45lc blackhawk. Needs cylinder throats reamed.

[crow#2]

OK...that don't work on smaller diameter bores.
Short explanation....the faces of the caliper used to measure a inside diameter have small "flats"
on them and won't let you get a "true" measurement. You are actually making contact at 4 points.
Using them on IDs. of larger diameter for a somewhat "rough" measurement they are sorta ok.

I see what you are saying. If that's what I'm doing I would get smaller measurements.Now with that ehat gets me is I could not drive the 452 lead bullet through the cylinders. Guess I will call Ruger thanks

 

[crstrode]

from the reading I've done.i literally can not drive the .452 lrnfp bullet through the cylinder. I'm ok with it as long as it's not dangerous pressure wise or short term damage to the gun. Read that it can cause peening of the cylinder I believe. Whatever that means.

You "measured" a cylinder as .445, but cannot drive a .442 bullet trough. This indicates that your measurement techniques are invalid.

 

[hittman]

Measuring my OM that way mine comes out to 0.4495

 

[Dave P.]

If you really want to measure it yourself you can buy relatively cheap split ball small bore gauges. I would say
with those and a actual micrometer you could get somewhere under .001 and maybe within .0005 with
practice of actual dia.
If you can approximate how wide the jaw faces are on your calipers and say a bore of .450 you can do the geometry
and see about how far off your calipers are at that diameter......just don't ask me to remember the math to do it.
The wider the faces and the smaller the bore the more they're off actual.

 

[rkrcpa]

Pin Gauges are cheap.

 

[BULL'S-EYE]

You've already received the correct reply. Send it to Fermin...He's forgotten more about the art of obtaining peak accuracy from a revolver than most will ever know...A call to Ruger will only provide you with the standard "it's in spec!" canned response. Ruger has LONG been notorious for undersized chamber throats, especially in 45 Caliber.

Fermin C Garza's Customized Shooter's Resources

Blending Old and New; Forging ahead as we proudly walk in the footsteps of Giants

fermincgarza.com

 

[seasterl]

Do you prefer to load and shoot cast bullets or jacketed? If jacketed, I'd just leave the throats alone and shoot it. If you want to start casting or buying a certain sized bullet, then most get the throats reamed to 0.4525". I did that prematurely on some 45Colts, then decided I thought they shot better with jacketed and I preferred to load jacketed. Different strokes for different folks, though. I'm sure it's already been mentioned, but you need to measure the throats with pin gauges.

 

[Rclark]

They are small if you can't force a .452 lead bullet through with finger pressure. Simple as that. Now if .451, you 'may' get away with shooting lead bullets from the cylinder. Anything less than that and your accuracy will fall off, leading will usually result. Best to get the cylinder to one of the above mentioned guys to make it 'right'. The worst one I had to ream was .449 throats (using pin gauges). Once I corrected the throats, my groups shrank by half. Worth it (to me) . Oh, and for SAAMI pressure cartridges ... the gun is perfectly safe to shoot them as is -- just may lead and not be as accurate as it could be. I don't ever shoot jacketed in any of my revolvers.... But as above different strokes for different folks .

 

[contender]

Another vote for a call to Fermin & getting him to PROPERLY work over the cylinder,, if it needs it. if he gets it,, and it's NOT in need of work,, he'll tell you that too!

 

[s4s4u]

measured with a digital caliper set. The bullets measure almost exactly what they should. Like I posted earlier I could not drive the .452 lead bullet through the cylinders. With hammer and dowel.

Drive that bullet, or a lead sinker, through the bore and then see if it will slip through the cylinder throats afterward. If the slug won't slip through the throats after being pushed through the bore, you need the throats opened up. If it will pass through the throats after being sized to the bore, you are good.

 

[Outpost75]

Why do you think the gun needs work?
Something Ruger can address for you?

Here's a picture of measuring.Hard to hold everything and get a pic.

Using a vernier caliper will not give an accurate measurement, because the knife edges bridge across the interior radius of the chamber throats. Best is to use zz-minus gage pins or lacking those or an adjustable ball gage or you can use bullets whose diameter you have measured with a micrometer. Ideally ball end gage diameter should be groove diameter up to +0.0015", but not smaller. Larger up to +0.005" is not unsafe, but may cause leading.

 

[vlavalle]

I've never had this type work done. Only reason I would do it is I don't want a problem later or to high of pressures.
Can I just shoot it or is it dangerous. And who do you reccomend for the job?I know I can buy reamers but this is not up my alley.
Thanks

I do not understand why this would be an issue to raise in the first place. I am an owner of new model a Ruger Blackhawk .45 LC/ACP Flattop, and I shoot both jacketed and all lead bullets. This gun came with two cylinders, and one is for shooting .45LC, and the other is for shooting .45 ACP rounds. I have zero problems with any manufactured ammo, whether new or remanufactured ammo, and this is true for both cylinder.

As for safety, there are 3-4 high powered .45LC rounds made (mainly by Buffalo Bore) that are not SAMI specified (but they should be). Since my Ruger is a Flattop, I am not allowed to shoot the top 3 most powerful .45LC rounds, but I have shot many times the round that delivers 1,214 ft. lbs., and the gun REALLY kicks with this load. The max BB .45LC load is 1,344 ft. lbs. (Buffalo Bore). I think any .45 ACP, including .45 Super would fire just fine, and these can go up to 694 ft. lbs. (Buffalo Bore).

 

[Outpost75]

Cylinder throats which are smaller than groove diameter will shoot jacketed bullets OK. But lead bullets exiting the tighter cylinder throats will not produce a positive gas seal in the barrel, resulting in powder gases leaking past the bullet and causing bore leading via ablation.

DougGuy over on the Cast Boolits forum has done my Ruger .45 and .44-40 cylinders for me. He also uniformed and cleaned up a 1914 Webley MkVI in .455 which had non-uniform throats and frosting from use of wartime ammunition loaded with corrosive primers.

He uses a Sunnen hone which is very precise, resulting in perfectly round throats of uniform diameter, having a mirror finish. The work is affordable with fast turn-around. He can also hone out your bullet sizer die to match the corrected cylinder.

Reaming does not do as good a job and tends to leave circumferential tool marks.

 

[contender]

Listen to Outpost75. Excellent points made there.

 

[daveag.]

I bought .4525" reamer from Brownells. Hand reamer takes to .453". Perfect .001" clearance. Use a good cutting oil. I use Tap Magic.

 

[daveag.]

Cylinder throats which are smaller than groove diameter will shoot jacketed bullets OK. But lead bullets exiting the tighter cylinder throats will not produce a positive gas seal in the barrel, resulting in powder gases leaking past the bullet and causing bore leading via ablation.

DougGuy over on the Cast Boolits forum has done my Ruger .45 and .44-40 cylinders for me. He also uniformed and cleaned up a 1914 Webley MkVI in .455 which had non-uniform throats and frosting from use of wartime ammunition loaded with corrosive primers.

He uses a Sunnen hone which is very precise, resulting in perfectly round throats of uniform diameter, having a mirror finish. The work is affordable with fast turn-around. He can also hone out your bullet sizer die to match the corrected cylinder.

Reaming does not do as good a job and tends to leave circumferential tool marks.

It's clearance. A tool mark doesn't hurt as bullet doesn't touch. Reaming, with a good cutting oil works fine.

 

[snakeeyes4445]

A set of minus pin gauges from .25 inch up to .50 won't set you back more than 150 dollars or even half that. If you are going to do it right, Mr Garza might like to know what the bore slugs at. Then there are gauges that Brownells sells for you to check your forcing cone depth which is important.
Throats that small may produce end shake from the pounding. Read up on this by Googling your questions as they occur to you and you will end up with many nice tools.

 

[contender]

The OP has mentioned he's on a tight budget. A set of pin gauges at $100-$150 isn't likely in his budget.

 

[Dave P.]

To beat the almost dead horse a bit more...
The issue with reamers besides the possible slightly poorer finish compared to honing is the sizing is
often times a crap shoot. I have reamed many many holes to size mostly for dowels in various materials.
In the common sizes I use I have several reamers of each size and if measured accurately no two of them
make the same size in the same material. Reamers seem a simple tool but the reality is they're not, it takes
experience and a bit of luck to hit sizes if you need to be down in the .0001 to .0002 range and repeat it.
A " do it yourself tool " that I would suggest are lapping pins...look up ACRO lapping tools. Not the quickest
and you do still need the gauge pins for measurement but the laps will work well and you can hit whatever size
you can measure to.

 

[Dave P.]

The OP has mentioned he's on a tight budget. A set of pin gauges at $100-$150 isn't likely in his budget.

Don't buy the whole set just buy individuals appropriate to the caliber.