There have been lots of threads regarding the tikka T3 and M595 actions, their bedding systems, and other details. However, most folks don't have both models available to really see the differences. Lucky for me, I've got a T3 in 243win and an M595 in 22-250rem.
This thread will show the differences between the two and highlight the many subtle changes that Tikka made in order to streamline manufacturing while still preserving the accuracy these rifles are known for.
Here's an overall shot of both rifles, with the M595 on top, T3 below. Even with the camo tape, you can see the M595 has a bulkier, more down turned grip. The palm swell on the M595 is pronounced and fills the hand nicely. The T3 is slimmer and more swept back (possibly to reduce weight). The forend of the T3 is also slimmer, and the "checkering" is not as sharp than the M595.
Here's a bottom view of both rifles. You can see the mag release button on the M595 is along the right side, while the T3 is just forward of the magazine. The bolt handle of the M595 is more of a round knob with a wide shank, with the bend at the knob, while the T3 knob is conical, hollowed out, with a narrow tapered shank the the bend closer to the bolt.
Re: tikka T-3 vs M595 detail views & changes shown
Both models feature a removable magazine, available in 3 and 5 rounds (they come with 3 round mags, but the 5 round mags can be ordered online, especially from cheaperthandirt.com). This image shows 3 and 5 round M595 mags on top, and the 3 round T3 magazine below. As you can see, the M595 mag has a cutout along side which acts as a catch, while the T3 has a molded-in standoff on the front of the mag. The standoff is certainly easier to produce. Also, the 5 round M595 mags are steel but both 3 & 5 round T3 mags are molded plastic. Lastly, the T-3 has a molded rib structure along the outside with thinner sidewalls, presumably to save weight (and reduce material consumption during molding?)...
This next image shows a top view of the disassembled stocks. The image isn't great but you can see the (upper) M595 has a flat plate molded in forward of the front action screw hole, with a counterbore that engages a standoff on the action for a "recoil lug". The (lower) T3 has a drop in (silver) metal bar that mostly resides within the stock, but protrudes about 1/8" to engage a slot on the action for a "recoil lug". This view also shows the T3 stock is noticeably slimmer in the midsection, and the cutout is definitely longer. Both rifles are short action, but the T3 has a standardized stock and bottom metal for both long and short actions. The trigger guard of both models is molded plastic, quite rigid and certainly durable enough for the application. The M595 finish is smoother and glossier, a tribute to the finer surface finish of the molds, compared to the texture finish on the T3 components. To make up for this, the T3 has a more sleek trigger guard than the standard M595 appearance. Here you can see both mag release buttons, which are both plastic and should wear approximately the same. The plunger on the rear corner of the M595 mag cutout assists with dropping the magazine is omitted on the T3. The T3 has metal washers co-molded into the action screw holes, which provide a positive surface for the action screws to bottom out. The M595 uses nicely machined countersunk bushings that drop snugly into molded counterbores on the triggerguard. Both use the same screws.
This next image shows the two primary weight saving changes of the T3 compared to the M595. On top is the T3, with the M595 below. The barrel contour of the T3 is noticeably slimmer and the action is slimmed down as well. Both trigger assemblies appear the same, and both actions have a groove for scope rings (rings included). Both also feature a side bolt release. Personally, I prefer the M595 bolt release because of its pronounced geometry, compared to the "ramp" style on the T3. My finger finds the M595 quickly with no pressing on the wrong spot. (This is a sublte difference of little consequence, what other $479 rifle has a side bolt release!!). In this view you can also see the T3 slot and the M595 stud for the "recoil lug". Also, you can see at the rear action screw, the M595 has a pronounced second stud feature that stands about 1/4" proud, compared to an almost unnoticable taped edge feature on the T3 that is more like 1/16". For a .243 and .22-250, these features are certainly sufficient, but I still wonder about a larger caliber...
Lastly, in this image you can see the difference in the bolt handles mentioned above, as well as the taper on the locking lugs of the T3. Not sure what difference the taper makes, except possibly weight reduction?
Re: tikka T-3 vs M595 detail views & changes shown
This is a neat view that I wanted to highlight. The M595 bolt is on the left, with the T3 bolt at right. Both bolts have a beautiful sako ejector and plunger setup with tight firing pin holes. However the M595 bolt has a slot machined in the right locking lug, which registers into a rail inside the action to create a smooth nonbinding action that is a real pleasure to cycle. This feature is omitted on the T3 action, although the T3 still has a very smooth action. The Stainless action is a bit more gritty, probably could be better if it was polished at the factory. (I may have cycled this smooth M595 action a little TOO Much during my last Wyoming prairie dog shoot! You know its hot when you need to move your gun into the shade to cool off....)
Hopefully everyone enjoyed this little write-up about the differences between these two wonderfully accurate and budget priced rifles. Although I have a preference for the M595, the T3 is a great value and offers many features only available in high end rifles (ie, side bolt release, removable mag, adjustable trigger, accuracy guarantee, scope rings included, sako extractor, etc). If you ever have a chance to purchase either of these rifles, jump on the opportunity. I can assure you; you won't be disappointed!
By the way, the long action version of the M595 is the M695, which I'm sure is just as nice as the M595 except I don't own one to review it thoroughly.
I'll be shooting both of these rifles soon to retest their accuracy, although I must admit the 22-250 has quite a few more rounds fired and its handloads are not tuned quite as well as the 243. By now, I'm sure most of you have seen the spectacular groups that this 243 provided when it was brand new!