45 Colt Bisley Blackhawk What size throats needed?

[cas6969]

If you're just buying it, don't do anything but shoot it.


It may be fine as is. Even if it's not you need to make sure all the bugs are worked out before you spend any time and money on it.

 

[lark63]

Thank you CAS. That is what I tried to say in my post earlier.

 

[Bucks Owin]

Howdy

For what it's worth, .454 bullets are for older guns. Originally, the groove diameter of 45 Colt was .454. After Colt reintroduced the Single Action Army in 1956 they changed the spec to .451. This was so it would be the same as the spec for 45 ACP, which had always been .451.

Ideally, you want a bullet about .001 over barrel groove diameter when shooting lead bullets, so .452 is a perfect bullet for modern 45 Colts. When determining bullet size, it is best to work backwards from barrel groove diameter. Bullets should be .001 over barrel groove diameter. Chamber throats should be no larger than perhaps .001 over bullet diameter, so the bullets will chamber, and so the bullet does not upset while traveling through the throat. Too large a chamber throat also allows the expanding gasses from the powder to escape around the bullet, softening its sides. This can be a major cause of leading with lead bullets.

You can slug your bore if you want, but most manufacturers these days do a very good job of keeping 45 Colt barrels to .451.

You can use your .454 bullets if you like, as long as they are reasonably soft and you do not approach max pressure. But with a properly set up 45 Colt revolver, .452 is the ideal bullet size.

I agree in the main, however those who do run across a .45 LC with overly large throats (and they're out there, both M-25 and .45 BH) can probably improve accuracy with a .454" lead bullet. In my own case, throats run .456"ish with .452" groove. Linebaugh recommends a trial of .454" bullets in these sixguns and my own tests proved him out. No perceptable change in velocity (pressure) even using his hefty charges of W296/H110 but a marked improvment in accuracy. I think the pressure issue of a thou or two oversize cast lead bullet (of any BHN) is not much of a worry. I don't recommend the practice of course, just saying... :wink:

What I'd like to know is why there are otherwise fine M-25s and BHs with SAAMI max allowable chambers and .45/70 size throats in the first place!! It's not like they are still used in the indian wars and need to accept dirty dented gvmt ammo in the heat of battle!.... :roll:

I've seen an Italian knockoff built with perfect post WW2 .45LC dimensions. (eg charge holes approaching .480" with .452 throats, .451" groove) If I wasn't stricken with ".45 LC Magnumitis" I think I'd have swapped my BH for it! With it's "old style" lockwork and tight slick cyl, it was damn near orgasmic! Whats the problem with US manufacturers? It's a disservice to the both the caliber and the buyer. Ever see a SBH or a M29 with such ho hum variation? Me neither.... :x

Anyway, enough rant I guess....

 

[Dale53]

Bucks Owin;
You and I are on the same page. I suspect that the over large chambers are the result of carry over from the 1870's when no one had the ability to hold tolerances.

However, when you have the present day capability it boggles the mind why manufacturers continue to offer this mishmash of dimensions.

My particular examples of Rugers (a Bisley Vaquero and a SS Bisley Convertible 45 Colt/.45 ACP) had somewhat undersize throats. In the Vaquero, it actually worked well with black powder (the black powder apparently bumping up the diameter after the bullet cleared the undersize throats). However, my SS Bisley Convertible BlackHawk it leaded and within thirty shots was shooting "off call". An examination of the barrel, showed leading in the trailing edge of the lands all the way down the barrel.

After reaming the cylinders of both, tests showed accuracy maintained "forever" and NO leading whatsoever with the Vaquero and smokeless (as well as black) and both cylinders in the Convertible. Now, I have "custom" dimensions in all of the cylinders and this is one happy shooter (as are my two friends whose convertibles I also did).

About three years ago I bought a new S&W Model 625-8 (4") Jerry Miculek Special. It worked so well and shot everything I fed it "spooky accurate" that I desired another but with a 5" barrel. As luck would have it I found an estate sale LNIB 5" Model 625-6 Model of 1989 at the very next OGCA show. The price was decent, it was the only 625 I saw at the show, and I brought it home. It, again, shoots "scary accurate". These were both .45 ACP revolvers.

I measured the cylinder throats and they will just barely admit a .452" cast bullet. In fact, when I load a Keith 250 gr (NOE Lyman clone of the 454424) I can feel the front band (.452" diameter) enter the cylinder throat.

Needless to say, I am more than happy with my various .45 revolvers because they have the correct dimensions and shoot accordingly.

It's a shame that the Rugers didn't come with the correct throat dimensions. However, at least with undersize you can correct them rather easily. If you don't want to/or can't fix it yourself, then send to CAS for a quick professional job that won't cost you an arm and a leg.

Dale53

 

[gobe]

If you're just buying it, don't do anything but shoot it.


It may be fine as is. Even if it's not you need to make sure all the bugs are worked out before you spend any time and money on it.

cas ... email sent.

'gobe'

 

[Onty]

Just make sure you use the reamer and not some "split dowel rod and sandpaper" crap.

For that matter, just send it to cas.

AMEN!

Dale53

It always amazes me over on castboolits when this subject comes up, the number of people that will recommend the dowel method. Then, they will tell you all the downsides of using the right tool and how their method is better and seemingly get offended that you even recommended the right tool :roll:

Nothing against castboolits at all btw. Great site with more information than should be allowed by law.

FWIW, you can even buy the reamer, use it, and sell it for about $5 less than you paid in less than an hour in the classifieds. Seen it happen several times.

Seems to me that wooden dowel and sandpaper method came from here http://www.beartoothbullets.com/tech_notes/archive_tech_notes.htm/59 .

It could be done, but by very few of among us. Great majority will just ruin their cylinders. So, play safe and order proper reamer, or send cylinder to expert who knows what he is doing.

 

[pps]

Dowel, sandpaper and chamber throats = BAD MOJO.....not even in the cards. I'll size the bullets, see how she shoots, but will probably end up sending to CAS if there are issues.

 

[guitarpicva]

If you are nearer the West coast, you might want to contact Rod at Dixie Firearms. He's a Ruger SA specialist.

http://www.dixiefirearms.net

 

[gobe]

Thanks for all the info, guys. Contacted Cas and the cylinder is in the mail to him today. Will be anxious to get it back and head for the range!

 

[pps]

Here is the new baby!!! Crappy cell phone pic.

STUPID STUPID STUPID 10 day wait. Dozens of guns in the safe and I need a ten day "cooling off" period.....grrrrr