Ruger Blackhawk conv.

[big bore 99]

I recently picked up a new Ruger Blackhawk in .45lc/.45acp. I've read a lot about the cylinder sizing vs throat dia. I am wondering what the cylinder dia, throat dia. and optimum cast bullet might be? I'm a retired toolmaker of 48 yrs, so I can measure these. Just wondering what you guys would call near perfect. Thanks all!

[DougGuy]

I would say the majority of us will size 45 to .452" as nearly 100% of the 45 caliber cylinders that I ream or hone, leave with .4525" - .4528" throats.

[John Van Gelder]

bigbore 99

I have one of those I got back in 1975, it has been a great gun, the option of using .45ACP brass, which is easier to find than .45 Colt is a real benefit. I size my bullets at .452.

[Guesser]

Mine was new in 2005, I slugged the chambers, throats were all smaller than .451, all 12 of them. I slugged the bore, a nice smooth .451, no frame choke. I reamed all 12 throats to .4525. Works very well, but the ACP cylinder is more accurate than the 45 Colt cylinder. I had a batch of several hundred 45 A.R. cases, so I sought out a 45 ACP cylinder that fit my gun and had it faced off so I can shoot the 45 A.R in my gun. It is now a 45/45/45, seems to work well and makes a conversation piece as well.

[John Van Gelder]

Guesser

A number of folks over time have commented that they get better accuracy with the ACP cylinder, my guess would be that the smaller volume case gives more uniform ignition.

[John Van Gelder]

Guesser

A number of folks over time have commented that they get better accuracy with the ACP cylinder, my guess would be that the smaller volume case gives more uniform ignition.

[LazyTCross]

Slug your barrel and find out what your throats need to be. If the barrel slugs at .452 you need to be .0005-.001 over that with your thoats and bullets. Also make sure when you slug the barrel that you don’t feel any resistance in the frame area. If so I may require lapping


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[Land Owner]

My Ruger 45acp/colt convertible with 7.5" bbl is a shooter. For the colt, I cast the Lyman 454190; a 250 gr RN and is "just right".

[Walks]

My old NM Blackhawk in .45COLT was fitted with a .45ACP cylinder in 1984. My bore measures out a .4515 diameter. My .45Colt chamber mouths measure out at .451-.452, My .45ACP chamber mouths measure out at .451-.4515 .

I shoot a .454dia Lyman#454190 sized .454 in the .45Colt and a .452dia RCBS #452-201-KT sized .452dia in the .45ACP.

I have other loads I've tried, in both calibers. It does not seem to matter as long as the bullets are sized at least .452

The .45Colt load is more accurate then the. 45ACP load. By a 1/2 inch, I don't think it really matters.

[Wayne Smith]

PM DougGuy and take a trip over to Wake Forest with your gun. All your questions will be answered.

[DougGuy]

My old NM Blackhawk in .45COLT was fitted with a .45ACP cylinder in 1984. My bore measures out a .4515 diameter. My .45Colt chamber mouths measure out at .451-.452, My .45ACP chamber mouths measure out at .451-.4515 .

I shoot a .454dia Lyman#454190 sized .454 in the .45Colt and a .452dia RCBS #452-201-KT sized .452dia in the .45ACP.

I have other loads I've tried, in both calibers. It does not seem to matter as long as the bullets are sized at least .452

The .45Colt load is more accurate then the. 45ACP load. By a 1/2 inch, I don't think it really matters.

You may be sizing to .454" when you load, but those boolits will exit the front of the cylinder at throat diameter as your cylinder is basically a multi-port sizing die at this point. Same with the 45 ACP cylinder. Now if you were to have those throats all evened out, you remove a lot of the inconsistency with the pressure, uneven throats cause variations in pressure which makes the gun recoil differently from shot to shot so it opens groups accordingly. Even throats fixes this, and is actually the most important dimension for the cylinder, you can always size to fit the throats, but you can't size to fit uneven throats.

[John Van Gelder]

Ruger revolvers traditionally need a little throat adjustment, and Brownells does quite a good business selling throat reamers.

[LenH]

I have a Convertible BlackHawk in 45Colt/45ACP, bought back in the late 70's. I never have tried the ACP cylinder. I still have it but never tried it, up until I started shooting Bullseye I didn't
have a setup to load .45 ACP. I have shot tons of 454-424 255 gr SWC out of that old revolver and 454-309 235 gr. WC. For some reason I never bought the 454-190,
probably money issues way back when. I sized everything .452 and have never had any leading issues.

[beagle]

Shoot .451s in the .45 ACP cylinder and accuracy is better than the .45 Colt cylinder. The 454190HP is my favorite bullet in the ACP cylinder. Advise. Try it before you tinker with it. You may be pleasanty surprised./beagle

[mdi]

I would say the majority of us will size 45 to .452" as nearly 100% of the 45 caliber cylinders that I ream or hone, leave with .4525" - .4528" throats.

Here ya go. I normally size my cast bullets to the same diameter as the cylinder throats, which should be a few thousandths larger than the groove diameter (Don't have my gun notes here so I won't guess at what my bbl slugs at)...