First let me say hello, since this is my first post. I've lurked for a while and i have gained a wealth of knowledge from many in regard to revolvers and handguns in general. I've been mostly a rifle kinda guy since i was a wee lad and it hasn't been until the last 5 years or so that i've moved to handguns, in particular SA revolvers. As an engineer by education and profession i can never leave well enough alone if it can potentially be made better, or i am not satisfied with performance...

the problem i find is consistance with anything from my 5 1/2 inch bisley blackhawk. yes i understand that grip and such makes a huge impact... i've spent a while trying to be consistant and handloading in order to improve accuracy. with a rifle i fully understand this, especially when it comes to long range shooting with a long gun.

Through research here i have found many folks quoting dimensions on BH's and such but no where have i found what "ideal" dimensions of say throats, chambers, forcing cones, gaps, bores, lands, backlash, end shake, cylinder thrust, etc actually are.

I have measured most of the things i have listed and some agree with what others have found and other dimensions seem fairly where they should be...

maybe i am just missing something in the whole scheme of things...

but to help my piece of mind.. of the aforementioned list of items what would "ideal" dimensions be for a BH chambered for 45 colt. What else should i consider... i have lightened and polished trigger and that has helped immensly... but i still find it very difficult to get any kind of group (under 4 inches) at even 25 yds with any factory or handload... i can't be that bad a shot... heck i rebarreled, crowned, cut the chamber, bedded action, set the trigger and trued the action on my 700 mountain rifle and with handloads i can make one ragged 5 shot load at 150 yds off of the bags... and not break a sweat... i can also shoot free hand with my sig 229 in 40 S&W... bone stock and put em where i want at 10 yds...

please give me some help.. just want to make her as right as i can...

thanks for taking the time to read my ramblings... if tehre are any specifics anyone needs to know just ask..

Thanks and God bless

Jamie

Welcome. What are the throats currently measuring on the Blackhawk, and what is the groove diameter of the barrel?

Welcome. What are the throats currently measuring on the Blackhawk, and what is the groove diameter of the barrel?

throats are measuring .4505 - .4509 and the after slugging the barrel i come up with .4515 and .445 on the rifling...

gap is .006 with cylinder thrust about .002

i am getting some terrible leading of the top of the forcing cone and first inch or two of the barrel... 250 or 300 gr hard cast anywhere from 800 - 1300 fps.. doesn't seem to matter...

thanks for asking...

Yup, typical. Need to open the throats to at least 0.452", for starters.

Welcome to the world of Ruger Single Action Revolvers.... America's best do it yourself kit!

I can sympathize with your predicament. I'm in the process of writing an article on exactly what you're dealing with at present.

First off, you'll need to address the throat dimensions. Ideally you'll want to see them at .4525", and you can either hone them or ream them, or of course send it off to a smith and have them opened up for about $40.00.

Next on the agenda is to address the constriction in the barrel where the barrel-shank screws into the frame: you'll find anywhere from .001"-.0035" constriction on that .45 Colt due to the thread crush when the barrel is torqued into the frame. The best cure for this is fire-lapping, and at the same time the fire-lapping will ease the top of the forcing cone where your revolver is cursed with slightly more than usual cylinder/bore mis-alignment judging from your description of the uneven nature of your leading issues in the barrel.

Personally I like to see no more than .001" cylinder thrust deflection, and .002"-.003" ideal cylinder gap. However, this isn't nearly as critical as many make it out to be, so long as the throat/bore dimensional relationship is put into it's proper proportions and the thread-choke constriction is lapped out of the bore while at the same time truing up the forcing cone with the axis of the chambers of the cylinder.

These couple of modifications will make that revolver shoot like an entirely different firearm, and that's a promise!

You might check out our Beartooth Bullets Technical Guide (http://www.beartoothbullets.com/bulletselect/book.htm) where you'll find detailed instructions for the processes mentioned above, and for more specifics on preferred dimensional relationships in revolvers. Too you might be interested in our Fire-Lapping Kits (http://www.beartoothbullets.com/bulletselect/firelapping_kits.htm).

I hope this information helps you acheive the superb accuracy potential your revolver is capabe of delivering!

God bless,

Thanks for the continuing replies. I appreciate the information and suggestions. I've been meaning to purchase the whole lapping kit for a while i have just been lax about it. Maybe now is a good time.

As far as throat reamers / hone... can anyone enlighten me to the BEST tool available from say Brownells? I am not against purchase of this since i honestly plan to aquire another bisley in SS in the next week or two...

Thanks to all.

Jamie

PM me with your email address and I'll send you some information on this. Brownell's has a kit but you can do it quite a bit cheaper, if you are handy with metalworking tools.

PM me with your email address and I'll send you some information on this. Brownell's has a kit but you can do it quite a bit cheaper, if you are handy with metalworking tools.


I just want to thank you Mike, we'll be reaming tonight... 11.5 mm straight flute and turned my own bushing from some 7075... Therefore we'll be prepared when Marshall's lapping kit arrives... I finally decided what the hey... it can't hurt ;)

Thank you for everyone's input...

Never too late to teach an old dog new tricks.. not like i am really OLD or anything :rolleyes:

Jamie

Just as an update,

Put about 75 rounds through the gun on Sunday afternoon. The throats were opened up to just under .453 and the forcing cone was smoothed out a bit. Result was no appreciable leading of the forcing cone. It actually appeared pretty darn clean. The throats were just powder coated with no leading. Barrel still leaded up pretty heavily even with the LBT Blue soft on the hard casts. Bullets removed from the dirt pile revealed no lubricant left on them... so it was deposited in the barrel. Accuracy was still a bit to be desired but that may be me as much as the gun. We'll be giving the bore a good fire lapping treatment this week and try her again next weekend...

Thanks for everyones help

Jamie

What is your bullet diameter? Cast should be at least .001 over groove diameter. WHen I shoot undersized bullets in my rugers, they lead badly.
Select after fire lapping and reslug barrel.
Humpty