is it just me or does it seem like ffg need to standardize the weapon stats across all the games?

nope. FFG more or less tries to keep their systems as capable of working with each other as possiable. this is good for both us and them because then we can adapt stuff from other books. for example, because all their 40k stuff basicly works, black crusade's not having vehicle rules isn't THAT big a deal. we can make due with rites of battle and only war to have pretty much a full compliment of veehicle rules and stats

i understand that...what im saying the weapons have vastly diff stats across game line...astartes bolter and legion bolter for instance(they use the same ammo) have vastly diff damage rates...it causes compatibility issues

well for a start they're more or less then same when you look at the errata (deathwatch errata'd the stats for most of it's weapons boltguns lost their full auto for example) once you take the errata into effect the differance between the Legion boltgun and the Astartes Boltgun is that the astartes one has slightly more ammo but weighs more. it's a differamce but not one that is unuseal.when you consider that the Legion bolter likely represents and older pattern, sucha s the crusade pattern boltgun,

whereas the Astartes bolter is supposed to represent the stats for the newer godwyn boltgun used by modern space marines.

so in short the differnt stats once errata is taken into account aren't too bad.

thats fine...but here is something else to point out...gw will say imperial tech is on the decline then say that chaos has older les advanced tech...yet they also say that the traitor legions got the most advanced tech due to bad info and logistic errors when the heresy happened and from that point things degraded yet they also try to say that they dont use stuff as advanced and modern marines...its a case of they cant keep their story strait

you're looking at technology as a universal constant. when it advances everything advances. except technology can move forward in one area while other areas see losses. for example we're considerably more advanced then the middle ages, but have lost the secrect to making Damascus steel weapons.

this is PARTICULARLY true given how technology is advanced in the 40k universe. where innovation is a dirty word. and all tech advances are recovered by discovering fragments of STC "how to" guides. lose a "guide" and you lose the tech

At the heart of the matter are the changes to some of the more subtle game mechanics. It has been said that the reason a Lasgun's Damage is given as d10+3 is because the average Toughness of a Human is in the 30-39 range. Since then, there have been subtle changes to AP structures, such as the stacking of certain AP values, or changes to the way Toughness mitigates Damage, most notably the newer mechanic for Unnatural Characteristics. I think weapon Damage listings have been altered along with the subtle changes in core mechanics, and "standardizing" weapon stats may not necessarily be as much an issue as the OP suggests. One game might list an Autogun as having Damage of d10+3, another d10+4, and it could simply be viewed as inferior blueprints, an older or more robust Mk, better forge facilities, etc. When something like this occurs in my cross-referencing I look at it as a way to introduce something (insignificantly) new- that d10+4 Pen 0 Autogun might become d10+3 Pen 1 to reflect a specially manufactured ammunition (which is likely more difficult to acquire but ultimately less expensive than Man-stoppers).

Special Ammunition are also divergent throughout the game lines, as are some Pen values and many Weapon Qualities. Then there are some considerable changes to the way Skills and Talents behave within the rule mechanics...

I think it's safe to say that "standardization" of the game lines is unlikely...unless the ten-year anniversary release of Dark Heresy proves me incorrect.

NPCs in Deathwatch books still typically use the pre-errata stats.

Which I suspect will actually work better under the BC/OW ruleset, since autofire was their main unbalancing factor.

Deathwatch core book weapon stats will nto work with BC rules; for instance an astartes bolt pistol will be better in melee combat than an astartes chainsword, because in BC you can fire semi-auto in melee with a pistol.

They also do damage based arounf the pre-BC Unnatural Characteristics rules.