.357 Carbine-.38 spl. Ammo-Carbon Problem?

[Ringo]

Does shooting .38 spl. in a .357 carbine create the same carbon build up in the breech chamber as in the cylinder of revolvers?

[Taurian]

The short answer is yes.

I have a Rossi M92 20" lever gun cambered in .38/.357. After shooting numerous .38 specials I decided to switch over to .357. While the rounds chambered alright, they would not extract properly; the extractor would climb over the rim of the shell casing. I thoroughly cleaned the bore and returned to the .357 magnum loads, which then extracted without a problem.

The shorter .38 loads did indeed buildup a ring in the chamber area that prevented the longer .357 shells from extracting as they should.

Now, I shoot one or the other, but not both in the same shooting session. That said, you can shoot .357 prior to shooting .38 specials and have no extraction problems, assuming the rifle is functioning properly.

[Ringo]

The short answer is yes.

I have a Rossi M92 20" lever gun cambered in .38/.357. After shooting numerous .38 specials I decided to switch over to .357. While the rounds chambered alright, they would not extract properly; the extractor would climb over the rim of the shell casing. I thoroughly cleaned the bore and returned to the .357 magnum loads, which then extracted without a problem.

The shorter .38 loads did indeed buildup a ring in the chamber area that prevented the longer .357 shells from extracting as they should.

Now, I shoot one or the other, but not both in the same shooting session. That said, you can shoot .357 prior to shooting .38 specials and have no extraction problems, assuming the rifle is functioning properly.

If you were to alternate rounds, wouldn't the .357's clean out any build up round for round?

[Taurian]

If you were to alternate rounds, wouldn't the .357's clean out any build up round for round?

The .357 cases are longer than the .38 special. If you have fired a .38 special round, the .357 case rides over top of the rings left by the .38 rounds after they fire. The powder ring decreases the circumference of the chamber. When the hot .357 load fires, the case expands against the chamber wall and the powder ring, which adds resistance. Since the circumference of the chamber at the powder ring is now smaller than designed, the .357 case may stick and be hard to extract or not extract fully or at all, which puts additional strain on the extractor.

If you are going to fire both .38 and .357 magnum ammunition, it is best to fire the .357 ammunition first, since it is the longest. The ring left by firing the .357 magnum is ahead of the chambered .38 and will not interfere with extraction. Whether doing so will "clean out" the residue left by the .357 magnum is left to speculation at this point; it may or may not happen.

Also, working the lever of a lever gun takes some speed on the part of the shooter. The lever is designed to be worked fast (as are bolt-actions). Ejection of the fired round is somewhat dependent on the next round being chambered. The force of the next round coming up into place for loading helps to clear the previously-fired casing from the gun before the next round is loaded, as it is under spring tension from the loader and must align with the bore to be chambered. The faster that you can work the lever, the better the ejection will be. You will see a lot of lever action shooters hold the thumb alongside the receiver rather than wrapping the thumb around the comb of the stock; doing so helps the shooter work the lever faster for follow-up shots.

The Rossi, surprisingly, has pretty tight tolerances. It will chamber .38 special loads all day, every day with ease. The longer (and straight-walled) .357 round can be persnickety about loading and I put a dent in many many a case in the early days of this gun until I caught on to what was happening during the extraction-ejecting-loading sequence.

Note that even with revolvers, firing .38 special loads before firing .357 loads, may cause the .357 cartridges to chamber with difficulty, and even not fully chamber at all and also be hard to extract after firing.

The same holds true with .22 short/.22 long rifle and .44 special/.44 magnum.