Ammo for Open-Top Revolver?

[scotjute]

Have an 1872 Open-Top revolver in .38 spl on order. What ammo is ok to shoot it in? Was thinking about using Buffalo Bore wadcutters at 850 fps but still meeting .38 spl. pressures. Is anything ok as long as it rated .38 spl? Have seen stories about the guns being stretched by ammo pressure. Thanks.

 

[ontarget]

I am sure any gun of modern manufacture would be rated for any standard modern load. Plus P? I'd check the manual when she arrives.

 

[Pete D.]

Your gun is a modern repro. If it is an accurate copy, it is helpful to remember that that design was meant to contain black powder loads. In 1872, the .38 Special did not exist. It was introduced by S&W as a black powder cartridge in 1898 and then as a smokeless load in 1899.
Despite modern materials, the open top design is inherently weak as compared to modern top strap guns.
Pete.

 

[45 Dragoon]

Scotjute, your revolver will be fine with standard off the shelf ammo. European firearms are proofed for higher pressure loads than USA made firearm standards.
If you get the short arbor corrected, it will give you lifetimes of service. Fact is, the open top platform is extremely robust and will be fine. I shoot a Pietta made 1860 Army (cap and ball, open top design) with a Kirst conversion in 45 Colt. I shoot the same "warm" loads in it that my Dragoons (cap and ball, open top design) get.

Mike

 

[CraigC]

It's fine for any standard pressure .38Spl loading. I'm not going explicitly recommend it but probably even +P. Only 3000psi separates the two and in the US .38Specials are proofed at the same pressure as .38 +P. As Mike posted above, the Europeans proof even higher.

 

[Michael Tinker Pearce]

When people talk about an open-top design 'stretching' what is usually happening is that the arbor is pulling out. Your open top is, as folks have said, a modern firearm that has met European proof. Off-the-shelf standard-pressure ammo will be fine. I assume this is a recreational shooter, so no need for delving into +P loads.

 

[StrawHat]

Your “open top” is as strong as it needs to be. The top strap was added at the request of the Military. European firearms are proofed to a standard. US firearms are not proofed, unless by the factory but there is no standard.

If there are proof marks on your revolver, it will handle standard pressure loads with no problem.

Kevin

 

[mavracer]

Besides it's not exactly pressure that stretches the frame it's thrust. That BB standard pressure load 148@850 is probably gonna stress the frame more than most domestic (not boutique) +p 125gr loads

 

[45 Dragoon]

Besides it's not exactly pressure that stretches the frame it's thrust.

Yes, because of the short arbor allowing the cylinder to act as a slide hammer which ultimately will wreck the weapon! And, it's not "frame" stretching, it's "arbor end" stretching (if anything is actually stretching) or "imprinting" (usually brass frames) or pulling the threads (as MTP posted). Most of what folks will experience is wedge deformation. It gets battered because of the short arbor.

Mike

 

[scotjute]

Thanks everyone. Will definitely stick to .38 spl loads.

 

[35 Whelen]

Recently someone somewhere else asserted that a certain Italian-made .38 Special SA was not OK with +P loads, contrary to what the revolvers manual indicated, so I did a little research.

C.I.P. (Europe's version of SAAMI) does not have pressure specifications for "standard" and +P .38 Special ammunition. They have a specification for a single .38 Special load whose maximum average pressure is set at 1500 bar or 21,775 psi, which is higher than even American .38 Special +P ammunition. Further, ammunition for proofing European-produced .38 Special revolvers, such as your Open Top, has a mean proof pressure set at 1900 bar, which is a bit over 28,000 psi.

So I think it's safe to say your revolver is plenty safe with any commercial ammunition loaded on this side of the pond.

List of TDCC - Tab IV - Pistol and revolver cartridges

Cartridge Pressure Standards

35W

 

[Pete D.]

For myself, at least....there is a lot there that I did not know. Now I do. Thanks for the info.
Pete

 

[Driftwood Johnson]

Howdy

Yes, Uberti proofs all their firearms in government proof houses to standards that exceed our SAAMI standards. So in theory, anything they make should be fine with standard ammunition sold off the shelf here.

HOWEVER...................

This is a Merwin Hulburt Pocket Army that left the factory some time in the 1880s. As you can see it is an open top design. It is chambered for the 44-40 cartridge. If you look very closely you can see the barrel/cylinder gap is a bit on the wide side.






I don't have it in hand right now, but I seem to remember the gap is on the order of about .012 or so.






I am quite certain this revolver did not leave the factory with a gap that wide.

What has happened over the years is something has bent. No, the arbor is not being yanked out as can happen with brass framed Cap & Ball revolvers.

With this design, the arbor does not lock the barrel in place. The barrel slips over the arbor, but the rotary joint at the bottom of the frame is what keeps the barrel snugged to the frame. Over the years, something has actually bent to open the barrel/cylinder gap to where it is now. I suspect the lower portion of the barrel has actually bent a little bit. And that has resulted in the overly wide barrel/cylinder gap.






Clearly, this old revolver is not made from modern steel, as a modern Uberti is. That probably contributed somewhat to the wide gap. In fact, the next version of this revolver did have a top strap, with a similar rotary joint at the rear of the top strap. This was added because it was recognized that a top strap would make for a stronger gun.

Just a caution, about Open Top revolvers.

Yes, I do shoot it, but only with ammunition loaded with Black Powder.





By the way, a friend has a couple of Uberti Open tops, chambered for 38 Special that he shoots all the time in CAS. But he only shoots them with Black Powder.

 

[35 Whelen]

I've often wondered if the top strap was really added because of the desire for more strength, or for a better sighting system than the V notch in the hammer.

35W

 

[Driftwood Johnson]

I've often wondered if the top strap was really added because of the desire for more strength, or for a better sighting system than the V notch in the hammer.

Not with the open top Merwin Hulbert. The rear sight was a V groove on the top of the frame. Not a V groove in the hammer like a Colt C&B.






Later, when a top strap was added, the rear sight was part of the top strap. With Merwin Hulbert anyway, the top strap was added for strength, not to take the place of a V groove in the hammer.

 

[Old Stumpy]

Your “open top” is as strong as it needs to be. The top strap was added at the request of the Military.

Still waiting for an open-top .44 magnum.