.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.

[Petrol & Powder]

Getting back to the OP;
If you were to look at a cross section of a 38 Special chamber and a .357 mag chamber you would see that the major difference is the .357 mag chamber is roughly 0.135" longer. If you are using the same bullet and loading in 38 Special casings and .357 mag casings, the difference becomes the case volume behind the bullet. If both cartridges are loaded with the same bullet, crimped in the same crimp groove, the volume in the .357 mag casing will be larger due to the slightly longer case. This is why slightly more powder is used in the .357 mag casing to achieve the same velocities when assembling light target loads.
The smaller case capacity in the 38 Special loading can result in more consistent velocities. This is exactly what 220 was speaking to in post # 15.
Now, let's look at what happens when the shorter 38 Special casing is placed in the slightly longer .357 mag chamber. The bullet leaves the casing and travels forward into the throat (the bullet diameter section of the chamber immediately forward of the casing but still within the cylinder). As the bullet nose enters that throat the base of the bullet is still in the casing. The additional 0.135" (slightly more than 1/8") is far less than the total bearing surface of the bullet. So while the front of the bullet is entering the throat, the back of the bullet is still in the casing.
Rifle shooters often find that placing the bullet closer to the throat improves accuracy. I think revolver shooters sometimes want to apply that same technique to their cartridges in the hopes that they will reap the same improvement in accuracy. Unfortunately, in revolvers other factors generally outweigh that issue in terms of accuracy. One of those issues is that smaller case volume tends to produce more consistent velocities and therefore has a bigger impact on accuracy than the bullet's relationship with the throat.

So, without making the waters too muddy........Accurate cartridges can certainly be made to shoot well in .357 mag chambers with both 38 Special casings and .357 mag casings but the smaller case capacity of the 38 Special casing may help to generate more consistent velocities and therefore overall more consistent accuracy, with all else being equal. That is NOT saying that .357 mag casing cannot be made to shoot equally as well. It is saying that other factors are likely more important in terms of accuracy.

[Gus Youmans]

Work up the load in whichever case you are going to use and find a load that meets your accuracy requirement. If there is an overall advantage one case has over the other in your gun it will usually be so small that you would have to do all your testing from a machine rest to ascertain the difference. I have worked up target loads for some of my revolvers using both .357 and .38 Special cases but the charge weights are usually different and sometimes a gun will like one powder in the longer case and another powder in the shorter case. If the only variable in a load is the cartridge case, assuming safe loads for both, you will find some shoot better with the long case and some shoot better with the short case. It all depends.......

Gus Youmans

[fecmech]

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.
220--Are you saying these fellows are shooting .357 chambered guns with .38 sp. cases and light bullets??

[tazman]

It all depends.......


Those three words contain the wisdom of this discussion.
Just try it and find out how it works out for you and your guns.

[Bonz]

From what I have heard, on a rifle bullet, you can increase the accuracy by getting the bullet/projectile as close to the beginning of the lands & grooves as possible. I have also loaded ammo for a friend that competes in bullseye shooting. He gives me his Glock barrel to test the COL length with because he wants me to get the JHP bullet/projectile as close to the beginning of the lands & grooves as possible.

[Forrest r]

Well accuracy to 1 person is different than someone else's accuracy standard. I've owned/shot allot of different 38spl's & 357's over the decades and still own/shoot 10 different bbl'd 38/357's as of today. Some thing I've tested in the past is the/bbl cylinder gap.

I own dan wesson 357's and the bbl/cylinder gaps can be set on them with a feeler gauge. Typically the best accuracy is with the bbl gap set to .002" to .003". At least that's been my experience with 10+ bbl's over a couple of decades of shooting. The same holds true with my fixed bbl'd revolvers with .003/.004 performing the best. The larger the bbl/cylinder gap the worse accuracy got as the velocity increased. I've had 38spl's that were border line, .007/.008 gap and they shot light wc target loads fine. Get into anything hot and they just sprayed and prayed.

As far as bullet jump in the longer 357 chambers, as others have said , it depends on the chambers. I've had 38spl's that had loose chambers and the bullets were more accurate when they were seated out. Heck, had a colt trooper III that had super tight cylinders, darn thing shot lights out. I just hated have to load special loads/bullets for it. Anything over .357 and bad things would happen. Started getting fouled from lead/lube bad things would happen. Finely got tired of pampering the darn thing and sold it.

I see a lot of reference to the ppc days. My Schneider built ppc revolver has extremely tight cylinder and eats hbwc's seated flush like candy.
http://i162.photobucket.com/albums/t242/forrestr-photo/e6829466-93ce-4750-bc18-fbb123a52c86_zpslfeojztg.jpg (http://s162.photobucket.com/user/forrestr-photo/media/e6829466-93ce-4750-bc18-fbb123a52c86_zpslfeojztg.jpg.html)

Schneider was famous for his cylinder work on the ppc revolvers and he patented the "short" ppc cylinder that was specifically made for the flush seated wc/hbwc's. The cylinder was just long enough to hold flush seated wc/hbwc bullets in 38spl cases.

I always test different seating depths of the bullets when I do test loads in all of my revolvers. A s&w custom shop 686 and testing 38spl's in it. This is what I consider accurate or an accurate load, 6-shot groups @ 50ft.

http://i162.photobucket.com/albums/t242/forrestr-photo/keepers_zpsrmfa629l.jpg (http://s162.photobucket.com/user/forrestr-photo/media/keepers_zpsrmfa629l.jpg.html)


I've loaded the h&g #50 148gr wc long for decades when used in all my 357 cylinders. The 686 is no different, the h&g #50 wc's are crimped in the middle lube groove. And those 640 loads pictured above are 38spl's with the mihec 158gr hp/640 crimped in the bottom lube groove. How convient that that bullet has 2 different crimp grooves.:brokenima

http://i162.photobucket.com/albums/t242/forrestr-photo/8e26ef61-5d72-4232-9996-108bde84fb55_zpsymwzcftj.jpg (http://s162.photobucket.com/user/forrestr-photo/media/8e26ef61-5d72-4232-9996-108bde84fb55_zpsymwzcftj.jpg.html)

The 686 revolver that shot those 6-shot 50ft groups with the bullets loaded long.

http://i162.photobucket.com/albums/t242/forrestr-photo/686_zpseezfnjnz.jpg (http://s162.photobucket.com/user/forrestr-photo/media/686_zpseezfnjnz.jpg.html)

Some bullets you can't load long like these short 110gr h&g#41 wc's. They have to be loaded in 357 cases when using a little heat on them Heat ='s 1300fps for plinking loads in a couple custom 357's.

http://i162.photobucket.com/albums/t242/forrestr-photo/110gr357s_zps6cepphtj.jpg (http://s162.photobucket.com/user/forrestr-photo/media/110gr357s_zps6cepphtj.jpg.html)

While that h&g#41 load I do not consider accurate by any means, I always move the bullet in or out when I can when looking for loads in the 38spl/357's. Some 357 test loads that will work in either pistol as plinking loads/range fodder/powder burners.

http://i162.photobucket.com/albums/t242/forrestr-photo/neednewbrass_zpsrwuvxmxu.jpg (http://s162.photobucket.com/user/forrestr-photo/media/neednewbrass_zpsrwuvxmxu.jpg.html)

I don't know about everyone else, but yes, I absolutely move the bullets around to see any differences for the same load.

[David2011]

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.

I have one of those old style PPC revolvers. It's fun to shoot but I agree, no more accurate than my Colt Trooper MKIII using the same boolit and charge but that Colt is probably the most accurate revolver I own. When the cylinder is shortened to wadcutter length the cylinder throat is machined away. How does that affect accuracy? It may not because the wadcutter is in the rifling before it clears the cartridge.

David

[44man]

I have never obtained the same accuracy from shorter brass in any revolver, .38 in .357, .44 SP in a mag or .480 in a .475.
It IS NOT distance to the cone for the boolit to move. Since my BFR in 45-70 is the most accurate revolver ever with near a 3/4" jump. Most of my boolits are not near the end of the cylinder in any gun either. Fact is I don't want a boolit so close to the end anyway.
Something else is in play that I never figured out even by using a long boolit to enter throats.
I wish I could say why but the difference is so small anyway, most will never know.
Might be the transition from the end of the brass to the throats. That 1/10" might have boolit entering it.

[SirMike1983]

There are some very good posts and explanations here. It's funny that the Trail Boss suggested loads for .38 spl and .357 magnum have the same powder ranges, at least according to the manufacturer. I use this powder because (1) I have it and (2) it is very good at filling case space while also producing mild loads. I'm shooting .358 swaged semi-wadcutters of 158gr. I don't mess with lighter bullets because my fixed sight revolvers (Model 10 and Model 1905) are regulated for 158. The Model 19-3 has the adjustable sights. I make up a lot of .38 spl because any of these guns can shoot it. The size of the jump in the 19-3 seemed pretty big, which is why I asked about all this.

I have the .357 brass, just have to dig it out of the pile, so as others mention, I'll give it a try. The explanation above about bullet bearing surface, bullet shape, and throat is interesting. The throat and bullet shape may explain why size of jump seems to matter more in cap and ball revolvers than in modern cartridge revolvers.

It's great that after 175 or so years of revolver shooting, if you go back to the cap and ball days, people are still talking about getting more from their six guns.

[220]

220--Are you saying these fellows are shooting .357 chambered guns with .38 sp. cases and light bullets??

No the top guys are using pretty much custom guns in 38 but in my experience you will still get all the benefits in a 357 chambered gun.

Started another thread with pics here
http://castboolits.gunloads.com/showthread.php?298833-Deep-seated-boolits&p=3532062#post3532062

might help anyone having trouble understanding what I mean by deep seated.

[USSR]

Regarding the discussion of "deep seating light boolits". One of my favourite loads is the Lyman 358480 133gr SWC with 3.5gr of Bullseye. Since this boolit doesn't have a crimp groove, proper seating is to crimp just north of the front band, if you crimp at all.

Don

[PAT303]

There are some very good posts and explanations here. It's funny that the Trail Boss suggested loads for .38 spl and .357 magnum have the same powder ranges, at least according to the manufacturer. I use this powder because (1) I have it and (2) it is very good at filling case space while also producing mild loads. I'm shooting .358 swaged semi-wadcutters of 158gr. I don't mess with lighter bullets because my fixed sight revolvers (Model 10 and Model 1905) are regulated for 158. The Model 19-3 has the adjustable sights. I make up a lot of .38 spl because any of these guns can shoot it. The size of the jump in the 19-3 seemed pretty big, which is why I asked about all this.

I have the .357 brass, just have to dig it out of the pile, so as others mention, I'll give it a try. The explanation above about bullet bearing surface, bullet shape, and throat is interesting. The throat and bullet shape may explain why size of jump seems to matter more in cap and ball revolvers than in modern cartridge revolvers.

It's great that after 175 or so years of revolver shooting, if you go back to the cap and ball days, people are still talking about getting more from their six guns.
There is a lot of confusion over Trail Boss loads,the loads aren't max rated for pressure but velocity,in Oz when shooting steel the max velocity is 900fps for handguns so that is the reason both the .38 and .357 have the same powder charge. Pat

[SirMike1983]

There is a lot of confusion over Trail Boss loads,the loads aren't max rated for pressure but velocity,in Oz when shooting steel the max velocity is 900fps for handguns so that is the reason both the .38 and .357 have the same powder charge. Pat

That's interesting. The pressure quotes I see for it are indeed low for those calibers, and the felt recoil is very, very low. I have no real need for 900+ fps with these rounds, so not a big deal for me at least.

[Paul_R]

Well I don't load .357/.38 for extreme accuracy and can't add anything to the great posts in that regard. That said, I use prefer to use .357 cases for all pressures simply because I don't want the problems associated with the crud ring from .38 specials in my cylinders.

[Petrol & Powder]

Aggggghhh, there it is again. The infamous "crud ring".

Does ANYONE clean their guns????? :veryconfu

[Paul_R]

Aggggghhh, there it is again. The infamous "crud ring".

Does ANYONE clean their guns????? :veryconfu

Not at the range between reloads I don't! Doh!

[chutesnreloads]

Aggggghhh, there it is again. The infamous "crud ring".

Does ANYONE clean their guns????? :veryconfuWell yeah.....sure...but shooting them seems more entertaining:kidding:

[tazman]

If you want to shoot 357 mag cases in your 357, don't shoot a bunch of 38 specials as a warm up. 50 - 100, 38 special cartridges fired in your 357 chamber early in your session may be enough to make it so the magnum cases will no longer chamber in your weapon until you clean it. Been there- done that.

On a side note, I also had the same thing happen when I used 22 short ammo in a 22lr chamber. after a couple of boxes of 22 shorts, the 22lr would no longer chamber easily. If you pushed them in and fired them, they were difficult to remove until the chamber was cleaned.

[PAT303]

That's interesting. The pressure quotes I see for it are indeed low for those calibers, and the felt recoil is very, very low. I have no real need for 900+ fps with these rounds, so not a big deal for me at least.
Shot about 60 .38 loads of 4grn under a 150grn RCBS boolit today,in rapid fire the low recoil gives a very big advantage,my 586 likes the 200grn Lyman 358430 boolit the best also over 4grns of TB giving really good 25m accuracy. Pat

[220]

Shot about 60 .38 loads of 4grn under a 150grn RCBS boolit today,in rapid fire the low recoil gives a very big advantage,my 586 likes the 200grn Lyman 358430 boolit the best also over 4grns of TB giving really good 25m accuracy. Pat

If you think your loads have little recoil try the 105swc deep seated, 1/2-2/3 the projectile weight, less powder, just a matter of watching the front sight and stroking the trigger as quick as you can, in a heavy gun recoil is like a 22.

[Forrest r]

If you think your loads have little recoil try the 105swc deep seated, 1/2-2/3 the projectile weight, less powder, just a matter of watching the front sight and stroking the trigger as quick as you can, in a heavy gun recoil is like a 22.

You nailed it!!!!
Light bullets are worth their weight in gold for low recoil loads. A couple of light bullets that I load/shoot, the h&g#41 wc and the h&g#225. The #225 can either be loaded as a swc or be turned around and loaded as a button nosed wc. 4.5gr of trail boss and either bullet loaded in 357 cases make an excellent low recoil highly accurate load.

[SirMike1983]

Shot about 60 .38 loads of 4grn under a 150grn RCBS boolit today,in rapid fire the low recoil gives a very big advantage,my 586 likes the 200grn Lyman 358430 boolit the best also over 4grns of TB giving really good 25m accuracy. Pat

I also noticed again last night how Trail Boss gives almost no flash from the cylinder gap sides. I took a few revolvers with me to the range last night. I brought 2 boxes of .38 ammo made with 3.2gr of 700x powder and one box of Trail Boss rounds. 3.5gr of Trail Boss (in the middle of the manufacturer's range chart) had little recoil and no visible flash/flame at all. The 700x rounds (at the lower end of the reloading manual range) gave a moderate flash from the cylinder gap, basically like factory ammo. Recoil in the 700x rounds was factory-like. The 700x was sootier. The powder was the only difference in these rounds- same bullet, brass, primer, length.