Primer flattening with not so heavy loads???

PoFF

PoFF

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I went to the range yesterday to test my new .44 Magnum target loads, on which I used to use WLP, but since LeBaron ran out of them, I switched to No. 150 Federal Large Pistol.

The load if the following :

Mixed brass (Winchester & Remington)
Frontier 245 grains CMJ
9.2 grains of Titegroup (8% under max load listed in Hodgdon book)
1.598" to 1.602" OAL
Heavy crimp.

I've been using this load for over a year with WLP now, without a single problem (no overpressure signs at all), but on 15 shots with Fed primers and the same load, all primers were heavily flattened after beign fired (IIRC, this is a good overpressure indicator). I know that Federal primers are 'softer' than Wincherter ones, but I never expected that it would make such a drastic difference.

Should I worry about that?
 
A flattened primer is a possible sign of over pressure, but can occur for various reasons well within safe pressures. An enlarged primer pocket on the other hand, is a sure sign of overpressure.

Given that you are using a published load, certified as under max, and used previously by you in your gun, I would not be concerned.
 
Two things... the cups on federal primers are also softer which means they will show more pressure signs.

AND changing primers can radicaly alter the pressures generated. IN some cases testing found pressure changes of as much as 20%.

I note that your load uses a heavier bullet (5 grains heavier) and that the manual data was for a Remington primer. So you're really not that close to the "load" in the manual.

If you are really concerned here is the way to do this all more safely and consistently that guessing. (As taken from an article in "Handloader")

The best way to determine whats "safe" in your gun is to start out with EXACTLY the recipe given in the manual, work up to the max load and chrony your shots.

The values you get for velocity with the "max load" (or the one that shows other signs of being "max" but not in excess of the manual) in the recipe are the values you need to take special note of. This is the max safe speed (and thus pressure and load) in your gun, any load with that bullet weight that exceeds the "max velocity" is going to be over the pressure in the table regardless of signs or no signs. Often there are no signs even when a load is very far overpressure simply because of the superb quality of modern guns and components. That doesn't mean its safe though.

Then when changing to other components, monitor the chrony results. Drop loads back and build up again each time you change a component. When the chrony reads the same as your "max load" that you recorded with the exact original manual recipe, thats the max load for that combination of components.

When playing with bullet weights remember that increases in weight will increase pressure peak. If it was me I'd work up a load using the exact bullet given inthe manual, and then once I had made the above outlined steps for the other component changes I wanted then I'd look at the bullet.

For ones that are significantly over weight I'd use the next heavier weight loads to start from. Velocity and weight should be fairly close to a cubed relationship over SMALL weight variations.

So in your case you have a 245 gr bullet instead of 240 gr bullet. Thats an increase of 2.1% (=100*(5/240)). So then you would take your max velocity reading (we'll use the number from the table for the example since we don't have your "developed" velocity.) and reduce it by the cube of that amount. The velocity is 1292 for a 240 gr bullet. But you increased the bullet to a 245 gr weight (2.1%) so we will reduce the max velocity by the cube of that percentage (9.3%). So we reduce the 1292 to 1172 (=1292*(100-9.3)/100). This is the new max velocity you will build your load up to with the heavier bullet, but all the other components unchanged. In this example we worked up from a very slightly lighter bullet.

This is not an exact result but should give you something reasonably close. Certainly closer than using the 240 gr numbers. (als you'll note that based on this reduction in speed that its probable that your 8% load reduction from max for a 240 gr bullet actually puts you very close to max or maybe slightly over with a 245 gr bullet.

(You can look at the 325 and 330 grain manual values from Hodgdon as a test to see what the effects are and do calculations to see how close you actually get. .)

I know it seems like lots of work, but only you can decide if its more than you want to be bothered with or if its good insurance against losing fingers or an eye...

As always I recommend you read the best sources of information available. (the "Handloader" magazine article is superb.) And make your own conclusions. I take no responsibility if you blow yourself or anything else up. :shock:
 
Well, thanks alot for that little course, I guess that it'll be more efficient and safe than blindly following published loads.
 
Note: Published loads have many $1000's of dollars worth of development in them. The problem is that they are really only applicable to the exact combination of components.

Thats part of what the article I mentioned from Handloader points out. The menthod outlined, basically is just to make sure that you don't exceed the limits set out by the manual loads when changing to other components in the recipe.

Its basically a means to calibrate your gun to their results. Then you can use the chrony to make sure you don't go over those levels by accident.

One way to see if you're getting siginificantly different pressures is to take your load with the Win primers and chrony it, then take the same load with the Federal ones and see if it chrony's differently. If the velocities are the same the pressures are too. If they are different then the pressures are different. 8)
 
Bah, disclaimers aren't very useful anyways here in Kanada... plus I'm not the type of person who puts the blame on other easily. Reloading is a very personal business IMO
 
Primer flattening is one sign of overpressure. I would check velocity with a chono. You might have dumped more powder in that case that you think..

The other culprit is headspace - on a revolver - cylinder movement back and forth.
.44 mag handgun do wear faster than others smaller caliber. Excessive headspace will get you flattened primer all the time.

Make sure the chamber(s) is (are) very clean - for the brass to grab and seal - check for a leaded barrel - this will get pressure up very fast - and on a revolver - cylinder throat and forcing cone for lead or jacketed material. Heavily fouled barrel - be from jacket or lead - will get pressure up.


Federal primer are softer but not to that extend. Instrumentation will be needed to see the difference between the brand..
 
PoFF said:
I went to the range yesterday to test my new .44 Magnum target loads, on which I used to use WLP, but since LeBaron ran out of them, I switched to No. 150 Federal Large Pistol.

The load if the following :

Mixed brass (Winchester & Remington)
Frontier 245 grains CMJ
9.2 grains of Titegroup (8% under max load listed in Hodgdon book)
1.598" to 1.602" OAL
Heavy crimp.

I've been using this load for over a year with WLP now, without a single problem (no overpressure signs at all), but on 15 shots with Fed primers and the same load, all primers were heavily flattened after beign fired (IIRC, this is a good overpressure indicator). I know that Federal primers are 'softer' than Wincherter ones, but I never expected that it would make such a drastic difference.

Should I worry about that?
Click to expand...

TARGET LOAD MIXED BRASS

With this load those two phrases concern me more..Their like female logic
 
blindside said:
TARGET LOAD MIXED BRASS

With this load those two phrases concern me more..Their like female logic
Click to expand...

Sorry or the confusion, I should have used the 'Plinking load' term, that would have been much more accurate. I wanted to distinguish from my Hunting loads.

Hunter :

The muzzle flash is present, but not heavy. It's dark orange flame, and from the shooter point of view, I would say 1 to 1.5 inch radius around the barrel. It's nothing like a H110 load, with bright yellow flame, with a 1.5 foot radius around the barrel and 3 feet lenght (under lowlight conditions). Recoil and muzzle lift are moderate, since the muzzle velocity of the bullet is quite low for a Magnum load (1150-1200 FPS approx). Overall, Titegroup makes a good plinking, and even a good target cartridge if you put enough attention into it, and the good thing is that it requires only a regular large primer. I can't compare it to 2400 since I've never used this power.
 
Do your primers look flattened or riveted? Sometimes, with shorter than usual brass in an auto (or in a wheelgun with endshake) you can get riveted brass.
Extract one primer and check if it looks a bit "mushroomed". Measure the inside diameter of the primer pocket on clean unfired brass and on your fired brass.
If the pocket diameters are the same, chance is that your primers have extruded upon the first phase of firing and have been flattened when the pressure peaked.
Check for endshake.
Good luck!
PP.
 
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