.38 vs .357 target loads and revolver gap

[SirMike1983]

Has anyone here found that reducing the gap from bullet to forcing cone improves accuracy? I ask because I have both .38 and .357 brass. I'm shooting light target loads using Trail Boss. Their website calls for largely similar loads in .38 and .357 because the powder more or less maxes out after a certain point. The basic difference between the rounds is the size- the .357 Trail Boss loads have a small jump to the forcing cone on my S&W 19-3. None of these loads approach true .357 pressure or velocity, nor do I want them to. What I'd like to know is whether it is worth using the .357 brass to get the bullet closer to the cone, or whether that just does not matter in cartridge revolvers. I also shoot some cap and ball revolvers, and the gap does make a difference in them, though that is with a round ball and black powder.

[FergusonTO35]

Conventional wisdom holds that it does, however a wide variety of other factors are at play also. If you have a favorite load just try it as a .38 and a .357 and see which works better.

[tazman]

I don't know about the difference between using 38 special as opposed to 357 brass. I haven't tested it. What I have done is load my wadcutters long by crimping in one of the grease grooves for use in my 38 special.
In almost all instances, having the boolit nose actually enter the cylinder throat improved accuracy somewhat. It seems to improve boolit alignment with the throat and therefore with the barrel. I had one load that I actually had to push the cases firmly into the chambers because of the tight fit with the throats(boolits were sized to throat diameter). No fast reloads there, but the accuracy was great.
The Lyman or NOE 358432 achieves this pretty much by design. The nose is slightly smaller but allows some alignment. Since the boolit is seated more out of the case leaving more space inside the case, you can use full power powder charges for semi wadcutters quite safely.

[Petrol & Powder]

The jump between the cylinder face and the forcing cone does not change with the length of the brass in the chamber. The cylinder gap is the cylinder gap. I think you're mixing your terms just a bit. The throat of the cylinder is the section ahead of the chamber within the cylinder. The forcing cone is the breach end of the barrel where the bullet transitions into the rifling.

That being said, I've never seen a significant difference with 38 spl cases in a 357 mag cylinder, other than less powder will achieve the same velocity in the smaller casing with all else being equal.

[Dale53]

Many years ago, we shot a lot of PPC around here. Leo's and civilians competed regularly. Competition was fierce. My club hosted a number of matches. I had access to a Ransom rest and tested a good number of fellow competitors' guns. Many of them were chambered in .357. Using VERY good wadcutter ammo, most guns shot as well with .38 cases as the longer .357 cases. However, occasionally, a revolver did consideraby better with the magnum cases.

There is NO substitute for actually testing a particular gun.

Dale53

[Baja_Traveler]

I rebarreled my redhawk with a heavy 10" flutted barrel many years ago with the intention of using it for IHMSA silhouette. I made the barrel/cylinder gap very tight, and soon discovered that the occasional lose primer pocket would let a fired primer extend just a bit, causing the cylinder to drag.

[Scharfschuetze]

I have found no difference in accuracy between 357 and 38 Special brass on targets when used in a 357 cylinder with similar loads, often at high levels of competition. Your intuition dictates that there should be a difference, but in over 40 years of shooting the two out of several 357 revolvers, I've never been able to really see much difference. I do increase the powder charge by a couple of tenths in 357 cases to maintain an equal velocity with 38 cases in my target loads.

Back in my PPC days on the PD, one of the PD team members (a very good shot) actually had his S&W 357 revolver rebuilt with a shaved cylinder which was cut to the length of a flush seated HBWC in the 38 Special case. The heavy PPC barrel for it was extended back through the frame to mate up with the shaved cylinder. Guess what? It shot no better and no worse than my heavy PPC revolver with either of us shooting them. While the boolit had virtually no jump from the case to the forcing cone, it provided no better accuracy than a standard PPC revolver.

As far as cylinder gap, as long as it isn't extreme either way, it isn't any real big deal. If it's between about .005" and .008" you'll be in good shape to keep your cylinder from dragging due to a high primer or lead build up on your forcing cone or cylinder face. Velocity loss won't be noticed if indeed there is any with the loads that you are contemplating. While one can fit a cylinder up tighter, reliability may become an issue as noted in the post above.

It's not necessary to say this: but for consistency's sake, at least keep the brass segregated for shooting and reloading.

[phonejack]

I have 4 .357's. What you describe does make a difference in all of mine. For that very reason I only use 158's with their longer length.

[RogerDat]

Best excuse for using 357 brass is magnum loads, for years most of my 357 plinking ammo was 38 special. I could not tell any real difference in accuracy between that and 357, but sometimes it is nice to shoot actual 357 magnum loads. Can be a bit more area to clean from the shorter brass I guess but no harm from it that I have ever noticed.

[220]

My favourite light target load at present is lee 105swc deep seated over a light charge of quick powder.
By deep seated, by which I mean as far as I can get them in a 38spl case, nose of the projectile is about 1/8" below the case mouth driving bands would be about 1/2" below the case mouth.
Does it effect accuracy, hell yes and all for the better 10 shot groups at 25m average about 1.5" from a stock standard 686.

[fecmech]

When we speak of testing PPC loads and other target loads in the .38 spl vs .357 chambers we generally are speaking of hollow base wadcutters which are the perfect bullet for the extra long jump. The soft hollow base expands quickly and easily to prevent gas cutting and the long length helps to maintain alignment. It has been my experience that with other designs such as SWC's,RN,RNFP's and lighter for caliber bullets such as 125 gr bullets there is a definite difference in accuracy using mag brass vs .38 brass. Pretty much meaningless inside of 25 yds but shows up at longer ranges.

[Le Loup Solitaire]

FWIW; Old handloader saying, 357s make better 38s. LLS

[.429]

My most accurate plinker in my gp100 is 5.2gr Unique over 130gr RF Accurate in 357 casings. They are 38spl velocities. I don't shoot 38spl casings in that pistol anymore, because of the carbon ring making it difficult to chamber 357s.

[Petrol & Powder]

Well we made it all the way to post #13 before the "carbon ring" thing came up. Frankly that was farther than I thought we would make it.

[220]

When we speak of testing PPC loads and other target loads in the .38 spl vs .357 chambers we generally are speaking of hollow base wadcutters which are the perfect bullet for the extra long jump. The soft hollow base expands quickly and easily to prevent gas cutting and the long length helps to maintain alignment. It has been my experience that with other designs such as SWC's,RN,RNFP's and lighter for caliber bullets such as 125 gr bullets there is a definite difference in accuracy using mag brass vs .38 brass. Pretty much meaningless inside of 25 yds but shows up at longer ranges.

Have a look at what the top shooters are using, in Australia light for calibre SWC deep seated has become the standard, not just me that it works for. Look at the WA1500 world rankings, half the top 10 are Aussies using similar loads.
These blokes aren't trying to hit the 10 ring but trying to keep every shot in the X ring even at 50y.

[40-82 hiker]

I am having very good results shooting H&G #50 150ishgr. wadcutters from .38Spcl. wadcutter cases in a Colt Trooper Mk III .357. The boolits are very soft, however (soft SOWWs only plus 2% tin). In other words, I am having pretty much the same results as most. Oh, BTW, 2.7grs. of Bullseye.

I shot several thousand rounds of the above load last year and see no problems, and don't think I will.

[Ia.redneck]

Thanks for that info 220, I'll have to give those a try in my 686.
Never thought about that combo.
Any chance you could PM me that powder & charge?
Thanks

[SirMike1983]

Gap is probably not the best word. It is more bullet jump and is the distance from bullet nose to forcing cone. These loads are both soft, so the real difference is the overall length of the . 357 lowering the jump. I guess people are having different results with difficult guns. I will have to try it.

No issues with carbon rings here- I clean after every range session and they never seem to build up much.

[357Mag]

Sirmike -

Howdy !

IMHO - I can't imagine why a shorter .38SPl cartridge would fer sher out-shoot a suitable .357Mag " target " load... in a .357Mag revolver.

I've had such good results shooting a no-kidding " magnum-level " load for target work w/ my .357Mag "N"-frames; that I see no compelling reason to use " .38's " .
But hey..... that's just me.


Info note: .357Mag cartridges assembled fit "N"-frame cylinders.... run a bit shorter in c.o.a.l. than what many other .357Mags can accomodate.


With regards,
357Mag

[220]

One thing that deep seating light boolits does achieve is a significant reduction in case capacity.
It would almost eliminate any variation due to powder positioning and hence give much more consistent shot to shot velocity.
Also despite what some may claim Im yet to see a shooter who's shooting improves as recoil increases, with these loads recoil is almost non existent. If you think a 148grWC has no recoil then think about a 20% or more reduction in that again. Recoil recovery is far quicker so it is no surprise those chasing the best scores have adopted it in competition where allowed.
Any reduction in accuracy seems to be well and truly out weighed by the benefits.