Reading pressure signs/other problems

[thermox9898]

I'm going to test my first 308 reloads this Saturday and I'm looking for good resources on reading pressure signs and other issues. There's tons of info on the internet just wondering if any of you have a recommended source. I know a little bit from reading manuals, forums, and watching youtube videos just wanting to learn more.

Thanks!

EDIT:
Test platform is an IMI Tavor 7 with a 16" barrel. 1:12 twist.
I loaded 50 rounds in PMC brass.
CCI #34 primers
Win748 powder
5 round groups, starting at starting load and increasing half a grain each group.
Last group is a few tenths of a grain below max, so I want to know how to read the signs when/if I get there.
150gr Hornady FMJBT

I bought a chronograph so I intend to collect velocity data as well.

Read More

 

[arakboss]

I'm going to test my first 308 reloads this Saturday and I'm looking for good resources on reading pressure signs and other issues. There's tons of info on the internet just wondering if any of you have a recommended source. I know a little bit from reading manuals, forums, and watching youtube videos just wanting to learn more.

Thanks!

What loads did you put together? What type of firearm(s) are your first loads being fired in?

 

[thermox9898]

What loads did you put together? What type of firearm(s) are your first loads being fired in?

Test platform is an IMI Tavor 7 with a 16" barrel. 1:12 twist.
I loaded 50 rounds in PMC brass.
CCI #34 primers
Win748 powder
5 round groups, starting at starting load and increasing half a grain each group.
Last group is a few tenths of a grain below max, so I want to know how to read the signs when/if I get there.
150gr Hornady FMJBT

I bought a chronograph so I intend to collect velocity data as well.

 

[arakboss]

Test platform is an IMI Tavor 7 with a 16" barrel. 1:12 twist.
I loaded 50 rounds in PMC brass.
CCI #34 primers
Win748 powder
5 round groups, starting at starting load and increasing half a grain each group.
Last group is a few tenths of a grain below max, so I want to know how to read the signs when/if I get there.
150gr Hornady FMJBT

I bought a chronograph so I intend to collect velocity data as well.

For me in a semi-auto, I would watch out for flattened or popped primers and ejector marks or smears. The ejector marks/smears should show up before the primers flatten. Report back with results.

 

[thermox9898]

For me in a semi-auto, I would watch out for flattened or popped primers and ejector marks or smears. The ejector marks/smears should show up before the primers flatten. Report back with results.

Yeah, absolutely!
I've heard some talk of soot on the outside of the case in videos. What is this a sign of? I know that a critical part is that the case expands and "sticks" to the chamber wall. If there's soot on the outside of the case, is that a sign that this is not happening for whatever reason?

 

[arakboss]

Yeah, absolutely!
I've heard some talk of soot on the outside of the case in videos. What is this a sign of? I know that a critical part is that the case expands and "sticks" to the chamber wall. If there's soot on the outside of the case, is that a sign that this is not happening for whatever reason?

Lots of cases will come out sooty in many of my firearms, I am not sure how that would relate to overpressure.

And regarding ejector marks, they don't necessarily mean your round is overpressure but the gun could be overgassed or in some cases that may just be normal for that firearm. Flattening of the primers should be a more reliable method. Although it's possible the harder cups on the #34 primers will resist flattening until you get to a higher pressure but I am just guessing. Hopefully the professionals will roll along soon.

 

[thermox9898]

Lot's of cases will come out sooty in many of my firearms, I am not sure how that would relate to overpressure.

And regarding ejector marks, they don't necessarily mean your round is overpressure but the gun could be overgassed or in some cases that may just be normal for that firearm. Flattening of the primers should be a more reliable method. Although it's possible the harder cups on the #34 primers will resist flattening until you get to a higher pressure but I am just guessing. Hopefully the professionals will roll along soon.

Yeah I'm not sure either, just a reloading guy I watch on youtube always comments on it, but I haven't seen him actually explain why.

I intend to fire some factory rounds out of it, too. I have some Hornady Superformance 165gr SST and some Hornady White Tail 150gr Interlock to run through it. That way I can compare cases to my reloads. I'll also chrono the factory rounds to relate everything. I'm especially interested in the 150gr since it's somewhat similar to my loads.

Thanks for your insight

 

[thermox9898]

Right now I'm reading this page:

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

seems to have a lot of good information on it with accompanying pictures

 

[arakboss]

Yeah I'm not sure either, just a reloading guy I watch on youtube always comments on it, but I haven't seen him actually explain why.

I intend to fire some factory rounds out of it, too. I have some Hornady Superformance 165gr SST and some Hornady White Tail 150gr Interlock to run through it. That way I can compare cases to my reloads. I'll also chrono the factory rounds to relate everything. I'm especially interested in the 150gr since it's somewhat similar to my loads.

Thanks for your insight

Good luck it will be interesting to see the chrono results for factory ammo vs your handloads.

 

[thermox9898]

Good luck it will be interesting to see the chrono results for factory ammo vs your handloads.

Yeah, only bummer is forecast says rain on saturday. I'm going to go buy 2 of those $40 walmart canopies. One for me, one for the chrono . Hopefully it works for me under the canopy I've never used a chronograph before.

 

[arakboss]

Yeah, only bummer is forecast says rain on saturday. I'm going to go buy 2 of those $40 walmart canopies. One for me, one for the chrono . Hopefully it works for me under the canopy I've never used a chronograph before.

Well you're still one up on me, since I don't even own one

 

[thermox9898]

Well you're still one up on me, since I don't even own one

Hah yeah I might have went a little nuts buying reloading equipment. I felt a chrono was money well spent though, especially for $100. Good info to have when developing loads.

I'll also be testing about 150rds of 9mm. I did ladder loads for 4 different types of powder in .2 grain increments. CFE Pistol, Accurate #5, Titegroup, and HS-6. 115gr and 124gr. I'll be chronoing them as well. Can't wait to get my powder charges in the ballpark so I can start rolling some ammo!

 

[WillametteWill]

Yeah, absolutely!
I've heard some talk of soot on the outside of the case in videos. What is this a sign of? I know that a critical part is that the case expands and "sticks" to the chamber wall. If there's soot on the outside of the case, is that a sign that this is not happening for whatever reason?

For me, I see soot on my underpowered loads. From what I have read (and as you described), the brass is not able to do its job and expand to seal in the chamber.

 

[thermox9898]

For me, I see soot on my underpowered loads. From what I have read (and as you described), the brass is not able to do its job and expand to seal in the chamber.

That makes sense. I wonder if you could see some false pressure signs from that happening. I imagine if the case isn't 'sticking' to the chamber, the amount of force pushed back on the bolt could be more, leading to more ejector ring/wipe or other case head related signs.

 

[Stomper]

Yeah, only bummer is forecast says rain on saturday. I'm going to go buy 2 of those $40 walmart canopies. One for me, one for the chrono . Hopefully it works for me under the canopy I've never used a chronograph before.

Keep in mind that if your chronograph is the type that uses the two overhead screens like this...


.... a canopy may impede its proper functioning as it requires a lighted background so it can read the "shadow" of the bullet passing under the screens.

Looking forward to hearing your follow up!

 

[thermox9898]

Keep in mind that if your chronograph is the type that uses the two overhead screens like this...

View attachment 760228
.... a canopy may impede its proper functioning as it requires a lighted background so it can read the "shadow" of the bullet passing under the screens.

Looking forward to hearing your follow up!

Yeah, I'm quite worried about that. It says 60% chance of rain Saturday, so hopefully the canopy isn't necessary. If it is necessary and it does impede function, I'll just have to let it get wet for short periods of time. Maybe the rain will interfere with it too, I have no idea. Like I said, never used a chrono before so we'll see what happens. With any luck if it does rain I'll have windows of dryness that I can use it in. Definitely not going to go up there without a canopy though cuz I know this state likes to pour on me when I go shooting .

Oh and yeah it is a caldwell light sensor type

 

[Stomper]

Yeah, I'm quite worried about that. It says 60% chance of rain Saturday, so hopefully the canopy isn't necessary. If it is necessary and it does impede function, I'll just have to let it get wet for short periods of time. Maybe the rain will interfere with it too, I have no idea. Like I said, never used a chrono before so we'll see what happens. With any luck if it does rain I'll have windows of dryness that I can use it in. Definitely not going to go up there without a canopy though cuz I know this state likes to pour on me when I go shooting .

Oh and yeah it is a caldwell light sensor type

Perhaps a canopy that is made of white material instead of one of the darker colors....

 

[thermox9898]

This is the one I was looking at because it's $40:

Robot or human?

but I do notice a white one, but its twice the price and out of stock:

Robot or human?

Good idea though!!!

 

[Stomper]

This is the one I was looking at because it's $40:

Robot or human?

but I do notice a white one, but its twice the price and out of stock:

Robot or human?

Good idea though!!!

Yeah.... that blue canopy will most likely give you trouble.

Maybe you can hang a light source (out of the way) up in the peak of it so the screens are backlit a bit.

 

[thermox9898]

Yeah.... that blue canopy will most likely give you trouble.

Maybe you can hang a light source (out of the way) up in the peak of it so the screens are backlit a bit.

I thought that artificial light could fubar the light sensor chronos? or is it just florescent