SO, I REMEMBER SEEING A POST ON THE CORRECT SIZER USED FOR REVOLVER BULLETS BASED ON THE CYLINDER THROAT DIA., BUT I CANT FIND IT.
i MEASURED EACH CHAMBER, 2 @ .356, AND THE OTHER 4 AT .357.
WHAT SIZE SHOULD I SIZE THE CAST BOOLITS?
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SO, I REMEMBER SEEING A POST ON THE CORRECT SIZER USED FOR REVOLVER BULLETS BASED ON THE CYLINDER THROAT DIA., BUT I CANT FIND IT.
i MEASURED EACH CHAMBER, 2 @ .356, AND THE OTHER 4 AT .357.
WHAT SIZE SHOULD I SIZE THE CAST BOOLITS?
Contact member DougGuy and have him hone your chamber throats to .3585". The chamber throats need to be at least as large as your groove diameter.
thank you.Quote:
Originally Posted by nicholst55
^^THIS^^ I have a RBH 45colt that had 0.4505" avg throats. Shot ok with cast but always got early leading. Opened them to 0.452" & leading pretty much went away & accuracy was better.Quote:
Originally Posted by nicholst55
I've had a Ruger Blackhawk 357 magnum since 1970 , the Lyman manual at that time instructed to size them .357" which I did for 40 years .
Tried .358" a couple years ago and the accuracy is the same ...5 shots touching and 1 shot 1/4" away from the rest ... there always seems to be one .
I might be tempted to leave the 4 throats at .357" and have the other two reamed to .357" to match ... but ask DougGuy what would be proper ...he's the expert...
... hole reamer :holysheep :)
Gary
Not sure how the oversize ones (all of them) are ever going to get smaller to .3585"????? That would be a trick!Quote:
Originally Posted by triggerhappy243
That would work.Quote:
Originally Posted by gwpercle
I had Doug work my 45lc Blackhawk. Highly recommend his work
How did you measure your chambers?
I guess my question is, are you confident in your measurement?
Yeah unless you are using pin gages or inside micro, its a guess. Sized bullets as pin gages may be ok, if you can accurately measure those.Quote:
Originally Posted by JustinP
So .3585" is smaller than .356" and .357"?Quote:
Originally Posted by Tall
OK.
Not to discourage having work done, but if you have a sizer it is simpler to just size a bullet and see if it goes through the chambers. Then you will know for sure if your measurements are right and if you need to spend effort having the gun worked on.
Not to overcomplicate the issue, but before starting work on the cylinder, I would start by checking for frame crush first, and work backwards from there.
You can check this with pin gauges. If the bore diameter of your barrel will allow - for example - a maximum of .346" or .347" pin gauge to start down the muzzle, but it won't push past or gets tighter at the junction of frame and barrel, then you have probably .001" to .002" of compression from when your barrel was screwed in under force. This can cause leading if your bullets can't obturate back up to the correct diameter of the rest of the bore.
Look up some of our threads on fire-lapping your barrel with grit impregnated bullets. This will hone out your frame crush, and if you're clever enough to only shoot your lapping bullets out of your tighter chamber throats, you can possibly bring those up to the same spec as the rest.
But once any frame crush is gone, you can properly slug your bore for groove diameter, and make determinations on what your cylinder may need from there. Odds are you have a .357" groove, will ultimately want .358" bullets, and a baaaaaaarely larger than .358" cylinder throat.
Basically, start with the barrel and work from there.
+1 - Doesn't make a difference if all the chambers are the same diameter if the barrel swages them down further. Having all of the chambers set to .359" wouldn't make a lick of sense if the bore measures .360" either.Quote:
Originally Posted by Bigslug
In addition to the thread choke there can also be a restriction along where all the warnings and info is stamped/roll pressed into the barrel. I found this in my 80's RedHawk and Ruger Speed Six using pin gauges. As mentioned, a proper fire lapping regime can fix a lot.Quote:
Originally Posted by Bigslug
I bought manuals/components from both NECO Pressure(fire) Lapping https://www.neconos.com/category/PRESSUREFIRELAPPING-20 and Beartooth Bullets, Technical Guide, A Comprehensive Guide for Unsurpassed Performance Using Cast Bullets by J. Marshall Stanton. Marshall Stanton's book is a genuine treasure to me. Unfortunately Beartooth Bullets and Marshall Stanton seem to have sailed into the sunset.
edit: there is a Beartooth Bullets Technical Guide listed on Fleabay for about twice what I paid ten years ago.