May need cylinder throats reamed?

[brewer12345]

My security six is my favorite revolver and I shoot it a lot. Since taking up casting, I have had issues with leading in even low power 38 loads that isn't related to lube or alloy. As an example, my standard dewc target load is very accurate in the gun for the first 50 shots, then degrades and I have a leaded barrel to clean. Suspicious, I took a bullet and tried to shove it through the cylinders. No go. In fact, what I decided to try as hard as I dared it got stuck badly enough that it required a punch and mallet to back the bullet out. In contrast, the snub which has never leaded at all only required modest pressure to get a 358 sized dewc through the cylinders.

I think what is happening with the security six is the tight throat swages the bullet too small for the barrel. It the skids until the pressure obturates the soft alloy. I get good accuracy anyway until the leading gets too bad and the initial skidding is why the leading is mostly in the first inch or two of the barrel.

I think the solution is throat reaming, which I am unwilling to attempt myself. How do I make sure this is the solution? Would a good.Smith be able to confirm and figure out how much the cylinders need to be reamed before doing it? Anything else I have not thought of?

 

[Hooda Thunkit]

I had the same problem with both a Security and a Service Six. I had the throats honed to .3585, problem disappeared.
You'll need to look around for a Smith to do the reaming.

Me, I have so many revolvers that need reamed, I'm going to spend some money with Dave Manson. I'll just buy the reamers and do it myself.

 

[edwardware]

First, slug the throats, and barrel, and measure. If you're casting, the only tool you might need to add is a micrometer. Measure each throat individually.

I've fixed leading and disappointing cast accuracy in 3 of my revolvers by honing the throats to 0.001" over groove diameter.

Measure first.

 

[Arkansas Paul]

I need to do the same thing to my Blackhawk in .45 Colt. I sized a bullet to .452 and can't get it to push through a single cylinder throat. It's not nearly as accurate with cast as it is with jacketed.
I don't know the exact measurements of mine because I don't have a micrometer or a set of pingauges, but I know they're under sized.

Hamilton Bowen is one of the most well known revolver smiths in the country.
Per his website, he charges $75 to ream cylinder throats. If you can't find anyone locally, that's a good option.
There's also a guy over at the castboolits site that is known for doing a good job of it.

 

[e rex]

Tight throats on my S&W 686 also. Gas checks are about the only alternative to reaming.

 

[BSA1]

Have the forcing cone on the barrel recut to 11 degrees first. Look closely at your barrel and you will see it does not have proper angle. It is a inexpensive and easy job for a gunsmith. I had a gunsmith do a couple of mine. It took him about 10 minutes per gun and cost me $20.00.

 

[tranders]

I have a smith in North Carolina do all my cylinder throats. Very reasonable and quick turn around time. He goes by DougGuy on Cast Boolits forum.

 

[joed]

About 10 years ago while on the S&W site there was someon trying to sell a model 25-5 in .45 Colt. No one wanted it because he had the throats and forcing cone done. To make a long story short after a conversation with him he offered it to me and I paid him a fair price for it.

That gun was the most accurate .45 Colt I ever owned. In fact it was one of the most accurate revolvers I owned. I'm a firm believer in having that work done.

 

[brewer12345]

Ok, finally slugged this thing. The barrel cones out to 357 on the nose. The cylinders appear to be mostly .357 to .3575. Should I get the throats reamed? I am thinking the answer is yes.

 

[LOLBELL]

I suspect leading will stop if you have throats reamed to .3585. Dougguy over on the Castbollits forum does an outstanding job, is very reasonable and has a quick turn around time.