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NicVerAZ

Grand Power X-Calibur: technical discussion

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I stripped my X-Calibur today to review the internals and I noticed a few things.

I strongly recommend watching this video several times and keeping it for reference, in case you forgot something:

Also for reference is the diagram located at: http://www.grandpower.eu/download.php?files=51c19226a9368_132.pdf

First, the trigger pull came up at 3lbs clean. I managed to go slightly under by pre-compressing the trigger but not much lower, like 2.8-ish.

I read that 2.5lbs was to be expected but this was not the case. I used my 1911 for reference, which had a nice trigger job done. The smith delivered me a 2.5lbs trigger per my request and 2.5lbs is what the trigger pull gauge was reading, very consistently. 3lbs is what the gauge was reading on the X-Calibur, very consistently. And it feels like 3lbs to me.

My goal was to do the mod that Canuck mentioned, where removing the "firing spring back-up" (#52) would reduce the trigger pull. I indeed can testify that now the trigger pull is of 2.5lbs. It is crisps and breaks nicely, very consistently. The double-action is also lighter as a result and it remains strong throughout. My gauge could not read what the pull was but it is probably slightly over 8lbs now. I will test the gun at the range tomorrow, just to make sure it still fires nicely and then take it to a night match this week.

I suspect that one could go even further by using a shorter or lighter hammer spring (#33), but lighter strikes would also be expected and misfires as a result. I would recommend not going beyond removing #52.

Note that the hammer spring has a nice amount of gear grease (it was dry on my MK6 and MK7). If you handle it too much, you will lose some of that grease and it should be replaced.

Another thing I noticed is that the "slide stop spring" (#28) is absent on my MK12. At first I thought it might have fallen but I could not find it on my clean work area. I watched the take down video and it is obvious that he does not deal with that part either, which requires a dab of grease in the hole where it sits in order for it to stay put during reassembly.

One thing that I noticed while shooting is that the gun does not always go into slide lock. It can be an issue, especially in IDPA where one is required to go to slide lock in order to do a non-retention reload. I actually wonder if that specific part would actually help or if it was removed in an attempt to fix that issue. If anyone has this issue, please let me know.

The slide lock issue bugs me a little bit. As I shoot limited minor these days, it does not bother me much during matches but as soon as I shoot production, it will definitely be an issue.

Edited by NicVerAZ

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Nick, if the slide stop spring was missing when you test fired the gun, you would have had problems with it locking open early, not failing to lock open.

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Of course. The primary difference in the Mk12 insert compared to the Mk7 is the front is cut differently for the new takedown system. Also we had to return to a relief cut under the barrel seat to avoid warping during the heat treat process.

Here is a video of the various steps in production. If you fast forward to 7:08 you can see that right after installing the frame into the grip, the assembler is going to check for slide stop tension. It's of course possible for a spring to be missed. However, it would then have to be overlooked by the assembler as he completes the gun, the shop QC foreman who handles each gun before it leaves the assembly cell, and our QA team who test fire each gun with 10 rounds before packaging.

http://youtu.be/M6jy1gs9Wjk

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Ok. So how can were order replacement parts in the US? I'd like to stock up.

Also is there an advantage in the steel recoil guide?

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Call Eagle Imports, and ask for Matthew.

I'm using the steel guide rod, but tastes vary.

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I was just about to ask this too, thanks for the preemptive strike.

Ok. So how can were order replacement parts in the US? I'd like to stock up.

Call Eagle Imports, and ask for Matthew.

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I found the little spring under the trigger bow. Classic...

I also believe that the spring may, in some cases such as mine, be too strong, which is why my gun does not slide lock.

Without it the slide locks every other round even when not empty. I suppose there could be some tweaking in this area.

This spring measures 1/8" x .300". Good luck finding one if you lose it.

Edited by NicVerAZ

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Okay, so...wow. I obviously liked my X-Cal right out of the box, but it is now just astounding. I can't vouch for the removal of the block below the hammer spring, as I have not personally tried it. But I just can't imagine how it could work any better than what I've got right now...

So I did my first detail strip of this gun after two range visits, amounting to only 300-400 rounds, total. Two things bugged me: 1) The DA is stiffer than my mk7 P1's, which are totally stock. I have two and both (one almost new, one with a couple thousand rounds through it) seem to be a couple pounds lighter. 2) I had a bit of grittiness that seemed to be in the hammer. I assumed it was a bit of debris from machining/assembly that would work its way out. But it was actually getting worse as I fired it, despite cleanings and liberal oiling.

Turns out I was making it worse...the problem was the grease in the hammer spring. It's...gritty. That grease gradually works its way downward and started mixing with the light oil that I was hoping would wash any heavy particles away. I cleaned it out of the hammer spring, and it is pretty damn sparkly. I replaced it with a similarly thick (but stickier, and not gritty) high temp automotive grease. Synthetic caliper lube, to be specific.

I considered the removal of the mentioned piece in the hammer assembly. I did not like the idea of that spring sitting directly on the retaining pin, as it is not static. It rotates around the pin as the hammer is cocked, and may also move in a circular motion as the spring is compressed. Part #52 should act sort of like a bearing, letting the spring turn during compression and spread its load evenly across the surface of the pin.

So I decided to modify the spring, rather than just giving it more space. I took the smallest amount off of it that I thought could possibly make any kind of difference. Exactly one coil...the removed piece is almost completely flat, consisting most of the dead end of the spring. So the modded spring has almost the exact same free height, it's just lacking the dead coil. I filed it a tiny bit to smooth out ther clipped end, and even went as far as to hit it with some 600 grit sandpaper. I also sanded the other end of the spring, with the dead coil intact. Because I'm working under the theory that keeping the short, stiff hammer spring from binding may be a key thing, I put the flat (non-clipped) end of the spring down, with the clipped end inside the hammer. I wanted the part of the spring touching this part 59 to be nice and slippery. As a final touch, I polished the bottom of 59 (the side that touches the retaining pin) to a mirror finish.

I put it back together and started dry-firing...I'm in awe. The DA now feels as smooth as the P1...well, smoother...but the actual force required it about the same. SA feels like it has gone from maybe 3 pounds to what MUST be 2.5 or less. Could even be closer to the '2' side of things. Hammer still seems to fall with authority. Will test it on some hard primers, but I highly doubt I've had even a marginal effect on primer ignition.

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Okay, I'm sitting here continuing to dryfire this thing, and I just can't stop. The difference between what I have now and what I had felt the whole rest of the time I've had this gun...it's night and day. And it was already excellent during the 'night' phase...

...but that 'day' bit. My god. I've never payed for gunsmithing, but I would imagine that for a person who doesn't mind spending a bit to get a gun optimized...this would be that 'must have' professional trigger job...someone could spend $250 on this and be as happy as a clam...they'd never guess it was so little work to make such a huge improvement, to what is now arguably as perfect an SA handgun trigger as is even possible. To find something better would mean venturing past SAO 9mm handguns and into crazy expensive match guns (.22's and airguns and such) with triggers measured only in ounces.

...just felt I should make my feelings clear here...

edit: via crude gravity-powered measurements, all I can say for sure is: SA falls between 2 and 2.5 pounds...definitely less than 2.5...

Edited by phucheneh

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Sounds like you need a cigarette and a shower. Welcome to the addiction....

When it comes to the basic architecture of the trigger system, it's hard to improve, but it can be tweaked, cautiously.
The hammer and sear engagement surfaces are very clean. With a good sear fixture and guide, they could be very lightly polished, but any change in final position is liable to increase weight.

Reducing the area below the sears edge can make for a quicker and crisper feeling break, but also very quickly leave you without a working safety.

Reducing the hammer spring length slightly and thinning the spring cap or removing it entirely are also options, but can lead to ignition problems.



Play safe folks.

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Out of the box my pulls weights were: 3.75# SA and 9# DA

Detail stripped/cleaned and removed part #52: 2# SA and 7# DA

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Out of the box my pulls weights were: 3.75# SA and 9# DA

Detail stripped/cleaned and removed part #52: 2# SA and 7# DA

That sounds low. 2lbs SA? I only removed the spring end cap myself.

What did you do?

No misfires with 2lbs?

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Personally, I think that if you trimmed the spring the proper amount that it, with the little steel follower, is roughly analogous to the power of the stock hammer spring with the follower removed, and then polished that follower, and thoroughly cleaned and regreased the spring pocket in the hammer...you would be knocking on the door of 2lb flat. I think sub-2lb SA is probably possible while still igniting any generic USA-made primer (but maybe problems with Tulammo, Wolf, Monarch, and the like).

I seem to remember reading about people swapping Tanfoglio hammer springs into GP6's/K100's. I might need to do some experimenting.

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I tore down both my mk7 P1 and my mk12 X-Cal yesterday, as well as a Tanfoglio, to make some comparisons.

The hammer spring in the X-Cal appeared identical to the P1's. Obviously, there could be important differences that I cannot perceive by eye...e.g. a slight increase in the diameter of the wire could make a spring that looks pretty much the same (same height/width/number of coils) be notably stiffer. But I would venture a guess that they are, indeed, the same part.

The followers are different. The diameter of the large part is the same, roughly the same as the width of the springs...but the thinner tail section that fits inside the spring is different. The X-Cal's fits snugly inside the spring, whereas the P1 has a narrower piece...this is important, as it allows the P1 follower (or whatever we should choose to call this part 59) to fit inside a Tanfoglio spring. They are slightly taller and OD is significantly less. Their smaller diameter seems like it would make for too much spring rate...but, I do seem to recall reading about some people having success with aftermarket Tanfo springs. Don't know if they were having to cut coils or not. To have any hope of using these springs in a new X-Cal, though, you would need the old style spring follower.

I increased my cutting on the stock X-Cal spring to 1.5 coils. So that means I removed the dead coil, and approximately half of the first active coil. I may have overdone it...I would recommend against cutting more than 1/4 of a coil after the flat end coil is removed. That would probably have been perfect.

That said, I am still fairly certain this will still ignite off-the-shelf ammo from US manufacturers. I would not be surprised if it still lights off Tulammo with issue, really. We shall see; will get some range time in this week. Best guess, trigger pull is down to about 2.0 lbs in SA, with DA at maybe six? Hard to measure DA pull when you're just using gravity, so I'm guessing on that one...assuming it was 8-9 out of the box and my P1 was 7-8...yeah, I gotta go with about 6.

Canuck, do you know if there is any chance we could get different hammer springs? Or is the one model of spring just universal with GP guns? Coil cutting is definitely not optimal on this kind of spring design...really need replacement springs of a lower rate that keep the same (or even a little more) free height to really tune trigger. Certainly something for them to think about with regards to our market...they seem to build their guns to ignite anything...which I love; but I think US competition shooters are going to be very willing to trade off the ability to shoot the cheapest of cheap ammo for a much-improved trigger pull.

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Right, I feel like trying doing the same but it is part of the reason why I asked about the availability of parts before I start screwing around with it.

It seems that polishing the sear and hammer is something I'd like to attempt but, again, I don't want to screw up without backup parts.

What specific grease are you using for the hammer spring?

Also you can test if your hammer is still strong enough by loading a case with just a primer. Itty bitty loud, but not that much. Fire under a pillow and even the cat won't notice. Do it 10 times.

Edited by NicVerAZ

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I admit that I got a little overly ambitious. I think it'll still work, but it's not an optimal solution...the hammer does feel super sexy now, though. You feel like you barely have to touch it and it automatically locks back to half-cock, heh. Thumbing to full cock makes it feel like you're working a tuned cowboy revolver.

I'm seeing spring supply places that may have what I need, though. Maybe even in stock as premade parts; there are also options to have small springs like this custom made. Seems like a nice option if the price is right.

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You are spending too much time trying to achieve a goal which may be irrelevant in the long run.

What you want is a trigger that feels good to you based on your shooting experience. I like short reset and trigger between 2 and 3 myself. I know people who have a sub-2lbs trigger but I find it lacks feedback and is prone to cause accidental discharge. I have seen someone shoot the dirt and getting DQed because of too light a trigger. And that is a dangerous incident.

That said, I agree that the removal of the spring cap is a bit of an ugly trick and one should be able to keep something on. Different spring options could be an idea, as well as a smaller cap.

I would spend more time doing dry fire practice, getting used to the trigger. It takes work and it rewards.

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I am hoping to be that odd duck that just runs one in competition as built.

Giving up the Glock Pat?

Say it isn't so (not that I run a Glock)

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Coming from open 1911's to this. I'd be happy at 1.5

I guess you could do that but beware light strikes. I would not use CCI or Federal, that's for sure :)

You may have to tune the firing pin assembly as well. But you are going to end up having bigger issues eventually.

BTW folks, clean up the firing pin channel every now and then. There are some videos that show how but it is not that complicated. Pin out, turn 1/4 turn, extract, Q-Tip will Hoppes 9 and reassemble.

Especially if you use dirty powder such as Unique or even TG.

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I am hoping to be that odd duck that just runs one in competition as built.

Giving up the Glock Pat?

Say it isn't so (not that I run a Glock)

Nothing in stone for sure. But with so many alternatives to the old "G" I like to shop around. And that X-Cal is VERY tempting!

Heck, I think the bottom dollar K100 Mk7 is fantastic!

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I am hoping to be that odd duck that just runs one in competition as built.

Giving up the Glock Pat?

Say it isn't so (not that I run a Glock)

Nothing in stone for sure. But with so many alternatives to the old "G" I like to shop around. And that X-Cal is VERY tempting!

Heck, I think the bottom dollar K100 Mk7 is fantastic!

I offered Mr. Kelly an opportunity to shoot my gun even.

I have to admit my XDm has served me well but I have been feeling like something is missing so I too have been shopping around a bit. Not that my bank account says I can do anything but dream, but hey doesn't mean I can't do research and hope.

Edited by Iggy42

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