I have a rifle that is shooting horrible groups with the factory ammunition I've tried. I am trying to decide if it is worth my time/effort to try to develop a load for this rifle before doing some gun smithing.

What are the worst groups and best groups expected for a given rifle, assuming the shooter does her/his part?

ddunn, if you can't get a rifle to shoot one or more factory loads under 2", I would think you have something wrong w/ your setup, either the rifle or scope.

shooting groups of 5 shots, 4 group total of 20 shots. a gun that average under 1" at 100 yards is the BEST (all shots fired, first fouling to last) The worst would be over 3" average. This is factory guns. A hunting gun is a keeper if it shoots on average under 2"(all shots fired). But more important is that the gun holds zero (you dont have to make large scope adjustments when you shoot the gun in the next season.) If you have a bad barrel, all the glass bedding , free floating barrels will not help inprove the accuracy.

My best rifle's best 5 shot group at 100m is .48"
The same rifle's worst group with the worst load ever tried is 1.4"

My worst rifle's best groups that do not stay on the 8.5x11" paper so who knows?
It has to be bigger than 8" and is probably much bigger.

ddunn,

Something you have possibly left out of your post is caliber, twist, and selection of ammo tried. For example; 69 gr bullets out of my scoped .22-250 were on the order of 8" group at 100 yards but same bullet out of one of my .223's were under 1" with iron sights at the same distance.

Don't write off the gun before you have verified that the combinations you have tried are compatible.

I think I'd give a good gunsmith a crack at the rifle first. Most newer rifles today require glass or pillar bedding and barrel floating to shoot their best. It also could be something simple like a heavy trigger. Trigger pull is ridiculous today, and it does affect accuracy. Don't do anything drastic until you've checked out the more common reasons for a rifle shooting poorly. Best wishes.

Cal - Montreal

Many times factory ammo will not shoot well in a gun...

Try some good handloads first...

Accruacy from a factory gun should be 2" or better IMO....glassing can make a big difference sometimes, but one needs to know what the gun wants in the way of glassing...3 point bedding, free floating or tight...This can be established prior to glass bedding and then glass accordingly. the gun will choose....