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Birdshead 45 acp Firing Pin question.

This is a discussion on Birdshead 45 acp Firing Pin question. within the Ruger Single Action forums, part of the Pistol & Revolver Forum category; This new Ruger SA has less striking distance or protrusion extending from inside face of frame than all my other Ruger centerfire SAs. I made ...


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Old October 31st, 2019, 03:45 PM   #1
 
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Birdshead 45 acp Firing Pin question.

This new Ruger SA has less striking distance or protrusion extending from inside face of frame than all my other Ruger centerfire SAs. I made sure gun & parts were scrubbed.

I have loaded 'fired' empty cases in cylinder and then lowered FP on each with hammer, all empty cases pushed forward into chamber as expected.

However, the transfer bar does NOT push firing pin flush with face of Firing Pin hole as it does with my other centerfires.

The FP seems solid but have had light hammer strike missfire with 'only one' product line of ammo.

Waiting to decide if want to send to Ruger service department but GLAD TO HEAR any thoughts? ....especially since this cartridge does not have a rim like all my other 45s.

Meanwhile will be testing several brands of ammo.



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Old October 31st, 2019, 04:45 PM   #2
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SA45, Because 45 ACPs headspace on the case mouth, the length of the brass is very important. Why? There should be about .010" headspace (distance between the case head and recoil shield) when a full length case is chambered (.898"), Most cases are shorter than SAAMI specs so that adds to headspace. As an example, if a case is .010" short (quite common) headspace will be .020". Considering firing pin protrusion is only about .035", that leaves a primer dent just .015" deep, which may not be enough to detonate some primers.

Firing pin protrusion can fool you because Ruger uses inertia type firing pins. That means the firing pin actually travels farther than you would expect when struck by the hammer hitting the transfer bar. To measure, remove the cylinder then cock the hammer. Use a tool to push directly on the firing pin …. not the transfer bar. The firing pin should protrude from the recoil shield by about .035". I use a gap gauge blades to determine when the firing pin is flush with the blades.
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Old November 1st, 2019, 07:50 AM   #3
 
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Thanks IOWEGAN! Very interesting about the 'inertia' designed FP and remember reading something about this design in a fascinating 'SA Dry Fire' thread too.

BTW, I had already pushed FP further in (not using transfer bar) just like you suggested and it did protrude much further in Birdshead but will measure.

Also, tried putting cyl in a different New Vaquero (45colt) using same empties, the FP appeared to strike a deeper dent into all previously fired primers.

Last edited by SA45; November 1st, 2019 at 08:01 AM.
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Old November 1st, 2019, 09:18 AM   #4
 
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Try this:

Make sure you gun is unloaded. Check it again. Then, take a No.2 wooden pencil with the eraser on the end, the eraser should be new and unused. Hold the gun muzzle upward and cock the hammer. Drop the pencil, eraser down, down the barrel so that the eraser sits on the firing pin hole.

Now, pull the trigger. The pencil should jump clear of the muzzle. If it does not, you are not getting enough firing pin impact.

Your firing pin may be broken, or too short if this test does not jump the pencil out.

Bob Wright

Last edited by Bob Wright; November 2nd, 2019 at 12:21 PM.
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Old November 1st, 2019, 10:38 AM   #5
 
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Measured FP protrusion at .029" using Transfer Bar.

When not using Transfer Bar, it is very near .050"

Last edited by SA45; November 1st, 2019 at 11:00 AM.
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Old November 1st, 2019, 12:48 PM   #6
 
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Quote:
Originally Posted by Bob Wright View Post
Try this:

Make sure you gun is unloaded. Check it again. Then, take a No.2 wooden pencil with the eraser on the end, the eraser should be new and unused. Hole the gun muzzle upward and cock the hammer. Drop the pencil, eraser down, down the barrel so that the eraser sits on the firing pin hold.

Now, pull the trigger. The pencil should jump clear of the muzzle. If it does not, you are not getting enough firing pin impact.

Your firing pin may be broken, or too short if this test does not jump the pencil out.

Bob Wright
A great sounding experiment, thanks Bob. Will give it a try as soon as I find an unused one. Will compare it to other Ruger SAs as well. I love experiments.
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Old November 2nd, 2019, 05:28 PM   #7
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Bob, I've used the pencil trick to test 1911s and it works great but my Blackhawks and SBHs only push the pencil a couple inches. Just for grins, I pulled out a 4 5/8" 357 Mag BH New Model that has factory springs. After several tries, the best I could get was about 2" of travel …. no where near enough to push the pencil out of the muzzle, yet the firing pin puts nice deep dents in the primers.
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Old November 3rd, 2019, 11:55 AM   #8
 
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""IOWEGAN SAID: After several tries, the best I could get was about 2" of travel""

Will try this, want to compare distance traveled using other guns for sure. So thanks for FEEDBACK all !!

But HUNTING started back up again so keeping me tied up with that for now. 😊

My gun is probably fine but it may like certain brands & product lines of ammo better than others. Accustomed to this caveat already in 45 acp caliber - in 1911s. If issue goes away with other ammo i might be ok with this.

Am hesitant to send it in for service because in this case I loose control on whats done to gun - where already like alot of things 'as is'. Plus cylinder seems a perfect tho very slight snug fit in my other stainless NV 45 colt too.

On another note, Colt cyl from other gun slightly too snug for this 45 acp Birdshead BUT may be perfect after its had a breaking in period, without mods needed perhaps? Snugness doesnt worry me because I keep'em clean and these are not defense guns, yet.

Last edited by SA45; November 3rd, 2019 at 05:07 PM.
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Old November 12th, 2019, 10:34 PM   #9
 
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Image below where primers at bottom were struck only once in Birdshead 45acp gun. Had misfire w/ light FP strike with this batch of ammo.

Primers at top were struck again using a different gun to perhaps visually determine if a deeper dent. Am not sure I can tell any difference now.

Perhaps there is someone on the forum who may have better depth perception than I do. If not, no worries .... will be testing other ammo anyway to see if any more misfires.


20191112_231224_1573626482602.jpg
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Old November 13th, 2019, 03:51 AM   #10
 
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I'm having the same problem with a Flattop that was made last year.
It has great firing pin protrusion into the frame if you push directly on the firing pin, but when the transfer bar is doing the pushing, not so much.
I've tried installing different transfer bars, trigger and hammers.

Iowegan suggested removing some off the top flat of the hammer so there's more impact onto the transfer bar, and also making sure the hammer is going fully forward and not being held up because of rough edges that prevent it from going all the way forward.

Nothing has seemed to help, and I too am reluctant to send it back, as I like it the way it is (except for the light strike issue) and don't want it replaced with another, just fixed.
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Old November 13th, 2019, 06:53 AM   #11
 
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Thanks for feedback. From where am at now, it appears the inside of transfer bar and/or the frame channel that bar rides in is slightly interfering perhaps, could be a burr where I cannot see inside bar area or even a machining tolerance there.

Of course, consistent case length dims would be extremely helpful too, for definite proper headspace. The attached image shows at least a decent primer strikes but have seen them deeper elsewhere I am pretty sure.

Will keep an eye on hammer flat too, as far as felt or visible machine burrs go, there is a very slight burr on hammer face yet its seems to be on side edge more so(perhaps not interfering), will work on all of it and consider heavier spring too. Also, once had a burr on SRH 44 mag hammer face as well that cleaned up.

BTW, the previous pencil experiment showed less travel than all my other SAs.

Last edited by SA45; November 13th, 2019 at 06:55 AM.
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Old November 13th, 2019, 08:43 AM   #12
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SA45, The primer dents in all the cases in your post #9 look plenty deep. Full sized fames are shipped with a 23 lb hammer spring and mid-frame SAs are shipped with a lighter spring …. 19 lb I think?? That would explain why the pencil trick doesn't move the pencil as far and would also explain why you get light primer hits.

Last edited by Iowegan; November 13th, 2019 at 09:10 AM.
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Old November 13th, 2019, 09:43 PM   #13
 
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Thanks Again. .... it is a great little gun, and dont mind working with it or any of revolvers especially.
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