Loading FMJ vs TMJ

[epsanto2]

I am looking to load 95 grain .380 FMJ using Win 231. In looking at the Speer, I only find TML loads, the Hodgdon's Reloading magazine has FMJ loads for the 95 grain bullet... powder charges of 2.9 to 3.2 with a test coal of .970. They differ noticeably from the Speer manual. Is this because of the TMJ vs FMJ bullet? I have also looked at the Hodgdon web site for reloading data and it is the same as the magazine. Has anyone used the Reloading magazine/web site loads and are they reliable?

Thanks

 

[Hondo 60]

Total Metal Jacket is Speer's name for full metal jacket.
AFAIK that's the only difference.

The differences in charge weights are usually because one tester was willing to push it a bit faster.

 

[epsanto2]

Thanks, Hondo 60. But what is AFIAK? Since I only use it for plinking, the lessor loads from the magazine would be safe?

Thanks

 

[RandyP]

AFAIK = as far as I know

TMJ bullets have a totally enclosed jacketed bullet. FMJ has an open lead base, plated bullets, regardless of their shape, are also totally covered in copper plating.

My local indoor ranges prohibit bare lead reloads.

 

[Jim Watson]

TMJ is Speer's trademark for bullets so heavily plated that they can be treated like drawn full metal jackets - "Totally Metal Jacketed." If it ain't a Speer, it ain't TMJ.

There are FMJs with closures inserted in the jacket base so as to not expose any lead. I have a stock of Hornadys made that way.

 

[Hondo 60]

I agree with Mr Watson - Hornady is a prime example.
I have several Hornady fully encapsulated bullets which are refered to as "FMJs"

TMJ is strictly a Speer moniker.

 

[LiveLife]

I believe the term TMJ (Total Metal Jacket) has been around long before Speer trademarked it as "TMJ® - encased-core full jacket" for their Plinker rifle bullets.

For pistol bullets, if I remember correctly, TMJ (Total Metal Jacket) bullets were FMJ (Full Metal Jacket) bullets with a disk to cover the exposed lead base (see picture below).

Here's another definition:

Total Metal Jacket (TMJ) bullets are FMJ bullets of special design in which there is no exposed lead. Closed base eliminates lead vaporization during firing. These bullets are suitable for indoor shooting.

They differ noticeably from the Speer manual. Is this because of the TMJ vs FMJ bullet? I have also looked at the Hodgdon web site for reloading data and it is the same as the magazine. Has anyone used the Reloading magazine/web site loads and are they reliable?

As to OP's question, I think more and more newer published load data refer TMJ as copper plated lead core bullets instead of FMJ with disk to cover the lead base.

For me, when I look for load data to use with plated bullets, I look at the diameter of the plated bullets to determine whether I use jacketed or lead load data (most commercial plated bullets now have thick enough copper plating to no longer worry about plating separation of some 10+ years ago). Rainier/PowerBond and other manufacturers use the same diameter as jacketed bullets and the smaller diameter bullet base will leak more powder ignition gas around the bullet - which requires you to use more powder to generate more consistent chamber pressure. Most of Berry's bullets' are typically larger, comparable to lead bullet diameter - which results in less powder ignition gas leakage and requires less powder to generate more consistent chamber pressure (this is the reason why their website ask to not exceed mid-range jacketed load data).

 

[longdayjake]

Gotta love bds going above and beyond with every post. I am left wondering if he took that picture and added labels just for this post or if he did it for another post earlier. Good work. However, you leave nothing left for us to add to the conversation.

 

[LiveLife]

I am left wondering if he took that picture and added labels just for this post or if he did it for another post earlier.

I took that photo for another thread. BTW, some of the bullets in the line up were bought from you.

Gotta love bds going above and beyond with every post.

Thanks ... This is THR and I try to be factual (most of the times)

However, you leave nothing left for us to add to the conversation.

Not at all. There's been plenty of threads discussing the virtues of TMJ vs CMJ. I kinda liked the distinction of TMJ for FMJ with disk bottom and CMJ for plated bullets. Now that Speer has the trademark for TMJ, maybe we'll see more usage of CMJ by other bullet manufacturers.

Hodgdon's Reloading magazine has FMJ loads for the 95 grain bullet... powder charges of 2.9 to 3.2 with a test coal of .970. They differ noticeably from the Speer manual. Is this because of the TMJ vs FMJ bullet?

Lyman #49 indicates 2.1 to 2.9 with OAL of .900". Looks in line with the Hodgdon's load data for the longer .970" OAL.

I have also looked at the Hodgdon web site for reloading data and it is the same as the magazine. Has anyone used the Reloading magazine/web site loads and are they reliable?

I do all the time and consider them very reliable. I tend to consider the "current" published powder manufacturers' load data (paper / web) more accurate (compared to older reloading manual load data) as changes in powder formulation would be reflected on powder manufacturers' load data before reflected on bullet manufacturers' load data.

 

[epsanto2]

Thanks to all for the great information. I appreciate it.

epsanto2