I have looked around the forum and have been exercising for around a month or two with reasonable gains in strength and size doing 4 sets of 6-8 reps in an fbw 3 times a week.
I was just looking around T-nation when it said that for pure mass growth the ideal rep range in 12-15. I know that reps like this are unlikely to result in strength gains. I have found other contradictory info elsewhere.
Does anyone have any input upon this?
Thanks

12-15 for hypertrophy haa
its already clear that 8-12 is optimal.

Most individuals who are not genetically gifted or chemically enhanced find that any given scheme results in slower or no gains (in strength and/or size) if followed for an extended period of time. Therefore most of us have found that varying rep range, number of sets, exercises, frequnecy, etc. and even diet (carb and/or calorie cycling) over time is necessary. It also helps keep you from getting bored from doing the same thing over and over. So you might want to stick with your current scheme for 4-8 weeks and then try 3 sets of 10-12 for a few weeks and then go back to 4 sets of 6-8 later...

agree with above,start of with higher reps then lower the reps while increasing the weight over the wks that way you take advantage of strength and hypertrophy both are covered
2wks 15reps
increase weight
2wks 12reps
increase weight
2wks 10reps
increase weight
2wks 8reps
increase weight
2wks 5reps.

I do sets of 4 of 8 reps. is that good?

Sounds ok to me ^^

I always vary my reps every session, sometimes ill do like 3x6 or even 3x4, then other times i may do 3x10 or even 2x10.

I am getting pretty good results right now going with 4 sets at 10,8,5,5....with every set at a weight that just let's me get that last rep. It's kind of a LeBrun method. Hypertrophy? not really, but the strength gains are quite good for me, and those last two sets absolutely kill. No rest between the first three (except for swapping out plates), then I rest about two minutes between the last two. After about 2 weeks I can add the minimum weight and still get them cranked out.

BTW, these 4 sets do not include a warmup set, which might even just be the bar for some people/excercises.

There is more and more studies revealing that there can be different optimal rep ranges for different people. You should try some different rep ranges and see what you get the best results off. Its all about which rep set scheme gives your individual the biggest testosterone response. There are so many arguments like higher reps for postural muscle etc etc. There is so much contradictory information that you need to find what works for yourself.