RCBS taper crimp die...?

[woodperson]

Loading Berrys Bullets 125 gr in .357 Mag. Got a new RCBS taper crimp die to crimp with. How do I tell how much crimp to put on it? The Lee dies I generally use say a light crimp is 1 turn after touching the case. Does that sound about right for the RCBS die too?

 

[Jimbo357mag]

When crimping copper plated bullets I usually do it by feel. Set the die so it is just touching the case lip and then add an 1/8 to a 1/4 turn until you feel the bullet and case getting squished. Look at the round and see if you like the crimp. Try pressing the bullet into the case. A little visible crimp is usually enough.

 

[PO2Hammer]

I crimp about .007" on my plated bullets( .377" over the bullet, .370" at the case mouth), or just to the point where I see a slight distortion in the bullet's surface at the case mouth. Recovered bullets show the crimp line, but no peeling or cutting through.

 

[Luckyducker]

I little crimp goes a long way with plated bullets. When I first started loading plated bullets I left my dies set where they were for other bullets and found that I was actually making a waist in the bullet from over-criming. This is where the term "less is more" comes into play, and if you just put enough crimp on the cartridge to say that you can see, it is enough.

 

[Rick Courtright]

Hi,

I tried to see what RCBS has to say about their taper crimp die, but my browser came back with a big note about how they had their website incorrectly set up and it wasn't gonna let me go there. So I went to visit Chuck Hawks, who usually has a couple of valuable tidbits:

http://www.chuckhawks.com/adjust_reloading_dies.htm

Note in his discussion of taper crimping he says all cases must be the same length for best results. This will probably stir up the inevitable "trim or don't trim" conversation relative to handgun brass. Let's save some time and condense that one to a few words and move on: I trim mine, some people don't, and neither of us is very likely to change our ways at this point! So the best I can suggest is to use Chuck's advice for starters and experiment for best results. If you choose not to trim, you can always take your caliper and pick out some of the longer cases, adjust the die for them, and be reasonably comfortable with the result on the shorter ones.

Just go a little at a time, regardless of whose die you use. I use the Lee Factory Crimp Dies (FCDs) for all the cartridges I load, and each caliber requires a tiny bit different adjustment for best results. On one or two, the range from "unsatisfactory to perfect back to unsatisfactory" may be as little as just a hair over 1/4 turn! So remember, slow and easy...

Good luck!

Rick C

 

[Chuck 100 yd]

If your neck expander/belling die leaves the neck tight enough that you have good tension on the bullet,you only need to taper crimp enough to remove the belling from the loaded rounds case mouth.
I test this in a revolver by measuring overall load length of a round that is marked with a magic marker. I then fire several cylinders full of five rounds each while the marked round just goes along for the ride in the sixth chamber. Measuring the marked rounds length every five shots will tell you if the bullet is jumping crimp or not. Plated bullets are not meant to be loaded with magnum loads and neck tension alone usualy is enough.

 

[woodperson]

Thanks, guys. I had checked the RCBS and other sites and could not find much. I did finally find the instructions that came with the die. The taper is 7 degrees and results in rolling the edge in a little like a roll crimp. RCBS says to measure at the front of the case and try for .001 to .002 crimp. I assume that is for lead bullets. On the plated bullets I think I have about half a thousands crimp. I tried a couple of dummy rounds and pulled them with my inertia puller. They come out fairly easily. The crimp leaves a little belt around the bullet but does not seem to hurt or even mark the plating when it pulls. Will try 50 of these. I think it will be enough. The copper plated bullets do seem awful slick and hard. I loaded and shot some 9mm previously and did not seem have problems. The 9mm bullets have a thicker and tougher plating than the .357. Looking at the RCBS diagram I can see why uniform case lengths are important if you are trying for a light crimp.

 

[powder smoke]

I think Chuck nailed it, neck tension plays a huge factor.
I expand my cases as little as possible, therefore less crimp is needed. YMMV. ps

 

[Ka6otm]

Just enough to iron out the bell from the expander die.

 

[Jimbo357mag]

Just enough to iron out the bell from the expander die.

That may be fine on a 9mm but the OP is talking about 357mag cartridges. I would make sure there is a good crimp on those cartridges for ignition and especially if loaded in a tube magazine rifle. Check the neck tension on a dummy round either by pushing in on the bullet or with an inertia puller.

 

[Rick Courtright]

That may be fine on a 9mm but the OP is talking about 357mag cartridges. I would make sure there is a good crimp on those cartridges for ignition

Hi,

Jimbo, I think the discussion took a slight twist because the OP had purchased a taper crimp die, and a lot of us just don't think of taper crimps for the .357 Mag or other revolver cartridges.

Apparently, Berry's is in agreement, as they addressed the crimp question in their FAQs when someone asked about the lack of cannelure on Berry's bullets:

"Question: Why is there no cannelure in your bullets?

"Plated bullets are very difficult to cannelure, it requires an extra step after the plating process and if not done carefully, can ruin the plating. We only put a cannelure on two bullets (45-70 and 500 S&W), you shouldn't need a cannelure on our other bullets. If you feel the need, you can use a snug roll crimp to keep bullets in place. Just ensure you don't get the roll too tight, such that it severs the plating and destroys the bullet."

https://www.berrysmfg.com/faq.aspx#FAQ8

An earlier question also addresses crimp and how much to apply:

"Question: Do you have load data available? COL or OAL?

"We do not research or publish the load data...

"We recommend a light crimp on the bullet, just enough to put pressure against the bullet without denting or deforming the plating. If you were to pull the bullet out of a case with the proper crimp you would find no more than a scratch on the surface of the plating. If you are denting or deforming the bullet, your accuracy will suffer and the bullet may start to tumble before it hits the target."

https://www.berrysmfg.com/faq.aspx#FAQ3

I dunno about how hard it is to put a cannelure on a plated bullet. I used West Coast brand plated bullets in the .38 Spl/.357 Mag for several years, and they were cannelured. They worked nicely when loaded with mid-range cast bullet recipes and just enough crimp (in the groove) to eyeball. I believe that while the company is now called Extreme Bullets, their bullet designs remained the same. Someone may correct me on that.

Otherwise, note Berry's suggests a roll crimp despite the lack of a cannelure, and what's "just enough" or "too tight" seems to be left to the reloader to determine on his own. The same experimenting to find the "sweet spot" probably applies to the taper crimp for revolver use just as it does for auto cartridges. In other words, start with nothing, work up in small increments until the results start to deteriorate, back off a little and go shooting!

Rick C

 

[woodperson]

Got to try some of the taper crimp loads today. 125 gr over 4.5 grains of Trail Boss, so it is a very mild load. I would load 6 and check the last one before firing it. No movement. So I think I am okay with just a little crimp. No rifle or tube magazine. Accuracy same as other loads in the gun. Does not shoot to far from my 158 grain Hornady XP loads. I actually got a couple of pretty good (for me) groups at 20 or 25 yards. I was shooting 2 heavy guns. A Blackhawk and a 686. I will load a couple more dummy loads and pull with the inertia puller and try to get a feel for how much grip I am getting. I also load Berry's 115 grain in 9mm. The 9mm die set comes with a taper crimp but I ordered the .357 TC seperate. Based on how well these worked I ordered a TC die for my .41 Mag. But then I looked at the Berry's prices for .41 Mag b ullets and decided to shoot something else. The Bayou bullets I have been shooting in the .41 Mag work well and have the channel for the crimp and are a lot less expensive. I really wish someone would make a 170 or so plated or coated bullet for the .41.

 

[Ka6otm]

Just enough to iron out the bell from the expander die.

That may be fine on a 9mm but the OP is talking about 357mag cartridges. I would make sure there is a good crimp on those cartridges for ignition and especially if loaded in a tube magazine rifle. Check the neck tension on a dummy round either by pushing in on the bullet or with an inertia puller.

The OP said he had a taper crimp die plus there's no cannellure, so he's going to have to settle for a light crimp and a light load. A heavy crimp would probably cut the plating and accuracy would go out the window.

He's got the wrong bullets for tubular magazines or magnum level loads.

 

[Carry_Up]

Loading Berrys Bullets 125 gr in .357 Mag. Got a new RCBS taper crimp die to crimp with. How do I tell how much crimp to put on it? The Lee dies I generally use say a light crimp is 1 turn after touching the case. Does that sound about right for the RCBS die too?

I'm getting confused after reading through these comments. Woodperson, why did you order a taper crimp die for .357? I am at a loss why manufacturers even offer taper crimp dies for revolver ammunition, but to each his own. In any case, don't pay attention to the instructions: measure it yourself!

Quite aside from the real question, a taper crimp die is intended to be used for automatic rounds such as .45 Auto which headspace on the mouth. Taper crimping simply removes the damage you just did to the mouth by expanding. That dimension will be measureable with 15 dollar calipers, and the case will slip easily into your cartridge gauge - the one that all reloaders keep next to their press.

For making revolver ammunition, you need a roll crimp die. Naturally you don't have to apply a severe roll crimp - that depends on how far you screw in the die. For your .357 mag and all magnum ammunition, roll crimping is especially required, as perhaps it may not be for .38 spl. The whole point is to prevent the bullet from creeping out of the case when the gun is fired. For example, round #6 will have been subjected to 5 magnum recoil events and bullet #6 may slip out of the front of the cylinder if not correctly seated and crimped. Most plated bullets don't work well with .357 mag anyway. Go to lead or FMJ, since the plating usually flies off the bullet on its way downrange. Just a few off the record comments.
CU

 

[Jimbo357mag]

Most plated bullets don't work well with .357 mag anyway. Go to lead or FMJ, since the plating usually flies off the bullet on its way downrange. Just a few off the record comments.
CU

Not necessarily true. I shoot lots of 357mag copper plated bullets in revolvers and in a rifle and they work fine if you don't push them too hard or crimp them so much that you cut the plating.

 

[protoolman]

I generally agree with what Carry up said. Jimbo says not necessarily true but misses the point. Yes you can make plated bullets work in a revolver but why make compromises to make it work?
Best loading practices for revolvers require a bullet design with a crimp groove on unplated lead or a cannelure on jacketed bullets and a roll crimp.

 

[woodperson]

I got the taper crimp die in .357 to load 125 grain plated bullets with no crimp groove in my .357. I am loading light loads. So far the loads seem to work equally well with just a light roll crimp or with the TC die. I have not figured how to adjust the TC die correctly yet. I get a little indentation from the edge of the case with either of the dies. The bullets are relatively easy to pull with an inertia puller but so far I think the roll crimp is a little tighter. When I pull the bullets I do not get any scratching or cutting of the plating. The plating seems extremely tough to me. Why use the plated bullets? I do not cast and the bought cast bullets are extremely expensive compared to the plated. Plus I like the plated bullets and they seem not to lead. Why not use jacketed bullets? Because everybody here told me that if I load the jacketed bullet slow I am risking a stuck bullet and "wasting" money. Plus I sorta like the combination of the plated bullet and Trail Boss. I am currently shooting coated bullets with a crimp groove in my .41 mag and like them also. But I wanted lighter bullets in the .357 to try to make the light loads hit to about the same POI as the heavier bullets and loads with the 158 gr jacketed. If they do not pull in a 9mm in a light gun it looks like they would hold in lower velocity loads in a heavy .357. So far I have checked several time and have not seen a bullet pull. I do not think the plating comes off. But so what if it did after it leaves the bore? I think of the plating more as a lubricant and leading preventer. Be nice to find some 170 grain coated or plated for the 41 Mag but nobody seems to make one. I have shot the Sierra 170 jacketed but at higher velocity than I would like.