Bore size

[b247s3st]

Hi:
I'm new here so please be easy with me. I own a Colt SAA 45LC w/71/2"barrel. I bought the gun new in 1972 with a ser # of 57XXXSA. I reloaded back then and after a few years I put the gun away and just recently pulled it out again ready to pick up where I left off. My question is does anyone know the bore size? From what I remember it was .451 and from what I am reading the gun is post WWll and should be .451. If it is .451 what size lead can I load? Would .454 be too big or would .452 be a better fit. I still have my older reloading books which will serve as a good starting point.

Thanks
Bob

[Kid Sopris]

Stick with .452. If you go too large you will shave lead and gum up the forcing cone, not to mention throwing lead out the sides.

PS.... Welcome!

[b247s3st]

Thanks for your answer Kid. .452 does ring a bell. Do you know if the bore size is .451? Thats the question I need to know.
Thanks
Bob

[smkummer]

To find out you really need to slug your bore. That is to drive a slightly over size lead ball down your barrel and measure it. Post war Colt single actions should have a .451 groove diameter barrel but only one way to know for sure.

It is often talked about reloading for 45 Colt that even though the bore may be .451, several report better accuracy when using .454 diameter bullets. Modern dies account for .451/.452 bullets but the chamber throat area is usually still oversized. The steel sizing dies made after WW2 will size the 45 Colt case with a ever so slight bottleneck to account for slightly smaller bullets. The carbide dies size the whole case smaller. If firing any loads that are not right at max. sammi specs. such as cowboy loads, one finds that the cases will be much sooted up from powder gasses as the case seldom fully swells back completely from a carbide fully resized case. My technique is to size only the top 1/3 to 1/2 of the case but these loads will only fit back in my Colts (including a Anaconda) I have noticed that with my 3rd generation Colt SAA will shoot .454 diameter bullets better than 452. It is common for jacketed bullets to be sized right at bore diameter of .451 but lead bullets to will be sized at .452.

[Ken S]

I have two third gen .45 Colt SAA's, and I use .454 in both.
I load the Schofield cases with 6.4 Unique and have found the
.454/250 RNFP to be the most accurate.

I have used the .452/230 RNFP and 6.3 Unique, but it's not as accurate as the .454

452's will group 2 to 3 inches offhand at 50 feet. good enough for Cowboy or plinking. However, they are not as accurate at 25 yards.

.454's will group in the 2 inch or less range offhand at 50 feet, but will go into 2 1/2 inches at 25 yards.

It's the cylinder throat that is the important measurement. If the .452's fall through, they are too small. If the .454's catch as you drop them in, that will mean better accuracy.

[b247s3st]

Ken and Smkummer: Thank you for your replies. Your right, the only way to be sure is to slug the bore. I am new to my area of Tennessee and am still finding my way around for supplies. Yes my cases were sooted up. I never loaded very high. I like your ides about only sizing 1/3 to 1/2 case length. I also believe the cylinder walls are still at the older size. I find it interesting that you would use .454 in a newer gun. Over a long period of time might this cause a problem with the bore? Also would it cause excessive pressure?
Thank you once again
Bob

[Ken S]

about the .454 /250. Mike Venturino suggests to use that size in all his .45 Colts. I miked the cylinder walls in my new .45 SAA, and they run .454 to .455. So, .454 is the correct size.
Like I said, I use the shorter Schofield cases with 6.3 to 6.4 Unique, and the .454 would not cause excessive pressure.
The SAA factory load in the .45 Colt case is 8.0 Unique and the same .454/250 grain RNFP., so I'm well below that.
Using lead bullets, this is well within pressure limits for the gun.

For plinking, I still load the .452/230 grain. with 6.3 Unique, but it's not as accurate. 3 inches at 50 feet,where the .454 will do 2 inches or so.
And thats offhand with 64 year old eyes.