Have they snapped yet?
It could just be the compression of the rods, as they are loaded and during the cast.
Believe me, 2¾ rods can cast a fair bit of weight a good distance, perhaps you are just trying to cast to much weight further than you need to.
It sounds like it could also be the rods actions, some rods are very tippy which are great for playing fish under the rod tip but might not have as much power in the rod butt section.
Have a quick read through this, it might help -:
Types of Carp Rods
When choosing carp rods you need to know what type of carp fishing you are going to be doing. You must be aware of whether you will be margin fishing, stalking, distance casting, float fishing, casting heavy leads or method feeders or maybe you just want a rod for spodding or as a marker float rod. The reason for this is that carp rods, like all fishing rods, come in a huge array of lengths, strengths, actions and test curves and are made from different materials. So let's take a look at the different features of carp rods and what they mean.
Carp Rod Length
The length of a carp rod can vary between 10 feet and 13 feet, but a good all round size is 12 feet. For stalking, where you may want to be scrambling amongst undergrowth or climbing trees with your rod in hand, a 10 foot rod can be more useful, and for distance fishing, where a good line pick up is required on a strike, a 13 foot rod will do the job, but the most common length for all round ledgering tactics will be 12 feet. Remember that unlike other coarse rods, such as match rods, carp rods tend to be two-piece, and not three-piece, so make sure that you have room in the car for the chosen rod.
Carp Rod Strengths
The strength of a carp rod is known as its test curve. This is the amount of weight which when applied to the rod tip, will bend the rod at ninety degrees. Therefore if a 2 ½ lb weight were to be attached to the tip ring of a rod, and the rod lifted, if it bent at ninety degrees exactly, the rod would be said to have a 2 ½ lb test curve. The test curve determines how easily the carp rod bends under pressure from a fish and so the bigger the fish you catch and the harder it pulls, the sooner the rod will reach that ninety degree curve. This does not mean however that the rod stops bending there. As more pressure is applied, the bend in the rod will transfer further towards the thicker or butt end of the rod, therefore handling more pressure. Depending on where this transfer begins in the rod's length determines the rods action.
Carp Rod Action
A carp rod said to have a fast or tip action will reach the ninety-degree stage with only the tip of the rod bending to start with. However a carp rod with an all through action will reach that stage when much more of the rod is curved before reaching ninety degrees. A composite or all round rod will fall somewhere between the two.
Carp Rod Materials
Most carp rods these days are made from carbon fibre. This has the advantage of being very light and thin in section for its strength. Some older carp rods were made of hollow fibre glass and you will see the difference in these straight away, being much thicker and heavier looking. On some of the newer more expensive models, extra strength is added by including Kevlar in the compound, making an extremely strong but still lightweight material indeed.
Carp Rod Choice
So, with all of these factors to consider, which type should you choose. Well, as I said earlier, it all depends on the type of carp fishing you intend to do. If you want to travel light and stalk your quarry from a tree branch, then a 10 foot model is for you, but for most purposes look for a 12 foot carp rod. The test curve will depend on the weight to be applied and a 2 ½ lb test curve is a good all round model. If you are intending fishing mainly in the margins or close in work and the carp you expect to catch are mostly to be around the 10 pound mark, then anything between 1 ½ lb and 2 lb will be fine. But if you are intending casting to the sun, maybe with a method feeder attached or 3 ounces of lead, or if you are looking for a rod for spodding, then look at a 3 lb test curve. And if you are really serious about casting long distances for 40 lb plus fish, or spodding out a few pounds of trout pellet at a time, then maybe go as high as 4 lb.
Let's see action
As far as the action of the carp rod goes, if you want all round fishing then look at a compound taper rod. If however you are trying to hit the centre of a 20 acre gravel pit with four pounds of groundbait attached to your feeder, then a fast or tip action is required to really punch it out there. The tip will bend quickly on the cast, but the rest of the rod will hold plenty of reserve power as your cast follows through. For margin or close in work or floater fishing, an all through action carp rod will give you that control on the strike and while playing a fish at close range, using the whole length of the rod straight away.
Kevlar
Material wise, well if you can afford the superior Kevlar materials, and want the strength that this provides, then go for it. If however you just want a good carp rod for general everyday use, then an ordinary carbon fibre rod is fine and is still a very strong bit of kit. If anyone offers you a second hand fire glass rod, try it out first. You will find it much heavier and bulkier and it will be harder to cast due to the extra wind resistance.
Line
As a guide to help you decide, look at the strength of line you expect to be using. If you multiply the test curve of the carp rod by five, it should determine the required test curve of the rod to suit it. A line strength of 10 lbs therefore would be well suited to a 2lb test curve carp rod. Remember, choose a carp rod carefully and it will last a lifetime, but the wrong type of rod can spoil your fishing, be uncomfortable and maybe loose you that fish you have been waiting for.