What factors cause too high pressure ?

[hemiford]

1. Wrong powder / too much powder

2. Too tight neck fit / case crimp

3. Bullet too close to the lands

4. Aggressive leade angle

5. Rifle bore "tight"

6. ???

Are the following things not really causes of overpressure ?

1. Tight twist

2. Barrel length

3. Type of rifling / groove width, number of grooves

4. Below "minimum" powder loads

5. Headspace too tight

6. ???


Trying to educate myself before I begin handloading. As an example, if X grains of powder Y produces
a flattened primer, you could possibly either reduce the powder load, HbN- coat the bullets, or cut a
longer leade.
Please feel free to add to my list !

 

[Ucsdryder]

#1. Too much powder

Start low, work slow

 

[Frog4aday]

Bullet too deep in the case = increased pressure; farther out can lower pressure until you start jamming into the lands...then pressure goes UP again. Think of bullet depth in the case as a three bears situation. That's too deep (bad). That's too far out (bad). That's somewhere in between ("just right!") = good.

#4 in your second list ("Are the following things not really causes of overpressure? 4. Below "minimum" powder loads") should be #6 in your first list - Too little powder (below minimum listed in manual) can be DANGEROUS. Win296/H110 powder specifically comes to mind, but there are others. These powders do not do well below a certain minimum and pressures can skyrocket ('detonation'}. Follow the reloading books and you'll stay safe. Start getting "creative" and you can get in trouble. And at 70,000+psi, that can be an 'explosive' education that takes eyes, limbs, and perhaps a life. Not worth the risk. Don't be creative. Be smart. You are asking questions; that's smart!

 

[Mikecr]

First, 'too high of pressure' is just that, and not problems manifesting as you go up in pressure.
Can be a significant difference.

I vote #1 wrong powder
You can't really count 'too much powder' as only so much fits in a case, and if it's the right powder, full don't matter.
I purposely find loads between 100-104% case fill with every cartridge I've had. No problem.
It just has to be the right powder.
QuickLoad software helps with this.

 

[Rich Coyle]

You didn't ask for suggestions, so I will give one. Put only the powder you are using on the loading area. Before you put it away, reread the label. This procedure saved me from a catastrophe. I loaded up twenty cartridges with 4831. Then as I was checking the powder on the loading area I noticed it was 3031! That happened when I was old enough to know better.

 

[3chester]

Have seen more than 1 guy starting out in reloading and didn't buy a case trimmer or a dial caliper to measure cases. They kept reloading same cases til bolt was hard to lift, before they asked someone, what's going on here.

 

[Jeffrey Van Zandt]

1. Wrong powder / too much powder

2. Too tight neck fit / case crimp

3. Bullet too close to the lands

4. Aggressive leade angle

5. Rifle bore "tight"

6. ???

Are the following things not really causes of overpressure ?

1. Tight twist

2. Barrel length

3. Type of rifling / groove width, number of grooves

4. Below "minimum" powder loads

5. Headspace too tight

6. ???


Trying to educate myself before I begin handloading. As an example, if X grains of powder Y produces
a flattened primer, you could possibly either reduce the powder load, HbN- coat the bullets, or cut a
longer leade.
Please feel free to add to my list !

Understanding Pressure :: Primal Rights, Inc

Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.

www.primalrights.com

 

[Philward]

I loaded some 280 rem last week to try a load I shot the week before and it seemed pretty accurate, so I loaded up a few more to check it. First shot I couldn't lift the bolt, had to pull pretty hard and it came open. Ejector mark on case, Ejector jammed with brass. Same load shot fine without any hint of pressure the week before. Got ejector freed up and made sure everything was working correctly. Fired another one and it was fine as were all the rest of them. No flattened primers and no stiff bolt lift.

Maybe that bullet was a little larger diameter than the rest?

143 Hammer Hunters, IMR 4955 powder. Remington 700 Mtn rifle.

 

[Reelamin]

Search has every answer x 1000 you are looking for.

 

[Rich Coyle]

Have seen more than 1 guy starting out in reloading and didn't buy a case trimmer or a dial caliper to measure cases. They kept reloading same cases til bolt was hard to lift, before they asked someone, what's going on here.

Recently I started having high pressure on an old load. Then I measured the brass length: Too long! Trimming solved the problem.

 

[comfisherman]

Seen a lot of guys have custom rifles built with reamers that were much tighter than their Factory rifles with shorter freebore causing some pressure spikes.

Have seen this more recently, guys switching brass brands without changing load. The shortages have made this a little more common. Your reloaded wimchester brass is gonna be different than adg...

Single greatest issue I've run into causing overpressure is believing loads you see on the internet for Wildcats. I've had a couple of friends who started loading specifically because they saw data that was just amazing... specifically the 22 Creedmoor when it first came out. Had a buddy end up with one he believed was just magically efficient.... well except even quality brass couldn't keep a primer pocket. Eventually real data came out and surprise surprise his load was probably in the upper 70s kpsi. This happens a lot with new wonder "efficient" wildcats.

 

[436]

Scale weights/charges are not correct due to the scale not functioning properly nor checked with weights and other scales in the setting range. A bad scale you think is correct can bite you right in the "A" just my 0.2 Cheers

 

[Old Rooster]

I have had carbon in the bore increase pressure.
Edit to add:I had an over pressure problem and know for certain I was under max with a known accurate load.
I checked for copper and got very little out but when I ran a patch of Free All coated patch I had dark patches of carbon fouling.Cleaned that out and had another layer of copper under that,cleaned that out and had more carbon and cleaned the barrel to bare metal that day and always use a good carbon solvent to detect and clean carbon as copper will layer on top of carbon and accuracy will go down hill.
Just my experience.

 

[MagnumManiac]

Excessive pressure, be it found through conventional load testing or found unexpectedly, is normally caused by an excessive amount of the correct powder, or the use of a wrong powder.
Other causes, which are not loading technique caused, are tight neck clearance within the chamber, tight bores and rough bores.
I rarely see excessive pressure over the Pressure Trace II system to show up on the brass and primer until 70,000psi is reached…however, some rifles exhibit other nuances that they only exhibit once excessive pressure, even slightly, is reached. 2 of my Winchester Model 70's exhibit cratered primers once 70,000psi is reached with no stiff bolt lift, no stiff extraction, case swelling or primer flattening. I have other actions that are exact copies that don't do this, Rugers, Kimber's, and CZ actions that don't do it. They do get stiff bolt lift though.

Cheers.