I’m a member at a small club that has 100 yard bullseye matches. I am thinking about trying these.

I have a LaRue match upper on an old Superior lower with an original Magpul M93b stock and a LaRue trigger.  The only glass I have is a Primary Arms 1-8.

I have some Prvi Partisan 69 grain ammo that the gun seems to like.

I’m thinking I just zero at 100 yards and go from there. Is there anything else I need to know or do?

Practice & try different ammo or reload your own.

8x will work at 100yds just fine.

Fiocchi Exacta 69 gr works great on my 1/9 upper, while the Hornady Black 75 works better on the 1/7 upper

Range time/practice will do more than the rifle.

Agreed, however four kids means I don’t get to practice as much as I like.

Don’t really know the course of fire yet. Supposedly it changes every month to keep it unexpected and interesting.  I just know the distance. I am told there will be occasional times when they will throw in some 25 yard and 50 yard shots to see how you compensate.

My current plan is to show up and give it a try. See what works and doesn’t and have a little fun. After a few matches, maybe I can change some stuff.

I can't tell if this is a trick question..

Confirm zero at desired range.

Practice in the conditions of the completion if possible.

Bring the kids.

I go to a club in a different state that holds a 100 yards match. It would sometimes have service matches that I bring my garand to.

One time I came in 2nd place, and I'm not a super great shot at all. lol. I used federal 62gr m855 ammo, believe it or not.

I just recommend going there with whatever you normally practice with and use that. They say don't switch things on game day and that's true here. Different ammo equates to different zero, so don't change anything, even the lot number of that particular ammo. Chances are you're probably a better shot than you think.

Learn how to adjust for wind at 100y ranges it is small how much a bullet can get pushed around at 100y but it still happens.  Since you cannot practice at the range a lot practice dry firing, breathe control, and learn to snap your shot between heartbeats.

Dry fire in all the conceivable positions, and do it at least daily.  Do some live fire practice in those positions and make sure you know any potential zero changes from position to position. Write your zeros (for positions, and ranges) on a cheat card.  Practice changing your sight settings while dry firing.

Believe it or not dry firing is way more beneficial. Matter of fact just taking a few minutes every day and concentrating on the trigger pull (feel how it moves, and how much pressure you have to apply before it breaks), all the while doing front sight concentration (or if optics just concentrating on keeping the dot on something) will help you tremendously, probably more so than actually going to the range. Shooting really comes down to fundamentals and that's trigger pull and sight concentration.

Don't just blinding dry firing but really concentrate on the fundamentals like trigger pull and front sight concentration. As a matter of fact, the pandemic has helped me greatly become a way better shot and I shot way less than I ever did before. All that changed is I did more dry firing at home by just concentrating on the trigger pull and front sight concentration. I went to the range and was amazed by how much I improved.

NRA/CMP tournaments limit scopes to 4.5x maximum magnification. If it's just a fun tournament, the organizers can make any rules they like.

You need a heavy shooting glove for your left hand (I'm assuming you're a righty), an easily adjustable sling (I prefer leather slings), lace up boots and suspenders. The boots give you more stability in standing and a better platform when sitting. The suspenders eliminate a pulse at your waistline when in the sitting position. No belt.

Practice dry firing at home every evening prior to the match. Put a well-lit target on the wall, the same width as your front sight post and practice firing offhand, unsupported. Use your left elbow resting against your rib cage for support. Wear the heavy glove. Slings aren't allowed in standing.

Be honest about your calls when the trigger drops. Follow through is important. Be patient and relaxed, trying to squeeze the trigger as the front post aligns under the bullseye without jerking it. If you can't get aligned after a few seconds trying, set the rifle down on a chair and start over fresh.

You are going to have to make a magazine change in the rapid fire events. Service rifle competitors load two rounds and fire both, before swapping magazines (8 rounds in the second mag) and completing the course of fire. Once the second magazine is inserted, you can cant the rifle and slap the bolt stop to send the carrier home or rack the charging handle, it's your choice.

NRA tournaments start the rapids already in position. CMP tournaments start from the standing position which makes establishing a NPA (natural point of aim) critical when hitting the ground. Controlling your breathing, timing your shot sequence, concentrating your focus on the front sight post, squeezing the trigger straight back and holding it until recoil has subsided will greatly improve your scores.

I try to shoot holding my breath with 2/3 lung full of air. Some people use 1/2 lung full of air. Some people let their breath out. If you let all of your air out your eyes will suffer. 60 seconds in the rapid sitting is plenty of time with an AR-15, it's enough time with an M14 and it's a hell of a time with a bolt action.

I use a shooting jacket and have for over 40 years. Buying one mail order sucks, because you really need to try them on and get into position wearing them to make a choice. Camp Perry has many for sale during the National Matches, I suspect you could buy them in Chillicothe, OH too. Champion's Choice and Creedmoor Sports are major suppliers.