Chamber and barrel diameters

[monkeymt]

Hi,
I am having some trouble understanding some dimensions on two Colt SAA 45 Colt's I have. I am trying to work up a good CB load and have slugged the barrels, both (an original 2nd gen and a 3rd gen) they are at .451. The chamber mouths on both of these guns is a whopping .456. I am using steel plugs to measure the mouths and have cross checked these with two sets of calipers and it still comes up to .456. How can I expect to get decent accuracy when I have to use a bullet that might be sized to .452 at the most. Any help is appreciated.
Mark

[leadman]

Well Mark, Mark here also.
Dave Scovill, the editor for Handloader magazine has written several times on this very subject. You are going to have trouble getting this revolver to shoot accurately the way it is. His best solution, along with Brian Pearce, is to replace the cylinder with one for a smaller caliber, say 44 or 357 and have a gunsmith rechamber it with correct dimensions, probably .452" throats.
The original bullets for the 45 colt were hollowbased (I've read) so they would expand to fit the throats and then get sized down to the barrel dimensions. I have some black powder 32 S&W boolits that are hollow based.
I'm sure others will have suggestions also. If Mike Venturino is on the site he would probably have some good ideas for you.

[monkeymt]

Thanks Mark,
It has been through Handloader that I have learned much about the slugging and cylinder measuring process. The 2nd gen is all original and it has the Stagecoach box and papers, I really should put this away as it is in 80% condition. The other Colt is a 1902 with a 2nd gen barrel and 3rd gen cylinder but it is very good shape and has been tuned by Tom Sargis so replacing the cylinder would be no big deal. The other option I am looking at is buying a USFA Single Action in 45 Colt. From everything I have read they are built right and the issues I am dealing with would be eliminated. I have just recently began shooting my handguns again and love cast boolits and reloading.
Thanks again.
Mark

[leadman]

It would be great if you can measure a gun before purchasing it. The process of measuring a bore would probably make most shops hesitant to let you do this. The cylinder should be no problem.
I had a stainless Blackhawk about 15 years ago that had similar dimensions to your gun. Ruger said this was not a problem. Sold that one quick.

[runfiverun]

buy the usfa get some 452 boolits and have fun.
oh yeah watch out for the light crisp trigger, correct sizing, superb accuracy,and well you know.
a gun that is actually worth the money.

[monkeymt]

Yea,
I think you guys are right. Called USFA today and am looking at buying a 45 Colt and a 44 Special. Love the big bores with cast boolits!
Mark

[Heavy lead]

If you want to shoot it buy some of the Remington 255 grain swaged hollow base boolits. These are actually .456 (at least the ones I have are) and I tumble lube them with JPW and shoot them with no problem out of a Blackhawk with .455 throats and a .452 groove barrel. They have a profile very much like the Lyman 454190.

[StarMetal]

I have Smith Model 25 45 Colt. The groove diameter is pretty tight, smaller then .452. My cylinder throats are around .456. I shoot the RCBS 255 SWC out of it sized to .452. Ask 44man how good it shoots. Don't always go by that cylinder throat dimension as long as it's larger then the barrel groove size. If it's smaller you're in trouble. Best thing to so is shoot it first. I think you'll be pleasantly surprised.

Joe

[Mike Venturino]

Just use .454 inch bullets and it will shoot better than most of us mere mortals can hold. If you use ww alloy or 1-20 tin to lead the extra .003 inch going down the barrel won't cause a bit of harm.

That said, the USFA guns are exceptionally fine. I've got four - three are .44-40s and one is .45 Colt.

Good luck.

[monkeymt]

Thank you all.
I have not been able to try the swaged Remington bullets but did load some more .451 255 gr cast with Unique, Titewad and Bullseye with all performing better than expected. I do get some vertical groups but then I also get some pretty decent ones as well. I will get some .454 bullets and give them a try. Looking forward to the results. I have 44 special USFA on order and think it just wonderful that I have found yet another reason to buy a new gun and more reasons to shoot the ones I have more often. One of the reasons I began this post was because a well known dealer in cast bullets, after I told him of my dimensions, said that that these guns would never shoot worth two bits and if I did not have a new cylinder made I was wasting my time. Interesting.
Thanks again.
Mark