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Old December 8, 2000, 02:24 AM   #1
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Join Date: November 7, 1999
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Cannelure Groove Bullet/RCBS Roll Crimp:
357 SIG Bullet Setback Test

I have two basic ways of reloading the 357 SIG. In fact, I have two sets of 357 SIG dies always ready to go. The first die set is adjusted for using soft copper plated bullets such as the Rainier 124 grain flat points, West Coast 124 grain flat points, Speer 125 grain Gold Dot HP's, etc. The second die set is adjusted for using hard-jacketed bullets such as the D&J 124 grain flat points, etc.

For the die set using soft copper plated bullets, I first apply a cannelure groove on the bullet and then I apply a strong RCBS roll crimp during the reloading process. I use little or no belling of the case mouth to help hold the bullet in place. And the RCBS crimp die is only about 4/1000" from touching the Dillon shell plate (about the thickness of a piece of bond paper).

The second die set was adjusted for using hard-jacketed bullets only. Little or no case belling is used so the neck has plenty of tension to hold the bullet in place. I use little or no taper crimp, otherwise the bullet can get loose and slip into the case easily. After the seating die stage, the case mouth diameter generally measures around .379, which is still less than the .381 SAAMI standard.

The Test

The main purpose of this experiment was to test a cannelure groove and strong roll crimp to see how well this method works.

A Hornady once fired brass was used because I've found that bullets can slip the easiest with this brand. I have nothing against Hornady. I can tighten the crimp slightly to compensate for the difference between Starline and Hornady brass.

I used a Corbin Cannelure tool to groove the Rainier bullet. This is a very easy and fast process.

I then loaded one dummy round with no powder or primer. The original OAL began at 1.1165.

I performed the thumb pressure test (55 lbs as measured on a weighing scale). OAL became 1.116. Generally, 45 lbs is considered good enough to simulate the bullet hitting the feed ramp in a pistol.

I cycled the dummy round 10 times (full force) through my pistol. OAL became 1.1155.

I then did another thumb pressure test two times (55 lbs). OAL became 1.114. So far, after 13 forceful tests, the bullet has slipped .0025. Note: If I had used my normal Starline brass, slippage would be even less. Using Hornady brass is my worse case scenario.

I then did one more thumb pressure test at 90 lbs (double the necessary pressure)! OAL became 1.108. The Rainier bullet nose was still above the case mouth and the bullet could be crimped correctly if desired. If I had loaded a mild 12.2 grains of AA No 9 powder, the bullet would now be fully supported by the powder and not slip anymore. A higher charge would have kept the OAL longer of course. But this dummy round test must continue

Lastly, I went to the garage. I grabbed my Dillon flat wrench to help support my thumb pressure. I forcefully did a thumb pressure test against the cement floor, literally banging the bullet as it first hit the cement. I did this four times before the bullet succumbed and plummeted into the case. The last four extreme tests, brought the total to 18 tests. The only normal tests in this series, was the forceful cycling of the dummy round through the pistol ten times. All the other tests were greater than would be expected during a normal cartridge feeding cycle in a pistol, except for possibly a feed jam of some kind.


I really had a sore thumb joint for awhile

The cannelure groove on a soft copper plated bullet in conjunction with a strong roll crimp really does work well!

Many calibers can succumb to the thumb pressure test and cycling test pretty easily. This is NOT just a 357 SIG issue. But a 357 SIG reloader needs to be especially cautious because of the short neck.

For example, I remember a little over a year ago when I had a feed jam with my Glock 21. I examined the cartridge after I ejected it. I was surprised to see a bullet setback issue with part of the nose in the case. And I had made a strong crimp. I was so glad that I had not fired it. Can you say, "Kaboom"!

There are a number of safeguards regarding 357 SIG ammo. Obviously, I prefer a cannelure groove and strong roll crimp. I don't understand why factory ammo cannot use this safe technique. It also seems to cut down on large velocity spreads in general.

Important safeguards:

1. Use a soft copper plated bullet with a cannelure groove and strong crimp.
2. Glue/sealant is used by some ammo companies.
3. A crimp ring on the case neck can be used.
4. Belling the case mouth little if at all is necessary so there is enough tension to hold the bullet.
5. For hard jacketed bullets, you need a light crimp, otherwise the bullet can easily slip into the case and/or the case can even get wrinkled/damaged.
6. Using one of the slowest pistol powders, AA No. 9, can work as a compressed powder to prevent the bullet from slipping into the case too far.


1. Spot check a few rounds in your box of ammo with the thumb pressure test, or by cycling the rounds through your pistol using the full force of the slide slamming into full battery. But be careful so you don't have an accident. Measure the before and after length with a caliper.
2. Check ammo visually: Face all the bullets up in the box and then look to see if there are any bullets lower in the case than the others.
3. Don't assume factory ammo is somehow infallible. Following the safe checks as mentioned here is useful for all calibers. It's not just a coincidence that so many pistols of various calibers have blown.

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Old December 8, 2000, 01:37 PM   #2
Join Date: January 13, 2000
Posts: 54
First and most importantly, I want to commend Petej88 on taking the time & effort to post the results of his extensive testing on reloading for the .357 SIG. This post and several other posts on this and other forums have provided a lot of good information. I have been reloading this round for several years. I think it is one of best and most interesting calibers on the market. I welcome any information I can gather regarding it.

The one fear I have is that many people may be shying away from shooting/reloading .357 SIG due to all the 'scary' things they keep reading on all the firearms related forums.

If I were someone that had been contemplating .357SIG, I know that with all the 'concerns' that I have heard regarding this round lately, I would be thinking that it is just not worth the hassle & worries.

Folks, shooting/reloading the .357SIG is simply not as "danger filled" as it has been portrayed as of late. Please do not be discouraged from trying this fine round.
I have reloaded and shot many thousands of rounds, so I feel I have enough knowledge to comment:

Do you need to be careful when reloading for .357SIG?
- Definately (just like any other caliber)
Is extra attention required?
- Yes, bottleneck = extra crimp attention
Do you need to be fanatical?
- Not to the extent that you lay awake at night wondering if there just might be a lone round in that box of 500 that somehow escaped the Nazi thumb test!!

Maybe I am the exception, but my reloads are only chambered once...just moments before they are fired. I don't chamber and rechamber any rounds (practise or carry) dozens of times. You are asking for trouble with any caliber if this is done.

A carefully adjusted taper crimp with my Lee dies gives me safely loaded rounds 100% of the time.
That being said, I make sure to adhere to the following:
- proper bullet selection (ie: short ogive)
- no mixed brass
- pay attention to "feel" the crimp being applied (last week I loaded up 600 rounds of .357SIG. There was one lone round that didn't "feel" the same when crimping as the others. I immediately noticed and checked it. This one slipped slightly when I subjected it to the thumb test, so I put it aside.)
- thumb test ALL of the first few rounds when first setting up your dies until you are confident that the crimp is good. Do a periodic thumb test once you are rolling just to make sure the settings are still good.

Petej88, please, please don't think I'm flaming you or anyone else that posts concerns regarding the .357SIG. I enjoy reading your posts and welcome any further info I can gather. Please keep posting your test results with this round!
My only intent in posting is to try and prevent people from being turned off from the round because it appears to be too much hassle and/or worrysome.

Just like most things in life, you can go to extremes or you can keep it simple. There are merits to both approaches.
The same goes for reloading .357SIG.

My reloads are simply done, but 100% safe.
They probably would not stand up to a dozen rechamberings and/or being smashed into a concrete floor, but my needs don't require that.

I just want people to realize that you can safely reload the .357SIG without much more effort than any other caliber.

If you anticipate that your reloads may be subject to a lot of rough treatment, and you want to ensure that they are safe, Petej88 has shown us the way!

Cheers & be safe!!
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Old December 8, 2000, 07:07 PM   #3
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Thanks for your reply. I agree with your attitude 100%.

Maybe it backfired, but my purpose of this post was to show that the 357 SIG is darn tough and can take tremendous abuse if loaded correctly. I was thinking more in the line of factory ammo which is loaded and unloaded many times by those who carry concealed and by agencies. This seems to be a hot spot right now.

If you plan on just loading your practice ammo once and firing, it's mostly all a moot point as long as your dies are set up correctly --- it's a cake walk.

Actually, I reload the 357 SIG exclusively now, because the bullets are very cost effective (9mm), it's accurate, and it's easy to reload once you know how to do it. At my home web site for the 357 SIG, I'll be rewriting my reloading faq to give all the facts without the fright.
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Old December 8, 2000, 07:24 PM   #4
Join Date: January 13, 2000
Posts: 54
Pete, just out curiousity, have you tried a roll crimp into some of the softer bullets (Rainier, WestCoast) without putting a cannulure into them first?
I haven't reloaded any caliber with a roll crimp, so I'm not sure if you absolutely need a cannulure groove or not on the softer bullets.

I ask because I may end up getting a progressive press to replace my turret. If this happens, I'm guessing I would not be able to "feel" the crimping stage like a can now.
If this happens, I would be tempted to give the roll crimp a shot. It would be nice if I could avoid the time & cost of a cannulure tool.

Maybe it would not work as good as roll crimping into a cannulure groove, but would a lighter roll crimp without the groove work as well or better than taper crimping?

I would appreciate any comments/feedback.
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Old December 9, 2000, 11:58 PM   #5
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From my experience:

1. cannelure groove with strong roll crimp using soft copper plated bullets works "excellently". Great if you have to keep chambering the same ammo.

2. Strong roll crimp using soft copper plated bullets works "good" if you plan on shooting the ammo with a minimal amount of chamberings.

3. Light taper crimp and very light case belling works "OK" with a hard jacketed bullet if you plan on chambering the cartridge only once or so. Be careful to find a hard jacketed bullet that is compatible.

I just finished testing all three methods and put the details in my article, "357 SIG Safety & Reloading FAQ"

[Edited by petej88 on 12-11-2000 at 12:17 AM]
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Old July 12, 2001, 09:29 PM   #6
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i to love the 357 sig but i dont carry it just shoot it may start using it in some matches my redhawk is off the the shop out of time right now.another way to deal with bullet setback for the people that carry is to only chamber the round one time the next time use a different round.the way i shoot up ammo it would work great for me might be a problem is you only shoot 2 or 3 boxes a year but i dont feel like the 357 sig is a round for a green horn any way
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