I shot Juggernauts in F-TR competition for years at ~2725 fps over Varget from 30" 11-twist barrels. This is the same node
@LVLAaron mentioned above. Those loads were stupid accurate/precise, I'd say conservatively somewhere in the 0.3 MOA range for 5 shots at 100 yd, perhaps even a tick better. Depending on the freebore length, predicted pressures (QuickLoad) should run in the 59-60K psi range. I have run those loads in both large rifle primer and [later] small rifle primer brass. Even though predicted pressures were well below SAAMI MAX (62K psi) the [Lapua] large rifle primer brass life wasn't great, maybe 5-6 firings before the primer pockets would start to go. With SRP brass, pressure is a non-issue.
If you are having an issue achieving velocities in excess of 2600 fps with 185s and Varget out of a 30" barrel, something is wrong. Without knowing your setup specifics, it could be having a relatively short freebore/short COL.
Edited to add: I just saw that you listed the freebore as 0.168", which is plenty. Disregard the short freebore statement. My issues with pressure and poor primer pocket life occured before I had my competiton barrels throated out appropriately. At the time I was using chambers with .085" fb (COL = ~2.895-2.900"), which is really much too short for the 185s. Alternatively, the barrel may not have "sped up" yet, or it could just be that you have a relatively slow barrel. In other words, there could be a number of reasons. However, I will say that IMR4895 is probably not the best powder choice for 185s. In order to hit the node comparable to Varget at ~2725 fps, you would probably have to push the 185s closer to 2800 fps with IMR4895, probably not where you want to be at this point. You might be able to dial up the speed a bit with IMR4895m but it's going to take substantially more than 40.5 gr of powder to do it. I am loathe to tell someone else how much powder to use in their setups when I don't know the rifle specifics, but somewhere above 43.0 gr would not be an unreasonable guess. It is likely that the 42.8 gr Varget you mentioned trying is about halfway in between nodes, possibly on a scatter node. There is no reason you should be able to obtain similar precision at the higher velocity, as long as you can actually hit the higher node up around 2725 fps or so. Obviously, there will be a little more recoil at 2725 fps versus 2550 fps, but in no way would it be unmanageable, and F-TR shooters have been loading Jugs with excellent results at the faster node with 30" barreled rifles for many years. So it can definitely be done, but you have to find the higher node(s) and tune the load accordingly.
If there is some other reason other than possibly short COL that your rifle is generating low velocity and/or excessive pressure with Varget loads in the 43-44 gr range, perhaps it might be a good idea to have a gunsmith look it over. Some folks simply don't like to run the kind of loads typically found amongst F-TR shooters. F-TR shooters often run Varget and/or N150 loads with 185 gr + bullets using 30" barrels that have >95% fill ratio and velocities ranging from ~2650 fps (200s) to over 2750 fps with lighter bullets. These loads typically fall somewhere near SAAMI MAX pressure (i.e. ~59-62K psi), which is one reason why SRP brass is a popular choice. Not everyone wants to do that. I get that, and it's fine. What I'm saying is that if you think there might be some other reason for the relatively low velocity such as a tight or constricted spot in the barrel (i.e. not by choice), then having someone look the rifle over might be wise.
Another alternative might be to give the 168 Hybrids a try. If your already running the Juggernauts, chances are good that freebore, tiwst rate, and barrel length will be just fine for the 168 Hybrids. In fact, the 168 Hybrid is one of the few bullets I've ever used where it is possible to equal (or surpass) the performance of the next higher weight class of bullets; in this case, 185 Juggernauts. The G7 BC of the 168 Hybrid is a little lower than that of the Juggernaut (.264 vs .284), but you can run them much faster due to the lighter weight. In fact, the BC of the 168 Hybrid is high enough that the extra velocity is sufficient to make up for the BC deficit, something that rarely happens. I ran the 168 Hybrids in the same .085 freebore F-TR rifles at ~2900 fps over H4895, and they shot very, very well. The 168s performance out to 1000 yd should be almost identical to that of running the Juggernauts at a velocity approximately 150 to 175 fps slower.
Edited to add: every barrel can be different, but if I had to guess, you probably didn't go quite high/fast enough with Varget. In some people's hands, there seems to be a very good node with Varget and Jugs at ~2650 to 2675 fps from a 30" barrel. Then there can be the next higher node at about ~2725 to 2750 fps. Because each barrel can be different, those numbers are only a guideline, not written in stone. If you didn't quite reach the "sweet spot", that might be the reason accuracy wasn't what you'd hoped it would be.
