So, I used to be one of those guys who was like "Fast playing is emotionless bullshit, you gotta feel it and play melodically and thats real music!" But after becoming significantly less ignorant, and watching youtube videos of people who put me to shame on skill, I've decided to venture into faster playing, or "shred" if you will.

I've been playing for 8 years, mainly in the Classic Rock, Jazz, and "Jam Rock" fields and I have a more than neccessary understanding of theory, and my improvisational skills are satisfactory for myself (for right now)

But to put it simple, I'm pretty bad when it comes to playing fast notes. I can sweep alright and tapping isn't an issue right now, but my alternate picking is pretty shitty. I've been trying to work just my alternate picking speed.

I've selected the mozarty passages from Scarified (Gilbert) that I want to nail at near the written tempo. When I started my speed practicing, i could pick this completely accurately only at a tempo of 88, and I could get it up to about 100 with playing sloppy. Now, 4 weeks later, I can play it pretty damn clean at around 104 and really sloppy (but intact) around 114. Written tempo is at 140

My problem is, I can't seem to get any faster than this, and my progress is seemingly stagnant. I've been practicing for multiple hours a day exclusively with a metronome. I need some advice on technique and mental ideas that can break the barrier between, pretty fast, and REALLY FAST! I'm getting very frustrated because of of the past 2 days i've seemed to make negative progress, not being able to keep up with my performance from the previous day. I'm currently trying to focus on efficiency of finger movements, and 0 tension in the picking hand.

TL;DR: How to get over what seems to be a mental block in developing speed? How long should I expect results (140) to take at this rate?
take a break
for like a day i think your stressing too much about it
when you come back to it youll feel better and your playing should improve
at least it does for m when i take a short break
realistically you gotta risk sounding horrible and raise the tempo and shoot for that higher standard. even if you can't play it at that speed it'll give you a goal to reach for. though if you wanna try it, use wieghts on fingers or something. maybe that'll help.
My Gear:
epiphone les paul cusom, Limited edition. evo dimarzio pick ups
Parker P-38
epiphone hummingbird
line 6 flextone
crate vtx 120

head full of ideas.
Speed comes in bursts, it sucks but you can't expect your hands to constantly improve at the rate they do when you start getting into it. You just have to keep going at it and sometimes raising the tempo up a bit will be make it easier to play it at the speed your having trouble with. I find leaving whatever it is that is giving me a mental block and practising playing something in a completely different style can help get over a mental block.
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Quote by Hart_Attack
realistically you gotta risk sounding horrible and raise the tempo and shoot for that higher standard. even if you can't play it at that speed it'll give you a goal to reach for. though if you wanna try it, use wieghts on fingers or something. maybe that'll help.

No, just do what Paul Gilbert did, he stopped trying to play fast and started playng everything correct, slow it right down and make sure you are using proper technique. Then when you think you're ready to speed it up, play it right some more then speed it up. Think of it this way, everytime you make a mistake, you are practicing it wrong. Play it slow and DON'T **** IT UP!
Yeah, I'm going for more of a "you can't play it fast unless you can play it slow ABSOLUTELY PERFECTLY" approach.

what exactly is the method behind fingerweights? never really heard of that idea before.
I just trill for extended periods with all finger combinations about once a week. Noticed huge difference in my playing after just doing it a few times, it just builds strength in your forearms. Just trill like 30 seconds every finger with every combination of fingers at first then kick it up to about a minute per. Its a good workout.

Read a Steve Vai article in guitar world where he recommends doing this to improve just about everything. Strength in the correct muscle=better coordination with this kind of thing.
Play some other tunes. Sometimes you just need a break from a song that you've been drilling. Don't play Scarified for a few days. Try out some other (maybe slightly less difficult) tunes and then come back to it.
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Tbh, alternate picking is the hardest thing to push the metronome on.

I would strongly recommend practising lots of complex licks that you will never play at your "top speed" - working on your string crossings and skips is more important than working endless reams of notes on single strings.

Now, as for the road block -

Try and make sure you're doing nothing "wrong".
See where/why/how you start getting tense and try and fix it.
Keep practicing - work on accents, dynamics... Speed isn't that big a deal.

Don't worry.

This stuff all takes time to integrate and sink in. I know this will sound crazy but I'm still feeling the benefits sinking in of practice I did more than a year ago (although at the time I felt like I was at a roadblock).

Why not write some etudes? That way you'll have some fun pieces to play and practice and you'll get some neat music written you can use in songs with your bands etc.