Try pre-exhausting your chest by doing the flys first. Also, lower reps, like the 5 x 5, aren’t conducive to a great pump. And, if you incline press at a 45 deg angle try moving down to around 30 deg. You’ll get more chest fiber activation.
You should train like a BB then, you are plenty strong enough. Try this:
A. Squeeze press 2 x 15 (activation)
B. Incline (30°) DB press with double contraction 3 x 10
C. Machine or cable flies (hold contraction 3 secs) 3 x 10
D. Decline DB press (0302 tempo) 3 x 15
E. Bench (pause 3 secs on chest) 2 x 6-8
How wide is your grip for those bench press and are you tucking your elbows like a powerlifting bench press. An option is to decrease the weight a little, increase the reps 8-12 range and try a wider grip but keep the elbows high (dont tuck them, drive them back and up). Try with a bar first to feel the stretch in the pecs. If you want a good stretch and pump, I found this works really well with incline bench.
Get yourself some strength bands. I recently started using a pair. I attached handles to them, then anchored them about 10ft apart (use the distance to create the tension level). Set up a bench in between them (incline seems to work well). I then do a sort of hybrid flye/crossover; slow eccentric and 1-2s contraction at the top with arms slightly crossed. After 12-15 reps it was seering pain and awesome pump in the target area.
The squeeze press is something I am currently doing on my arms day for the triceps. It is the only exercise I have ever done that gives my inner chest a good pump. I actually more chest pump on arms day than on chest day all thanks to this exercise.
When you say a 30 degree incline press, I am not sure what you mean by double contraction. Can you clarify please?
I also only have access to free weights with no cables or machines available.
The 5 x 5 is likely more of a strength-based approach whereas growth is typically thought to be better in the 8-10 rep ‘bodybuilding’ range but to what degree is probably different from individual to individual. Personally I like to flat bench for strength and incline/decline press in the higher rep ranges.
EDIT: I’d like to qualify that last sentence by saying it’s always been more of an ego preference for me in that I find it hard not to want to go heavy as I can on bench press :^ /
I foolishly forgot to give you one during my earlier post, which you’ll be able to easily do given your equipment: Reverse 21s - 7 full reps, 7 top partials and then 7 bottom partials.
I got this from Dr Scott Steveson’s Fortitude Training (FT), which I’ve been on for a while, and I love it for a few moves, including the flat DB press. I found a Ben Bruno post on TNation demonstrating it. However, he does the bottom partials before the top ones. Probably no big deal.
Technique wise, you want continuous tension; no locking out or pausing (the guy in the video does both). You want a nice slow eccentric, even on the partials. If you get the load right, you will fail on the last few partials. If it’s too light, just rep out til failure. One set is all that is needed. If you want to smoke you pecs, afterwards pick up some light DBs and go into a loaded stretch at the bottom of the flye position and hold til the pain says otherwise. That’s the essence of FT right there.