38 special brass??

[DMW1116]

Is there something to be said for keeping the process the same? I reload 3 rifle and 3 pistol cartridges. I measure, trim, and bevel all of them so I don’t have to remember to treat each one differently. I don’t trim every time and beveling only needs to be done once but when I load it the first time it gets the full treatment, rifle or pistol.

 

[buck460XVR]

The throat is a barrel or cylinder dimension, or both. Obviously if the cartridge can be loaded into a cylinder and closed it isn't a case dimension issue. Cases don't encroach on the barrel throat, bullets do that. In the case of a revolver, if the bullets were actually causing a problem with the barrel throat, the out-of-spec OAL wouldn't allow the cylinder to turn because bullets would be jamming against the barrel forcing cone. You may be forgetting that a revolver cylinder is the chamber unlike a rifle or pistol.

I think what Bob Wright is referring to is over length cases and not too long of OAL. A roll crimp will shorten the case enough to allow the cartridge to chamber, but when fired the crimp will unroll and tighten neck pressure on the bullet due to throat constriction, impeding the initial bullet movement and raising pressure. Revolver cases stretching enough to do this would come from very high pressure rounds like .454, .460 and Ruger type .45 Colt loads. One would trim these anyway since they need consistent length for consistent crimp. These are also the calibers used most for hunting and demand high accuracy. Bullet jump is very real also and to prevent, a consistent crimp is needed. This can only be obtained by having cases of consistent length.

 

[BobWright]

I think what Bob Wright is referring to is over length cases and not too long of OAL. A roll crimp will shorten the case enough to allow the cartridge to chamber, but when fired the crimp will unroll and tighten neck pressure on the bullet due to throat constriction, impeding the initial bullet movement and raising pressure. Revolver cases stretching enough to do this would come from very high pressure rounds like .454, .460 and Ruger type .45 Colt loads. One would trim these anyway since they need consistent length for consistent crimp. These are also the calibers used most for hunting and demand high accuracy. Bullet jump is very real also and to prevent, a consistent crimp is needed. This can only be obtained by having cases of consistent length.

Thank you for that clarification. You stated my intent much better than I did.

But, as you point out, an over-length cartridge case will chamber, and when fired is a booger to extract. This from experience.

Bob Wright

 

[BobWright]

The throat is a barrel or cylinder dimension, or both. Obviously if the cartridge can be loaded into a cylinder and closed it isn't a case dimension issue. Cases don't encroach on the barrel throat, bullets do that. In the case of a revolver, if the bullets were actually causing a problem with the barrel throat, the out-of-spec OAL wouldn't allow the cylinder to turn because bullets would be jamming against the barrel forcing cone. You may be forgetting that a revolver cylinder is the chamber unlike a rifle or pistol.

I have experience with that using a 625. Ammo over the OAL due to bullet creep will lock the cylinder up tight. They simply can't be fired.

How does that happen? The OAL is within spec when the cyl is closed. Firing the revolver pulls the bullet and OAL becomes too long which locks the cyl.

O.K. Here's what I should have said, to clarify my original post:

"Umm...............I'll differ with your there. Revolver cases stretch until they encroach on the CYLINDER throat. The roll crimp will allow over length CARTRIDGE CASES to chamber and fire, which does increase pressure and makes for stiff extraction. And, differing lengths will lead to inaccuracy. Its best for all cases be the same length."

Bob Wright

 

[CoalTrain49]

Now we're getting this sorted out. Revolvers typically don't headspace on the mouth of the case, although they could if the case is too long. That can cause problems because the rim isn't contacting the cylinder where it should and it isn't head spacing on the rim. In that situation the rim is a few millimeters away from the cylinder and not where it should be. Too long and things don't work the way they should. Too short and nobody knows. Hence 38 Spl. in a 357 chamber.

I need to measure my brass. Never suspected that might be the cause of hard extraction. Please, no jokes.

 

[Palladan44]

I've never cared too much, except when I'm loading WW-296 or AA-300MP where the OAL needs to be correct AND the case mouth needs to line up right in the middle or upper middle part of the cannelure for a nice roll crimp, and the only way to achieve consistency there is usually to trim. Sometimes a batch of once fired/matching will work good enough. I've done it both ways.

I've noticed a lot of my target loads/general purpose loads line up noticibly in different areas along the crimp groove. Even though the OAL is the same, the difference comes in different lengths in brass....if I were to guess, I'd say there can be up to .001 to .0015 difference in brass lengths in some of my mixed lots....I cannot shoot well enough to notice a difference. These loads receive a light taper crimp. Lots are loaded in .38 cases to be fired in 357 guns, in which case I'm pretty sure it makes no difference.

 

[Palladan44]

Anyone have data showing the difference in group size between same-headstamp and mixed-headstamp cases in the 38 Special?

I'm sure not. It's like Speed-waxing a tank to reduce drag so it goes faster, and still goes the same speed after.... that's how I've found splitting hairs with handgun shooting unproductive.
Hand weighing projectiles and organizing them in batches so they're all within .10gr to trickle charging powder....just to still have the same ragged hole at 15 yards. Most of my front posts sights on my handguns completely cover an 8 1/2" x 11" sheet of paper at 20 yards. Maybe it's the engineers of the firearms trying to tell me something....
I have no scopes on any handguns, and don't plan on it.

 

[joneb]

Well,I trim all of mine to get the same oal and crimp the same.

The length of the brass will not effect the COL of the finished round, but it will effect the crimp. Not all brass is created the same, some is thicker and some is of a different brass alloy. This will effect the case neck tension on the bullet, which will effect everything.

 

[BobWright]

I need to measure my brass. Never suspected that might be the cause of hard extraction. Please, no jokes.

The first time I noticed this was many years ago I had some old .44 Magnum brass that had been loaded many, many times, until I no longer trusted them with serious loads. I shot these in an old S&W .44 Magnum and had to drive the stuck cases out by pounding on the extractor stem with a plastic mallet. So now whenever I start to get sticking cases, to the trimmer I go!

Bob Wright

 

[BobWright]

Now we're getting this sorted out. Revolvers typically don't headspace on the mouth of the case, although they could if the case is too long. s.

Even then the cartridges don't really "headspace" of the case mouth. Revolver cartridges typically have a roll crimp that allows the cartridge to "ride up" over the shoulder of the cylinder throat and the rim does contact the face of the cylinder. When the bullet leaves the case mouth, it swages down slightly at the heel to get out of the restriction of the case.

This was the idea behind the old .32-44 and .38-44 S&W cartridges, where the case was full length of the cylinder. There was no "bullet jump" with these cartridges, and case length was of no concdern.

(Don't confuse the .38-44 S&W with the .38-44 S&W Special.)

Bob Wright

 

[gonoles_1980]

I trimmed both 38spl and 357 brass for a while when I was using the seat and crimp at the same time. Now I just use a four step process and use the Lee Factory Crimp die, it seems to work just as well. I shoot well enough to hit around the bullseye and a few inside, I doubt trimming made that much difference to me.

 

[Bazoo]

My wife’s 686, 15y from the bench I was getting about 3” groups with mixed, Untrimmed brass. I switched to sorted and trimmed and groups cut in half and some into 1” range. On a good day, I can cut a 1” group or better offhand at 15y with a handgun.