What are high pressure indicators on 9mm

shiyfire · September 5, 2012, 01:41 PM

I am new to loading pistol rounds.What are signs to watch for on 9mm brass when it's too hot?

RampedRaptor · September 5, 2012, 01:46 PM

Wait you can load too hot? J/k stick with respectable manufacturers load data and always work up.

TheTinMan · September 5, 2012, 02:01 PM

Inspect primers for "cratering" around firing pin strike and/or "flattening". Measure case diameter just above the case head and compare fired case with resized case. How much has it expanded? Past SAAMI max for that cartridge? Hint: if the case sticks in the chamber at all, you're too hot.

Brian Pfleuger · September 5, 2012, 02:29 PM

There aren't any really reliable visual indicators.

Primers are horrendously unreliable. I have loaded 357sig rounds to levels that would be about 9mm starting loads and get pierced, flattened and mushroomed primers using Federal while loads that are "stout" beyond SAAMI spec show no signs of pressure whatsoever with CCI primers.

TheTinMan · September 5, 2012, 04:10 PM

Brian, with respect, a pierced primer is telling you that something is violently wrong.

Brian Pfleuger · September 5, 2012, 04:12 PM

Yes, it's telling me that Federal primers are a bad choice in 357sig, or any other round that develops pressure levels near STARTING loads for the round.

**Mike Irwin** · September 5, 2012, 05:17 PM

The slide sticking out of your forehead is always a clue...

NWPilgrim · September 5, 2012, 05:38 PM

Pistol cartridges do not generate enough pressure, unlike most rifle cartridges, to give early warning on brass. If you see unusual brass deformation, imprinting the you are way too high.

There is no practical reason to push pressure limits in pistols. Stay with the vast amount of tested data. Otherwise you can needlessly batter your pistol or cause injury.

shiyfire · September 5, 2012, 07:15 PM

I basicly just want to load up some safe plinking ammo ,but after some reading it seems like pistol ammo is pretty sensitive to OAL and powder charge.

Brian Pfleuger · September 5, 2012, 07:21 PM

Follow published data, start low and work up, if you want more power. Don't work up if you like the starting loads. Stay within published data. Use good techniques and quality control. You'll be fine.

mrawesome22 · September 5, 2012, 09:51 PM

Recoil, sound, feel, location of ejected brass, chronograph readings.

sudo passwd root

NWPilgrim · September 6, 2012, 02:51 AM

Yes, pistol cartridges and especially smaller ones such as 9mm can be very sensitive to OAL changes. Almost all published data includes the OAL used for the given loads and pressures. Follow the published data and you are good to go, starting at the start loads or 10% below max.

I have been reloading for 25 yrs and never load to the max published level. I usually end up about midway between min and max listed loads, or closer to the minimum/start load. The main thing I look for is reliable operation of the recoiling slide and feeding of next cartridge. Then I want the point of impact to be close to the point of aim height wise. I see no reason to try for maximum velocity and beat up my pistols.

SL1 · September 6, 2012, 07:04 AM

+1 on advice from mrawsome22.

But none of those are sure things for exceeding SAAMI peak pressure limits. Going with unusually fast or unusually slow burning powders can produce higher or lower PEAK pressures than the more normal buring rates while still producing similar feel and sound when fired.

So, the best thing to do is stay with the components and loads in your data, And, if you need to change the COL to obtain reliable feeding in your gun, evaluate the effect on pressure that your change will produce. (Folks here with the QuickLOAD program will help you with that, if you post a request.)

Most 9mm guns are made pretty well, and are much more likely to prematurely wear and batter into a state of inaccuracy rather than blow apart with loads that are somewhat too hot. On the other hand, some of the guns made for lower pressure rounds, such as .25 ACP and .32, and perhaps .380, may not be made out of materials that are as tough. Pushing those is more likely to create a blow-up.

SL1

WESHOOT2 · September 9, 2012, 08:41 AM

Quote:

signs to watch for on 9mm brass when it's too hot

Easiest sign: When you've exceeded published data.

September 5, 2012, 01:41 PM	#1
shiyfire Member Join Date: March 28, 2000 Location: KY. Posts: 29	What are high pressure indicators on 9mm I am new to loading pistol rounds.What are signs to watch for on 9mm brass when it's too hot?

September 5, 2012, 01:46 PM	#2
RampedRaptor Junior Member Join Date: February 20, 2012 Posts: 7	(: Wait you can load too hot? J/k stick with respectable manufacturers load data and always work up.

September 5, 2012, 02:29 PM	#4
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	There aren't any really reliable visual indicators. Primers are horrendously unreliable. I have loaded 357sig rounds to levels that would be about 9mm starting loads and get pierced, flattened and mushroomed primers using Federal while loads that are "stout" beyond SAAMI spec show no signs of pressure whatsoever with CCI primers. __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

September 5, 2012, 04:12 PM	#6
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	Yes, it's telling me that Federal primers are a bad choice in 357sig, or any other round that develops pressure levels near STARTING loads for the round. __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

September 5, 2012, 05:17 PM	#7
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,390	The slide sticking out of your forehead is always a clue... __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.

September 5, 2012, 02:01 PM	#3
TheTinMan Senior Member Join Date: December 8, 2008 Posts: 102	Inspect primers for "cratering" around firing pin strike and/or "flattening". Measure case diameter just above the case head and compare fired case with resized case. How much has it expanded? Past SAAMI max for that cartridge? Hint: if the case sticks in the chamber at all, you're too hot.

September 5, 2012, 04:10 PM	#5
TheTinMan Senior Member Join Date: December 8, 2008 Posts: 102	Brian, with respect, a pierced primer is telling you that something is violently wrong.

September 5, 2012, 05:38 PM	#8
NWPilgrim Senior Member Join Date: September 29, 2008 Location: Oregon Posts: 2,346	Pistol cartridges do not generate enough pressure, unlike most rifle cartridges, to give early warning on brass. If you see unusual brass deformation, imprinting the you are way too high. There is no practical reason to push pressure limits in pistols. Stay with the vast amount of tested data. Otherwise you can needlessly batter your pistol or cause injury.

September 5, 2012, 07:15 PM	#9
shiyfire Member Join Date: March 28, 2000 Location: KY. Posts: 29	I basicly just want to load up some safe plinking ammo ,but after some reading it seems like pistol ammo is pretty sensitive to OAL and powder charge.

September 5, 2012, 07:21 PM	#10
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	Follow published data, start low and work up, if you want more power. Don't work up if you like the starting loads. Stay within published data. Use good techniques and quality control. You'll be fine. __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

September 5, 2012, 09:51 PM	#11
mrawesome22 Senior Member Join Date: November 9, 2005 Location: Ohio, Appalachia's foothills. Posts: 3,779	Recoil, sound, feel, location of ejected brass, chronograph readings. sudo passwd root

September 6, 2012, 02:51 AM	#12
NWPilgrim Senior Member Join Date: September 29, 2008 Location: Oregon Posts: 2,346	Yes, pistol cartridges and especially smaller ones such as 9mm can be very sensitive to OAL changes. Almost all published data includes the OAL used for the given loads and pressures. Follow the published data and you are good to go, starting at the start loads or 10% below max. I have been reloading for 25 yrs and never load to the max published level. I usually end up about midway between min and max listed loads, or closer to the minimum/start load. The main thing I look for is reliable operation of the recoiling slide and feeding of next cartridge. Then I want the point of impact to be close to the point of aim height wise. I see no reason to try for maximum velocity and beat up my pistols.

September 6, 2012, 07:04 AM	#13
SL1 Senior Member Join Date: November 8, 2007 Posts: 2,001	+1 on advice from mrawsome22. But none of those are sure things for exceeding SAAMI peak pressure limits. Going with unusually fast or unusually slow burning powders can produce higher or lower PEAK pressures than the more normal buring rates while still producing similar feel and sound when fired. So, the best thing to do is stay with the components and loads in your data, And, if you need to change the COL to obtain reliable feeding in your gun, evaluate the effect on pressure that your change will produce. (Folks here with the QuickLOAD program will help you with that, if you post a request.) Most 9mm guns are made pretty well, and are much more likely to prematurely wear and batter into a state of inaccuracy rather than blow apart with loads that are somewhat too hot. On the other hand, some of the guns made for lower pressure rounds, such as .25 ACP and .32, and perhaps .380, may not be made out of materials that are as tough. Pushing those is more likely to create a blow-up. SL1