Modified firing pin for 6 Oclock Ignition - RimfireCentral.com Forums

Go Back   RimfireCentral.com Forums > >

Notices

Join Team RFC to remove these ads.
Reply
 
Thread Tools Display Modes
  #1  
Old 10-27-2019, 10:46 PM
Bigbore
NRA Member - Click Here To Join!

Join Date: 
May 2002
Location: 
Miami, Fl
Posts: 
854
TPC Rating: 
0% (0)
Modified firing pin for 6 Oclock Ignition



Log in to see fewer ads
Think it would work? The bolt could probably have the radius cut with a carbide slotting wheel. A prototype firing pin could be made from tool steel similar to a knife blank.

Just a concept, not a final design.





Reply With Quote
  #2  
Old 10-27-2019, 11:13 PM
Bigbore
NRA Member - Click Here To Join!

Join Date: 
May 2002
Location: 
Miami, Fl
Posts: 
854
TPC Rating: 
0% (0)
This might be a little more elegant and easier to cut into the bolt:

Reply With Quote
  #3  
Old 10-28-2019, 12:24 AM
Nolan

Join Date: 
Mar 2011
Location: 
Milpitas, Ca.
Posts: 
1,171
TPC Rating: 
100% (1)
If you're going to that much trouble, I would go to a double impact point, 6 & 12 o'clock. Add or leave (depending on your point of view) a firing pin protrusion at the top (12 o'clock). The Freedom Arms pistols have a firing pin that hits at 12 & 6 o'clock. I think the Ruger action has enough hammer impact for it.

Nolan
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old 10-28-2019, 12:43 AM
ms6852's Avatar
ms6852
US Army Veteran NRA Member - Click Here To Join!

Join Date: 
Oct 2008
Location: 
Converse Tx
Posts: 
680
TPC Rating: 
0% (0)
Quote:
Originally Posted by Nolan View Post
If you're going to that much trouble, I would go to a double impact point, 6 & 12 o'clock. Add or leave (depending on your point of view) a firing pin protrusion at the top (12 o'clock). The Freedom Arms pistols have a firing pin that hits at 12 & 6 o'clock. I think the Ruger action has enough hammer impact for it.

Nolan
Exactly what I was thinking.
Reply With Quote
  #5  
Old 10-28-2019, 06:22 AM
FlysAlot's Avatar
FlysAlot

Moderator
Join Date: 
Jul 2003
Location: 
Made back to FL 430
Posts: 
11,917
TPC Rating: 
100% (3)
There's no way to ask this without appearing 'snarky' however I have 2 questions:
1. For 56 years and 6-7 Million examples (plus clones) the 10/22 has worked just fine with 12 o'clock ignition.
2. What's the point of 6 o'clock ignition?
__________________
http://www.washingtonpost.com/wp-dyn...011903278.html

Pro Patria

Cives Arma Ferant

Cuiusque Devotio est Vis Regimenti
Reply With Quote
  #6  
Old 10-28-2019, 09:09 AM
GH41

Join Date: 
Feb 2015
Location: 
SEUS
Posts: 
2,100
TPC Rating: 
100% (1)
Two questions.. Wouldn't losing case support over the slot be an issue? At what point would increasing the weight of the firing pin require increasing FP and hammer spring rates?
Reply With Quote
  #7  
Old 10-28-2019, 09:12 AM
Bigbore
NRA Member - Click Here To Join!

Join Date: 
May 2002
Location: 
Miami, Fl
Posts: 
854
TPC Rating: 
0% (0)
Quote:
Originally Posted by FlysAlot View Post
There's no way to ask this without appearing 'snarky' however I have 2 questions:
1. For 56 years and 6-7 Million examples (plus clones) the 10/22 has worked just fine with 12 o'clock ignition.
2. What's the point of 6 o'clock ignition?
Snarky is fine, I was hoping someone would ask.

Of all the ignition schemes I've seen, 6 o'clock is the one that intuitively makes sense to me, I think I read about it in Bill Calfee's book. The theory is that there may be empty space in the cartridge at 12 o'clock, 6 o'clock insures the ignition occurs at a location guaranteed to ignite the maximum amount of powder.

I don't know how much of the case volume is empty in the different brands and styles of rimfire cartridges but 6 o'clock ignition makes it unnecessary to even consider.

Good to see you posting, you've been scarce lately.

Last edited by Bigbore; 10-28-2019 at 09:35 AM.
Reply With Quote
  #8  
Old 10-28-2019, 09:17 AM
Bigbore
NRA Member - Click Here To Join!

Join Date: 
May 2002
Location: 
Miami, Fl
Posts: 
854
TPC Rating: 
0% (0)
Quote:
Originally Posted by GH41 View Post
Two questions.. Wouldn't losing case support over the slot be an issue? At what point would increasing the weight of the firing pin require increasing FP and hammer spring rates?
I actually though about the unsupported case and I'm not sure its an issue. Were an engineer to declare it one, the protrusion that strikes the case could be sized so that the face of the pin supports the case until bolt movement starts. The case would show clear signs of pressure and there should be no risk to the shooter.

Last edited by Bigbore; 10-28-2019 at 09:24 AM.
Reply With Quote
  #9  
Old 10-28-2019, 09:20 AM
Bigbore
NRA Member - Click Here To Join!

Join Date: 
May 2002
Location: 
Miami, Fl
Posts: 
854
TPC Rating: 
0% (0)
Quote:
Originally Posted by Nolan View Post
If you're going to that much trouble, I would go to a double impact point, 6 & 12 o'clock. Add or leave (depending on your point of view) a firing pin protrusion at the top (12 o'clock). The Freedom Arms pistols have a firing pin that hits at 12 & 6 o'clock. I think the Ruger action has enough hammer impact for it.

Nolan
Quote:
Originally Posted by ms6852 View Post
Exactly what I was thinking.
It should be easy enough and I have read about a few double strike designs. I think it would be interesting to try 6 o'clock first and see if a quantifiable difference can be observed. My hope is two ignition sources wouldn't be needed if you light the bottom of the powder pile.
Reply With Quote
  #10  
Old 10-28-2019, 09:36 AM
FlysAlot's Avatar
FlysAlot

Moderator
Join Date: 
Jul 2003
Location: 
Made back to FL 430
Posts: 
11,917
TPC Rating: 
100% (3)
Quote:
Originally Posted by Bigbore View Post
Snarky is fine, I was hoping someone would ask.
Good to see you posting, you've been scarce lately.
Work, life, a little burned out, thanks for asking... I really didn't mean to be snarky just couldn't think of a way to ask w/out putting in the caveat.
__________________
http://www.washingtonpost.com/wp-dyn...011903278.html

Pro Patria

Cives Arma Ferant

Cuiusque Devotio est Vis Regimenti
Reply With Quote
  #11  
Old 10-28-2019, 10:06 AM
22/45 Fan
NRA Member - Click Here To Join!

Join Date: 
Sep 2007
Location: 
SW PA
Posts: 
1,343
TPC Rating: 
0% (0)
Quote:
Originally Posted by GH41 View Post
At what point would increasing the weight of the firing pin require increasing FP and hammer spring rates?
A way to avoid this issue is to take the TandemKross approach and make the firing pin out of Titanium. It will be lighter than the factory steel firing pin.
Reply With Quote
  #12  
Old 10-28-2019, 10:20 AM
GH41

Join Date: 
Feb 2015
Location: 
SEUS
Posts: 
2,100
TPC Rating: 
100% (1)
Quote:
Originally Posted by Bigbore View Post
Snarky is fine, I was hoping someone would ask.

Of all the ignition schemes I've seen, 6 o'clock is the one that intuitively makes sense to me, I think I read about it in Bill Calfee's book. The theory is that there may be empty space in the cartridge at 12 o'clock, 6 o'clock insures the ignition occurs at a location guaranteed to ignite the maximum amount of powder.

I don't know how much of the case volume is empty in the different brands and styles of rimfire cartridges but 6 o'clock ignition makes it unnecessary to even consider.

Good to see you posting, you've been scarce lately.
I understand the 6-12 o'clock thoughts but the priming compound in a 22LR covers the full circumference of the case bottom. Does it really matter where you impact it? Have you ever shot a snake with a 10/22? Did the gun go off? I don't doubt ignition would occur quicker with the FP submerged in powder but I think you would have a heck of a time measuring the difference. Before I put a lot of effort into a prototype bolt would conduct a simple experiment.. Alternate firing upside down and rightside up across a good chronograph.
Reply With Quote
  #13  
Old 10-28-2019, 10:23 AM
Bigbore
NRA Member - Click Here To Join!

Join Date: 
May 2002
Location: 
Miami, Fl
Posts: 
854
TPC Rating: 
0% (0)
Quote:
Originally Posted by 22/45 Fan View Post
A way to avoid this issue is to take the TandemKross approach and make the firing pin out of Titanium. It will be lighter than the factory steel firing pin.
I will speculate that the amount of additional material is inconsequential.

My goals were to make it simple and backward compatible with the current design. It is not a radical departure from the current design like a cylindrical internal firing pin, which I personally consider a superior design but I'm dancing with the girl I brung.

Last edited by Bigbore; 10-28-2019 at 10:26 AM.
Reply With Quote
  #14  
Old 10-28-2019, 10:34 AM
Bigbore
NRA Member - Click Here To Join!

Join Date: 
May 2002
Location: 
Miami, Fl
Posts: 
854
TPC Rating: 
0% (0)
Quote:
Originally Posted by GH41 View Post
I understand the 6-12 o'clock thoughts but the priming compound in a 22LR covers the full circumference of the case bottom. Does it really matter where you impact it? Have you ever shot a snake with a 10/22? Did the gun go off? I don't doubt ignition would occur quicker with the FP submerged in powder but I think you would have a heck of a time measuring the difference. Before I put a lot of effort into a prototype bolt would conduct a simple experiment.. Alternate firing upside down and rightside up across a good chronograph.
I'm in complete agreement with you, especially about the difference it will make. It would be easy to test with a 10/22 by shooting it upside down over a chronograph.

The main points are: We're just having fun with it and I'm only hoping to sell half as many as the pinned firing pin market--head down!

I am serious though, I'm not trolling. IIRC, Calfee thought it deserved serious consideration.

Last edited by Bigbore; 10-28-2019 at 10:40 AM.
Reply With Quote
  #15  
Old 10-28-2019, 10:43 AM
MKnarr's Avatar
MKnarr
US Air Force Veteran NRA Member - Click Here To Join!

Join Date: 
Mar 2005
Location: 
Durango, CO
Posts: 
5,933
TPC Rating: 
100% (1)
Although it's being done in some benchrest rifles, the jury is still out. I think a lot of Bill Calfee but he does have some theories that are wrong. What you ar talking about is a 10/22, not a $3000 benchrest rifle. There are a lot better ways to improve the precision of a 10/22 that are known to work than a 6 o';clock firing pin.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off




All times are GMT -5. The time now is 10:41 PM.

Privacy Policy

DMCA Notice

Powered by vBulletin
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Search Engine Optimisation provided by DragonByte SEO (Lite) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright 2000-2018 RimfireCentral.com
x