Hello SMF and welcome to the forum. You have asked a good question in your first post and it can seem a bit confusing but the truth is yes, you can use a Bisley hammer in your New Vaquero it just requires some work to look right with a non-Bisley grip frame. All Ruger grip frames and main frames use the same bolt hole pattern for the five fasteners that secure the grip frame to the main frame and this hasn't changed since the first Ruger Single Actions from the 1950s. The Bisley grip frame does have a different shape to the area around the back of the hammer and the opening for the trigger is longer to accommodate the shape of the Bisley trigger but the location of the holes for the two pins on the New Models is the same whether the gun is using the standard hammer and trigger, the Bisley or the Super Blackhawk hammer.

Your gunsmith's comment about the SBH hammer being the better swap is based on the fact that a SBH hammer is a pretty easy swap and usually takes a few minutes and you're good to go. You can actually swap out the Bisley hammer just as easily but there will be a noticeable "hump" of material sticking out between the grip frame ears. This excess material is pictured in the slightly out of focus photo below. The scribed area on this Bisley hammer is what protrudes out when you drop a Bisley hammer in either a plow handle or birdshead grip frame.

The solution is to cut/grind/file/remove this excess material and reshape that area to match the profile of your non-Bisley grip frame.

For an example of a finished project the New Vaquero below was shipped as a 5.5" Bisley and is now a 3.75" birdshead. To get the birdshead grip frame to look right the hammer was re-shaped as mentioned above and the opening for the trigger was enlarged to accommodate the Bisley trigger. You didn't mention using a Bisley trigger but you can if you want with that modification to the grip frame.

So that's the long answer to your question. It's not the easy swap out like a SBH hammer but it's also not an overly complicated major project either. Good luck with whatever you decide to do and let us know what the outcome is.

 

Thank you so much for all that information, Waveform! I really appreciate it! I didn’t even think of a bisley trigger. What kind of difference would that make? Sorry if that’s a stupid question. This is all new to me, so still a bit of a learning curve. Also why I didn’t want to tell the gunsmith, I know I know next to nothing, but think you’re wrong, lol.. I had wondered if he was just telling me you can’t since the SBH hammer is less work for him.

I love that birds head!!! I wish I could have gotten the shorter barrel here in Canada. I hadn’t even thought of buying the 5.5” bisley and just shortening the barrel, I wish that had occurred to me. Good to know for the future.

I’m almost wondering if it’s easier to find another gunsmith than trying to explain to this one that it can be done. I’ve had a hard time finding one though, at least in Canada anyways

 

The Bisley trigger has a little more curve in it and I believe that's to pair with the ergonomics of the Bisley grip shape. If you like the Bisley trigger it's another option while you're in there swapping out parts but it does mean enlarging the opening in your grip frame. If you decide later you prefer the standard trigger you'll have a larger opening in the grip frame that might look odd. In my case I wanted to reuse the hammer and trigger in my project so down that path I went.

Reshaping a Bisley hammer isn't very difficult and certainly should fall well within the capabilities of a real gunsmith. But it's not easy to find a real gunsmith these days - seems like a lot of guys that know how to assemble an AR or mount a scope or swap out parts want to call themselves a gunsmith. I don't pretend to be one myself - I'm just a guy who likes to tinker on his own guns for his own amusement. But I and others here on the forum have done the Bisley hammer modification for use on a non-Bisley grip frame.

The Super Blackhawk hammer is an attractive option too and a lot easier. Here are before and after pics of a heavy frame Vaquero that I did a SBH hammer swap on a few days ago. I prefer a lower hammer spur and it only takes a few minutes. A SBH hammer is around $30US and is a fairly simple DIY project - it can even be done without messing with the pesky gate spring. Paying someone to reshape a Bisley hammer would obviously cost considerably more. But a SBH hammer is not a Bisley hammer so only you can decide what look you really want and how much you're willing to pay someone to do it (or to what extent you're willing to do it yourself.)