You will get different answers on this I'm sure, and they may both be right, and that makes it even more confusing. At one time I thought you absolutely had to have a recoil lug, but the last 40X I built for myself I fitted the barrel without using the lug and it shoots as well as the one I have that's fitted with a lug? Gene Davis has built some great 40X BR rifles without using the lug, as has Lamon Loggins. Some of the best shooting 40X's I've seen didn't use the recoil lug on the barrel shank. I've also seen some great shooting 40X's that did use the recoil lug. Was that because they didn't have a recoil lug. I really don't think so. I think it was because they had a great barrel that was fitted and chambered correctly and had proper bedding and great ignition, and all the other little aspects that make up for a great BR gun.
Of course, I've only mentioned 40X's which is the only ones I've had experience using with and without a lug. Like I said, you'll get different answers and they may all have merit depending on the situations. You didn't mentions what action you were using.