| fiatcrew |
| (.224 member) |
| 11/03/22 03:36 PM |
Which cartridge to use in a shotgun conversion
|
I am going to start building a double rifle on a 1924 Belgian shotgun frame. My son and I
are having a debate on which cartridge to use. He wants a English nitro or BP caliber. I said to
go with an American case such as a 45-70, 45-90 50-70 or 50-110.The cases are more available and cheaper. What are your thoughts? I was going to post on the building site but there have no new posts in a long time.
| lancaster |
| (.470 member) |
| 11/03/22 04:49 PM |
|
Re: Which cartridge to use in a shotgun conversion
|
I would not spend my lifetime for building something ordinary like a 45/70
take 50/110
NitroX
|
| (.700 member) |
| 11/03/22 09:55 PM |
|
|
Re: Which cartridge to use in a shotgun conversion
|
A shotgun conversion merely for cost reasons is probably not a good plan. Unless a person already possesses good gunsmithing skills and experience and knowledge of double firearms, probably not the best route to end up owning a worthwhile double rifle.
Edited to add: an observation in general, not knowing a person's specific circumstances.
A good way to enter the double rifle world is to look for a good second hand modern(ish) dr.
| degoins |
| (.333 member) |
| 12/03/22 12:12 AM |
|
Re: Which cartridge to use in a shotgun conversion
|
'A shotgun conversion merely for cost reasons is probably not a good plan. Unless a person already possesses good gunsmithing skills and experience and knowledge of double firearms, probably not the best route to end up owning a worthwhile double rifle."
Unless you just want to mess with a project, I'd scrape my pennies until I could buy a proper double, otherwise you'll never truly be satisfied. Of course that's Just my .02 for what it's worth.
| crshelton |
| (.333 member) |
| 12/03/22 12:16 AM |
|
Re: Which cartridge to use in a shotgun conversion
|
+1 on NitroX opinion of having necessary skills and equipment.
another +1 on lack of activity by gun builders sub forum since the passing of Birdhunter50.
|
NitroX
|
| (.700 member) |
| 12/03/22 12:36 AM |
|
|
|
Re: Which cartridge to use in a shotgun conversion
|
Quote:
I am going to start building a double rifle on a 1924 Belgian shotgun frame.
I think more information might be needed on the donor shotgun.
| 3DogMike |
| (.400 member) |
| 12/03/22 02:25 AM |
|
|
Re: Which cartridge to use in a shotgun conversion
|
Shotgun conversion: I would avoid big NE calibers.
After the fact resale value of a "home built" will be nowhere near what went into it, AND the liability concerns if it comes apart in the hands of non family would be astronomical.
As above, better to source a pre owned by a real maker………they are out there in .45-70, .500 BP Express, etc.
- Mike
| rigbymauser |
| (.400 member) |
| 12/03/22 03:01 AM |
|
|
Re: Which cartridge to use in a shotgun conversion
|
Ditto above.
Find a decent hammerless or hammer .500BPE and go shoot(It have to be re-regulated).
Many things can be done to prove "I-can do it". When this written...by all means all gunmakers started somewhere in their carrier to gain experience until mastering the trade.
| DarylS |
| (.700 member) |
| 12/03/22 05:23 AM |
|
|
Re: Which cartridge to use in a shotgun conversion
|
.450 #2 Musket.
| fiatcrew |
| (.224 member) |
| 12/03/22 07:09 AM |
|
Re: Which cartridge to use in a shotgun conversion
|
This is one of the things on my bucket list since I was young. Other things include gutting and rebuilding a house, restoring a car and building the engine. I have a group of friends who are smiths and hobbyists. I started out building muzzle loaders, then cartridge rifles, now I think it may be time. I may never fire it but I will not take bets on it. The shotgun is a 1924 Belgian based on its proofs there is a lion over a large PN which is black powder proof I am not sure on Nitro since the proof chart is a bit ambiguous. There is also a large oval with a crown over it and E LG * German BP proof, and a French looking EL which is the provisional proof 1924 on.
I have plenty of 50-70 this would make a light recoiling rifle with low rear thrust. It may take aq while but I hope I have time.
| 3DogMike |
| (.400 member) |
| 12/03/22 12:54 PM |
|
|
|
Re: Which cartridge to use in a shotgun conversion
|
Quote:
This is one of the things on my bucket list since I was young. Other things include gutting and rebuilding a house, restoring a car and building the engine. I have a group of friends who are smiths and hobbyists. I started out building muzzle loaders, then cartridge rifles, now I think it may be time. I may never fire it but I will not take bets on it. The shotgun is a 1924 Belgian based on its proofs there is a lion over a large PN which is black powder proof I am not sure on Nitro since the proof chart is a bit ambiguous. There is also a large oval with a crown over it and E LG * German BP proof, and a French looking EL which is the provisional proof 1924 on.
I have plenty of 50-70 this would make a light recoiling rifle with low rear thrust. It may take aq while but I hope I have time.
Bucket List item? Well then…...
Good luck on the project, get video of it actually being fired!
- Mike
| Marrakai |
| (.416 member) |
| 12/03/22 12:54 PM |
|
|
Re: Which cartridge to use in a shotgun conversion
|
fiatcrew:
These conversion projects are always interesting, provided the sums are done to confirm safe pressure, and the builder goes in with both eyes wide open.
Please keep us updated (with pictures!) as the project develops.
O&BTW:
Best way to fix a low post rate on the Gun-building forum is to move this thread over there.
Quote:
I was going to post on the building site but there have no new posts in a long time.
Thought I just posted a new thread there a couple of days ago...
Post before that ended on the 6th, one before that was just last month...
A new post will illuminate the light-bulb and members will go there to check it out!
|
NitroX
|
| (.700 member) |
| 12/03/22 04:13 PM |
|
|
|
Re: Which cartridge to use in a shotgun conversion
|
Shifting the thread. Good luck with the build.
I looked to have a .577 LNE build on a Greener Empire E17 shotgun in 12-bore. Rolf Babnick built Marrakai's short barrelled "Fat Lady", which is now Mick's/264's. Of course then I needed a second shotgun so I could have a DR AND 12-bore barrel set.
Ralf told me he doesn't build them anymore, too much liability, and he claimed similar cost.
For a gunsmith I understand the first. Someone blows off half their face ... Perhaps overloads, plug in barrel, or make?
Cost the same? Doubt that. A modern .577 dr is usually quite expensive, more than say a .470.
Myself I wouldnt dream of doing it myself lacking the skills.
So I have a nice old Greener Empire in 12-bore for fox and duck shoots.
Actually I think a .577 Light Nitro Express would be nicer with external hammers.
So what cartridge chambering?
My choice with zero info on the donor shotgun, is the .577 2 3/4" Light NE.
|
NitroX
|
| (.700 member) |
| 12/03/22 04:17 PM |
|
|
|
Re: Which cartridge to use in a shotgun conversion
|
http://forums.nitroexpress.com/showflat.php?Cat=0&Number=231050&an=&page=0&vc=1
W.W.Greener Double Express:- .577 x 2 3/4 Light Nitro
| fiatcrew |
| (.224 member) |
| 13/03/22 02:12 PM |
|
Re: Which cartridge to use in a shotgun conversion
|
AHHH! .577x2 3/4 would be nice and fit the parameters but what about brass? 50-70 or 50-110 would be easier, and cheaper.
| Marrakai |
| (.416 member) |
| 14/03/22 09:36 AM |
|
|
|
Re: Which cartridge to use in a shotgun conversion
|
fiatcrew:
I know its well-covered in the book recommended above, but please do the math on back-thrust to satisfy yourself that the conversion is safe.
ie 3 1/2 tons for a shotshell, multiplied by the cross-sectional area (sq in) of the 12-bore case-head, compared with 10 tons or thereabouts for a "light nitro" multiplied by the cross-sectional area of the proposed rifle case-head in sq in.
If considering a full nitro conversion, the new pressure may be 18 or 19 tons (or more!).
Not meaning to be alarmist, but I did feel compelled to add that caution.
These conversions can be marvelous things, but your face is only inches away at the point of discharge, so please err on the side of caution!
| DarylS |
| (.700 member) |
| 14/03/22 10:40 AM |
|
|
|
Re: Which cartridge to use in a shotgun conversion
|
Quote:
This is one of the things on my bucket list since I was young. Other things include gutting and rebuilding a house, restoring a car and building the engine. I have a group of friends who are smiths and hobbyists. I started out building muzzle loaders, then cartridge rifles, now I think it may be time. I may never fire it but I will not take bets on it. The shotgun is a 1924 Belgian based on its proofs there is a lion over a large PN which is black powder proof I am not sure on Nitro since the proof chart is a bit ambiguous. There is also a large oval with a crown over it and E LG * German BP proof, and a French looking EL which is the provisional proof 1924 on.
I have plenty of 50-70 this would make a light recoiling rifle with low rear thrust. It may take aq while but I hope I have time.
The old Accurate Arms (red) loading manual has data for .50/70 with smokeless powders. I recall they used AA2015?, seems to me and got REALLY impressive velocities at quite low pressure.
I don't have that manual. My now gone buddy did & I never wrote it down.
| 3DogMike |
| (.400 member) |
| 14/03/22 11:19 AM |
|
|
|
Re: Which cartridge to use in a shotgun conversion
|
Quote:
fiatcrew:
I know its well-covered in the book recommended above, but please do the math on back-thrust to satisfy yourself that the conversion is safe.
ie 3 1/2 tons for a shotshell, multiplied by the cross-sectional area (sq in) of the 12-bore case-head, compared with 10 tons or thereabouts for a "light nitro" multiplied by the cross-sectional area of the proposed rifle case-head in sq in.
If considering a full nitro conversion, the new pressure may be 18 or 19 tons (or more!).
Not meaning to be alarmist, but I did feel compelled to add that caution.
These conversions can be marvelous things, but your face is only inches away at the point of discharge, so please err on the side of caution!
+1
| fiatcrew |
| (.224 member) |
| 12/06/22 11:12 AM |
|
Re: Which cartridge to use in a shotgun conversion
|
Marrakai Thank you for the information, I had only considered breech pressure and not thrust.
I did the math and found these results.
12 gauge .73 rim diameter 11,500 psi max pressure 4810 bolt thrust
50-70 .6630 22,500 2472.57
45-70 .6015 28,000 2532.61
If these numbers are correct a conversion to either 45-70 of 50-70 seems prudent.
is there anything that I am missing, or figured incorrectly?
| crshelton |
| (.333 member) |
| 12/06/22 12:08 PM |
|
Re: Which cartridge to use in a shotgun conversion
|
Fiatscrew,
Thanks for putting in the max 12 ga pressure as it reminded me that not all shotguns were proofed at the same pressures. Keeping it short and simple, my Beretta 12 ga factory proof pressure was 17,000 + psi.
This was higher than some other 12 ga proof pressures.
Every little bit counts.
I concur with the comments which recommend playing it safe.
Also, a nice benefit of the .45-90 is that it can be had just by extending the chambers of a 45-70.
Also, you can still shoot 45-70 factory ammo for little game such as deer and Pronghorn.
Then use the .45-90 for bigger b
game as needed. Or just load in the 45-90 case to keep pressure down.
That was my route with My Beretta 45-90 and it still shoots .45-70 fine.
Another recommendation to keep pressures down is to use VV N133 which usually generates 12,000 PSI less pressure than other powders at the same velocity !!! I bought Pressure Trace II just to check peak pressures in some of my rifles.
+ slow and easy will provide the best solution for your rifle.
| DarylS |
| (.700 member) |
| 12/06/22 03:37 PM |
|
|
|
Re: Which cartridge to use in a shotgun conversion
|
According to AA manual, pressures for full BP load in a .45/70 with 500gr. bullets was 26,000psi, iirc.
The .45/90 w/300gr. (2.4" case) was 27,000psi.
I'm stretching here, but the .50/70 with 450gr. was under 20,000PSI. Again, IIRC.