Shot some 300 gr Corbon for first time - some Ruger related questions

[Wedge]

I have a Blue 5/5" barrel Ruger Blackhawk and I shot some of the .45 Colt Magnum +P 300 gr soft points today. They were awesome to say the least. I felt that they were very comfortable to shoot, most likely due to the single action grip design. I need to start reloading so I can make some more heavy .45 Colt lods. The downside was the accuracy. Grouping was awful.

I have been having some accuracy problems with the gun before. It seems like no matter what I do I can't get the gun to group well. I borrowed some calipers and feeler gauge and made a few measurements.

Cylinder chambers: 0.479"
Cylinder throats: 0.446 - 0.448"
Cylinder - Barrel gap: 0.005"

How are these numbers? The chambers could probably be a little smaller but there isn't much I can do about that. The throats have to be reamed, right? Even if I shoot jacketed bullets they are at best 5 thousanths smaller than the bullet size, which seems bad.

Is the Belt Mountain base pin worth it? I measured my base pin to be 0.245". Belt Mountain's base pin is 0.295".

 

[HSMITH]

Those throats are WAY too small. They need to be .4515" to .452". Even .454" would be a TON better than what it is now.

All of the guys I know that like to pound the Rugers use the Belt Mountain pins.

 

[J Miller]

Sounds like the chamber throats are undersized. The Ruger .45's are good for that.
Calipers arn't really good for measuring chamber throats though. It's best to use a non steel rod to tap a soft slug through the throats and then use a michrometer to measure them. I use a hollow fishing sinker bought at Walmart.

Suggest you check out www.45throatdoctor.com . His web site has a lot of good information in it. He did my Ruger cylinder and it made a noticable difference in accuracy and consistancy.

All the other measurements you mentioned sound normal.

The Belt Mountain base pin, in conjunction with a Wolff extra strength base pin latch spring will do two things.
First, it will reduce cylinder woble. This can improve accuracy.
Second, it will help prevent the basepin jumping the latch and locking up the gun.
I've had two NM's do that to me. Now every Ruger SA I get has a Belt Mountain B.P. installed.

 

[Wedge]

J Miller, I know that slugging the throats would be the best way to do the measurements but using the inside caliper measurement was the best I had available. I plan on getting the throats reamed out.

What is the Wolff extra strength base pin latch spring? Is it necessary even with the locking base pin?

 

[Jim March]

What is the Wolff extra strength base pin latch spring? Is it necessary even with the locking base pin?

No, it isn't.

The extra strength latch spring is for people who either don't have a lockscrew base pin or don't want to use the lockscrew. People who have convertible guns for example may want to go with the Wolff spring versus locking the base pin for easier cylinder swapping.

The locking base pins and that spring are two ways of solving the same problem. I haven't heard of anybody that needed BOTH.

 

[444]

I just slugged my .45 Colt Ruger Blackhawk a couple days ago. I used Danielson Size 8 Egg Sinkers. I am fairly certain you could find something like that pretty easily, like at a Wal-Mart or a fishing tackle shop. I pounded the sinker in the hole with a wooden mallet and then drove it through with a dowel rod. The idea of using a fishing sinker offers two advantages. #1 they are made of very soft alloy, possibly pure lead. #2 the sinkers have a hole through the center for fishing line which serves to prevent spring back of the lead after passing through the bore.
I purchased my Blackhawk probably close to 15 years ago. I have shot it fairly extensively with both cast and jacketed bullets. I decided to get more serious about cast bullets and the first step was to fire lap it. I wanted to see what the dimensions were before fire lapping and to make sure my cylinder throats were larger than my bore. Obviously if they wern't, I would need to have it reamed; the fire lapping and precise bullet fit would be moot. I got the following dimensions: Bore = .449". Throats = .4515". So I am good there.
The gun has always provided adequate accuracy. I have never done any serious bench shooting to find it's true potential accuracy, but I have always been more than satisfied with it's performance.

I suggest that you slug your bore and throats using pure lead slugs. Then make your measurements with a micrometer. Of course if you just get your cylinder reamed for $25, this would be far cheaper than buying a micrometer if you can't borrow one.

 

[Wedge]

444, I do have access to a micrometer. I will pick up some sinkers today and make some measurements tomorrow in the shop at work just to be sure. If the throats are indeed smaller than the bore, I will send the cylinder off to be reamed.

 

[RCL]

Wedge, here is another link to a fellow who does cylinder throat reaming.

http://free.hostdepartment.com/c/cas45reamer/index.html

A portion of every .45 job he does goes to the educational fund set up for the sons of a friend of his, Pete Martin, a NY fireman lost on 9/11.
"Cas" has been posting for a long time over at Sixgunner.com, my usual hangout.

 

[444]

RCL, I guess I will have to send that guy my cylinder. I had thought about it and decided to send my cylinder away and have it reamed even though it is already slightly bigger than the bore dimension. I was going to send it to the guy at www.45throatdoctor.com, but I have a soft spot for my brothers of NYFD: note my signature line.

 

[Wedge]

Sending out the cylinders tomorrow

I am going to send out both my cylinders tomorrow and have them reamed out to 0.4525" by www.cylindersmith.com. Base pin has just been ordered. I actually had trouble chambering a 300 gr. bullet in one chamber and I think the tight throats caused that, causing really poor accuracy. I'll post how things turn out.

 

[tex_n_cal]

On Belt Mountain Base pins...

check those dimensions again?

I installed one in my Bisley Blackhawk - the original checked .2472", and the BM pin was exactly .2500". It removed a noticeable amount of slop.

If your pin checks .245", the BM pin should help it quite a bit, and the cost is reasonable.

 

[biere]

If you start off on the bear tooth bullet site you should be able to get to some sort of discussion site. Run a search in their revolver section, heck it has been so long I don't know if they have a single action section or not.

These guys had threads and articles about fixing up the rugers in 45 colt since they seem to almost always be sized poorly, at least everyone with one that was bad posted about it.

I think beartooth had a kit for fixing the gun up yourself. From what I recall reading it was something I was willing to do myself since I had the time to do it and am willing to work a little and then check things out.

I learned a lot on that site when I was debating on what caliber to get my blackhawk in, they discussed the pin mentioned above and all sorts of stuff.

The site may be sixshooter.com but I have not dropped in over there in a long time.

I even recall they may have had a reamer they all bought together and then just sort of sent around to those in need.

 

[444]

Another subject sort of along the same line is firelapping. This past weekend I firelapped my Ruger in .45 Colt. I fired 50 firelapping bullets though it. 6 with 220 grit compound and the rest with 320 grit compound. I personally don't think it did much, if anything. The lapping rounds severely leaded my barrel. I cleaned it every 18 rounds so I would be lapping the barrel steel and not the lead. I didn't notice any increase in accuracy, or velocity and no decrease in leading. After lapping the gun, I fired about 20 rounds consisting of 255 grain cast bullets at about 1110 fps. These SEVERELY leaded my bore.
Today I fired 150 rounds loaded with 255 grain cast lead bullets. I fired three loads ranging from the low 700s to the low 900s fps. I still got some leading dispite the low velocity. The bullets were sized .452 which should be fine for my .449 barrel and .4515 throats.
So, I am thinking about sending my cylinder to that guy mentioned, and fire another 50 firelapping bullets through the gun and see where that gets me. This time I think I am going to clean the barrel every six rounds to keep leading to a minimum and make sure the abrasive is contacting the barrel itself and not the leading.