Seating depth and compressing powder charges for handgun

[TTv2]

GIven that I often use bullets of the same weight, but different profiles than what loading data I have, I'm often concerned about seating too deeply as I want to avoid an overpressure load by compressing the charge.

Recently I tried Speer 100gr half jacket .308 bullets in .327 using Titegroup as my powder charge because it's not sensitive to the position in the case and Hodgdon's data says 5.2gr is the max for a 100gr Hornady XTP bullet. Given I was using a different bullet I aired on the side of caution, used 4.5gr and seated the bullet to two different depths and the deeper seated bullets shot better.

I've run into this with 200gr Berry's for .40/10mm where with Blue Dot I'm not loaded to max and the base of the bullet is nearly touching the top kernels of powder and it gets me concerned and I don't seat the bullet as deep as I would like.

I guess the question I want to know is how much compression does it take until things become dangerous in handguns?

 

[fxvr5]

Compressed powder is not a bad thing and can be useful. Follow published load data and you'll be fine.

Here is what Hodgdon says about compressed powder charges:

"Hodgdon notes in its reloading data if the subject charge is a compressed load. A full case, or lightly compressed charge is an ideal condition for creating loads with the most uniform velocities and pressures, and oftentimes, producing top accuracy."

Hodgdon – Hodgdon Powder Company

hodgdon.com

 

[film495]

less space is more pressure, but - that isn't necessarily just the internal volume of the case, it is the expanded volume of the case pressed up againt the chamber. this isn't something I've worked with, but I believe I've read some powders are not good for compressed loads and some are fine, just know what you have and if that is manufacturor approved from whatever powder it is.

 

[TTv2]

Compressed powder is not a bad thing and can be useful. Follow published load data and you'll be fine.

Here is what Hodgdon says about compressed powder charges:

"Hodgdon notes in its reloading data if the subject charge is a compressed load. A full case, or lightly compressed charge is an ideal condition for creating loads with the most uniform velocities and pressures, and oftentimes, producing top accuracy."

Hodgdon – Hodgdon Powder Company

hodgdon.com

As I said, I do follow published data for the bullet weights, but I'm often not using the same bullet being used so that if I were to load to the OAL suggested I could have a full case, possibly a lightly compressed charge, when the published data isn't calling out for either.

I do try to measure with my calipers to see how deep the top of the powder is from the case mouth, but this is not something that instills confidence.

So, my question is should I seat bullets further out to avoid having a full case or is there nothing wrong with having one? Is there anything wrong with having a lightly compressed charge if it's not in published data? What even constitutes a lightly compressed charge?

 

[TTv2]

less space is more pressure, but - that isn't necessarily just the internal volume of the case, it is the expanded volume of the case pressed up againt the chamber. this isn't something I've worked with, but I believe I've read some powders are not good for compressed loads and some are fine, just know what you have and if that is manufacturor approved from whatever powder it is.

So check and see what powders manufacturers say are okay with compressed loads? Will do. Does anyone know what common handgun powders are okay to be compressed?

 

[fxvr5]

These are questions only a manufacturer can address. Ask them directly.

 

[film495]

you might want to consider a lower volume powder as an option as well, food for thought. I don't load .308 or .327 so, specifics I'm no help with.

 

[ArchAngelCD]

You said you seated the Speer GDHP bullet tom 2 different depths. You should be seating to the manufacturers supplied crimp groove. It is not necessary to.have data for the same exact bullet you are using. The data for a bullet of the same weight and composition is safe. There are exceptions like a solid metal bullet but most bullets follow the above guidelines.

Remember, crimp into the supplied crimp groove. That is the proper place.to.crimp That bullet.

 

[NMexJim]

Yep, I know just what you’re talking about - using published data for an unpublished bullet - one with a different shank length or ogive profile. I think that gives us all pause at some point time.

I’ve used a fired case and dropped in or pushed on the bullet to see if I’m on powder. Probably better is what film495 says, use a reduced powder charge and work up. I’ve not experienced a problem using weight for weight, but caution is a good thing.

 

[TTv2]

You said you seated the Speer GDHP bullet tom 2 different depths. You should be seating to the manufacturers supplied crimp groove. It is not necessary to.have data for the same exact bullet you are using. The data for a bullet of the same weight and composition is safe. There are exceptions like a solid metal bullet but most bullets follow the above guidelines.

Remember, crimp into the supplied crimp groove. That is the proper place.to.crimp That bullet.

I did not do that, I don't know why you think I did, if I was loading a Speer Gold Dot I would have called it a Speer Gold Dot and loaded it to the crimp groove or cannalure.

This is the bullet I used and I would have loaded to that edge of the jacket, but I felt that would be too deep. Apparently it would not have been with Titegroup because Titegroup doesn't fill the case much. With a different powder it may have been too deep and that's kind of the question I'm posing. What is too deep?

 

[TTv2]

Yep, I know just what you’re talking about - using published data for an unpublished bullet - one with a different shank length or ogive profile. I think that gives us all pause at some point time.

I’ve used a fired case and dropped in or pushed on the bullet to see if I’m on powder. Probably better is what film495 says, use a reduced powder charge and work up. I’ve not experienced a problem using weight for weight, but caution is a good thing.

I know all firearms are proofed for more pressure than their normal operating levels, but I try not to exceed such pressures unless I know the firearm is capable of it, like with Ruger Redhawks where I will load .45 ACP to low end .45 Super levels with ease because the frames are built to take .44 Magnum pressures.

The ones that concern me the most are .32 and .327 because I go off into left field with my handloads for that caliber and maybe 10mm when I use Blue Dot, but Blue Dot gives me such good velocity I don't want to stop using it!

 

[Walkalong]

Compressed powder is not a bad thing and can be useful. Follow published load data and you'll be fine.

Here is what Hodgdon says about compressed powder charges:

"Hodgdon notes in its reloading data if the subject charge is a compressed load. A full case, or lightly compressed charge is an ideal condition for creating loads with the most uniform velocities and pressures, and oftentimes, producing top accuracy."

Hodgdon – Hodgdon Powder Company

hodgdon.com

Yep, it’s case volume reduced by seating depth, not powder compression

 

[243winxb]

it’s case volume reduced by seating depth

This is why bullet set back on chambering, is so dangerous. (Autos)

Reduced case volume & fast powders like Bullseye Powder will raise pressures, very quickly.

 

[murf]

when your chrony readings suddenly jump 100 fps.

different loads act different with different components in different guns. watch your velocity when altering components and don't make any big changes.

luck,

murf

 

[AJC1]

Seating with compressed powder is a function of powder speed mostly but not always. Tightgroup is a powder I've never run compressed based on powder density. Unique in 9mm good, 4046 in 308 good. Slower will give compressed loads. Faster powders are an indication something is off. Compressed is not bad, but if your compressing Tightgroup in 9mm brace for rapid disassembly. If you want to see what is happening download and play with grt.

 

[ArchAngelCD]

I did not do that, I don't know why you think I did, if I was loading a Speer Gold Dot I would have called it a Speer Gold Dot and loaded it to the crimp groove or cannalure.

........
........
Recently I tried Speer 100gr half jacket .308 bullets in .327 using Titegroup as my powder charge because it's not sensitive to the position in the case and Hodgdon's data says 5.2gr is the max for a 100gr Hornady XTP bullet. Given I was using a different bullet I aired on the side of caution, used 4.5gr and seated the bullet to two different depths and the deeper seated bullets shot better.
........

I mistakenly said a Speer GDHP bullet when I should have said a Hornady XTP bullet.
The bold highlighted statement in your OP lead me to believe you seated that bullet to two different depths. That what made me think you did that.
I guess by your reaction you didn't mean that. What did you mean?

 

[TTv2]

I mistakenly said a Speer GDHP bullet when I should have said a Hornady XTP bullet.
The bold highlighted statement in your OP lead me to believe you seated that bullet to two different depths. That what made me think you did that.
I guess by your reaction you didn't mean that. What did you mean?

Yeah, when I said "given I used a different bullet (than the XTP I have data for) I meant I was not using the xtp