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Discussion Starter · #1 ·
I’ve been loading for many years and always try to follow powder manufacturers recipes but in these times of getting what you can find for components how can you tell if your shells are approaching max pressure short of sending loads off to be tested?
 

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I’ve been loading for many years and always try to follow powder manufacturers recipes but in these times of getting what you can find for components how can you tell if your shells are approaching max pressure short of sending loads off to be tested?
No.
 

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Approaching? No.
Over? yeah, your action may lock back or over-under may open up. barrel could get stress cracking, or even fail. Basically stuff starts to break once you go over, but nothing indicates you are nearing there.
 

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On the hull side, you can experience primers blowing out, the heads expanding or rounding over, cracking of the steel rims, complete separation of 2pc hulls. Lots of different things, again once you are over pressure these happen.
 

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There are no pressure signs that you can measure or visually see on a shotgun hull. Flattened primers mean nothing. This includes hulls that were used for proof loads.

The best you can do is follow good reloading data.
 

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Texcl2,

DO NOT try to 'work up' loads to the point of experiencing any of the items that BBK has mentioned. None of those things will happen until you have pressures well past proof level. I have personally tested loads in a pressure gun and even at 20,000 plus PSI none of those items mentioned showed up.
 

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Texcl2,

DO NOT try to 'work up' loads to the point of experiencing any of the items that BBK has mentioned. None of those things will happen until you have pressures well past proof level. I have personally tested loads in a pressure gun and even at 20,000 plus PSI none of those items mentioned showed up.
You would have to have a pretty low IQ to think I suggested those things as what to look for when developing a load... I clearly said all of that happens over pressure. Over pressure means chance of losing your gun or face, figured that was pretty obviously something to avoid...
 

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BBK,

You and I might understand what you posted. Since the OP is not familiar with the subject, I thought it was worth mentioning that he shouldn't try to duplicate any of those "over pressure signs". I would hate to see anyone get into trouble.

I was not being critical of what you posted.
 
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I’ve been loading for many years and always try to follow powder manufacturers recipes but in these times of getting what you can find for components how can you tell if your shells are approaching max pressure short of sending loads off to be tested?
You can't; it is not like metallic where crushed primers give an indication
 

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Agree with the others stating there are no indicators.

I believe Tom Roster did a test with an 870 a few years back and there were no signs right up to the point where the barrel exploded. Somewhere north of 50,000 psi. In between that and normal pressure who knows what untold damage is being done or if a different or lesser gun would have exploded way sooner.

Stick with the published data.
 

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Muzzle velocity can give you some hints, but you have to be familiar with what your load should be making for velocity, and know that you have a reputable, safe load to begin with. Then watching your velocities and keeping them in line with expected is as close as you can get without pressure testing the loads.

So, follow established recipes. Make no unsafe substitutions. Which are unsafe? You can learn that by experience, but it's an expensive tutor.

There really are so many more variables with shotshell loading than with cartridge loading, that the approach to take to make safe loads is not the same between the two hobbies.

good luck, garrisonjoe
 

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I’ve been loading for many years and always try to follow powder manufacturers recipes but in these times of getting what you can find for components how can you tell if your shells are approaching max pressure short of sending loads off to be tested?
The pressure sign is when the barrel blows up and slaps you in the face. Best bet is to send them in for testing, starting from a known recipie.
 

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It's hard to discuss this subject unless and until we understand what the OP meant when he said "max pressure." Did he mean SAAMi MAP, which means "maximum average pressure" or something else? I'm thinking every response so far only assumed he meant something else.
 

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Discussion Starter · #15 ·
I meant pressure signs like you see in metallic reloads like flattened primers, blown primers, ejector impressions on the heads. I had never seen any of this with shotguns that’s why I asked. I guess the pressures just run too low.
 

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All powder manufactures have load recipes available, if you have components that aren't listed call or email them. I know I have emailed Alliant about subbing primers for a load and they responded the next day. Shotgun loading isn't like metallic other than it uses smokeless powder and primers. Use published load data.
 
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pressures being low is subjective.
i bet you don't see any pressure signs except for the top strap bending forward on your nice SAA colt either.
saami max pressure for your 2-3/4" 12ga. is what it is, anything over that is over pressure.
 

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First off I load my reloads to 1200 fps. Maintaining the same velocity means that I don't have to adjust my leads when changing between gauges. Another plus it's an easy to achieve velocity for a wide range of loads and powders And I can save a bit on powder. As a result all I have to do is follow a well established recipe and do a bit of chronograph testing to confirm/dial in the recipe to 1200 fps. BTW, I am primarily a Skeet shooter but do dabble in Trap and Sporting Clays on occasion and have found that 1200 fps will work just fine. Note, I've also found that #7.5 is best for Trap or Sporting Clays because those pellets carry the energy needed to break a target that's "out there". If I get the holdover correct I've found my "sleepy" loads will give nice clean breaks on a target 60 yards out.
 

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The only sure signs of over-pressure are when the gun blows up. If you want true pressure readings, have them tested. But also NOTE that European guns are proof-tested to CIP-standards which are different (lower) than U.S. SAAMI standards.
 

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I meant pressure signs like you see in metallic reloads like flattened primers, blown primers, ejector impressions on the heads. I had never seen any of this with shotguns that’s why I asked. I guess the pressures just run too low.
You are absolutely correct. Metallic reloading is a whole other ball of string. Shotguns basically don't show any sign of "too much" until it's way too much and the gun blows up.
One thing that shotguns do, though, is they do show you if there's some mechanical problem with the gun. For example if the firing pin hole is wore out, or if the mechanism is "loose".
 
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