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Sturdy As A Brick!

.45 Convertible Blackhawk

© 2014 – Ed Harris



When I worked at Ruger in the 1980s I was impressed with the abuse which single-action Blackhawks could take and keep going. While not your choice for combat, it is simple, sturdy, reliable, accurate and powerful. A great choice for general outdoor use. I've had a 5 ˝” .44 Magnum Super Blackhawk which I refitted with the steel Old Army XR-3 grip frame. It has killed lots of game and ridden many miles and spent many overnights in the bush as my only gun.

I recently picked up a Ruger 4 5/8” barrel New Model Blackhawk Convertible in 45 Colt with extra 45 ACP cylinder. I wanted the simple, rugged durability of a large-bore single-action as an outdoor companion in situations where it was impractical to carry a rifle. I find the 45 Colt quite adequate for whitetail deer and similar game at woods ranges and its defensive potential is well proven in some 125 years of military and outdoor use. I wanted the dual-cylinder option because I have other handguns and rifles in those calibers. Redundancy is good! My requirement was for a rugged, simple, very strong gun which could digest heavy experimental hand loads or gleaned ammo from suspect sources without worry. For survival use a convertible Blackhawk has the advantage of being able to exploit plentiful supplies of common .45 ACP ammo you might come across. They also make a convertible .357 with extra 9mm cylinder if that concept appeals to you. 

For backpacking carry the 4-5/8" Blackhawk is handy, only 36 ozs. It handles easily and shoots well, having manageable recoil. I have no trouble keeping groups under 2 ˝” at 25 yards with full power 45 Colt loads at 900-1000 fps. The gun came from the factory with skinny plastic grips like old Colt Single-Actions, which I promptly got rid of and replaced with Pachmyars, the same as I use on my .44 Magnum, because I wanted both of my single-actions to feel alike, it’s also better for comfort and control.

My other 45 Colt revolver is a Colt New Service Model of 1909.  Using unsized, as-cast bullets of .455" diameter my best loads in the old Colt produce 25-yard groups averaging 2 ˝” or slightly less at 25 yards. This is remarkable, considering its tiny fixed sights which are very difficult to see well. Firing the same standard pressure, but full power loads with unsized .455” bullets in the Ruger, having tighter .452" cylinder throats groups opened about 20%, 2 ˝” vs. 2" or less with bullets sized .452" to fit the Blackhawk's cylinder throats. This is not so much a difference to impair utility for field shooting. I can keep most shots on a 9" paper plate at 100 yards with the revolver firing from a two-handed sitting position. The carbine will hit clay birds at 100 yards with a proper zero and steady shooting position. 

If you are not familiar with the .45 Colt, these are typical firing results with 45 Colt hand loads I use in my revolvers and an H&R Handi Rifle:

45 Colt Loads with Saeco #954, 230-gr. FN, Starline brass, 1.285,” Winchester LP Primers, Alliant Bullseye, Wheelweight Alloy 12 BHN, bullets loaded as-cast, UNSIZED .455”Lee Liquid Alox (LLA), Cartridge Overall Length = 1.59”



RCBS Little Dandy Rotor – Bullseye Powder




Colt 5-1/2”

Ruger 4-5/8”

H&R 20”

Avg. of five 5-shot groups








Best in H&R Carbine 50 Yards

Recommended as "Standard Charge"



Tied BEST in Colt 25 Yards.







H&R Carbine at 50 Yards



Best in Colt at 25 Yards







Ruger revolver at 25 yards = OK




































Firing Table for 45 Colt Cartridge, 230-grain Ogival Flat nosed Bullet similar to M1887, C1=0.15










V (fps)







E (ft.-lbs.)







Path (inches)







Path (inches)








Firing .45 Colt ammo, loaded with fast-burning pistol powders in a rifle gives about a 150-180 fps advantage over firing the same ammunition in a typical revolver. Firing 45 Colt ammo from a carbine, striking energy at 100 yards is about the same as the same load develops from a revolver near the muzzle. Iron-sight groups fired with the carbine at 100 yards equal the best you can get by firing the revolver from sandbags at 50 yards. With a 100-yard zero you can take a 6:00 hold until the range is far enough that the bead covers a deer from backbone to brisket, at which point you hold center-mass, blot out your quarry with the bead and shoot.

The lever-action carbines don't feed semi-wadcutters reliably, so I have standardized the flat-nose, ogival radiused "Cowboy" style bullets. They feed in anything and perform well on game as long as the "meplat" or flat spot on the nose is 0.5 of the bullet diameter or larger.  A meplat larger than 0.7 is starts suffering from aerodynamic problems affecting long range accuracy deteriorates. 

The standard barrel lengths for the Super Blackhawk .44 are either 5-1/2" or 7-1/2". The older pre-transfer-bar flattop models came in a 6" barrel.

A charge of 7.2 grains of Bullseye with the Saeco 260-grain #430 Cowboy slug, or the #441 Keith style SWC gives 1000 fps from my 5 ˝” Blackhawk in .44 Magnum and 1233 fps in my H&R Handi-Rifle. I can shoot soft lead plain based bullets cast from anything which will melt and don't need gas checks. And about 1000 rounds per pound of powder! With Unique powder you have about 8 to 8.5 grains will do the same thing.

The single-shot break-open is completely forgiving as to bullet shape and will digest stuff which a lever-action won't. Besides 45 Colt and .44 Magnum barrels, I also have a 3" magnum 20-gauge modified choke shotgun barrel and a .30-30 rifle barrel for it. The Handi-Rifle rides along as the spare camp gun with its shotgun barrel and whichever rifle barrel matches the handgun or hunting rifle likely to be going along. I installed the Kensight reproduction M1 carbine type peep sights from Brownells on the 45 Colt and .30-30 barrels. This requires machining the barrel breech to form the sight dovetail, but there is lots of metal there and it is a simple job for anyone with a milling machine. John Taylor Machine did the work on my barrels.


A Sidebar on the Ruger .45 Convertible

After the 45 Colt Vs. Schofield shoot-off in Fouling Shot Issue 223, I put my Ruger .45 Colt cylinder away for the summer and decided to started fooling with the .45 ACP cylinder.  It was a good thing I did, instead of stashing it away until after zombies were invading the local Food Lion!  Its chambers were so tight that Winchester 230 JHP factory rounds wouldn’t enter the ball seat far enough to allow rounds to seat and allow the cylinder to rotate past the loading gate!  There were no problems with Federal 230 45D, Remington 230 grain Golden Sabers or TW55 hardball. 


SAECO 954 Bullet



SAECO 954 vs. 955 Bullet – Both are 45 Caliber

So I tried some H&G68s IPSC loads which my friend Bob uses in his M1911A1. They wouldn’t  go in either. Nor would my favorite “go to” loads with using the Saeco #954 Cowboy bullet.  After taper crimping to .470" mouth diameter they would enter with resistance, but bullets were visibly marked.

   BlackHawkLappedChamberThroat   P1010309


Close examination using a strong light and magnifying glass revealed that the chambering reamer had turned up a sharp wire edge at the stop surface where the case mouth rests, where the chamber  transitions into the ball seat.  Measuring the marked bullets, the chamber throat entrance was closer to closer to .450 than to .452  and all chambers were slightly tighter at the ball seat origin than farther up the cylinder walls, beyond the wire edge was turned up by the chambering reamer.   I decided to lap the burrs out by hand instead of firing a bunch of expensive jacketed loads.  This would let me control the process, because hand lapping vs. reaming by feel would be more difficult to screw up!

A .30-'06 case is of just the right diameter, with a slight taper. I coated one with 600 grit lapping compound, grasped in a ˝” drive tap handle, then carefully polished the entrance of the ball seat, without touching anything else.  In the color photo you can see the polished section of a lapped chamber throat where the blue is now gone for a short distance.  I’m not sure if it will show up when printed in black & white.

After some cautious cut & try interrupted by periodic cleaning and visual inspection I could see a mirror-polished angle where the lap had been working, the wire-edged burr caused by the chambering reamer was also gone.  I repeated the process around all six chambers, 100 turns total, 20 turns, back off, recoat the lap, insert again, repeat, repeat, wipe, inspect. 

Lapping took about an hour later until all six lapped chambers looked the same.  I took six lubed bullets, dropped them into the rear ends of the chambers and drove them a bit with a brass drift, tapped them back out and measured them.  The ball seat origin immediately in front of the case months now measured uniformly .452, without any constriction or burrs. The original ball seat untouched ahead of the lap was unchanged at .4515". It was time go to the range.


My .45 Cowboy Special brass would now fit into the ACP cylinder as well as my loads with Saeco #954 assembled in ACP brass.  I also tried Bob’s IPSC wadcutter load, using LaserCast H&G68, of 92-6-2 alloy at .452” diameter and unknown  blue lube loaded with 4.5 grains Bullseye, OAL 1.250" taper crimped to .470." Velocity chronographed 863 fps, five consecutive 6-shot groups at 25 yards from sandbags averaged  1.66".  My own loads didn’t shoot too bad either, as the table shows.  Yippeee!








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