I know the ac with the semi Independent suspention will handle a elk better than irs because you don't get body roll and the rear end dosen't slag as much when loaded.sure the irs works better on off cambers but i think solid akles work better for hauling heavy loads.
I think I would buy the 650 because i like to have the best ,i hate wishing that i had a better machine.or having a freinds machine out performe mine.

 

Only if the ACT rear suspension has adjustable shocks like the IRS. Go to a dealer and stick a heavy load on the back of the 650 with the shocks tightened up. You'll be very surprised at how well it does. My ACT 375 hauls heavy loads well, too, but it does not have the adjustable shocks, so for now, my 650 is the load bearing champ. Also, the track is wider on the IRS, adding to stability. Both haul heavy loads very well. I think the new 2004 400 ACT machines have the adjustable shocks now.

 

the grizzly's rear suspention kills me,i remember my friends grizz loaded with 1/2 an elk on therear and my old foreman with the other half on the rear.my foreman haul it easy but the griz had lots of sag and was tippy.its hard to beat those foremans for hauling game and i know the arctic cats do very well to.i have a polaris 700 and its rear sus is adjustable like the arctic cat but i havent hauled on it yet but if i do i will make sure my ac 400 is there just in case.

 

My 400 did not have any problems to haul this caribou out of the mountain side. It was not very heavy (less than 400 lb) but the cat took this and two people at a time without any problem.[img]i/expressions/face-icon-small-happy.gif[/img]
check out this pic picture

 

I haven’t had any other problems out of my 03 500 4x4 auto as of yet, out side the one's that have been mentioned like the skid plate buzzing, but I can live with that, the buzzing stops as soon as I start to move and the high low gear grinding still happens some time, but I think it's because I do not come to a complete stop before I start pulling on the lever. As for price I gave $6,000 stock, swapped stock tires and wheels for the 589 M/T AT27X9-12 and the chromed wheels for $580.00, front bush bumper $125.00, 2,500 lb Warn winch $300.00, large storage box with back rest that mounts on the rear rack $159.00 for a total of $7,157.00 plus tax ouch that hurt. Since I have bought my ride I have thought about trading it in on the 650, but decided that the 500 is much easier to work on when it comes to changing out jets and just routine maintenance. I had a Kaw 300 4x4 Bayou for seven years that I thought a lot of, but this beats the hell out of that. I like keeping them for a while and I think this one is a keeper. I like to ride in Colorado, Kansas, Missouri, Arkansas and Louisiana. I would like to take it up around the Great Lakes and ride on some of those great trails I keep hearing about. I have a brother-law living in Wisconsin, so I might get the chance before long. Good Luck "Keep'm Turning"

 

You could easily fix that skid plate buzzing by taking it off and then putting some kind of adhesive backed rubber at strategic spots. If you can isolate the location of the buzzing, it might be even more simple.

 

OK here we go! I have both A 2002 400I IRS 2x4 and A 2002 500I IRS 4X4. They are both great machines. I use them both for work and play. I put 1,000 miles of trail riding on each. WHAT A BLAST!! I use the 400 and 500 the same way for work and play. This is what I found. The 400 is a good machine, has done every thing i have asked it. YOU have to keep rpm's up on 400. A little under powered when in 4 th and 5th gear going up long small hills . KEEP the RPMS UP!! 500 has the POWER plus HI and LO range makes a BIG difference when working with the HEAVY stuff. (1000 pound trailer). 4x4 is NICE can do and climb hills easier and slower or faster than the 400. I feel the same about 4th and 5th gear on the 500 just does not have the pull on hills..TOP speed on both the machine are the same 50-55 mph. IF I had to pick one, I would take the 500 every time. IT's worth the extra $$$. plus its nice to have the extra power. I have had no problems with either and they are work horses. I hope this helps.