Russian artillery has gone in a very interesting direction, organizationally.
On the higher (read, division to corps equivalent) end, they've basically copied the US concept of a JAGIC cell - a dedicated hunting element who's job it is to use special purpose forces, drones, electronic detection and so forth to direct massive firepower onto prime targets via rockets and missiles, usually armed with cluster munitions and thermobarics. Depending on who's observations you take as accurate, the response time from detection to shooting is from 10-20 minutes. That is accomplished by directly linking the observer (manned or otherwise) to a command group of artillery types who in turn have direct links (both in terms of communications and organization authorities) to the biggest shooters. Then they flatten the area with a truly prodigious amount indirect fire - think on the scale of 70-80k submunitions dispersed over square kilometers. This is where the famous strike that caught two Ukranian BNs in their assembly areas came out of.
But it is well outside the scope of Combat Mission. Scenario wise, fires like that happened before the Russian player/commander ever got into the fight. Its why he only has to fight one company with a little bit of Blue artillery today, it isn't something he has on call. If he tried to get it on call, it would be a process of 45 minutes or more just to snake through the system according to the unclass US estimates. And it would probably be disapproved because once in a major powers shooting war, every time a major asset fires the other side is trying to eradicate it and both sides are pinging like mad with counterbattery radar. So your Russian player is unlikely to benefit from this largesse "in scenario."
As you go down to the BTG level, a BTG is usually plussed up with a lot of division equivalent support and retains its own internal artillery, lots of it. In general, a first class BTG will have two or three organic battalions of artillery depending on spending postures for the district,, and possibly a battalion of rockets, and then another three to six battalions pushed to it in support. This is a copious amount of artillery by western standards. However, the reality of coordinating that much artillery weighs heavily on Russian HQs at this level. Rather than serve as acentrla processing authority for lower units (more below), the BTG forms its own fire plans or directly hunts and shoots using BTG level sensors and scouts. Ukranians report receiving fire in "as little as ten to fifteen minutes" after being observed, that is usually from what most western analysts think are BTG HQ controlled observation platforms that have direct links back to the BTG HQ. This one is impossible to actually build in Combat Mission, because those UAVs and special observers are often sending information directly back to the BTG, who decides to shoot or begins a conversation with the battalion level element - meaning"the player" would only receive the benefit of these fast reaction times if he lost a great deal of his own autonomous control of the UAVs and observers present. Unfortunately, this is not within the scope of the game engine, but it does suggest that anything 152mm and higher would be at least a ten minute delay since that is how fast direct sensor-shooter link is processing Russian fires in optimal situations these days.
And finally we are at the "player" level of a battalion commander or lower. Russian attempts to emulate the western call for fire system, where ground commanders call up to a coordinating HQ who then divvies out fire in according to priority, has not been nearly as successful as their direct data-link has. See the part where the poor Russian artillery officers are trying to keep a hold of up nine battalions of guns and rockets moving around, shooting, and getting resupplied. Basically, the BN commander has a much long lag time in this situation than his western equivalent. Exact numbers are unknown, but it remains substantially higher than western formations, so likely in the twenty plus minute range for CM purposes. Since that is pretty unacceptable, the Russians use artillery at this level as either pre-planned fire or as direct attachments to the ground unit. When attached, as a poster previously noted, the attached battery actually sends it own special officer(s) forward to coordinate the fire serving as the link between the guns and line units. Which leads to a dilemma - the guy actually making this happen is basically trying to execute a pre-determined fire plan that the battalion commander told him to do. In CM terms, turn one prepped fires or preplanned targets. Or he is waiting for a sufficiently high authority to tell him to shift off that plan - which is NOT a squad leader or lieutenant making an on the fly call ala a western force. Most people think it is a company commander minimum (though he can delegate that authority) and then only for guns assigned to him, not the force as a whole. Meaning that attempts to use the artillery in a "see it, smash it" manner get substantially delayed by command authorities...unless you drive right up and use direct fire, hence the Russian preference for that as a quick reaction doctrinally. In a weird way, it is actually faster for Russians to deliver high level artillery than low level because of these dynamics. Which means, if anything, CM is probably being too generous in the response times available to the player.