Anschutz biathlon rifles are top of the line. They are also the most expensive, running about US$2K.
I haven't seen a Krico in years.
Izmash 7-4 are the second tier but still very solid. Their 7-3 model is smaller. These also have the straight-pull, Fortner bolt. They run around US$1,100 or 1,300. Do NOT buy a biathlon basic Izmash. They are nice rifles with a straight-pull bolt, but biathlon rules specify that you must use iron sights. I've not seen a Biathlon Basic that comes with any sights; ergo, you will be paying more to add them. Also, the basic doesn't have a magazine caddy to store extra magazines, so that's another expense. Nor mounting hardware for a biathlon harness.
I have a Lakefield/Savage B90. It's a standard turn bolt. They come with a basic snow cap, harness mount and a 4 magazine carrier built into a solid (but easily marked) wooden stock. They were made for about 10 mins back in the 90s. Hence they aren't easy to find. They are entry level, but they are very well made and very accurate. $400 to $500. I traded an XDM for mine.
When I started biathlon, I couldn't ski well (still can't) and didn't have a rifle, so buying an Izmash or Anschutz made no sense when seconds weren't going to matter. I like diy gun projects so I decided to build my first. It was tougher than I thought.
Some people buy surplus .22 training rifles and do custom wood work to mount the magazine carrier and harness mounts. I don't have those talents.
First, I bought a Winchester 69a--it was a fine and accurate rifle, but it didn't weigh enough. Biathlon rifles are supposed to be 7.5 lbs minimum.
I also bought a Savage Mark2, hoping to find a Lakefield B90 stock, so I could carry my extra mags while skiing. Great trigger, but I never found a stock. You might be more lucky or find a custom stock maker.
I found a Marlin 2000 with 5 mags for $300. Marlin 2ks are nice b/c the graphite stock is solid which allows for drilling and mounting (it's not honeycombed). Plus, the stock is puke blue, so you don't feel bad about defacing it. I started here.
I contacted Marc Sheppard at Altius firearms up in West Yellowstone, MT.
to ask what I would need to complete my project. Mark was brilliant in his advice. Bonus, he seems like a really nice guy.
He sold me an Altius carrying strap (solid, but don't cost too much) and its mount as well as an Anschutz 4-mag holder for my Marlin-shaped magazines. (Be careful here if you buy a magazine caddy separately: Marlin mags are straight. Savage/Lakefield are curved and wouldn't fit this particular model of magazine carrier. Marc helped me find the right caddy straight away.) A quick trip to the local hardware store and I was built. Another local (colorado springs) gun store sold me a snow cap for an Anschutz 54 and with a little filing at the inside, it matched up to the Marlin barrel.
If you are thinking of doing summer biathlon involving running or biking, you don't have to sweat the harness, b/c you won't usually be running or riding with your rifle. You will leave it in a rack at the range while you are running/riding your laps. If you are doing a roller-ski biathlon, you will be toting your rifle.
My advice would be:
1. Find out if your local biathlon group has extra rifles that you can borrow for races. There's no sense in waiting to play the game. It's fun and infuriating.
2. Ask if you can borrow someone's Izmash/Anschutz/whatever while on a training race. Most people will let you. It will give you an idea of what works for you.
3. Prepare for a long search. I used to troll the gunbroker.com site regularly when I was looking. There are other sites, but that is where I had my best luck. Search for both "biathlon" and "biathalon". I guarantee that you will find items under both. I found the Marlin under "biathalon" and was pretty much the only bidder. I also overshot the mark by buying 3 rifles to broaden my chances of completing my rifle in three different ways. My buddy only looked for a lakefield B90. He found it one summer day on an online auction site when biathletes are generally thinking of other things. Apparently, he leads a cleaner life than I do; you might also be that lucky.
Hope this helps a bit. Good luck with the biathloning.