"Regarding barrel for FA 454 Casull, did they changed steel later since noted forcing cone ring is omitted?
As for IMR 4227, I tried using it behind 325 SWC-PB (I designed it with 2 grease grooves) in 45 Colt, Ruger Bisley. Managed to get on first try about 3"/25m. However, I think that noted powder is not the best choice for this caliber. With original cylinder, gap was about .006" and no problems. However, with second cylinder gap was less than .002", and in about half instances cylinder was locked because of bird seeds. Obviously, IMR 4227 works much better in high pressure rounds like 357 SM.
P.S. One thing I learned about cylinder to barrel gap; if revolver is for hunting or as a backup, I would like to gap .004-.006". In this case, reliability is more important than dozen or so extra fps with a small gap."
----Onty
*****
Steel
I know neither the steel, nor obviously the heat treatment, used in M-83 barrels. At my last observation, which could be out of date, the Model 83 frame was made 17-4PH stainless at Ruger's Pine Tree Casting in Newport, New Hampshire. Freedom Arms barrels are plenty strong and tough and erosion isn't a problem with the high pressure .454 Casull. Bob Baker reported severe erosion from Hodgdon Lil Gun in .357 Mag, which I don't dispute.
Forcing cone insert
Freedom Arms introduced a forcing cone insert as an option, at my request, to reduce barrel face erosion under voluminous fire. The forcing cone insert threads into the barrel socket of the frame and is secured by a socket-head screw. The insert is smooth and acts as short FREEBORE. Which, contrary to some speculation, does not degrade accuracy in a revolver. Rather, it is my experience that bullet-diameter freebore improves accuracy in the presence of excess chamber-to-bore runout. Mind you, runout is not a problem with Freedom Arms.
Cylinder gap
Most Model 83's of my acquaintance gap firm, .001 to .003-inch. I haven't experienced drag, as the guns run ZERO or near-zero endshake; with cylinder square to barrel. My .44 Mag was the first Model 83 built that wasn't a .454 Casull. while most of the silhouette ammo fired through it was fueled by Winchester 296 and Hodgdon 110, plenty of Sierra 240 JHC, steamed by H4227 and IMR 4227 sailed downrange. Don't recall an instance of hangup on cocking, which includes loaning the pistol to others in championships.
Deep Seating .452 335 LFN Gas Check
Hard cast 335 grain Long Flat Nose GC, deep seated over 20 gr./H110 in .45 Colt brass, COL=1.555". prints 2-inches @ 100 yards from my M-83 . 454 Casull with 4-3/4" barrel. Velocity averages 1,109 fps with single digit extreme spread for 5 shots. Accuracy of 3" @ 100 yards, velocity 997 fps is available by deep seating over 12.5/HS-6; COL=1.696". A Leupold 4x28mm LER scope helps whittle down the human factor. I use a .45 Colt cylinder for .45 Colt brass.
Both of the above loads run 2" @ 100 yards, with a leak opening it to about 3-inches. I haven't verified whether a little flier is attributable to the bullet, or to the shooter. I detect no improvement from conventional seating, and to equal velocity takes another grain of powder.
As a rule I don't deep seat jacketed bullets. As a rule I deep seat cast bullets, lubricated or powder coat.
Maximum loads with slow powder require conventional seating. While I have great use for Freedom Arms accuracy, I have little use for Rocks & Dynamite loads in the .454 Casull.
David Bradshaw