.45 Colt RIFLE groove dimensions?

[Pilgrim]

Probably going to buy a .45 Colt rifle in the next few weeks. It will never see a jaxketed bullet while I own it. Are the dimensions of the Rossi and other imports .451/.452 groove or closer to .454? If the latter I'm probably going to need a custom mould or two as the only .454 mould of which I am aware is the RCBS 250 gr. FP mould. Everything else appears to be .452. Info, please....Pilgrim

[felix]

Groove dimension is not the problem, Pilgrim. It's the chamber LIKELY being too large for the brass available. 452s shoot fine in all the 45s I have, and it was fun to find the load for one gun compared to another in the "same" caliber. ... felix

[Outpost75]

The problem with .45 Colt is that the standard SAAMI chamber dimensions run larger than necessary, because they are based upon the original government drawings which provided generous clearances to allow for accumulation of blackpowder fouling. The throat and ball seat of my H&R Handi Rifle are .457" and I use as-cast and unsized .456" Saeco #954 230-grain bullets of 1:30 alloy with standard handgun charges of 6.5 to 7.2 grains Bullseye powder in mine and get 2" groups with iron sights at 50 yards. Groove diameter of my rifle is .452" and twist is one turn in 20." It shoots well with traditional style factory Remington or Winchester soft swaged 250-255 grain lead conicals.

Commercial hard-cast .452" bullets keyhole and shoot groups over a foot and lead the throat with any load!

If you can find a gunsmith having a reamer which cuts as close as possible to the minimum chamber, like a pressure barrel reamer, this is what you want. Many of the .45 Colt barrels out here have too slow a twist, 30" or slower, which won't stabilize bullets over about 250 grains. You want a 20-inch twist, same as was standard for the .45-70, but with .452" groove diameter, with tight bore of 0.448" or less, having equal width lands and grooves, aka "Ballard" style rifling, and a minimum chamber cut with a reamer having a reground ball seat with forcing cone entrance diameter not larger than .455".

[geargnasher]

I have several "import" .45 Colt rifles and their groove dimensions typically fall around .451".

But like Felix and Outpost75 mentioned, the chambers and throats can be rather "generous", to a fault. My H&R Classic Carbin has a .4525" groove diameter, LH twist, but will chamber a .456" boolit in Starline brass with about a thousandth to spare. My solution is to either size .452" boolits to .448" (a fuzz over bore diameter) and paper patch to fit snug in fired brass (two wraps of Meade Sketch paper does it) or just run a Lee .457-340 through a .454" die after lubing in a .458" (keeps the lube grooves from collapsing) and shoot them that way. If I shoot regular pistol ammo with .4525", 255-grain boolits, there is sufficient blowby as the boolit jumps through the throat to cause leading in the first few inches of the barrel. Some other rifles I have also have rather generous throats and chambers and can be picky about boolit selection, but not as bad as the H&R.

For 250-ish grain boolits in a levergun, it might be prudent to wrap a 1/8"-wide strip of cellophane tape around the case head right up against the rim to center each cartridge snugly in the chamber before the first firing, then ONLY size the brass in a carbide die just far enough to hold the boolit securely (like "neck sizing") for all subsequent reloadings. This, combined with seating far enough out to just barely kiss the lands if the action will allow will center the cartridge in the chamber and can greatly improve accuracy in the .45 Colt guns. Or just load them like normal for a revolver, make sure they'll cycle and chamber, and go to the range to see what happens; that's the first thing I would do.

Gear

[Catshooter]

Pilgrim,

You never know chamber/throat size or bore size until you measure. Just like any mould, the size listed is "nominal". That means somewhat close! :)

Both of Winchesters and my H&R have tight bores like .451 with matching chambers/throats. They shoot very well with anything over .452. Just lucky I guess.


Cat

[DougGuy]

I am looking at a Henry Big Boy in .45 Colt at some point in the future, how are the chamber/throat/groove dimensions on those rifles?

[Airman Basic]

I am looking at a Henry Big Boy in .45 Colt at some point in the future, how are the chamber/throat/groove dimensions on those rifles?
Same ? with Rossi 454. Looking at one in another thread. Any chamber/twist/groove problems ya'll can tell me?

[Catshooter]

Airman, Doug,

Read my post #5.


Cat