Too high pressure?

F

flintlock.50

New member
I'm working up a .357 mag load. Today, for the first time, I began to feel a little resistance when I ejected the shells. Primers look fine, with no sign of pressure. 1, maybe 2, out of 5 shots, are just starting to flatten. There is no sign of cratering on the primers.

With lighter loads I think the cases could have fallen out by themselves without physically ejecting them.

I understand that if it's difficult to eject shells the pressure is too high. Is what I'm seeing OK?

I may buy a box of HSM bear loads and see if they resist a little when I eject them.

Any help will be greatly appreciated.

Thanks!
 
That resistance is a sign that you are getting there. You can throw in the appearance of the primers and make a good determination.

A little resistance is OK. A lot of resistance means that you should back the powder charge down a little bit.
 
If the load you're using is within the Min and Max range given in your manual, there shouldn't be any resistance. What's the load?
"...just starting to flatten..." That is an excessive pressure sign. Shouldn't be with just a few though.
 
Fired primer condition isn't a consistent sign of high pressure. For my revolver shooting (I had "Magnumitis" for a few years when I started reloading my .44 Mag) I would measure the case and note extraction from the cylinder. If the case expanded more than .0005"-.001", right next to the rim I'd give the load a bit more thought. If I got sticky extraction, I'd back off the load. Sticky or hard extraction is having to use excessive force to push out the empties to the point of using a mallet on the ejection rod, and sometimes a "safe" load will be a little sticky, depending on a few different factors other than high pressure...
 
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I could easily eject these shells with finger pressure. It's just that the lighter loads showed zero resistance. These started to show some.

I'm shooting a 165 grain lead SWC with gas check from Matt's Bullets. My Lyman Cast Bullet Handbook doesn't list that particular bullet, but does list the following max loads of 2400:

155 grain bullet - 14.0 grains
158 grain bullet - 13.5
160 grain bullet - 15.5
170 grain bullet - 13.5

It's not obvious what my maximum load should be.

Thanks
 
How are you cleaning your brass ? Also how often are you cleaning your cylinders ? Were you shooting 38's in your 357 & 44 SPL. in your 44 Mag.? What make & model are you shooting , I feel S & W revolvers can't handle a steady diet of Magnum rounds. All my revolvers are S & W I just like them 2" 36 38 SPL. , 3" 65 357 & 8 3/8" 29 44 Mag. always reloaded mid range loads , better for the gun & my hands. The 3" 357 is like a flame thrower with magnum rounds.
 
I looked again at the primers. I misspoke earlier. Out of 30 shots, only 2 showed any hint of flattening, and that could be my imagination.
 
I clean my brass with a tumbler. This is Starline brass that came from a box of HSM bear loads I bought years ago. I've loaded them twice now.

I clean my cylinder after every trip to the range. I use a wet patch, let it soak, followed by a brush then more patches. The cylinder is clean.

I'm shooting a S&W model 19. I know it should not be fed a steady diet of hot loads, especially with light weight bullets. That's why I chose the 165 grain bullet. This load is strictly to carry as a backup (not hunt with) in black bear/pig country.
 
Flintlock.50,

Revolvers are peculiar in that there is s thin portion to the chamber wall on the outside of the cylinder. This is where an overpressure round stretches the steel most, and since steel can stretch further than brass can before it ceases to return completely to shape, if it traps the brass in the cylinder by returning to shape over a now-larger diameter piece of brass, then the stretching went beyond that limit for the brass, and that's the pressure sign. In some revolvers this happens before primer signs. Primer signs are not reliable beyond telling you that the primer you are using doesn't like the pressure. It is most variable in small primers because they come in a wider range of cup wall thicknesses than large ones do.

As to your particular load, lead bullets can come in a variety of lengths for a given weight which affects seating depth and thereby powder space and thereby peak pressure. Unless you know you are not seating deeper than Lyman did, that can be the source of higher pressure. If you do know you have the same seating depth as Lyman, you are very probably OK with their loads.

Seating Depth = Case Length + Bullet Length - Cartridge Overall Length

Most of the time, though, we don't know the load data's bullet length unless we have that exact same bullet and have to call the company and ask for it.

If you fire the rounds in a clean chamber and get some light resistance to ejection, it could be a pressure sign or, if the chamber has circumferential tool marks, it could simply be the brass is starting to get fat enough to start catching in that roughness. That's not necessarily an indication you are getting near the maximum load for your seating depth, but it probably does mean your are not many percentage points of charge weight away from it. If you up the charge another .3 grains and start to need lean on the ejector to get the cases out, then back that higher charge off 5% and call it a day. But if you just get more iffy drag, you probably aren't quite there yet.
 
flintlock 50
I also use HSM brass in rifle cases the box is listed HSM but the cases are FC , AMI & HSM . The cases used are thicker then Win or Rem. Case thickness shouldn't make a difference in ejecting though. Do the cases seem stained , your roll crimping , could you be overcrimping.
 
When there is slight resistance to ejection by hand pressure, meaning the rod "sticks" for a moment then pops free when you push on it, THAT IS A GOOD PLACE TO STOP!!

If the chamber (and brass) is clean, so there is no crud to make cases stick, if there are no obvious tool marks for cases to stick in, early, when they first start to stick, that's where you stop adding powder. PERIOD.

Doen't matter what the primers show, or don't show, at this point, if cases start giving you sticky extraction, that load is as hot as you ought to go.

because the next pressure sign you will get could be primer signs, and the same amount of case sticking, OR it could be cases stuck so hard you will need to drive them out with a hammer.

The gun matters, and every gun is an individual. A load that is hot, but still safe in one gun can be TOO hot in another. I've seen ammo fired in a S&W N frame that had slight resistance to ejection, then the cases popped free. Same ammo fired in a K frame and the cases had to be driven out of the chambers with a rod and a hammer. SAME AMMO, different guns.

It doesn't matter if you are below "book" maximums. It doesn't matter if you don't see any pressure signs on primers, if you are getting sticky extraction, that is the practical max load for that gun and ammo combination.

Another 50fps gets you less than nothing, if you can't reload the gun after you shoot. :D
 
Interesting. I'm using Starline brass. I also have some Federal and Winchester brass. I checked case weight. Starline was lightest at 73 grains. Federal was next at 75 grains. Winchester was heaviest at 81 grains. The difference between Starline and Winchester translates to 4% less case capacity for Winchester. (I weighed cases empty and full of water.) I'll definitely back off powder weight if I load some Winchester cases.

Heavier cases means more metal somewhere in the case. Any thoughts on whether it's better to use the heavier Winchester cases?

Thanks
 
Didn't Linebaugh's testing demonstrate that straight walled pistol cases that headspace on the rim can't be counted on to consistently exhibit any pressure signs at all before the gun blows?
My Lyman Cast Bullet Handbook doesn't list that particular bullet, but does list the following max loads of 2400:

155 grain bullet - 14.0 grains
158 grain bullet - 13.5
160 grain bullet - 15.5
170 grain bullet - 13.5

It's not obvious what my maximum load should be.
Click to expand...
From that data set, I don't think that it's really complicated to make an estimate of what the max load should be. If you like to live dangerously you could assume that 15.5 grains is the outside limit but much a more reasonable and obvious choice would be 13.5 to 14 grains.
 
I think that's right. The primers certainly fail to flatten reliably.

Flintlock.50,

More weight means less capacity only if the head dimensions all have the same diameter. A lot of case weight difference occurs because they don't, rather than because of capacity difference. You have to weigh them empty and weight them filled with water level to the mouth with no meniscus, subtract the empty weight and learn exactly how much water they will hold. That gives you a valid comparison.
 
"I feel S & W revolvers can't handle a steady diet of Magnum rounds."

I wouldn't go so far as to say that.;) Maybe for the light weights like the M19 or M66 that point is valid bit I cannot count how many full power loads my M28 has digested and it's still going strong.

Funny thing but after the M19 and M66 came out, reload data for the .357 mag was drastically reduced. At one time it was 15.5 gr. of H2400 (H being Hercules while current A2400 by Alliant appears to have been reduced to 13.5 according to what the OP posted. My load with the 158 gr. gas checked SWC is 14.0 gr. of 2400, fast enough and accurate as all get out. I have run that original 15.5 gr. load years back before the change and it was just a bit nasty in recoil and muzzle blast, especially the latter. I had an M66 for a while and that 14.0gr/158 SWC load was just fine. I just didn't like the gun so I sold it.
FWIW, Elmer Keith's pet load for the .44 mag. was also reduced from 22.0 gr./2400 to 20.0 gr. 2400. Seems the 1905 design "N" frame couldn't withstand the load. I know what it did the M629 I had, twice. S&W fixed it both times.
Factory loads for both cartridges have been reduced as well. I still have one box left of early 1960's Winchester .357 mag. ammo and shooting those will certainly get your attention. They'll also lead the hell out of your barrel in a hurry.
Paul B.
 
Yep. Filled with water. No meniscus. Difference was 4%.

FWIW, I recall loading some.357 shells decades ago using a Speer #9 manual. I was well below the max load, but the pimers severely flattened. I later read somewhere that Speer's data was widely known to be way too high. Perhaps the data had been measured in severely cold weather. And yes, I was using the correct powder and correct weight.
 
S & W 29 was sent to S & W for a problem called end shake. The company S&W told me its bad to shoot full loads all the time. I felt a magnum should be able to shoot magnums all the time. That's when I got into reloading. Shooting specials in a mag. didn't like the burn marks left in the cylinder when shooting specials. Even though I still like Smith.
 
S & W 29 was sent to S & W for a problem called end shake. The company S&W told me its bad to shoot full loads all the time. I felt a magnum should be able to shoot magnums all the time. That's when I got into reloading. Shooting specials in a mag. didn't like the burn marks left in the cylinder when shooting specials. Even though I still like Smith.
Click to expand...

The N frame dates back to 1907, though S&W has made modifications, there are stronger designs. If someone wants to shoot full power 44 Mag's all the time, A Redhawk or SuperRedhawk is a better revolver. Better get to know your hand Doctor because shooting full power magnums all the time is going to do nerve damage in your hand and elbow.
 
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