Having some issues here.

Swapped out the stock grip for a SD real type grip. Had previously been using an SD grip as well with no issues. Now for some reason I cannot find a working angle for the sear prong of the leaf spring. It either seems to be pushing too much and the hammer will only come forward half way when the trigger is pulled, or it isn't pushing enough and the hammer won't catch the sear. I have tried adjusting it in tiny tiny increments, but I can't seem to get it to work.

Any suggestions?

Has anybody had any problems with a trigger meeting an abnormal amount of resistence while pulling the trigger on their hi capa / 1911? It feels as if something is getting caught between the parts that are responsible in the back for the action (sear, stirrup, disconnector), and needs an excessive amount of force to overcome whatever is getting caught.

From most to least:

MEU, 1911A1, Hi-Capa 5.1, Hi-Capa 4.3.

This answer is theory based, factoring in the weight of the moving assemblies. It's pretty simple, the heavier the moving weight, the greater the kinetic energy required to move and be carried by the assembly.

The 1911's have a heavier spring plug plus barrel bushing combo. Because of these, they tend to have heavier kick than the Hi-Capas which do not have a metal barrel bushing, and also have a hollowed spring guide BUSHING rather than a plug.

Further, the differences between the single stacks, is simply because the MEU has the metal NOVAK open sight, whereas the 1911 just has the plastic rear sight. Again, the greater weight will make the MEU kick harder.
Same goes for the Hi-Capas... the longer slide of the 5.1 creates greater moving weight in the slide as well as the longer recoil rod bushing. Also, the 5.1 rear sight is larger than the 4.3 rear sight.

This answer does not factor in gas capacities or any other upgrades.

The 5.1... in stock form.

I haven't seen this issue before. I'd need it in front of me to diagnose and solve the problem.

This is not normal. You'll need to have it looked at, as I do not have a solution for you based on your description.

The only thing that I can think of, is that this only happens when the hammer is half-cocked. The solution, would obviously be to fully cock the hammer.

I found something peculiar. With the gun in natural position- all parts in resting position - something seemed to be exerting force on the rear part of the slide assembly causing it to lift up. I applied pressure in the opposite direction (down) and it seemed to fix the trigger problem I was having in my previous post. I'm in the process of figuring out what could be pushing up on the rear of my slide and making sense of how it all works in conjunction with each other.

EDIT: I've sanded down the legs of my BBU so they're perfectly flush with the slide and it hasn't made a difference.

http://www.tokyo-model.com.hk/ecshop/goods.php?id=6424

Dude.....I am sure some are looking for this...

Holy shit. I got really excited there. But... that's only the chamber, right, not all the hop up adjustment bits?

I swapped in the original BBU and it balanced out the rear part of the slide. The trigger pull is smooth now.

Yeah its just the chamber. And correct me if I'm wrong but Tokyo Airsoft does not ship to Canada.

That's messed up, man. Possibly something with the disconnector nubs not interfacing with your BBU correctly and thus making trigger pull annoying?

Yeah, that's what I understand as well.

The Lightweight BBU was too light for the steel outer barrel I put in so the front part of the slide was tilting forward, causing the rear to lift off, letting the disconnector nubs spring up a bit.

No. They ship to Canada. Just checkout and they will send you an email to confirm your order and how much for the shipping.

Hm. I've tried ordering and they would not allow a Canadian postal code with, or without the space in between the 6 letters and numbers.

Fill in whatever information you can. They'll contact you via email to confirm, then be sure at that point to give them the proper information. They are very good with e-mail and flexible with orders(ie, changing order after check out)

Just type in your full address with postal code under address, leave blank for the Postal Code.

Paypal is the only option for international shipping. Once you checked out, they will send you instruction how to paypal them

This guy has tons of capa parts, alot easier, even if its not listed you can ask him for it.

http://stores.ebay.com/Marui-Parts-Showcase