Curious question about some recent loads I made

Dave328 · Jun 29, 2015

I loaded up 50 .357 Magnum rounds the other day to shoot through my new toy. 158 gr Hornady XTP over 16.5 gr of Winchester 296 with a CCI 550 Mag primer. When shooting them Sunday, I noticed that I would get random fireballs from the muzzle. All loaded from the same sleeve of primers, same can of powder, same box of bullets, so my first guess was my crimp? All of the rounds felt identical, and all did a good job of cycling the slide every time. Not worried about it, was just more for my curiosity. Could a possible varying crimp cause intermittent fireballs from the muzzle? And if so, is it a tight or loose crimp that would cause it? Thoughts?

Metryshooter · Jun 29, 2015

I'm not sure of what the cause is Dave, but I'll tell you this, when I first started reloading years ago (9mm first) I was using a hand primer, single stage press, and a balance scale. I had no powder measure so I had no choice. I was so paranoid I even trickled to the exact tenth. What I did notice was that all the casing were within a very small area but I did get intermittent fireballs from the muzzle.

highstandard40 · Jun 29, 2015

Based on the data you provided, your load level for the components you listed seems about right. 296 is a magnum only powder that does not respond well to reduced loads. In fact, Winchester strongly advises against it. 296 does require a strong bullet pull (neck tension) and a firm crimp to burn properly. One way to tell if the case tension is enough is to look at a loaded cartridge and see if you can see a visual indication of where the base of the bullet is. Sizing dies should actually reduce fired case outside diameter to under factory spec and then the expander button in the next die should size the inside of the case to a dimension that assure a firm grip on the bullet when seated.

So first look to see that the case tension is as I stated and then be sure you have a firm crimp. Not enough crimp to deform the bullet. You should be able to find a picture in most reputable loading manuals that show a proper crimp. I prefer a roll crimp but opinions vary. I have fired many thousands of 357 Mag cartridges over the years shooting silhouettes and 296 has always been my go-to powder. In low light conditions, muzzle flash is common but should be consistent.

The_Shadow · Jun 30, 2015

Winchester 296 will yield a fire flash depending on how the gas exits the barrel and mixes with the air, as the oxygen is induced into the hot gases, you see an ignition of the residual gases. Good crimps can improve ignition properties, and the magnum primer can start the bullet moving before the powder fully ignites.

highstandard40 · Jun 30, 2015

The_Shadow said:
and the magnum primer can start the bullet moving before the powder fully ignites.

That can be an issue if bullet pull is too slight and not enough crimp is applied. Winchester and most reloading manuals do suggest magnum primers though when using 296.

gwpercle · Jun 30, 2015

Position of powder in the case could be a factor. If the powder is in the front towards the bullet that round could act differently than if the powder was positioned against the primer.
Next time do a test, shoot 5 , but tip the gun down, to get the powder up front, before each shot .
Then shoot 5 more , but tip the barrel up to position the powder to the rear of the case, before each shot.
I have a suspicion there will be a difference in the "fireballs".....and again I could be totally wrong.
Gary

The_Shadow · Jun 30, 2015

highstandard40 said:
That can be an issue if bullet pull is too slight and not enough crimp is applied. Winchester and most reloading manuals do suggest magnum primers though when using 296.

That's exactly what I was getting at mentioning the magnum primers, yes to a good rolled crimp to hold the bullet securely if there is a cannelure on the bullet.
Bullets without a cannelure you might want a faster burning powder.

Dave328 · Jun 30, 2015

Interesting thoughts! I am using a good tight roll crimp right at the cannelure. Now, is a variation between the "tightness" of the crimps between rounds possible? Sure. And I don't think there is much room left in the case with the 16.5 gr/ 158 gr combo. I have seen a 17.? gr load with 296/158 in an older reloading manual, so I gotta think that may just be about the max volume. Next time at the range, I will try the tip test just for the hell of it.

Danny Abear · Jun 30, 2015

I think you are using different brand cases and probable not all the same length; that will affect the neck tension and the crimp. 296/H110 is not position sensitive.

Dave328 · Jun 30, 2015

Danny Abear said:
I think you are using different brand cases and probable not all the same length; that will affect the neck tension and the crimp. 296/H110 is not position sensitive.

Hmmmm, didn't think about that aspect. Definitely was using different cases. I'll take a caliper to some of the cases and check lengths.

highstandard40 · Jun 30, 2015

Danny Abear is correct mentioning that 296 is not position sensitive. 296 requires a very high loading density (filling most of the available powder space) to burn correctly. Suggested loads are high density. So tipping the gun will make no difference whatsoever. In order of importance for to 296 to perform as intended, the things required are:

1. High load density with no reduced loads below suggested levels.
2. A good tight bullet pull (case neck tension). And don't assume all dies provide this. Check as I explained earlier.
3. Firm consistent crimp. Check case length and trim all cases to the same length.
4. 296 is well known to be hard to ignite. That's why magnum primers are suggested by the manufacturer. But if you don't follow items 1-3 you can experience what "The Shadow" mentioned......because with a magnum force primer the bullet can move before full ignition of the powder takes place. When this happens, you are in effect reducing load density and you can experience the issue the OP stated.

noylj · Jul 3, 2015

H110/296 reportedly produces fireballs or not all the time. This would be with perfect crimps or imperfect crimps, with matched cases or various cases. With exact charge weights or normal variations. It really doesn't matter. How were the groups?
The questions is: do you want to "waste" time chasing the cause (that seems to be in the nature of the powder) or spend more time at the range shooting?

Jmfox3 · Jul 3, 2015

Shot in the dark: You're describing an incomplete burn of the powder. Everything being equal did you inspect the primer pocket before you set the primer? If the primer pocket is fouled you could get poor ignition from the primer.

4thMiss · Sep 3, 2015

Win 296 and 158gr Montana Gold JHP @ 16.5 grain powder load with Magnum primers is my favorite load in my 6" GP100 and I love the fireball on an overcast day. A nice whitetail load if your a handgun hunter. My other fav is the 125gr JHP and 21.5gr of Win296. Consistant case length and a firm crimp are a must and fireballs can be expected.

Bayou52 · Sep 4, 2015

The flame is caused by the Win 296 powder. It is so effective as a magnum powder due to its slightly slower burn rate. The higher velocities produced by this powder result from its continuous burn all the way down the barrel. Thus the flame at the end - the powder is still burning.

I've loaded up to 16 grains for use in a GP 100.......full magnum authority, indeed......nice flame......

Bayou52

hunter5567 · Sep 7, 2015

I would sort all the cases and load 50 of one make of brass especially with the near max load you are using.
Hodgdon lists 16.7gr as a max load with the 158gr bullet. Different cases will have different case capacities especially with variations of brass thickness from one brand to another. I use a firm crimp when using H110/W296 powder.

noylj · Sep 9, 2015

Attached, if it works, is a pressure vs length plot for .44 Mag and 296. All powder that will burn is burned in first 1" or so.

Hillbillyjim · Sep 23, 2015

I am curious as to what firearm you shooting. Sounds like you are describing a semiauto which should not affect the fireball issue.
My personal vote is check case length and trim to uniform length.

Dave328 · Sep 24, 2015

Hillbillyjim said:
I am curious as to what firearm you shooting. Sounds like you are describing a semiauto which should not affect the fireball issue.
My personal vote is check case length and trim to uniform length.

It's a Desert Eagle .357
It needs to be fed some pretty stout ammo to cycle properly, hence the 158gr XTP over 16.5 gr of 296. Factory 158 ammo from Federal (JSP) gave me horrible fits with failure to return to battery, (and no fireballs). Not sure if they were bunny fart loads, or if the JSP was hanging on the feed ramp. I am going to return to my XTP's and try to pay more careful attention to my crimp, brush all primer pockets, and sort my cases to see if I can determine where the fireball comes from.
And just to reiterate, rounds in the OP functioned flawlessly. Just an inconsistent fireball. This is all just to satisfy my own curiosity.

Oh, and I have only shot my reloads in my SW681, so case length was never really an issue. I am going to have to mic some cases since OACL will be more crucial with a semiauto .357.

Curious question about some recent loads I made

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