Yes.Originally Posted by TripleF
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Yes.
easy to make and fun to shoot also,i made some with no riffling and some with.better the one with riffling
I want two 45/70's inserts to make a poor mans double gun.
I have concerns over the issue of bolt thrust in the larger cartridges like 54R. We'll see.
I think a lot of the larger and/or more powerful calibers would produce too much pressure on the action. a .73 bore shotgun at has a .42in^2 surface area, at 11500PSI that produces 4800 pounds of force on the action. That's the SAAMI limit.
a .44 magnum has 0,144in^2 of surface area, at 36000PSI that produces 5200 pounds of force. Already over spec for the shotgun. These are available - a bit odd since they could in theory produce excess pressures.
.45-70 has 0,165in^2 of surface area, at trapdoor levels of 28000PSI you'd get 4600 pounds which is OK, at lever action levels we'd have 6590lbs. Well over the limit.
30-30 has a case diameter of about .40, at 42000PSI we have over 5200lbs of force on the breech.
.308 can produce over 9000 pounds of force on the breech face.
I feel that for safety's sake thing should be limited to the lower pressure pistol rounds. Even 7.62x39 and .223 would exceed SAAMI rated breech forces in a shotgun barrel
tagged...very interesting
I could be missing something, however, is the physical insert/adapter not taking most of the pressures you outlined, instead of the shotgun's chamber, where by eliminating the pressure concerns? In other words, the main pressure vessel (the actual barrel) is the adapter while the shotgun barrel is more of an exhaust port.I think a lot of the larger and/or more powerful calibers would produce too much pressure on the action. a .73 bore shotgun at has a .42in^2 surface area, at 11500PSI that produces 4800 pounds of force on the action. That's the SAAMI limit.
a .44 magnum has 0,144in^2 of surface area, at 36000PSI that produces 5200 pounds of force. Already over spec for the shotgun. These are available - a bit odd since they could in theory produce excess pressures.
.45-70 has 0,165in^2 of surface area, at trapdoor levels of 28000PSI you'd get 4600 pounds which is OK, at lever action levels we'd have 6590lbs. Well over the limit.
30-30 has a case diameter of about .40, at 42000PSI we have over 5200lbs of force on the breech.
.308 can produce over 9000 pounds of force on the breech face.
I feel that for safety's sake thing should be limited to the lower pressure pistol rounds. Even 7.62x39 and .223 would exceed SAAMI rated breech forces in a shotgun barrel
That is not saying that I am completely eliminating the shogun barrel out of the pressure equation, but it plays a lesser role.
Its a bolt thrust problem. The rearward force against the bolt face is simply not that high for a shotgun. Can't say the same for rifles.
"We don't take souls, we leave that to wives and girlfriends, but we can do a layaway" - Grumpy Wolverine.
If you need religion to have good morals then you don't actually have good morals.
Very good info. As always, the devil is in the details - thank goodness someone thinks of these things!
The lower pressure rounds then. Maybe 7.62x25 because it is small and cheap and 45/70 ... well because it's awesome. Perhaps 45acp and 9mm would work as well.
That's the reason H&R uses two "different" (different heat treatment) receivers in their handi-rifles and shotguns. They will only install shotgun, muzzleloader, .357 and .44 barrels on the weaker SB1 receiver. The SB2 receives a different heat treatment and can take .500S&W, .308, .444, .45-70, 30-30 barrels etc. That gives us a sense of which calibers are suited to shotgun receivers and which ones aren't.
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