Bisley Conversion issue

[alleno]

I have recently converted my BH 45 (fairly new one with internal lock) over to the bisley conversin grip frame. After doing the conversion it ran fine. Now I am having a lot of light primer strikes while using the 45 ACP cylinder. I get as many as 4 or so out of 6 that wont fire. The 45 colt cylinder is unaffected..... I am using the same primer in both rounds but they just wont fire in the acp cylinder. I have tried various comercial loads with the 45 acp cylinder with the same results. What would make one cylinder run perfect and the other not? Other than the conversion (done by a smith) this gun is stock.
Thanks for any help!

 

[bnewberry]

1. Headspace
2. Light Hammer Spring
3. Interference between frame and hammer as it falls.

 

[Tellico]

Factory ammo or reloads? Improper crimp will allow .45 ACP to go too far into the chamber. .45 Colt is rimmed and ACP headspaces on case mouth. Factory ammo? See above.
Fred

 

[alleno]

I have this issue with both reloads and factory ammo.

What would cause headspacing issues with only the 45 ACP cylinder? Does anyone know if the hammer spring for a bisley and blackhawk are the same? I am assuming this issue has something do with the conversion since I had zero issues prior to converting it. Thanks for the help.....

 

[M'BOGO]

Did you use the spring from the hammer strut used in the lock equipped GF?

 

[alleno]

I used all the same springs that came stock with the blackhawk. Do you think this is my issue? The kit didnt come with any springs, only some pins, triger, hammer, and of course the grip frame.

Thanks

 

[Hondo44]

alleno,
The bisley hammer dimesions are slightly different than your original hammer. Try this test:
with the trigger held all the way back and hammer down, take note of how far the firing pin protrudes thru the recoil shield hole.
Now cock the hammer and with something flat, push the firing pin in the hammer slot flush with the frame. Now see if the firing pin sticks out further thru the recoil shield hole.

If it sticks thru farther, the problem is that the overhang on the top front of the hammer is too long and preventing the transfer bar from pushing the firing pin flush with the frame. You can also measure how far the overhang extends off the hammer face and compare that measurment with your original hammer.
File the overhang on the Bisley hammer until it matches the old hammer.

So why do the 45 Colts fire but not the ACP? You can measure the headspace with a Colt cartridge and cylinder in place with a feeler gauge and then the 45 ACP. I bet the 45 ACP has more headspace than the Colts. So the slight difference in firing pin protrusion results in misfires.

 

[alleno]

Hondo44, that makes sense to me. I am at work and will give that a try when I get home. Thanks for the help. I bet the combo of a bit more headspace on the ACP and a bit too long of a overhang on the hammer comes tegether for poor ignition.

Thanks

 

[M'BOGO]

alleno,

Agree with Hondo, all good information.

I've never measured the difference with the springs, between the GF with the lock and without, when they are not under load (another example why your old parts need to be organized). The distance in the GF between the lock, and a GF without, covers a bit more spring travel, maybe 1/4 or 1/8 inch. Also, the cocking of the hammer, at least on the midframes, feels lighter than the Bisley midframes, and the stock full sized Blackhawks. I'm going to suggest picking up a stock, or extra power hammer spring.

While you're in there check for some transfer bar rub. http://www.cylindersmith.com/Transferbar.html

 

[Hondo44]

alleno,

The guns with locks do have a shorter spring with less tension. But even they work perfectly with a Bisley grip frame if there are no hammer fitting issues. But I know you said that you used the correct Bisley spring.

 

[Calthrop]

The only heavier spring is made for the OA. I am not suggesting it be changed. I think the gun must pass the function test outlined by Hondo44. The problem could be that the hammer is rubbing or the strut was bent and the spring is binding. Were you certain that none of the parts had burs or are out of spec before assembly? I like to put a bit of grease on the strut to help it move. Conversions can be tricky on the outset I am confidant your will work out too. Hang in there you are with the right folks.

 

[alleno]

Hondo44, it appears your diagnosis was correct. The firing pin sticks out a substantial bit further while pushing on it than it does with the hammer down. Thanks for the help, its nice to know now whats causing my issues.

Thanks for the help.

 

[Hondo44]

You're welcome. Glad it's an easy fix.