Theory Question About Distance from Front Driving Band to Throat

[ejcrist]

When it comes to wheel gun calibers that you can shoot short and long cartridges in such as 32 Long/32 H&R, 38 Spl/357 Mag, 44 Spl/44 Mag, etc., I've always avoided shooting the shorter cartridges in revolvers chambered for their longer big brothers, and stuck to using revolvers chambered for the shorter cartridges only when I wanted to shoot them. My reasoning has always been the shorter cartridges would likely shoot more accurately in their respective cylinders due to the shorter jump the boolit has to make to the throat. I think this is especially true when shooting boolits such as the 45-270-SAA in Colts so chambered since the front band sits in the throat but wouldn't if shooting the 45 Colt cartridge in say a 454 Casull. I also figured you'd get a pretty good ring of lead around the lead up to the throat if you shot the shorter cartridges. I've never really tested this theory and was wondering if anyone has noticed much of a difference in accuracy when shooting the shorter cartridges in the "magnum" cylinders. The reason I'm thinking about this again now is because I'm thinking about getting one of the new Single Seven's chambered in 327 magnum but I want it more to shoot the 32 H&R since the cylinder is a bit short for some of my favorite CB's if loaded in the 327 and crimped in the crimp groove.

Thanks, Gene

[JSH]

Gene give me a year to report to ya one the S7. I am on the same track as you with 32's. Plan on using PC to keep the leading issue down, I hope.
I know there are folks that have real good luck shooting 38's in a 357. I am not one of them.
Jeff

[ejcrist]

Gene give me a year to report to ya one the S7. I am on the same track as you with 32's. Plan on using PC to keep the leading issue down, I hope.
I know there are folks that have real good luck shooting 38's in a 357. I am not one of them.
Jeff

Okay, sounds like a plan as long as I can stay disciplined that long. With my luck Ruger won't produce any more after the Lipsey's run, and then they'll cost a gazillion dollars on GB.

[DougGuy]

I'm kinda on the same track. Ruger made a fine Tier2 level revolver when they made the new vaquero and the new model flattop, but there is no cartridges for +P in .45 Colt, and these guns can't take the Ruger Only loads listed in the load manuals for the Blackhawks and early model Vaqueros, so I am thinking of rechambering a .45 ACP cylinder to .45 Schofield so I can develop dedicated Tier2 ammo, that runs in teh 23,000psi range, but has less case capacity than the .45 Colt so it should make for more efficient and consistent powder burn rather than have all the space of the full size case. Plus you can load whatever boolit style and crimp style you want being that it isn't headspacing on the case mouth, and the boolits will be in the throats and not laying in the charge holes like shooting .38Spl in a .357 cylinder. I think it's a worthy project that is a cheap conversion, all it takes is Schofield brass and a Schofield chamber reamer to do it. That and some load data.

[shooting on a shoestring]

In theory you're right. In reality it's not so clear cut. The difference in distance is only 0.100" between 38 Spl and .357. My Model 19 shoots and has shot many great groups with 38 cases and I've never had lead in the chambers nor a carbon ring. My boolits do fit and the gun gets cleaned before it's put away.

Now if the chambers were a bit large, so much so that the cartridge could lay in the bottom of the chamber a bit below the centerline of the barrel, then you might see a difference between long and short cases bc the long case might let the boolit center up by engaging the rear of the throat.

I've also fired some tiny groups using 32 S&W Longs in a 32 H&R Single Six.

Doesn't prove your theory one way or the other. Just my experience its a small matter compared to boolit fit and my trigger control.

[leftiye]

Ya think maybe how much boolit if any (or whether it flops down the chamber and hits the entrance to the chamber mouth maybe sideways) is still in the case when the full diameter band encounters the start of the chamber mouth/freebore might have anything to do with whether or not it transverses the chamber mouth/freebore straight or not? Nagant revolters do purty bad when 32-20 brass is used.

[Silver Jack Hammer]

I read Brian Pearse and Dave Scovill articles and although I cannot quote from issue and page from what I understand no one has been able to quantify any measurable decrease in accuracy when shooting short brass. I've shot .38 Special in .357 chambers for years without thinking about any ill effects. Mike Ventrino says the same thing to the best of my recollection. I have Schofield brass that works fine in my .45 Colt's and I shoot .44 Special in my .44 Magnums, and I have for years.

The only ill effect is that when you shoot a quantity of short brass you need to clean the chambers before loading long brass or the cartridges resist loading. The higher the pressure the loads the more crud forms a ring but short brass loads are usually low pressure loads. I do test high pressure .44 Special loads in my .44 Magnum but after a cleaning job I have no problems.

[rintinglen]

I have shot a ton of 38's from 357 revolvers. Any variation in accuracy seems to be idiosyncratic, dependent more on the gun than the ammo.
If your S7 is like mine, you'll play heck proving your thesis. Mine shoots 32 S&W long, 32 H&R, and .327's equally well to the limit of my ability to shoot. I would have to put glass on it to do any better, and that would defeat the purpose.

[JSH]

May just be my 19, but to use it for bullseye and shoot 38's in it is hopeless. Mind you this for 30 rounds. It fades around 12-18 rounds, goes from fair groups to large patterns. Thought maybe it was me so I had a couple of very accomplished shooters give it a go. Swap to 357 cases and all is well.
IMHO in a 357, using 38's and one can't chamber a 357 without cleaning, there is some type of skidding. Not relative to good accuracy in my findings.
I have loaded something similar to the old 38-200 where the bullet is in the throat with the shorter case and had no build up. So my thinking on the 32 mag in the 327 is to give that a try.
The build up ring of crud or lead in the 38 may be fixed with powder coating, plan to find out as time allows.
Brian, Dave and Mikes findings were in their guns with their loads with their accuracy standards. I am going to have to do some digging and see if I can find those articles.

[44man]

There really is a small difference in accuracy. I have tried many times and even .480 brass in the .475 can not equal the longer brass, using the same boolits that enter the throats.
The only theory I came up with is the lower velocity is not up to the twist.
Not anything you would notice with fast powders in both brass because you are not reaching what the longer brass should be loaded with anyway.
Some just seat longer so capacity is the same, best with slow powders, should work fine.
Maybe a .38+P would equal a .357 unless the boolits are far different weights. There is more to it then just case length.

[leftiye]

I'd guess that if there isn't a demonstrable difference, then there wasn't much fine accuracy in the longer cases in the first place. More to the point, if accuracy is so so or worse, you can't see the difference.

[tazman]

I tried that concept out this weekend at an indoor range. Sandbags, good rest, good lighting, and similar loads. The only difference was the brass. I couldn't tell any difference on the target at all.
I doubt that most people would be able to tell the difference in accuracy between them unless scoped and rested.
If you are a good enough shot, you can tell minor differences in loading or accuracy just by the feel of the gun during the shot.
This is a gift that only a few special people seem to have. I know I am not one of them.

[Dusty Bannister]

I also shoot the smith mod 19 which was purchased new in the late 60's. Also a 357 contender which was "well trained" when I bought it used. Yes, there is some slight build up of powder debris when shooting cast 38 special in both guns. But they are equally at home with either the 357 loads or the 38 special loads. I have to wonder if it is the alloy hardness (about 12-14 BHN), lube, sized diameter (.3585) or moderate loads. I gladly accept the performance of the 38 special rounds in the contender and do not really dwell on the "why" factor. Dusty