Super Redhawk .454 Chamber Throat Diameters

[Racer X]

Does anyone have first-hand knowledge on throat diameters in the .454 SRH? I know Ruger typically produces them undersize in the .45 Colt Blackhawks. However, I wonder if they pay more attention to detail when they cut the .454 throats in the SRH.

[Casull]

I can only answer for my gun, but the throats were not undersized.  It's been a couple of years since I measured them and then fire lapped the barrel, but if I recall correctly, the throats were around .458 to .459.  Again, this is based on memory.  I do recall they were a few thousandths larger than the bore.

[nicholst55]

Well, I'd hope they're smaller than .458-459", personally.  Ideal for jacketed bullets would be .451-452"; for cast, .452-453".  Smith and Wesson did a run of M25 revolvers (the M25-5) with .456-458" throats, and they tend to be relatively inaccurate with any kind of bullet.  My M25-5 throats run .456-457", and it shoots .454" cast bullets pretty accurately; .451" jacketed won't shoot better than about 3-4" at 25 yards, which I consider marginal at best.

Once I return to the States, I'm going to try the largest cast bullet that I can get to chamber in that gun - hopefully .458", and see how they shoot.

I'd expect your Casull to run .451-.452", or possibly a bit larger; but definitely less than .458-9".

[Casull]

I'd expect your Casull to run .451-.452",

If the throats were .451-.452, accuracy would be horrible.  That's smaller than the bore size.  Like I said, it's been awhile since I did the measurements.  Could have been closer to .456.  Just don't recall offhand.  What I did remember was that the throats were a few thousandths larger than the bore (as they should be).

[nicholst55]

I'd expect your Casull to run .451-.452",

If the throats were .451-.452, accuracy would be horrible.  That's smaller than the bore size.  Like I said, it's been awhile since I did the measurements.  Could have been closer to .456.  Just don't recall offhand.  What I did remember was that the throats were a few thousandths larger than the bore (as they should be).

So just how large a groove diameter does your .454 Casull have there, my friend?  It's a standard nominal .451-.452" barrel, not a .454" as the name implies.  If throats are .458-9" and the groove diameter is .451 or .452', then accuracy will likely be less than optimal as the bullet is inclined to tip before it enters the forcing cone.  Throats need to be at least as large as the groove diameter, but not a great deal larger, for best accuracy.

[Casull]

I stand corrected, nicholst55.  Call it a brain cramp, but I missed a decimal point.  The difference was not several thousandths, but rather several ten thousandths.  Again, I did the fire lapping a couple of years ago, so I'm relying on memory.  The throats were, I believe, around .4529, not .459.  Seems the bore was somewhere around .4523 or .4524.  I did have one bore constriction of about .0002 or .0003 where the barrel screwed into the frame.  The fire lapping opened that up pretty nicely.  I have my reloading stuff packed away, but if I can find my notes, I'll post the actual measurements (not those generated by memory).  But, as far as the original question, yes my throats were a little larger than bore size.

[nicholst55]

No harm, no foul!  I gave up trying to remember all this stuff long ago, because I'm old and have CRS. 

[454PB]

Mine are .452", and sizing even .001" larger will prevent the round from chambering.