded and fired, it will (should) be in the commands. 

And the difference in the commands is just another example of the CMP producing confusion among shooters.  

CR

And don't forget, the CMP has two different rule books; one for the Service Pistol/.22 EIC matches and one for the Games matches (as-issued 1911 match, etc.) and the commands are different in each one.