March
S M T W T F S
1 2
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31
Who's Online Now
6 members (Ken Nelson, SKB, skeettx, LRF, Lawrence Kotchek, Karl Graebner), 875 guests, and 4 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums10
Topics38,374
Posts544,009
Members14,391
Most Online1,131
Jan 21st, 2024
Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
Joined: Feb 2016
Posts: 148
Likes: 108
spring Offline OP
Sidelock
OP Offline
Sidelock

Joined: Feb 2016
Posts: 148
Likes: 108
I’m looking at the nitro proof on a 20 gauge I recently bought and am curious about what loads it can—and cannot—handle. With a 20, of course, you have a variety of load options, and I often use 2 3/4” shells with 1 ounce of shot. What’s the best way to know if that’s good to go with this gun?


[Linked Image from hosting.photobucket.com]

Joined: Dec 2001
Posts: 6,980
Likes: 397
SKB Online Content
Sidelock
***
Online Content
Sidelock
***

Joined: Dec 2001
Posts: 6,980
Likes: 397
The gun was re-proofed to 2&3/4" after the time that shot charge was part of the proofs. Originally a 2&1/2" gun I'm sure but an inquiry with H&H would confirm. I would shoot light loads in it most of the time myself, though I'm sure it would be fine with occasional 1 oz loads. CIP 2&3/4" cartridges operate at a fair bit lower pressure than our SAAMI cartridges.
Steve


http://www.bertramandco.com/
Booking African hunts, firearms import services

Here for the meltdowns
2 members like this: spring, Imperdix
Joined: Jan 2006
Posts: 9,398
Likes: 307
Sidelock
***
Offline
Sidelock
***

Joined: Jan 2006
Posts: 9,398
Likes: 307
The 1954 Rules of Proof “Highest Mean Service Pressure” equivalent transducer values as converted from LUP by Burrard’s formula:
3 tons = 8,960 psi = 618 BAR
3 1/4 tons = 9,800 psi = 676 BAR

Major Sir Gerald Burrard, The Modern Shotgun, Volume II, “The Cartridge”, 1955 3rd Revised Edition listed standard service load pressures:
20g 2 1/2” 3/4 oz. 2 1/4 Dr. Eq. - 9,632 psi
20g 2 3/4” 7/8 oz. 2 1/3 Dr. Eq. - 9,968 psi

Joined: Dec 2020
Posts: 886
Likes: 351
Sidelock
Offline
Sidelock

Joined: Dec 2020
Posts: 886
Likes: 351
What does the gun weigh?

The accepted formula is that you need 6 pounds of gun weight for every ounce of shot in the cartridge.

If you match the load to the weight of the gun, it will be kinder to both you and the gun if you use that as a maximum shot weight.

Remember, less can be more and a lighter load may keep you on target if you are not being knocked cross-eyed by the recoil of too heavy a load.

1 member likes this: Imperdix
Joined: Mar 2002
Posts: 7,693
Likes: 450
Sidelock
**
Offline
Sidelock
**

Joined: Mar 2002
Posts: 7,693
Likes: 450
I use 8,000psi as my default British proof 20 bore loads in both 2 1/2” & 2 3/4”. Remington 20 hulls are 2 9/16” so I no longer trim them to 2 1/2” but I do for the rest. It all comes down to being certain that every shell I have is safe to shoot I every gun. I could go up to 9,500psi and still be safe but I do not for two reasons. Old wood cracking is more of a concern than barrel failure. The second concern is shooting 2 3/4” shells in 2 1/2 chambers would result in slightly increased chamber pressures so I err on the safe side.

1 member likes this: spring
Joined: Jan 2009
Posts: 443
Likes: 47
Sidelock
**
Offline
Sidelock
**

Joined: Jan 2009
Posts: 443
Likes: 47
Vic,

All of the European ammunition and most shotgun ammunition manufactured by US companies here are CIP compliant and each box will have the mark of the proof house that tested the load.

Look for the "inspection of ammunition" proof mark on the box - they start on page 7 of this document https://www.anarma.org/media/kunena/attachments/1233/genco_en.pdf . The most common I see on US ammunition boxes are Birmingham, Liege and Munich but I have seen others.

I would have no hesitation shooting US made 20 gauge cartridges with 7/8 ounce of shot at 1200 fps or less in a nitro proofed gun. My only concern shooting 1 ounce CIP compliant loads would be recoil damaging the stock not a pressure issue; recall that recoil is mass of ejecta and velocity related and has nothing to do with pressure.

1 member likes this: spring
Joined: Jan 2006
Posts: 9,398
Likes: 307
Sidelock
***
Offline
Sidelock
***

Joined: Jan 2006
Posts: 9,398
Likes: 307
When a British shell box is labeled:

These cartridges are suitable for use in:
70mm case length: Guns with a chamber length of 2 3/4” or longer, nitro proofed to a service pressure of 3 1/4 tons per square inch (900 kg per square cm)
67 mm case length: Guns with a chamber length of 2 1/2” or longer, nitro proofed to a service pressure of 3 tons per square inch (850 kg per square cm)

The CIP transducer “Maximal Statistical Individual Pressure” of 850 BAR is for a “Maximal Average (Service) Pressure” of 740 BAR = 10,733 PSI
900 BAR is for a “Maximal Average (Service) Pressure” of 780 BAR = 11,313 PSI

Joined: Feb 2016
Posts: 148
Likes: 108
spring Offline OP
Sidelock
OP Offline
Sidelock

Joined: Feb 2016
Posts: 148
Likes: 108
Bob,
We need to chat so you can give me a lesson in this stuff!

Joined: Dec 2001
Posts: 2,961
Likes: 9
Sidelock
**
Offline
Sidelock
**

Joined: Dec 2001
Posts: 2,961
Likes: 9
Try the 3/4 oz loads that the 3/4 - 20 gauge pattern control wad make easy to load. They are pleasent to shoot and efective.
bill

Joined: Jan 2009
Posts: 443
Likes: 47
Sidelock
**
Offline
Sidelock
**

Joined: Jan 2009
Posts: 443
Likes: 47
Originally Posted by spring
Bob,
We need to chat so you can give me a lesson in this stuff!

Vic,

Give me a call 803 530 5380. I'm not available tomorrow but should have time Friday after about 9:30 until about 4:00 and almost all day Saturday. If I don't answer leave a message with a good time to call you.

Bob

Page 1 of 2 1 2

Link Copied to Clipboard

doublegunshop.com home | Welcome | Sponsors & Advertisers | DoubleGun Rack | Doublegun Book Rack

Order or request info | Other Useful Information

Updated every minute of everyday!


Copyright (c) 1993 - 2024 doublegunshop.com. All rights reserved. doublegunshop.com - Bloomfield, NY 14469. USA These materials are provided by doublegunshop.com as a service to its customers and may be used for informational purposes only. doublegunshop.com assumes no responsibility for errors or omissions in these materials. THESE MATERIALS ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANT-ABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. doublegunshop.com further does not warrant the accuracy or completeness of the information, text, graphics, links or other items contained within these materials. doublegunshop.com shall not be liable for any special, indirect, incidental, or consequential damages, including without limitation, lost revenues or lost profits, which may result from the use of these materials. doublegunshop.com may make changes to these materials, or to the products described therein, at any time without notice. doublegunshop.com makes no commitment to update the information contained herein. This is a public un-moderated forum participate at your own risk.

Note: The posting of Copyrighted material on this forum is prohibited without prior written consent of the Copyright holder. For specifics on Copyright Law and restrictions refer to: http://www.copyright.gov/laws/ - doublegunshop.com will not monitor nor will they be held liable for copyright violations presented on the BBS which is an open and un-moderated public forum.

Powered by UBB.threads™ PHP Forum Software 7.7.5
(Release build 20201027)
Responsive Width:

PHP: 7.0.33-0+deb9u11+hw1 Page Time: 0.083s Queries: 39 (0.062s) Memory: 0.8512 MB (Peak: 1.8988 MB) Data Comp: Off Server Time: 2024-03-28 21:48:25 UTC
Valid HTML 5 and Valid CSS