Crimp, How much is too much? Specifically .44mag and .357 mag Keith style

[Capt.Red.44]

I have cast quite a few different molds in the Keith style and have been playing around with crimp depth and using different crimp dies.
Molds:
1) lyman 429421
2) RCBS 44-250-K. Drops about 262 grn with carnuba blue and COWW +2% tin

Dies:
Lee , RCBS, Lyman. Dillon, Etc

Bullets sized to .430, carnuba Blue lube , heavy roll crimps, cylinder throats all exactly .430, no bulges in brass after crimping operation.

I have experienced no bullet jump when using a heavy roll crimp and a med-heavy charge of several powders. Unique and Blue dot are so far my favorites , due to shortages of everything else and I had plenty on hand. I follow very closely the guidance of printed load data and never exceed max loads. Im more looking for med loads for 100-200 yd range target work.

While using the exact same load in a few different dies i found pressures spiked, with blue dot and had 2 split cases. New starline brass. Kinda made me nervouse for my Smith 29-3 8 3/8" and 4" magnums. All rounds are crimped in crimp groove.

Does anyone have a diagram or information regarding the depth of roll crimp vs excessive pressure?
Can the lee factory crimp die cause excessive crimp?
How heavy a roll crimp is too heavy?


I am just getting set up to load for 38/357 using 38spec brass, NOE 360-172-swc- BC1 PB. And Arsenal molds 358-158- kt. Plan to size to throat size .358, 4" Smith 681, well used NYSP revolver.

Any guidance would be appreciated concerning , well, anything I can learn from.

[megasupermagnum]

Are you using the Lee carbide factory crimp die, or the collet factory crimp die? With a standard reloading die, or the carbide crimp die, I crimp until it seems the mouth is bottomed in the crimp groove. With the collet crimp die, I go until the collet starts to kiss the bullet front driving band. You will see four telltale indents around the bullet nose. If you have a short or non-existent front driving band, you may not see these.

I'm fairly sure Larry Gibson did a pressure test of light and heavy crimps, and found minimal differences. I wouldn't worry about it creating a dangerous situation. You really only over crimp if it is causing harm to the brass or bullet.

[StuBach]

Personally I set my crimp to put just enough tension on the bullet that it can’t be pushed back into the case. Especially with revolver loads like those you don’t need much since they won’t be subjected to auto loader putting much pressure on the bullet to drive it backwards. Not really data driven, just experience and personal preference driven.

With the two bullets your using, Keith 44s and Keith 357s, the crimp groove is usually nice and deep so I just set mine so they rest in the groove but don’t “size down” the groove.

If you have to pull the bullet for some reason you don’t want too heavy of a crimp or you’ll be pounding that hammer for a while.

[Wayne Smith]

I'd look at it the other way - as long as I have no boolit jump locking up my cylinder I figure I have adequate crimp. Don't need no more!

[Capt.Red.44]

Recently I have been using the lee carbide factory crimp 4 die set. Bullet was crimped in the groove below the front driving band. I guess i will run a little experiment when I get back to my bench on crimp depth even though all I have to go on is felt recoil. 1/8th turn increments for 6 rounds after each adjustment on the crimp die and measure for any bullet jump on the 6th round.

Now im wondering if it may have been a powder issue with the blue dot and heavy lead bullet?

[megasupermagnum]

This may sound a bit crazy, but you really can't over pressure a 44 magnum with bluedot and the Keith bullet. The old books show some really high number, like 18.4 grains. Newer manuals show around 16 gr max. Well it turns out both are kind of right. Larry Gibson did a test, not only with old vs new bluedot, but also old vs new load data. What he found was that pressure maxed out around 16-17 grains, but then started dropping once case fill became over 100%. At no point did pressure go above current SAMMI maximum. https://castboolits.gunloads.com/sho...loads-blue-dot

I personally have loaded up to 18.4 grains bluedot, although I've found lighter loads more accurate. 13 grains has kind of become my sweet spot at a touch over 1200 fps.

My question is, why do you think you are over pressure? Is it because of the split cases alone? I think you nailed it when you said it was Starline brass. I finally had to sell all my Starline brass, because it was giving me too many headaches. Some lots were ok, then the next were splitting all the time. I had Starline for many calibers, and there was no rhyme or reason on which calibers were bad or good. You could contact them, and they are good about exchanging brass. My advice is to trade or sell it for something like Winchester or Federal brass.

[Capt.Red.44]

I really appreciate that advice sir! I will contact starline about it. I was using a charge in the 14.5 grn to 17 grn realm. A hair under max in my lee and lyman books. WLP primers, new starline brass and said bullets. OAL was to the groove and almost touching the throat of the cylinder on front driving band. ( dont quote this data as I am not near my load data log. ) Im currently offshore in the Gulf.

That load was amazingly accurate with my hornady xtps, 240 grn projectiles. I loaded a test batch with the keith 262 grn projectiles seeking similar accuracy. Starting low and working up. I know, apples to oranges, but i needed to know what the 29-3 8 3/8 was capable of first.
I had three cases split, 1/8" long halfway down the brass, no gas at primer but recoil was as stout as a factory load.

[JSnover]

I crimp just enough. Start with just enough to remove the flare, shoot a cylinder or three, crimp just a "tetch" more if you need it until you get it right. Soon enough you'll know how it should feel and look. I can't accurately describe "how much," any more than I'd be able to understand someone else's description of theirs.
Just enough. Add more if you need it.

[Winger Ed.]

For increased brass life before it splits:

I use just enough flare to get a boolit to stand up straight in the case and not get shaved when it goes on in for seating.
Then just enough crimp on straight wall cases to chamber and not be able to push it deeper with hard thumb pressure.
For revolvers- just enough crimp to feel, and see it barely roll in under the top of the crimp groove.

[44MAG#1]

The way I do it, not saying it is correct but just the way I do it is,
I use a fairly heavy crimp and the only thing I may do for specific reasons is to lighten the crimp.
When I work up a load I use I use the "fairly heavy" crimp. Even with easily ignited powders I use the "fairly heavy" crimp. That way not much in surprises if at all possible.
Not saying my way is correct but it has served me well and I have been loading for a little while, wink wink.

[dahermit]

I remember one of the load manuals saying that factory cartridges should be used for all maximum or near maximum loads. In regard to that, look at how much crimp the factory loads exhibit... very little.

Given the seemingly extreme depth of Keith-type cast bullets, it is unfortunate that they seem to encourage hand loaders to use way more crimp than is necessary. Keep in mind that Elmer Keith was many things, but he was not generally known to be a temperate person.

I learned long ago that flaring and then crimping had the most effect on case life for straight-wall revolver cases.

[David2011]

If they’re new cases and they split halfway down the brass that sounds like the brass was too hard. That’s the kind of split I expect in my .40 S&W cases after 7-10 reloads. Those are taper crimped, though so not a 100% comparison.

I also use the 429421 but with Ruger and Contender only loads and a pretty deep roll crimp, just to make sure the pressure starts building before the boolit starts moving. Never had a .44 Mag case split. The boolits you listed aren’t really heavy for caliber; just normal weights for the bore. I don’t remember exactly what a factory crimp looks like in .44 Mag; last time I bought factory .44 was 1978.

[DougGuy]

With slow burning powders, a good efficient collet crimp can aid in ignition especially with heavy boolits. Seemingly it holds back boolit movement through primer ignition and then allows a good flame front to develop before boolit movement occurs. This actually does wonders for consistency and lowers SD dramatically. Enough so that it can be seen in group sizes fairly easily. You can certainly see it over a chrony. Take a string of loads with H110 and the 310 boolit and a roll crimp, compare the same exact loads to a collet crimp, the results speak for themselves.

Roll crimps and light crimps won't hold the boolit against the pressure of a standard primer lighting off much less a magnum primer. As such, you have an expanded case volume when the powder lights off, and I would also think that initial boolit movement would not be none too consistent either so this is akin to seating boolits to varying depths.

High case neck tension and a good stout crimp deliver the consistency with slow powders.

Another anomaly that no one has mentioned here is the tendency for a soft alloy (like a hunting boolit that you can scratch with a thumbnail) to swage into the crimp. This means for the base of the boolit to move forward pushing the lube groove and the crimp groove upward and into the crimp with previous shots fired as they are carried in the cylinder. Now the results will be varying amounts of case volume which have a huge effect on the initial pressure at ignition. More case volume = less pressure = inconsistent point of impact as volume increases incrementaly for rounds farther away from the first round fired. This is where a collet crimp shines, as it holds the boolit much more securely than a roll crimp.

Again, firing these soft alloy/gas checked loads over a chrony will have clear advantages over even a firm roll crimp. Been there done that, it just works.

[megasupermagnum]

It is absolutely amazing to me the number of people who criticized me for refusing to try and measure a taper on an auto pistol round, where crimp has almost no effect. Yet here are tons of people laser eyeballing a revolver cartridge crimp, which is far more important.

You have bad brass, that is all.

[44MAG#1]

I wonder how Elmer Keith made it? He probably used the KISS system. Find what works and stick with it. Crimp is one of those things.
I have gotten some bad brass that would occasionally split.

[mdi]

Often a crimp is for more than holding a bullet in place. I have loaded a lot of "Keith style" 44 magnums (mostly Lyman 429421) and have always seated bullets to the crimp groove and learned a medium/heavy crimp helps consistent velocities, especially with "lighter" bullets (I've reloaded 123 gr. balls to 310 gr ingots). After 4 -5 years of experimenting I now always use a medium+ roll or profile crimp with an occasional collet crimp (J bullets)...

FWIW; I used a Lee FCD for handguns on my 44 Magnum handloads, once. It now resides in a landfill somewhere in So. Oregon...

[JSnover]

Some range pickups I pulled down las summer; 357 and 44 mag, there were over a dozen lying on the ground so I decided to salvage the primed cases. You can see the crimp made quite an impression on these non-cannelure jacketed bullets (the one on the right seems like sintered metal or moly-coated lead). Anyway, this to me is way too much.

[Capt.Red.44]

Thanks for all the assistance fellas!. Ill have to give a collet crimp a shot if I have one somewhere. I tend to accumulate parts and pieces and random dies when I see them cheap, even if not immediately needed. If not, then ill try working back up from a lighter powder charge and lighter crimp till i get the 6th round to move even slightly. Then adjust crimp each time I work a smidge higher. The case rupture did concern me so did the seemingly heavy recoil from what was expected in a less than max load.

[justindad]

This thread motivated me to re-evaluate my crimping process, which may have been excessive. Here’s an image from Lyman’s 49th, followed by an image of where I stopped reducing crimp to eliminate the bulge shown in the manual. Note that the case touches the calipers at the crimp and at the base of the bullet - any tighter crimp and the calipers do not touch the case at the base of the bullet. This lighter crimp will be tested by measuring the length of the 6th round in my revolver, after shooting two groups... hopefully soon.

[44magLeo]

As justindad showed with the Lyman pic, You want to crimp so the mouth of the cases just bottoms into the groove. This is about the max a roll crimp die can give. Trying to crimp more can bulge the case and loosen the crimp.
Once the crimop gets to this point trying to go more causes the bulge because the crimp is formed by the shell holder pushing the case up against the crimp shoulder. Once the crimp reaches the max if you try to go furtjer the case cant press into the groovedeeper so the case bulges.
The crimp on the Lee carbide FCD is pretty much the same as most any roll crimpo die, Except it has a short straight section just behind the crimp that helps prevent the bulge.
There are some companies that sell a profile crimp die that does about the same thing.
Lee's collet crimp die can crimp more than a roll crimp die because the collet is pushed into the die not by the case but by the shell holder. This way no matter how hard you try to crimp the case won't bulge. If you look down into the top of theLee collet die you will see the jaws press into the case mouth. When crimp so the case mouth is down to the bottom of the groove you will see that the jaws have a gap between them.
If you wanted to you could add crimp untill the jaws are fully closed.
Doing this aboput 1/8 " of the case mouth will be pressed into the bullet. This will happen even with J-words.
I have used a roll crimp die since I started loading my 44 Mags in 1978. When adjusted as described in the Lyman pics my heavy loads always shot good and never had a boolit pull out of the case. On my lighter loads a lessor crimp proved ok.
For heavy loads I use 2400. Up to a bit over most books. In my Ruger SBH empty cases just fell out of the cylinder with just barley a tap opf the ejector rod. On the Red Hawk it took just a bit more of a tap because all six cases came out together.
I finally settled on a bit lighter load, not because I thought thse heavey loads were an issue but the recoil was substantial.
I think your trying to use powder a bit too fast for the load leves your look for.
In my testing the heavy loads with the SBH I was getting groups less than an inch at 50 yards. I could easily hit a gallon jug at 200 yards offhand.
The Red Hawk was a bit looser, the difference mostly from the SBH had the 7.5 barrel, thre Red Hawk the 4.
I might suggest tring about 17.5 to 20 grs of 2400 with most any primer, Mags not really needed. Comparable loads of H110/Win 296 may benifit with the mag primer.
For a good light load 8.5 grs of Unique under those boolits works almost as well as the heavy loads.
I've never had a case split such as you describe in all these years. Sometime a bit of crack in the case mouth. Being a new case I would think it was a bad case. On this I would contact Starline. I've not used much Starline brass but what I have used was good brass.
Leo