Imperial Guard shooting has a complex mix of short and long ranged weaponry and a lot is often made about both. The amount of long-ranged firepower accessible to the army is extensive and can be accessed very easily in every Force Organisation slot as covered here. What is often overlooked however is the large amount of ranged blasts (and ordnance blasts) Imperial Guard have access to. Combined with the ease of access to melta-weapons on multiple units and high strength ranged firepower and the Imperial Guard army is capable of having a unique set of effective firepower at all ranges against multiple opponents. Let's look at this a bit more closely and how it interacts with opponents on the table-top.
A very common setup for many Imperial Guard armies is a lot of ranged blasts (Manticores, Medusas, Russes, etc.) with some Hydras, Vendettas and then a bunch of Chimeras moving forward. This splits your firepower into neat little packets. Ranged blasts. Ranged direct fire. Close up direct fire. The problem is many lists often lack in the ranged direct fire department and are on platforms which aren't exactly durable (Hydras and Vendettas for example). This puts a lot more emphasis on ranged blasts (specifically Ordnance Blasts) to hurt tanks and makes many players think Meltavets are a must and need to drive forward and blast things to death. Whilst this can be effective, it's also very limiting in tactical applications and easy for your opponent to negate (block midfield, suppress ranged anti-tank, dismantle IG army).
What Imperial players really need to do is balance their blasts and their direct anti-tank and not have their direct anti-tank focus around melta-units. This will be a fallacy 40k post later but a lot of people use meltavets as suicide units when they are not. Meltavets should be advance as part of the army with the Chimeras handing out S6 firepower and the meltavets themselves providing varying threat bubbles to your opponent. This means as an Imperial Guard player your best direct fire anti-tank (the meltaguns) aren't always going to be in range (or willingly be in range) until mid-game. The Imperial Guard player therefore needs to think how many points are they investing in blasts, particularly non-ordnance blasts or single gun tanks. Whilst these blast options are great and have some utility against tanks (Manticore = castle ownage), they aren't going to reliably be suppressing or popping tanks. That being said, once squads are outside of their tanks, these blasts are invaluable in putting lots of wounds on these guys quickly and it's something direct anti-tank often has trouble with. That being said, do Imperial Guard really need help with infantry?
Looking at most lists you'll find there are always several Chimeras and whatever they hold. The Chimeras alone are going to be pumping out three S6 shots each and any backfield markers will have a further three S5 shots to add to the weight of fire. Let's say there are seven Chimeras with two heavy bolter variants. That's 21 S6 and six S5 shots averaging 11 wounds on an MEQ unit. This is going to quickly reduce small Marine squads and annoy the crap out of any ranged infantry units whilst the Heavy Flamers on the rest of the IG tanks will take care of hordes quickly enough. Add this on top of the firepower already evident in any given Imperial Guard list and a large amount of blasts often aren't as necessary. Couple this with the fact blasts become less effective as there are less infantry on the table and they fill a specific role.
What this then boils down to again is a balance of firepower. Blasts can generate a lot of damage quickly and ordnance blasts can hurt vehicles with some degree of reliability but one needs to make sure their ranged ability to hurt tanks isn't split up between a few units and then meltaguns. Furthering this, this firepower needs to be greater than S7. A lot of armies seem to spam autocannon like weaponry at range and then meltaguns for up close and personal work. This in theory covers all of your bases but what happens when you come up against AV12+ armies at range? Those meltaguns have got a long way to travel and your token Vendettas certainly won't last long. Again, this boils down to a balance of firepower. Rather than having just Vendettas + autocannons at range with lots of blasts, look to get a couple of blasts and higher strength firepower to compliment the Vendettas and S7 rather than them alone.
Ultimately, and without repeating myself too much.., it's all about balance. Like your army list which needs to be designed with multiple armies in mind, Imperial Guard firepower needs to exemplify this. One of the few armies who can have an excellent array of shooting options across all ranges, make sure each range type (long, medium and short) isn't also split based on effectiveness against a certain unit type (i.e. most anti-tank being short-ranged). If you do this, your opponent can dismantle your army more readily as certain parts of your firepower can be focused on and nullified rather than your opponent having to worry about your army as a whole. Get this balance of firepower right and Imperial Guard are very scary. Get it wrong and not so much.
