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Joined: Fri Feb 25, 2011 1:38 am
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Location: New Mexico

Post Posted: Sun Dec 02, 2012 7:20 pm 
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Recent resurgence of interest in the BHP has brought up some issues where tuning and fitting are concerned, so here are a few things worth noting...

The most sought after mods requested here, have been trigger work, sights and ergo's.

Action Tuning
Where trigger work is concerned, the BHP is quite sensitive to sear length for several reasons. If your sear length is too short, the safety has a tendency not to completely engage, and much the same as a 1911, you can partially disengage the sear by pulling the trigger with the safety on when this condition exists. This will lead to a surprisingly light trigger release, or release when the safety is disengaged.
A short sear also gives the false impression of a lighter trigger pull. Because of the design of the sear,length can be critical when spring tuning as well.
A sear thats only .010 short can lighten the trigger pull by a pound or two, as a result of the geometry.
Sears on the BHP have varied quite a lot over the years and some have been quite good while others have been utter junk.
I generally advise not to stone factory sears too much, because some are MIM, some merely case hardened, and very few take heavy stoning very well.
Most of the low quality (mainly case hardened) sears, will take a stone and polish, but deform VERY quickly and lead to hammer follow in a relatively short amount of time.
This is why I generally recommend just changing the sear, or hammer /sear combo, before attempting any trigger work.

Modern components allow reliable ignition with a 26/28 lb mainspring and the factory 32? is ridiculous.. Even on the .40's. A short sear compounds this by acting like a short hammer strut on a 1911 and reducing the weight of the mainspring. A heavier spring was the factory answer, better options are available.

******Since that last line has been misquoted as advocacy of just putting a lighter mainspring in, with no other changes, I would like to clarify, as stated in the last line, that better options refers to several component changes to address this area, including, but not limited to, a FB FPS. Some things are assumed to be understood, especially by some one notably familiar with the HP Design. My bad...:)******


Safeties
There are a few choices in safeties out there, some handmade and some factory. The biggest problem after finding one that suits you, is making sure its compatible with your frame.
There have been three sizes of safety plunger detents that I have come across. Those seen on the early models, with a pin retainer, Those on the later models, slightly larger detent and no pin, and those on the alloy frames.
The alloy frame has the largest plunger and corresponding detents in the frame. Using an early or late model steel frame safety and its smaller detent, can cause damage to the frame detent dimples and the bridge between them. NOT recommended.

SWITCH TOPPING
With the availability of the cheaper imports and surplus guns, it becomes tempting to have switch top guns. While this seems to work in most cases, caution MUST be exercised when trying to use an earlier top end, (those with a barrel tang) with a later model frame assembly and vice versa.
These must be checked for proper operation in that the trigger lever lift bar doesn't get impacted by the barrel during unlocking. This can, and will damage frames.

Accuracy
I have found, outside of slide to frame fitting, which benefits accuracy, as well as trigger pull, that the single most effective modification to the BHP accuracy, is barrel crowning.
A simple barrel crown has shown to increase the accuracy by as much as 25% in most cases.
This doesn't replace a good, match grade barrel, but the gains per investment cannot be beat...

Springs

Its been my experience that a huge gain can be had by replacing the stock 32 lb mainspring with the 26 or 28, and goes a long way to improving these guns in feel. I have found zero cause not to do this. I highly recommend in the .40 to go to a flat bottom firing pin stop. The stock trigger spring can also be replaced with a lighter one as well.
The stock trigger spring is about 2-2.5 lbs just in take up.


It looks like recent rule changes in some of the shooting sports will allow the BHP to be an option with the magazine disconnect removed. The availability of cheap, good quality, surplus guns should see more of them in action.

These are just a few issues that have arisen lately, and I'll add more as it arises.

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Last edited by Chuck Warner on Sat Dec 08, 2012 1:43 pm, edited 1 time in total.
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Location: Eastern Iowa

Post Posted: Mon Dec 03, 2012 4:20 am 
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Great info. Chuck....Thanks for this.

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Post Posted: Mon Dec 03, 2012 5:11 pm 
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All good advice Chuck. Interestingly, of the several switch top guns I've built through the years, it almost always seems as if the owner will play around with the two slides for awhile, and inevitably end up leaving one slide on the gun all the time and the other collects dust in the safe.

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Post Posted: Tue Dec 04, 2012 3:52 am 
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donw wrote:
All good advice Chuck. Interestingly, of the several switch top guns I've built through the years, it almost always seems as if the owner will play around with the two slides for awhile, and inevitably end up leaving one slide on the gun all the time and the other collects dust in the safe.

Mine always end up getting a new lower so I have two guns.

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Post Posted: Tue Dec 23, 2014 8:44 pm 
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Chuck,

I'm brand new here, hope you don't mind me jumping right in. I've been a Hi Power man for a good 25-30 years now, and I've had some interesting opportunities where Hi Powers are concerned.

Your write-up is excellent!!

Back in the ‘80’s I worked for a small arms importer and we imported around 10,000 Inglis Hi Powers from China, I’m the lucky SOB that got to go through each and every one…so I picked up a few things.

32lb Mainspring
First, another spin on the 32lb mainspring thing. That came about in the late ‘60’s when the Egyptians started making SMG specific ammo intended specifically for the Port Said copy of the Swedish K, and the British Sterlings which were both common in the ME at the time (not to mention oodles of UZI’s). The Egyptians wanted greater barrier penetration and ended up being the load that inspired the modern 124 grain NATO round. Any-hoo, since the ammo was rather hot, they put in very hard primers so the Egyptian Helwan (Egyptian licensed Beretta 1951) wouldn’t be able to fire that ammo and break the locking blocks. The SAS likes to operate in a manner that they can scavenge ammo when needed, and from the time of the Suez Crisis on past the 1967 Arab-Israeli war, the SAS when doing their sneaky-pete ops kept encountering this Egyptian SMG ammo. So the Brits asked FN to start making their Hi Powers with stiffer hammer strike. Since the Hi Power has always been first a military service pistol, FN decided to just make all Hi Powers with the 32lb mainspring, and that’s how we got saddled with the ridiculously stiff mainspring.

Sear Springs

This is a weak point on the Hi Power. Springs whether they be leaf or coil will take a “set” over time. The problem with the Hi Power sear spring is, it’s not real stiff to begin with and it’s not what I’d call “robust”;when it starts to wear, you can have the hammer to drop to half cock. But typically that only happens when dropping the slide on an empty chamber, NOT when chambering a round. The cushion of chambering a round is a bigger cushion than most realize. Even a well worn sear spring will often keep the hammer from falling to half cock when cycling…this is if you don’t muck with the sear spring. In the batch of Inglis Hi Powers this was the most consistent problem, almost all had to have new sear springs before we could sell them (second most common problem was cracked or broken cam lug on the old style barrels).

I caution gunsmiths to not tweak the sear spring on a Hi Power because of the wear factor. The thin portion of the sear spring that is the “spring” is too long and that long of a very think leaf spring is easily weakened. When you tweak that sear spring you greatly accelerate the wear and reduce the lifespan on the sear spring by a good 50-75%. That’s not a problem if the shooter is going to consider the sear spring as a wear part and periodically swap in a new one.

When I do a trigger job on a Hi Power, I always tell the customer to expect a very crisp 4.25lb pull, and I won’t do lighter because I won’t sacrifice reliability for a lighter trigger…it’s not a 1911, the fire control parts are significantly different so you can’t expect the same results. So pull reduction is gained by reducing the mainspring tension to 26lbs, swapping out the trigger spring, and setting the sear/hammer engagement right.

For those whose hammer drops to half cock, don’t sweat it. 99.9% of all Hi Powers that do that will still work perfectly, just be aware that your sear spring is starting to show signs of wear.

Hope ya’ll find this helpful.

Kevin

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Post Posted: Wed Dec 24, 2014 4:16 pm 
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Thanks for the info Dark Lord and welcome to the forum!

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Post Posted: Wed Dec 24, 2014 5:39 pm 
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Chuck,

Sounds like you need to get in the BHP part making business! :-)

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Location: New Mexico

Post Posted: Fri Dec 26, 2014 6:00 am 
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bluedog1 wrote:
Chuck,

Sounds like you need to get in the BHP part making business! :-)



Hmmmm....lmao


Welcome Kevin. Add whatever you can that's correct!


CW

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