C22,
Before guessing, try a few things first.

1) Repeated wash/rinse with Sweets 7.62 or Barnes CR-10 to remove all copper fouling. Then stroke that bore with JB Bore Paste 'til it screams. For dessert, give the bore a patch of moly bore paste.

2) Set seat depth of your preferred projectile (PP) to obtain an osculation betwixt PP and throat/lands. Kissing will almost always bear better fruit than jumpin'.

3) To compare/contrast, work up charge weights in 0.5 grain increments toward published maximums to find tightest group/pressure limits (like I'm going to tell you how much of a good thing to use in a public forum).

4) As a suggestion, try 130 gr TTSX's or 140 gr TSX's over R22 with 210M ignition.

Then you'll *know* if you need a new spout. To avoid an I toldya so, a #3/#4 finished at 24" or longer will be heavy in the bow and handle awkwardly in accord. You'd also likely have to have your stock's barrel channel dredged to inlet the fatter spout. A 22" dupe of your present sporter contour should shine in contrast.

Have fun, Brad!