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Caution:  The following load is above SAAMI specifications and should be approached with caution and used only in modern firearms.  The author of the article I read had a pet hog load of 20 grains of Alliant 2400 under a 300 grain hard cast lead wide flat nose bullet.  I purchased a Lee 300 grain .452 wide flat nose gas check bullet mold and cast my own.  This load chronographed from my Marlin 1894 Cowboy at 1500 feet per second (fps), and from the 7 1/2” Blackhawk at 1240 fps.  Pressure was measured at 32,000 PSI using a Pressure Trace™ unit.  Although this is beyond some published maximums for this caliber, many powder and bullet companies are publishing loads within this range specifically for use in modern firearms.

Planned Improvements
Ruger makes a fine single-action revolver.  But like most production firearm manufacturers they can’t afford to take the time to make the custom improvements to really make this revolver into an excellent shooter.  Based on Internet research, apparently Ruger revolvers have other problems that are counter-productive to accuracy, which I will identify later.  Beginning with the stainless steel Ruger Blackhawk 7 1/2“ barrel in .45 LC I planned to make the following improvements:

1. Install a Wolff spring kit.  I really like how this smoothes and lightens the action.
2. Lighten the trigger pull – at the same time eliminate some of the creep inherent in all Ruger single-action (SA) triggers.
3. Install a wide spur hammer ala Super Blackhawk.  I don’t want my thumb to slip off the hammer under the stress of “buck fever” (or should I say “hog” fever) or in cold or wet conditions.
4. Checker the hammer spur for greater purchase.
5. Install a Hogue single piece rubber grip.  These hog loads can kick quite a bit and the plow-share grip will rotate in my hand under recoil.  I want to control the recoil better.
6. Install a scope mount for a red dot sight or 2x pistol scope.  I want to be able to interchange the optics depending on the shooting conditions; red dot for close range, 2x scope for long range.
7. Port the barrel – I plan to drill 5 holes along either side of the front sight base to help reduce recoil.
8. Open up the chamber throats if necessary.
9. Lap the barrel – This will improve overall accuracy.
10. Convert existing pawl into a free-spin pawl.  This makes single reloads very easy.

I had thought about reducing the barrel to 6” for easy carrying, but decided I wanted the extra length especially because I’m going to port it.

Install Spring Kit and Wide Spur Hammer
First I installed the spring kit.  I purchased kit RSA-106 from Brownells which contained a reduced power trigger return spring, 17, 18, and 19 lb. hammer springs (factory is 23 lb.), and a stronger base pin plunger spring.  First I completely disassembled the gun and polished all trigger parts and pins.  I made sure the trigger was not rubbing against the grip frame.  (One of my Vaqueros wouldn’t work with the reduced power trigger return spring because the trigger was rubbing against the grip frame.  I had to relieve that edge of the trigger slot for the gun to function with the Wolff spring.)

After polishing, cleaning and oiling all internal parts I reassembled the gun using the spring kit with the 17lb. mainspring to test for reliable function.  I purchased a wide-spur hammer from Brownells and replaced the factory hammer at the time I reassembled the gun.  The gun functioned well and all springs worked as they should, but I encountered my first problem.  If I cocked the hammer and pulled the trigger back at the same time something in the lock work hung up which caused a very heavy trigger pull.  By holding the hammer back and pulling the trigger 2-3 times I could feel something flexing, then I heard a “click” inside the action and the heavy trigger tension was gone.

Over the years I’ve worked on dozens of Ruger single action revolvers and every one was just a bit different due to manufacturing variances.  This was one of those instances where, due to the manufacturing process, something was causing the lock work to hang up.

I discovered that the end of the trigger return spring was catching on the rear edge of the transfer bar arm as you can see in the left photo.  There was a small ridge left from the casting that would catch the end of the spring.  Eventually, the spring would rotate away from the arm causing the audible “click”, which relieved the spring tension.  I checked my other spring kit (I always keep a couple in the shop) and also compared it to a factory spring.  They were all the same dimension; therefore something had to be done about the trigger.

My solution was to relieve the inside edge of the transfer bar arm so the end of the spring wouldn’t catch.  I used my milling machine and a 1/8” end mill to make the relieving cuts, then smoothed it with the edge of a cutoff wheel and my Dremel tool.  I could have simply used my Dremel tool to relieve that edge, but I think it would have taken longer.  There is no weight or tension on the transfer bar, but like most things Ruger builds, this arm was probably over-engineered.  My relief cut should have no adverse effect on function, durability or reliability.

Lighten the Trigger Pull
There are some tricks I use to make a Ruger SA trigger lighter and crisper.  First and foremost is installing the spring kit as performed above.  With most Ruger SA triggers the trigger sear sits too deeply on the hammer notch.  Also the engagement surfaces are usually just rough ground as they come from the factory.  This makes a very safe, but long and creepy trigger pull.  Some of the things I can do are to reduce the hammer notch to about 0.014”, cut a break-away angle on the rear of the trigger sear, and bevel the edges of the trigger sear so less surface area engages the hammer.  These processes require special tools and jigs in order to keep the surfaces square.

I installed the hammer in my Power Custom Series 2 stoning fixture using the universal adapter.  I used the original hammer pivot pin inserted groove first into one of the holes in the adapter.  The pin was held in place by a set screw.  I made sure the set screw contacted the groove so as not to raise a burr on the outside of the pin.  I marked the front edge of the hammer notch with a blue marker and adjusted the fixture until my stone was flat across the front of the notch.  The notch in my hammer measured 0.022” so I took a 220 grit stone and carefully reduced the depth of the notch to 0.014”.

I then rotated the hammer so I could polish the engagement surface of the hammer notch as shown in the left photo.  I marked the surface with a blue marker and made sure to adjust the fixture so I was polishing this surface perfectly flat.  I used my hard Arkansas stone with a beveled edge to final-polish the surface.

 
Next I installed the trigger in my Power Custom Series 1 stoning fixture using the BH (Blackhawk) adapter.  I used a blue marker to mark the surface and adjusted the fixture until I was polishing the surface perfectly flat and square.  I used my coarse ceramic stick to polish off all of the grinding/ machine tool marks, then final polished with my fine ceramic stick.

Finally I cut the break-away angle in the trigger sear.  The arrow in the left photo shows which corner I cut.  Cutting this angle causes less surface area of the sear to ride on the hammer notch.  With the trigger still installed on the BH adapter, I rotated the adapter until I could cut the corner at a 45^o angle.  I used a 220 grit narrow stone to cut the corner.  I used about 30 strokes, then cleaned and oiled the surface.  I had to be very careful here.  If I cut the angle too deep the sear would slip off of the trigger.  The goal was to make the trigger pull crisp, but still be safe. 

I re-assembled the gun and tested the trigger.  With the 17 lb. hammer spring installed, it broke at exactly 2.5 pounds every time with no creep.  To test for safety, with the hammer cocked I pushed on the rear of the hammer with my thumb as hard as I could.  If the hammer didn’t slip off of the sear then I knew it was safe.

I decided to re-install the factory 23 lb. mainspring to get a little quicker lock time.  This brought the trigger pull up to a very crisp 2.75 lbs.  This should help me stay on target during that all important shot with the target in my sights.

Checkering the Hammer Spur
The wide spur hammer I purchased came with horizontal grooves cut in the spur.  I wanted to increase the grip by cutting vertical grooves thereby checkering the spur.

First I took a flat jeweler’s file and using the top groove as a guide, cut a deep notch in front of the spur.  This provided clearance for my checkering file.  I took my 20 lines-per-inch (LPI) checkering file and cut the vertical lines.  I believe the hammer was surface hardened because making the initial cuts was somewhat difficult.  Once I broke through the surface, however, the cutting proceeded smoothly.  First I cut all the vertical lines as deeply as I could with the checkering file.  Then I went back and cleaned up each individual line with a 3-square file.

After cleaning up all the individual lines I took a half-round jeweler’s file and cleaned up the excess cuts on the top of the hammer, then shoe-shined this area with strips of 320 grit wet/dry paper.  After re-assembling the gun I definitely got better gripping purchase on the spur.  The checkering digs more sharply into my thumb for more positive cocking.  This will be important in the field, especially in wet conditions or if I’m wearing gloves because of the cold.

Hand-checkering is a very time-consuming process.  Just to cut the vertical lines on probably 6/10 square inch of hammer spur took me over 2 hours.  But the result was well worth the effort.

Installing Hogue Mono-Grip
I purchased a Hogue slip-on one piece rubber grip for the Blackhawk.  I love these grips and have them installed on all my double-action revolvers.  They do an excellent job of helping to control recoil and they should do the same on the Hog Hammer. 

The grip is designed to fit both the Blackhawk and Super Single Six and comes with two cross pins for different sizes of grip frames.  I couldn’t get the nut to fit on my grip frame so I took a narrow Swiss pillar file and filed the bottom notch deeper in the grip frame.  Once I got the nut in place and installed the narrow cross pin, I slid the grip into place.  It didn’t fit perfectly so I took a knife and removed a bit of rubber from the inside bottom of the grip.  Now it fit perfectly and screwed down tightly in place.

Wow, this is a large grip!  It’s almost too big for my hand and may take some getting used to.  However, the size should help in controlling recoil, which was the original plan.  I’ll have to do some test firing to see how it feels in my hand, especially with gloves on.  In theory, by the time I port the barrel and add the weight of a scope mount and optics, recoil should be pretty tame.

Porting the Barrel
Ok, now for some serious metal work.  I planned to mill five 1/8” holes along each edge of the front sight base in a ‘V’ pattern, hence the name V-10.  The outside diameter of the barrel is 0.7” and the width of the front sight base is 0.37”.  That puts each edge about 30° off vertical center.  Rather than drill each hole pointing towards the center of the bore, I planed to drill them aligned as closely to vertical as possible, which should help control recoil more effectively.

Based on other articles I’ve read on the Internet, starting 0.325” from the end of the barrel, each 1/8” hole will be 0.1875” apart.  I set the barrel on a 1” parallel in my machinist vise and rotated it until the front sight base was resting against the edge of the vise.  Then I positioned the bit 0.010” away from the sight base itself.  With my dial indicator properly set up to measure distance between holes I was ready to begin milling.

The article suggested using a round end carbide bit to avoid leaving a burr on the inside of the barrel; bad idea!  Not only did I break two bits, but I left a burr inside the barrel on each hole.  In the left photo you can see the end of a broken bit at 3 o’clock inside the barrel.  What I should have done was use a flat end mill bit, and driven a copper- jacketed bullet into the bore to drill into to prevent burrs.  I used plenty of cutting oil to keep the bit and barrel cool, and plunged the bit very slowly.  Still I was plunging too quickly when the bit broke through on two holes and as a result I broke two bits.  

Ok, after cleaning up all the holes I had a number of burrs to remove.  First I chucked the frame and barrel in my vise muzzle up resting on a piece of leather, and started driving bullets down the bore.  I started with pure lead round ball, then went to hard cast lead, then finally drove copper jacketed bullets down the bore.  During this process I discovered another problem with this gun; there was a constriction in the barrel where the threads were screwed into the frame.  Apparently this is quite common for revolver barrels, especially Rugers of .44 and .45 calibers, and can’t be good for accuracy. 

There are some methods to correct this; either fire-lap, hand-lap, or swag the barrel.  I decided to try swaging by first impregnating copper-jacketed bullets with 400 girt lapping compound, then driving them through the bore.  After about 50 bullets or so all of the burrs were removed from the right port holes, but the left holes still showed some scraping of the bullets indicating a burr.  This was the side where I broke the two bits, which left larger burrs.

Hand-Lapping the Barrel
Hand-lapping involved making a pure lead lap, impregnating it with lapping compound, and running it down the bore by hand.  First, however, I needed to remove the barrel from the frame.  

I always feel as if I’m encroaching into a forbidden area when I separate a barrel from a frame; almost as if I’m not allowed!  There’s only one right way to remove the barrel from the frame and that’s with a barrel vise and action wrench; both of which are available from Brownells.  Before I completely disassembled the gun I used a prick punch to mark the position of the barrel in relation to the frame.  I placed the witness marks on the bottom of the barrel between the ejector shroud and cylinder pin holes so they wouldn’t show when the gun was reassembled.  These marks ensured I had the barrel properly indexed to the frame for reassembly. 

I attached the action wrench to the frame using the Blackhawk receiver blocks, and attached the barrel vise to the barrel using an aluminum bushing I had to make with my hobby CNC mill.  I clamped the barrel vise vertically in my bench vise and the barrel came off with very little effort.  Like my father used to say, “The job is always easier when you have the right tools!”  (Ok, I can calm down now; no damage and I didn’t mar the barrel!)

Now that I had the barrel separated from the receiver I was ready to begin hand-lapping.  First I had to make the lap.  I filled my electric lead pot with pure lead and prepared my dipper.  I took a .243 caliber brass cleaning brush and screwed it onto the end section of a multi-section rifle cleaning rod (no handle so I could push it out of the barrel after pouring the lead).  Then I wrapped the end of the rod where the brush screwed in with masking tape so it would fit tightly into the barrel.  I inserted this into the barrel from the muzzle end until the end of the brush was about 1/4“ below the forcing cone.  (I couldn’t pour from the muzzle end because lead would fill the ports and I’d never be able to remove the lap!)  Then I wrapped the barrel threads with masking tape, which protected them from both lead and lapping compound.  I wrapped a piece of suede around the barrel and held it at an angle with a pair of pliers, then used my lead dipper to pour lead down the barrel over the cleaning brush.  I stopped pouring just before the lead got to the forcing cone.  I put the barrel in my vise and tapped out the lap.

I started with 220 grit lapping compound and found this was so coarse that I had to drive the lap through the barrel with a mallet.  Because of this I drove the lap always from the forcing cone to the muzzle (same direction as bullet travel) and tried to line up the rifling the same way every time.  Once I mis-aligned the rifling so I had to remake my lap.  I thoroughly cleaned and oiled the barrel before doing another pour.  After every 20 passes I cleaned and slugged the barrel.  It took about 40 passes to remove the constriction in the barrel.

I cleaned the barrel and made a new lap and impregnated it with 400 grit compound.  This was fine enough that I could move the lap back and forth by hand.  I made sure I pushed and pulled the lap so most of it was exposed before reversing direction.  Note in Figure 16 above that the barrel is mounted in the vise using the aluminum barrel bushing I used to remove the barrel.  Some experts say that if you squeeze the barrel linearly in a vise you can cause the barrel to be somewhat egg shaped after lapping.  I tried final polishing with 800 grit but it was too fine and the lap was too small to really do much good.  After completing the hand lapping process I again slugged the barrel.  This time the barrel was smooth with no constriction and all burrs were removed.

Lapping Barrel Shoulder to Frame
Before reassembling the gun I wanted to lap the barrel shoulder to the frame.  Most production rifles and revolvers where the barrel is screwed into the frame are usually way too tight.  This can cause two problems; a constriction in the barrel at the threads (which I had!), and if the barrel shoulder and frame are not perfectly square undue stress is applied to both the barrel and frame which ultimately affects accuracy.  (Since every firearm is different this may not apply to every one.)  The solution to both problems is to lap the barrel shoulder to the frame. 

In the left photo above, I have begun the lapping process.  I was careful not to get any lapping compound on the threads.  This would cause a loose fit.  With the barrel shoulder just touching the frame, the distance between the witness marks was about 1/4“.  This indicated just how tightly the barrel was screwed into the frame.

With 400 grit lapping compound applied only to the frame I continually tightened and loosened the barrel by hand.  I occasionally recharged the compound again being careful not to get any on the barrel threads.  I stopped when the two witness marks were a little over 1/8” apart and cleaned off the lapping compound.  The grey area in the above center photo indicates that I’ve lapped the shoulder completely around the frame.  The above right photo shows the location of the witness marks after lapping.

Re-Attaching the Barrel
Now that the shoulder is lapped to the frame I’m ready to reassemble the gun.  Since the barrel won’t be as tight as before I used Loctite to make sure the barrel stayed in place.  I cleaned the threads on both the barrel and frame, barrel shoulder and front of the frame with acetone and a cotton swab.  I applied Loctite 222 to the threads, and Loctite 609 to the shoulder.  Loctite 222 (purple) is a low strength thread locker, and Loctite 609 (green) is specifically made for use where metal contacts metal such as for pressed fittings.  This is just right for use where the barrel shoulder contacts the frame.  I let this set for 24 hours before doing any additional work.

After waiting 24 hours I slugged the barrel again and was pleased to find the barrel constriction was gone, the burrs were gone, and the barrel was nice and smooth.  The slug measured exactly 0.451”, which told me I needed to size my cast loads to 0.452” for maximum accuracy.  I reassembled the gun using blue Loctite on all screws. 

Barrel/Cylinder Gap
One of the other advantages to lapping the shoulder of the barrel was to reduce the barrel/cylinder gap.  Since I removed metal from both the barrel shoulder and frame, the end of the barrel was now closer to the end of the cylinder.  After reassembling the gun my barrel/cylinder gap was less than 0.0015” which is way too small to be safe.  I used a 0.625” facing cutter with .45 pilot bushing and guide to cut the face of the barrel forcing cone to 0.003”.  Three thousandths should be more than enough for safety, but provide a nice tight gun.

I just lightly started to cut and it opened the gap to 0.003”.  I discovered the end of the barrel was not square because I only cut half of the surface, the other half was not touched.  I would have preferred 0.002” but this will be ok.

Reaming Cylinder Throats
Undersized cylinder throats are another common problem with Ruger single action revolvers.  The key here was to ensure the cylinder throats were close to the same diameter as the bullets.  Since my barrel slugs to 0.451” I need to size my bullets to 0.452”, which meant my cylinder throats should also be 0.452” – 0.4525”. 

I measured the cylinder throats using my smallest telescoping gauge and they were 0.451” – 0.4515”.  I had used 0.452” bullets to fire-lap, and from the cylinder throat measurements it looked like I did a good job of lapping just the cylinder throats; they were consistent, but undersized for 0.452” bullets.  As a comparison I measured the throats of two Ruger Vaqueros I have and my friend’s Bisley Blackhawk, all in .45 LC.  They measured from 0.450” - 0.451”, all somewhat undersized.

I cut a slit in a piece of 3/8” dowel and wrapped a strip of 320 grit wet/dry paper around it so it would fit snuggly in the chamber throat.  I attached the other end of the dowel to my drill, inserted the reamer through the chamber and ran the drill at a medium speed while moving the reamer in and out.  I reamed each throat until it measured 0.4525”.  This not only opened up the throats, but polished them mirror-smooth, which made them much easier to clean.  For each chamber throat I first reamed as described above, reversed the paper to use the other end and reamed again.  This was all it took to open up each throat.

Revolver Accuracy
This information is from my article Accurizing the Ruger Single-Action Revolver but it bears repeating here.  I’m going to pause a bit and ruminate on what I’ve learned about revolver accuracy.  With my Blackhawk in its original factory condition this is what would be happening:

1. Burning gunpowder forces 0.452”bullet out of case into cylinder throat.
2. Cylinder throat swags bullet to 0.450”.
3. Bullet jumps cylinder gap into barrel forcing cone.  Actually, you have to stop to think about this for a minute.  In reality, the base of the bullet is still in the case while the nose is engaging the rifling.
4. Barrel constriction swags bullet another 0.002” so it is now 0.448”.  (The barrel constriction in some Rugers can be as much as 0.004”!)
5. 0.448” bullet is 0.003” undersize for the 0.451” bore, bullet wobbles as it travels down the bore, gas leaks around the bullet causing leading, who knows how it will exit the muzzle, resulting in a very disappointing group.

This is what should happen with a properly sized, fitted and lapped revolver:

1. Burning gunpowder forces 0.452”bullet out of case into cylinder throat.
2. 0.4525” cylinder throat guides bullet into the forcing cone, no swaging occurs.
3. Bullet jumps cylinder gap into barrel forcing cone. 
4. No barrel constriction exists so 0.452” bullet enters 0.451” barrel.  Because the bullet is 0.001” oversize all lands and grooves are sealed.
5. 0.451” bullet is in constant contact with the bore because fire-lapping slightly tapered the bore.  Bore is sealed, no gas cutting/leading occurs.
6. Bullet exit from muzzle is consistent resulting in excellent groups.

Mounting Scope and Red Dot Sight
I purchased a silver Weaver mount made especially for the Ruger Blackhawk, but the slots were spaced too far apart to mount the red dot sight.  This looked like another job for the milling machine.  I wanted the sight to be as far back as possible so I used the rear slot as a guide and marked where I planned to mill a new front slot.  The original slots were 0.152” wide, so I first made a cut with a 1/8” (0.125”) end mill, then moved it 0.027” to finish the slot.

I chucked the base in my machinist vise, adjusted the horizontal, vertical, and depth of the end mill bit and made my first cut at the mark.  Using my dial indicator I moved the bit forward 0.027” and made the second cut without changing the depth.  Now I can successfully mount the red dot sight.

After mounting the red-dot sight I then mounted the 2x pistol scope.  This was a simple matter of mounting the ring bottoms to the scope mount, then mounting the scope and installing the top rings.  I put a thin layer of clear silicon RTV inside both ring halves and used blue Locktite on the ring screw threads.  Now this installation will not move under recoil.

Converting Existing Pawl to a Free-Spin Pawl
The pawl is the arm that extends from inside the frame of the revolver to engage the ratchet teeth on the rear of the cylinder as you cock the hammer to index the cylinder to the next chamber.  With the loading gate open the top of the pawl is in constant contact with those teeth allowing the cylinder to rotate in only one direction.  A free-spin pawl does not engage the cylinder with the loading gate open thereby allowing the cylinder to rotate freely in any direction during loading.  When the loading gate is closed the free-spin pawl works as normal to engage the cylinder when the hammer is pulled back.  Over the years I’ve tried using the after-market free-spin pawls but they seem to alter the trigger pull.  This was caused by the press-fit pin backing out causing the pawl to drag against the frame.  Refer to my article Making a Free Spin Pawl for a Ruger Single-Action Revolver for details on this process.

Ballistics and Sighting In
I am using Lee bullet mold C452-300-RF which is a 300 grain .452 wide flat point bullet that takes a gas check.  I hard cast this bullet using a linotype mixture.  At the time I size and lubricate it I install the gas check.  Although this is a very hard lead alloy, I still use the gas check because of the velocity at which I am pushing this bullet.  This bullet comes with two crimping grooves.  The chambers in the Ruger are long enough that I can crimp on the bottom groove, thereby reducing the amount of distance the bullet has to jump from cylinder to barrel.  (These long rounds would not fit in my friend’s Bisley Blackhawk because his 0.451” chamber throats were too narrow.)  By the way, I’ve used these rounds as a gauge to determine if the chamber throats have been reamed enough.

I measured the ballistic coefficient (BC) for this bullet at .24 for my particular atmospheric conditions.  (I did this by measuring the muzzle velocity and the downrange velocity.)  Lee publishes the ballistic coefficient at .233 which is very close to my calculations.  Using my ballistic program and knowing the velocity and BC, I calculated point blank range.  Point blank range is defined as the maximum distance the bullet can travel and stay within a specific diameter circle.  I wanted to stay within a 4” circle (+2.0” above the line of sight, and -2.0” below the line of sight.)  Based on this data the point blank range is 110 yards, sighted in at 95 yards.  (I’ll probably limit my shooting to 60 yards or less.)

To get the rounds sighted in I went to my local indoor range, which is limited to 25 yards.  Using the same calculations above to be sighted in for 95 yards the bullet should strike 0.75” high at 25 yards.  So this is where I will adjust both the scope and red dot sight.

With this accurized gun I regularly shoot 1/2" groups at 25 yards.  This made all my work worthwhile, and it certainly paid off in improved accuracy.

Lessons Learned
This project has taught me quite a bit about revolver accuracy.  I also discovered there are proper steps to accurizing the revolver depending on my goals.  If I didn’t want to adjust the barrel to cylinder gap I would have slugged the barrel to determine the correct cast bullet size, opened up the cylinder throats to accommodate that bullet size, and removed the constriction by fire-lapping.  Since I wanted to squeeze out as much accuracy as I could and I wanted to adjust the barrel to cylinder gap, I removed the barrel, hand-lapped it, lapped the shoulder and frame, reassembled, then adjusted the gap.  Then I adjusted the cylinder throats based on slugging the barrel.

As mentioned before, my friend’s Bisley Blackhawk has cylinder throats that measure 0.451”, his barrel has a 0.001” constriction, his barrel/cylinder gap is 0.007”, and the trigger pull is 2 pounds, but long and creepy.  At a minimum I would do an action job, open the chamber throats to 0.4525”, and fire-lap the barrel.  If he wanted the barrel/cylinder gap closed up, I would remove the barrel, hand-lap it, then lap the barrel shoulder to the frame.

Tool and Parts List
Following are the tools and parts I used for this project.