.357 Crimp Question


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Mantis
October 3, 2003, 08:51 PM
Hello everyone. I just found this site this week and this is my first post.

I'm loading some .357 mag for a friend. I’ve been reloading for a number of years, mostly rifle and .45ACP, but this is my first attempt at reloading for a revolver. I’m using .357 mag Starline brass with 125g XTPs. The dies I’m using are the ReddingTitanium Carbide Pro Series with a Profile Crimp die.

My question is, how can I tell what a proper crimp is for this load ? .45 ACP was pretty straight forward, where you crimp it down until you get a .469 crimp. Is there a similar target dimension for .357 mag ? Thanks in advance.

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P95Carry
October 3, 2003, 09:23 PM
I can't ''see'' an XTP in my mind - so not sure if cannelure or not.

However ... I load mostly for cast swc's.

Be that as it may ... I do not know of any specific dimensional guidance for the crimp. I use Lee stuff and do actually go thru one more stage when loading .357 mags ... a factory crimp die. It does not do much more than the bullet seating die can but - it is very much more consistent and, accurate to set up.

My parameters are ....... minimize flare pre seating ...... add just enough crimp (roll) so that it is visible and ''bites'' into bullet .... cannelure helps of course. I only go to point where I find bullet retention reliable ..... in other words .. if 6th hot load thru a revo shows no bullet movement then I'm pretty OK.

I also would not reckon to be able to turn bullet in case once crimped ....... and I dislike over crimping simply cos of the amount of working to the brass ..... it work hardens much quicker and so I get fewer reloads per case..... encourages splits.

Your 45 acp experience is a tad different .. you apply a taper crimp and, ignoring differences in brass thickness - can in fact judge fairly well by measurement .... a head spacing round is probably easier to judge that way if you find it works.

Standing Wolf
October 3, 2003, 11:11 PM
I used to duplicate factory ammunition crimps, but my only calibration device was my eye, which admittedly isn't accurate to 0.0001 inch.

I've recently started taper-crimping .357 magnums to save wear on brass. I shoot mainly light target loads, so I figure if I can't twist the bullet with my fingers or feel it move, it's tight enough.

caz223
October 4, 2003, 08:11 AM
The main thing is crimp selection in revolvers is the load selection.
If shooting light .38 special loads in a heavy revolver, minimal crimp is required.
Shooting full-power H110 hotloads in a snubby is a whole different story.
The recoil generated is enough that with a light crimp, the bullets can be pulled out (similar to using a kinetic bullet puller) and can tie up the gun, or worse.
When making full-power loads, a heavy roll crimp also helps accuracy, allowing slow burning magnum powders to fully ignite before the crimp lets go of the bullet.

Gary H
October 4, 2003, 05:47 PM
For never loading this caliber..you sure did a fine job of selecting dies. I'm new to .357 Mag myself. I've been loading .38 for a good while. I also decided to use Starline brass for my .357. Good choice. I've measured the crimp on some of the factory .357 that I had around and duplicated the crimp. The Redding Profile Die makes for a nice even crimp. When it is applied slightly, it will give you a taper crimp and when screwed down further a nice rolled crimp. No need to repeat the previous posts..good advice.

Mantis
October 4, 2003, 07:33 PM
Thanks for the replies.

There are a few details that I left out that I should have included before. My friend wants these loads to do some short range deer hunting, so the loads would have to be pretty hot. In addition to the Starline brass, I’ll be using CCI550 mag primers and Bullseye (because I already have some). According to my Lyman manual, the max load for Bullseye is 8.6 grains, so I’ll start lower and work up to that. That should give me about 1550 fps according to my Lee manual. I know there are other powders that would give me a higher velocity, but I’m hoping Bullseye will work. If anyone has had any bad experiences with Bullseye in a hunting application, please let me know & I’ll try something else.

caz223
October 4, 2003, 08:19 PM
Not to discourage you, but bullseye is prolly the worst powder I can think of for hot loads in .357.

Have you no other powders?
Here is a burn rate chart, rating powder from fastest to slowest.
http://www.lasc.ca/PowderBurnRateChart.htm

According to the chart, bullseye is number 7.

'Optimal' burn rate powders for hot loads in .357 (One man's opinion, mind you.) are somewhere 30 and 45.

Granted, there may be worse powders for this task, but not many.
It could be worse, you could be shooting 180 grain bullets with bullseye.
I would still recommending glancing over this chart, and maybe finding a slower burning powder?
Bullseye may indeed work, but there are so many powders that would work better.
For instance, blue dot, at number 20 is an excellent powder for hot loads in .357 magnum.
Just a footnote, for hunting anything serious, 125s wouldn't prolly be your best choice, either.
For anything bigger than varmints, dogs, or people, 158 JHP or better would make more sense.

caz223
October 4, 2003, 08:40 PM
Please don't think I'm trying to trash your powder selection.
I'm just trying to save you some work.
Maybe someone else could chime in and recommend a favorite load.

P95Carry
October 4, 2003, 09:02 PM
caz .... I would echo your comment! ''Just because'' you have some Bullseye ..... is not IMO a good reason to use it for this sorta round ... way too fast ... probably gives a very high pressure peak.

More in order is a slow powder in the category of 2400 etc .... in effect ... a fast rifle powder. You don't either IMO need quite max velocity ..... tho with those 125 XTP's you'll easily achieve your quoted target velocity i think.

I use a load with Vit N-110 ... which I believe is very close to H 110 ... using 14 grns behind a Lyman cast gas check 158 swc. That is my load tho .... and so only referred to as such ... it is not a recommendation. Check the load manuals.

If you don't have a slower power like I've mentioned you can work up a fairly good load with Blue Dot or even Unique ..... again, consult load data.

caz223
October 4, 2003, 09:28 PM
Good, sound advice.
I neglected to pick a favorite, because I didn't want to sound like 'brand X is the best' or any crap like that.
I DO have favorites (It's hard not to.)
I do think that a lot of different powders would work.
Of the ones that I have tried, I've had the best luck with H110, 2400, Blue Dot, stuff in that range.
Blue dot is my current favorite for .357 magnum.

Mantis
October 5, 2003, 12:06 AM
Absolutely no offense taken with the suggestions that Bullseye is a poor choice. I’ve done a lot of rifle reloading for competition, but I’m a revolver rookie. I really appreciate the suggestions. As caz223 said, it will save me a lot of work. What type of powders are 2400 and H110 ? I’ll be loading these in a Dillon 650 and I’m looking for something that will meter well.

P95Carry
October 5, 2003, 12:31 AM
Mantis ........

Whilst I haven't used H110 yet . I have some and it is a surprisingly fine powder for a slower one ..... like a small ''ball'' powder in some respects. I'd expect it to meter well tho being as fine as it appears ... I wonder whether any tendency to ''stick to sides'' of hopper... others can clarify that.

Vit N-110 is superb for metering ..... it's short rods in shape and thru my measures does fine.

2400 is better than it once was - being similar in apearance to Hogdon H110 ... should meter well for you .. fine for me. IIRC the old 2400 in the ''Hercules'' days was more flakey and not quite so good re flow and consistency of drop.

Chugach
October 5, 2003, 02:33 AM
During die setup, I judge by eyeballing and feeling the crimp of the reloaded round and comparing it to a factory round.

Win296 has been great for me. It's a ball powder, and meters well. Significant flash though.

WESHOOT2
October 5, 2003, 06:40 AM
N110 is a very good 357 powder.

The 'heavy' crimp should have a portion of the case that's 'rolled' into the cannelure parallel with the case body; that portion should be .003-.005" long.

caz223
October 5, 2003, 07:57 AM
A word of caution with slow burning ball-type magnum powders, esp. H110.
Do not reduce the loads below book numbers.
This causes a lot of problems, like poor ignition, hangfires, pressure spikes, and just general unpredictable behavior.
H110 likes to be loaded hot, and I'd assume, W296, 2400, and maybe even N110 are the same way.
H110 is prolly the worst offender, but when these loads say 'DO NOT REDUCE' , well then do not reduce.

Damon of Baltimore
October 8, 2003, 10:51 PM
I have used 7.5gr of bullseye under a 125gr bullet. While it works ok(no complaints for punching paper), I would think, as others do, there are better powders for your intended purpose.

Another thing to consider, if it makes any difference (I don't hunt or anything), bullseye produces a lot of flash, I mean alot!

Just something to consider, if you hadn't already made up your mind.

Damon

stans
October 9, 2003, 07:45 AM
Bullseye, W-231, AA#2 and such make a poor choice for high velocity loads in 357 magnum. They are great if you are looking for loads that duplicate 38 Special and 38 Special +P loads and need only a light crimp. For medium velocity loads, look at powders such as Unique and AA#5. For top velocity, try 2400, AA#9, W-296 (and its twin H-110). I would use a Magnum primer with AA#9, H-110 and W-296, since these are slow burning spherical powders and are the hardest to ignite in a uniform fashion. The slower burning powders also require heavy crimps. My experience with the 357 has shown that W-296 and H-110 give the highest velocities.

tex_n_cal
October 13, 2003, 12:56 AM
on your expander die, turn down the stem so it is at least .005" smaller than bullet diameter. This increase case neck tension, and has been proven to improve consistency. A tight crimp by itself won't do it.

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