What are extra-power firing pin springs for?

[fulloflead]

Hi. I'm having trouble with a Browning HiPower 9mm. When I use Corbon +P ammo the primer flows back into the firing pin hole and gets shaved off, leaving the fired case looking like it contains an unfired primer. The shaved pieces clog up the firing pin hole after a few rounds.

I had a C&S lightened spring kit installed, so I went back to all the factory springs to see if that would help, but it didn't.

So, now, I've got a set of several extra-power Wolf recoil springs that I'm going to try and see if that solves the problem.

They come with extra-power firing pin springs. What, exactly, does it do? If I use the extra-power recoil and firing pin springs in combination with the lighter hammer spring from C&S, will it cause light primer strikes?

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[HSMITH]

It might cause light strikes. The purpose of the EP spring is to pull the firing pin back faster preventing primer 'wipe'. It being heavier is going to resist the hammer more.

A longer firing pin or one that fits the breechface hole will work to correct your problem, otherwise look to lower pressure ammo. Speer Gold Dots would be one to try, the CCI primers are a little harder and might help some. Pressures are also likely lower and that will help some.

Getting a really nice trigger on a BHP isn't easy. Send it to C&S or someone like them if you really want a good pull.

 

[fulloflead]

Getting a really nice trigger on a BHP isn't easy. Send it to C&S or someone like them if you really want a good pull.

I did really nice work on mine. I removed the mag safe, polished the internals and bar, recut the sear, got a lighter hammer spring and bent back the sear spring a bit. I had a 4.5lb pull but was getting light strikes on S&B ammo and some of my reloads so I went heavier with the hammer spring until I was at about 6lbs. I'd be happy if I can just get this strange primer shaving thing fixed.

It might cause light strikes. The purpose of the EP spring is to pull the firing pin back faster preventing primer 'wipe'.

That sounds like the opposite of my problem. I think the primer is following the firing pin back into the hole and getting ripped off during extraction. Maybe I need a lighter firing pin spring so the firing pin stays forward longer. I was thinking a heavier recoil spring to delay unlocking a little longer.

I think the next thing I will do is use all the factory springs in the gun and replace ONLY the recoil spring with an extra power recoil spring and see if that works.

A longer firing pin or one that fits the breechface hole will work to correct your problem...

OK. That'll be where I go next if the spring thing doesn't fix the issue.

...otherwise look to lower pressure ammo. Speer Gold Dots would be one to try, the CCI primers are a little harder and might help some. Pressures are also likely lower and that will help some.

Yeah, I've got some reloads that work nicely and it doesn't happen with the non+P Speer Gold Dots. I'd rather fix the problem though, if I can.

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[model 649]

Other than a firing pin hole that is too big, it sounds like the ammo is simply too high pressured. Primer flow into the hole enough to have it cut off as the barrel tilts is NOT GOOD. Springs aren't a fix for ammo that is too hot. If magnum velocities are desired, try another caliber or gun. Be careful with those irreplaceable body parts, guys.
Josh

 

[HSMITH]

I don't think delaying the unlock is going to help your situation. A stronger mainspring might help some.

 

[fulloflead]

I don't think delaying the unlock is going to help your situation. A stronger mainspring might help some.

Jeez. I've got the factory one in there now, and I can barely cock the hammer with one hand.

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[Jim K]

Blanked primers 101.

"Pierced" or "blanked" primers are NOT due to too heavy a firing pin strike, they are due to too light a one, where the firing pin does not have sufficient momentum to keep the primer metal in check until the pressure drops.

Momentum equals mass times velocity, so it can be gained by high speed or weight. A light firing pin can have enough velocity to make up for lack of mass, or vice versa, but a light firing pin and a light mainspring will spell trouble every time. Without enough momentum, the firing pin is pushed back by the pressure inside the primer itself, and allows the primer metal to be forced back into the firing pin hole, where it is either smoothed up or cut off when the barrel drops to unlock.

My first recommendation is to stop fooling around and go back to all the standard springs. A heavy recoil spring won't help - the primer metal is back into the firing pin hole long before the recoil spring tension takes effect.

Jim

 

[fulloflead]

My first recommendation is to stop fooling around and go back to all the standard springs. A heavy recoil spring won't help - the primer metal is back into the firing pin hole long before the recoil spring tension takes effect.

Jim

But it does it with all the original springs in place. What's the next step?:banghead:

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[RecoilRob]

One spring company adds extra power FP springs with their stronger mainsprings to prevent the FP from indenting the primer when closing at the higher velocity.

I had a BHP that did the same thing as yours. None of the other 6 pistols I tried the same ammo in did anything so extreme. Yes, it WAS pretty hotly loaded but seemed moreso in the HP.

Did some checking and found the rifling origin or throat to be much shorter on the Browning. A LOT shorter. So much so that a certain 147 FPRN lead bullet would not even chamber in it while feeding and firing just fine in the other guns. I loaded up some dummies really long in once fired cases and carefully chambered them in the disassembled barrells. Each was pushed back in the case when the lands were encountered and the BHP's measured significantly shorter than all the rest. Sorry, it was a long time ago and I don't remember the exact numbers but it was like .200 less or thereabouts.

If your pistol is anything like mine was, the Corbon's are just too hot for it and there is nothing you can do......except maybe a barrel replacement.

 

[fulloflead]

If your pistol is anything like mine was, the Corbon's are just too hot for it and there is nothing you can do......except maybe a barrel replacement.

Crap. Maybe that's it, then. :banghead:

I haven't tried the 147s in my BHP yet, so I don't know about the other thing.

 

[Walt Sherrill]

I had heard that the extra-strength trigger springs were provided with extra-strength recoil springs, to minimize the chance of inertial firing pin strikes, as the slide slammed forward with extra speed/strength. (The extra resistance of the firing pin spring offset the extra slide force.)

 

[jerkface11]

I thought +P was a no-no in a high power.

 

[HSMITH]

You are back to dropping the pressure of the ammo, or getting a firing pin that is longer (heavier) and/or fits the breechface hole better.

If you are using 115-124 grain Cor-Bon +P I doubt the bullets are seating against the lands causing excessive pressure. It is possible, and you can check buy removing the barrel and dropping the rounds in to see if they will fully chamber by gravity alone, but unlikely. You shouldn't have any problems with commercial ammo hitting the lands as it will/should be loaded to SAMMI standards which considers OAL as well as ogive shape.

 

[fulloflead]

I thought +P was a no-no in a high power.

Nah, it was designed to handle NATO machine gun ammo.

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[fulloflead]

...or getting a firing pin that is longer (heavier) and/or fits the breechface hole better.

I'll start looking for that part.

I also emailed Bill from Cylinder and Slide. I don't know how he'll feel about giving free advise. We'll see, I guess. Maybe he'll sell me a part.

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