Thoughts on pistol brass canneluring -

[Grey_Lion]

I'm toying with the idea of possibly canneluring the .40 pistol brass I intend to use for my custom JHP's to better set seating depth consistency and to more uniform used range brass.

Does our audience have any recommendations on this from both a practice standpoint and tool recommendations?

I'm considering this tool at present - https://www.ch4d.com/products/equipment/bullet-tools/CanToo

 

[Aguila Blanca]

The tool is intended for adding a cannelure to bullets, not brass. I don't see how cutting into the outside of your brass will do anything for enhancing seating depth consistency of enhancing the uniformity of range pick-up brass. IMHO, all you're likely to accomplish is weakening the brass.

 

[Jim Watson]

I am in the process of canneluring a bunch of .45 ACP cases at the base of the bullets. The short slick plated bullets were setting back against the feed ramp. They won't now, by gum. Note: I have a custom made die that does it in one stroke on the press, not the crank tool.

Corbin, major maker of home bullet swaging equipment, thinks it is OK:
"Cannelures can be used for crimping grooves, for identification of certain bullet weights or designs, or (applied to the case) as a method of preventing a bullet from being pushed back into the case during the feeding cycle. This is especially effective on cartridges that headspace on the end of the case, such as the .45 ACP. "

That said, I don't know what it would do to:

set seating depth consistency and to more uniform used range brass.

 

[BillM]

Assuming your custom JHP's are a consistent .400-.401 diameter?
Range brass can vary a bit in case wall. Thin wall cases may not size
down enough to provide adequate tension on the bullet. I suppose
a cannelure could provide a "stop"--but it's really not addressing the
problem. I load a pile of 40 each year on a Dillon 550. I use a EGW U
(undersize) sizing die. 95% of my 40 uses Bayou 200 RN polycoat
bullets, and I have no problems with setback.

 

[Jim Watson]

I use a EGW U(undersize) sizing die.

Me, too... now; but I had ammo on hand that needed the cannelure.

 

[BillM]

Sort of on topic---in 45 ACP the worst brass I've ever seen was headstamped
A MERC. Horrible setback in autoloaders, bullets would pull out of the case
on recoil in my revolvers. It and 9mm cases with the internal step now go
straight to the scrap bucket.

 

[Jim Watson]

I had a few A-MERCs sneak through the last batch I loaded. I marked them PD for Pop and Drop so I would not get stuck with them again.

 

[Unclenick]

A lot of the old BP cartridges had cannelures at the bullet base. I read somewhere that in the days of more manual manufacturing, they provided the bullet stop, but I also read the position of the cannelure was merely to identify specific loadings, and, sure enough, you find photos of a lot of the old copper cases with the cannelure way down near the head, where no bullet would go.

The cannelure may stop bullet setback, but IME, pressure flattens them back out again, so they will need to be redone, maybe as often as every round if the pressure is great enough. But if it's the only way to keep the round safe for feeding, then go with it.

I used to have a lot of trouble with Remington-Peters 45 Auto cases failing to hold onto a bullet adequately after a couple of load cycles, so I would just scrap any I found. Their very thin necks (0.010") were work hardening to the point of being springy almost immediately, and my old Lyman carbide die just didn't squeeze them small enough to overcome that. I might get two reloads out of them before my fingers could push in or pull bullets out of them easily. But after I got my Dillon Square Deal B, that seemed to stop happening. Apparently, Dillon sizes its dies to err on the small side. It makes sense, as you don't want problems happening in the middle of a progressive load cycle, where you won't notice the difference in seating effort and they might escape the loader's inspection. The R-P cases did, however, start splitting earlier than my Winchester and Starline brass, so, as expected, the work hardening was exacerbated.

My point in mentioning all that is it might prove the A-MERC cases or other loose ones could be made to work using Dillon dies, and it might also overcome the need to use a cannelure to stop bullet setback with a slick bullet. A bit harder on the brass, but so is the cannelure going to be.

 

[Jim Watson]

AMERC is of generally dismal quality, I don't want to manage them, just get one shot out of the ones that sneak in.

I am done canneluring cases, the next run of plated bullets will be with undersized sizing die, giving enough "Coke bottle" to prevent setback.
After that, it will be one or another brand of coated bullet.

 

[Grey_Lion]

I make my own .40 JHP's from annealed & cut down 9mm junk brass with a lead core and pressed to size & shape in a BTSniper JHP forming die on a Walnut Hill swage press. A few years ago I changed my process from using a full length 9mm case to a cut down 9mm case. One of the outcomes of the old 187 grain long JHP is that it stretched/ran out the .40 cases - the case mouth was .403 to .410 and pretty much unusable after one load. The cut down 140 grain JHP design mimics the typical .40 S&W projectile OAL and the brass run out issue is no more. Indeed - these are the best performing JHP's I've ever taken the time to analyze for opening. The brass case opens like a daisy and effectively turns into a saw blade. The soft pressed core is semi-frangible and often separates from the case to blossom into up to 6 points and the core. Most solid center of mass hits stay in the target which is exactly the behavior I wanted. Current problem I'm trying to address with a seating canneluring crease in the .40 brass is to give me a consistent seating depth to the round and then I'll apply a heavy crimp. Seems that the lubed ( no additional lube applied - just a drop of light gun oil in the swaging process ) brass jacket made out of annealed 9mm brass is slick and doesn't want to stay put. The typical crimping process is fine for soft copper - but doesn't seem to do the trick on annealed brass which is harder.

 

[Grey_Lion]

I don't see how cutting into the outside of your brass will do anything for enhancing seating depth consistency of enhancing the uniformity of range pick-up brass. IMHO, all you're likely to accomplish is weakening the brass.

I'm planning to add a ribbed crease at a specific depth to the brass case to add friction and hold at the desired seating depth of the JHP projectile. As the jacket of these projectiles are made out of an annealed 9mm brass case, that ribbed creased cannelure ring will give me the needed friction to hold onto the 9mm shell ejector ring which is a harder material than a regular copper jacket, copper plating, or powder coated lead. It will shorten the life of the .40 brass case - but I don't typically go through high volumes of JHPs.

I want high consistency and reliability out of these. And I want to know I'm at a much reduced risk of an over-pressure condition because of a projectile set-back.

 

[Unclenick]

All the auto cartridge cases start to thicken in a taper after some distance down from the mouth. There is no SAAMI standard for case internals, but the industry designers all seem to be in on it, probably based originally on John Browning's specs. The purpose is to prevent case blowouts in barrels with unsupported or loosely supporting chambers. If you seat a bullet into the thick part, it expands that part out, and as you go still deeper where the thickening taper expands it further until you have seated deeply enough that your case OD is out of spec.

I've measured the taper starting point with pin gauges for 45 Auto and 380 Auto, and they start at 0.35" to 0.36" below the case mouth in the 45 Auto brass I have and at about 0.25" below the case mouth in the 380 brass I have. I don't know what it is for 40 S&W but there will be a seating depth limit.

Years ago I got a Lee mold made for a 300-grain 45 Auto bullet. I put a 5° boattail angle at the base to prevent interference with that thickening portion. I could shoot it to about 700 fps in a 1911 at standard pressure using Power Pistol, but the design suffered from feed issues. Great penetration, though. Anyway, I was thinking that if you can access a lathe, if you turn the 9mm rims off, you will be able to seat deeper if you need to. It's a lot of extra trouble, but it will work.

Hmm. Finding that link, I discovered you and I discussed this already, here.

 

[Grey_Lion]

Let's see if it'll let me post this pic again - in the longer 187 grain JHP's this is exactly what I was running into. And it's why I started cutting down the 9mm brass to reduce the projectile OAL.

 

[Grey_Lion]

I do have a micro-lathe but no - I don't want to boattail the 9mm shell extractor ring because it has a side benefit - After I've fired a LOT of cast rounds and have some leading of my barrels - the stock glock, the after market glock or the hi-point carbine - the extractor ring on the JHP shell cleans any & all leading out of my barrels after 2 rounds. Also - these JHP's are already a lot of work - putting them on the micro-lathe to boat-tail them is just more work..... If I were to develop a compelling desire or need for a 187 long JHP's, maybe - but I haven't yet had any such need.

 

[std7mag]

Cannaluring the case, i'm having a hard time wrapping my head around.
But if i felt the need to do it, i'm not so sure i would choose the 40S&W to do it on.

45ACP with pressures at 18,000 psi is one thing. 40S&W at 38,000 psi is another matter.

 

[Grey_Lion]

std7mag - valid points of concern esp the pressure issues - but consider that this is a JHP load I want to under-charge to prevent penetration. I want the round to blossom open but not pass through. Also - consider my reasoning for doing this is to keep the JHP from pushing in / setting back into the round which would create a smaller / tighter powder chamber that would lead to dangerous over-pressure conditions.

 

[MarkCO]

I've read the responses of the last few days and my thoughts are...

A cannelure in brass won't prevent bullet set back. Since I was curious, I put a cannelure in some .40 brass and with a force gauge, measured the force to shorten the OAL by 0.1". It was exactly the same. Granted, not chambered, but a chamber so tight so as to provide some extra support to maybe increase the amount of force needed to prevent set back would not be a good idea in a defense firearm.

If bullet set back is a concern, there are three methods, used and proven, to attack that problem:

1. Glue the bullets into the case. Some companies did this in the 1980s and 1990s. Labor intensive, but it does work.

2. Use a Lee FCD. This is propbably the best, and most utilized method of handloaders, and in fact, as the word "Factory" implies, most commercial loads use some form of such a crimp. Less distortion and better tension than roll or taper crimps.

3. Modify a Lee FCD to create a stab crimp. This is a crimp below the case mouth that indents the case with a groove that holds (and also slightly grooves) the bullet. IF your bullet has a cannelure or grease ring in it, stab crimping into that is a pretty darn solid lock. Folks who shoot very heavy recoiling straight wall revolvers are fond of this method. I have used it in a few calibers, most notably in the .450 Corvette (a higher pressure version of the .450Bushmaster) in the AR. I actually used a dual stab crimp and verified that the COAL could not be reduced. The case would bulge out before the case volume was decreased.

Use of a stab crimp on empty cases, then seating your bullet, would work to control seating depth better than a cannelure.

 

[9MMand223only]

Doing this to the case is useless. Literally useless.
The reason 357 and 44 mag is generally crimped is because of the heavy recoil in the strait wall case design. Its to prevent them from moving forward when they slam into the chamber from momentum.

9MM has no such thing, not applicable at all. A simple taper crimp is all that is needed, and the only reason that is good, is for smooth feeding so the edge doesn't catch anything.

357 and 44 mag are "roll" crimped in order for the edge to get pushed down into the cannelure of the bullet.

Roll crimp is for cannelure, taper crimp is for without.

 

[lll Otto lll]

Cannaluring the case, i'm having a hard time wrapping my head around.
But if i felt the need to do it, i'm not so sure i would choose the 40S&W to do it on.

Canneluring cases is a throwback to the black powder days of the early 1900's.
Black powder due to it's bulk, would fill the case and support the bullet preventing setback.
When BP was replaced with less bulky smokeless powder, cannelures were rolled into the brass to prevent setback in guns with tubular magazines.
Today, this practice is completely unnecessary but some habits never seem to die.

 

[Paul B.]

"Today, this practice is completely unnecessary but some habits never seem to die."

Another thing about cannelures, they iron out. Every time you resize that case you remove a bit of the cannelure and the brass has to go somewhere. The cases just get a tad longer. I have a fairly large batch of Winchester .38 Spl. brass that was used in wadcutter target loads. The have a double cannelure. I suppose it's to identify the brass as for the target loads. I can tell you this, those cases stretch badly and need to be trimmed frequently. Makes no difference if the loads are mild or even on the hot side, they stretch during the resizing process.
Paul B.