Revolver Ballistics (Hand Loading) Question

[ejcrist]

Let's say you had a Ruger BH 357 Magnum and were shooting a RCBS 38-150-SWC cast boolit over a given charge of "X" brand powder for a velocity of say 1,000 fps. Let's also assume this proved to be your most accurate load with this revolver-cartridge combination. Would your most accurate load when shooting 38 Special in the same revolver with the same brand powder and boolit combination, but with a different charge (due to the smaller case) to reach the same velocity also be the most accurate load? In short (and using this example), would accuracy be equal using the same components as long as the 38 Special was pushed to the same velocity as the most accurate 357 load? Or are there other variables that come into play that I'm not thinking of?

I've wondered this for a long time but never really tested it to find out. And now I'm contemplating buying a FA 97 in 357 with the extra 38 Special cylinder and I'm thinking about it again. If it's true then it wouldn't make much sense to buy the extra cylinder unless you planned to use completely different boolit designs, weights, etc. in the 38 Special loads. Otherwise you would just end up loading to the same velocity with the same components so there wouldn't be much sense. I do prefer to shoot 38 Specials in a 38 Special chambered cylinder for best accuracy, and I need all the help I can get, so I'm in favor of the cartridge specific cylinder concept, but I don't know if it would make any difference in the case of the 357 and 38 coming from the same revolver.

[tazman]

Usually, just getting the velocity the same isn't enough to insure the same accuracy when you change variable like you suggest.
When you change cartridge cases, you change the dynamics of the gun. In your case, you would also be changing the cylinder which is another can of worms.
Too many changes to predict results with certainty.
I like the concept but I don't shoot well enough to take advantage of the different cylinder having marginally better accuracy.

[35remington]

Not necessarily. The overriding factor here is the different bullet jump distance to cylinder throat when comparing the 38 and 357 case. It may be another bullet of a different style might make the transition from case to throat better when 38's are used in 357's. Maybe.

Don't know until you try. While many realize little difference in practical accuracy, I'm unaware of any bullseye shooters or PPC competitors that intentionally cut their 38 Special guns to the longer 357 chamber length. Having the bullet bounce around in the cylinder's chamber before it is centered up by the cylinder throat is usually considered a slight impediment to accuracy.

For most of us it might take a scope on the revolver to resolve the difference.

[ejcrist]

Thanks gents.

Tazman - I agree. Even in the case of the FA with two separate line bored cylinders (38 Spl and 357) the two cylinders would have minute differences that might require two completely different loads for best accuracy with each.

35 Rem - I think it can make a difference but like most things in this sport it's probably not absolute. I'm sure there's guys out there somewhere who own 357's and shoot better with 38 Spl WC boolits that they do with the same boolits in 357 cases. I probably should've used the FA 97 in the example instead of the BH, but would your answer be the same if you compared a FA w/38 Spl cylinder to the same revolver when using the 357 cylinder?

[fecmech]

I only have 1 .357 revolver, a Ruger GP100 6" with a dot sight mounted on it. Off a bench at 50 yds and greater mag cases give me better accuracy than special cases. The same holds true for my .357 rifles. That said, offhand shooting at 25 yds I don't think you can tell the difference.

[williamwaco]

PLEASE DO NOT LOAD .357 PRESSURES IN .38 CASES.

Sooner or later, one of those will fall on the floor or under the seat and wind up in somebody's .38.


.

[Scharfschuetze]

I think that you'd be just fine with just a 357 cylinder with your FA revolver. Save the money from a separate 38 Special cylinder for loading supplies.

While in Germany a few years ago, I shot with a German who had a FA 357 revolver and it was a most impressive pistol.

Over the years, I've fired a goodly number of 38 Special loads through 357 revolvers and to be honest, they seem to shoot just as well as a similar load in a 357 case. A lot of really good marksman on the PPC course of fire used 38 Specials in their 357 cylinder PPC revolvers and they shot some impressive scores... Often to my chagrin. :)

My best loads for match accuracy in the 38 Special and the 357 both use Bullseye powder under a 148 grain WC. The 38 gets 2.7 grains and the 357 gets 3.0 grains for about the same velocity. Both are classic loads and both will shoot the 10 and X rings out of the standard 50 yard B27 target from my Model 19 and Model 28.

[runfiverun]

one of the common themes I see with the switch cylinder black hawks is that the 45 acp cylinder will out shoot the 45 colt cylinder.
I know my NAA with the 45 win mag cylinder was more accurate than the longer 450 express cylinder, I could never locate a 45 colt cylinder to see how it stacked up.

having the extra length in the cylinder throats seems to help settle things down before the jump across the gap.

[35remington]

I would expect 38 accuracy to be quite good in a FA 357 cylinder. Whether getting a 38 cylinder is worthwhile would depend upon whether you were predominately going to shoot 38s or not.

[rintinglen]

In answer to your original question, I could only venture the observation that the two loads might be equally accurate, but don't bet your lunch money. The chances are excellent that the most accurate load in your 357 will use a different powder than the most accurate load in your 38 special. Even though the circumference remains identical, the change in volume alters the combustion chamber so that even if you put the same fuel in there, the combustion pattern will not be the same. The odds are long in favor that there will be some other powder that will do a bit better in the smaller case.

However, if we are taking good accuracy rather than best, I am the opinion that if your three five seven shoots 6.0 grains of Unique under a 158 grain SWC like a house a fire, a 5 grain load in a 38 will also shoot pretty well. But even discounting the manufacturing difficulties in making two "Identical" firearms, I don't think it unprobable that some other powder some where might do a bit better.

However, unless there is a scope on it, a bench and some sandbags under it, you couldn't prove it by me. My off hand skills and eyesight have diminished since I hit 50 a dozen odd years back. These days I'll settle for good and available over best and unobtainable.

[tazman]

However, unless there is a scope on it, a bench and some sandbags under it, you couldn't prove it by me. My off hand skills and eyesight have diminished since I hit 50 a dozen odd years back. These days I'll settle for good and available over best and unobtainable.

I have a similar problem. Except that my offhand skills never were very good, we are in the same boat.

[ejcrist]

In answer to your original question, I could only venture the observation that the two loads might be equally accurate, but don't bet your lunch money. The chances are excellent that the most accurate load in your 357 will use a different powder than the most accurate load in your 38 special. Even though the circumference remains identical, the change in volume alters the combustion chamber so that even if you put the same fuel in there, the combustion pattern will not be the same. The odds are long in favor that there will be some other powder that will do a bit better in the smaller case.

However, if we are taking good accuracy rather than best, I am the opinion that if your three five seven shoots 6.0 grains of Unique under a 158 grain SWC like a house a fire, a 5 grain load in a 38 will also shoot pretty well. But even discounting the manufacturing difficulties in making two "Identical" firearms, I don't think it unprobable that some other powder some where might do a bit better.

However, unless there is a scope on it, a bench and some sandbags under it, you couldn't prove it by me. My off hand skills and eyesight have diminished since I hit 50 a dozen odd years back. These days I'll settle for good and available over best and unobtainable.


Thanks rintinglen - that's the answer I was looking for. Personally I want the 357 and extra cylinder because I figured there are differences between the two and I'll end up with a different powder completely or maybe even a different boolit that will match or exceed the accuracy of the 357. That being the case I'd really want the extra cylinder because I like shooting 38 Specials a lot more than 357's. If however you'd reach the same accuracy by simply varying the powder of course it would be dumb to pay the money for that extra 38 Special cylinder. I asked because I wanted to see if anyone else had any experiences in this area.

I had a lot of guys tell me in the past that it doesn't make sense to shoot 38 Specials in 357's, or 44 Specials in 44 Mag's because you could just download the mag cartridges to equal the performance, and that's where I got the original idea from years ago. By doing this they said you'd maintain the best cartridge fit while only having to change the charge, which I agree with the cartridge fit part for accuracy but not necessarily the charge part. What they said certainly made sense but my experiences didn't support the idea. I have a Ruger SBH, one of my first revolvers, and even though the gap to the throat is longer when shooting 44 Specials than 44 mag's, the revolver shot the Specials a lot better to the tune of about 1/4" at 25 yards off a rest. I also used a different powder in the Specials to achieve that. The same powder that achieved the best accuracy in the Special didn't do well at all in the mag at the same velocity. As a result back then I really wanted a dedicated 44 Special for hunting that was lighter to carry but there wasn't any currently manufactured at the time that I could afford, and the good ones from days gone by were super expensive. I have two 44 Specials now, a Ruger BH and a FA 97, and I wouldn't give them up for anything. Those same fella's are still telling me I should've just used the SBH loaded down, and while I don't have any scientific ballistics data to backup my claim, I have one experience from when my SBH shot the Specials better using a different powder and shot worse using the same powder to achieve about the same velocity. I never did any extensive testing with different calibers but I'd love to do a thorough test one day and report the results. So I'm glad you passed that info along because that is what I thought the answer was and I still do.

[runfiverun]

all I'm gonna say about that is I have a lot of 38 special brass and no 38 special guns.

[DLCTEX]

My 357 BlackHawk convertible shoots 357 and 9mm to the same point of aim at 25 yds. I haven't really tested the accuracy of one vs. the other enough to know which is most accurate, but both do really well. Don't know if a designated 38 cyl would prove to follow.

[tazman]

all I'm gonna say about that is I have a lot of 38 special brass and no 38 special guns.

I do have guns in both calibers. That said, my most accurate revolver is a 357 mag shooting 38 special cartridges. My 38 specials are consistently accurate, but that one gun is a real tack driver.