WTK: Loading of TMJ Bullets

[Dane R. Marley]

I have a box of 180 gr .40 cal truncated bullets and the label is marked "180 gr TMJ". I think these maybe Speers Bullets. I purchased the bullets along with other bullets, pistol & rifle cases at an auction.

My question is, Do I load these TMJ Bullets like I would if they were plated lead bullets, or can I load them as if they were FMJ Bullets?

I am loading them into 10mm cases with Longshot powder. I will be shooting them out of a CMMG MK10 300 pistol.

 

[mcb]

Hard to tell for sure from your pictures but it appears those are jacketed bullets with a disc of jacket material crimped into the open bottom of the bullet. Often called Total Metal Jacket (TMJ) or Complete Metal Jacket (CMJ). If this is the case then treat them like a FMJ of the same shape and weight. I used many thousands of the Montana gold CMJ 180gr bullets in my 40S&W and always treated them as FMJ and got good results.

If they are plated then treat them like plated or if no data exists start with lead data for the same shape and weight and work up from there.

 

[1KPerDay]

Exactly ^

 

[eddiememphis]

A quick search shows 40047 coming up from multiple sources as a Hornady 180gr FMJ.

 

[LiveLife]

I have a box of 180 gr .40 cal truncated bullets and the label is marked "180 gr TMJ". I think these maybe Speers Bullets. I purchased ... at an auction.

My question is, Do I load these TMJ Bullets like I would if they were plated lead bullets, or can I load them as if they were FMJ Bullets?

My guess is they are jacketed bullets with disk covering the lead base but if you want to be sure, hammer the bullet to see if they are plated or jacketed.

"Total Metal Jacket" is Speer/Vista Outdoor trademark for thick plated bullet (Like Speer Gold Dot HP) with copper plating thickness on par with gilding metal for jacketed bullets around .015"+ - https://www.thehighroad.org/index.p...s-and-discussions.778197/page-8#post-10309500

Speer makes TMJ (thick plated) and other plated bullets with rounded base (Like most other plated bullets like Berry's/X-Treme) but TMJ bullets I have used have distinct "dished" base as shown below and found I could push them to high-to-near max jacketed load data without losing accuracy (Regular plated bullets with around .004" plating thickness will start to lose accuracy when pushed past mid-range jacketed load data).

As to the "TMJ" bullets bought at auction, they appear to have disk at the base which was applied to FMJ bullets with exposed lead base to eliminate exposed lead (Some companies used the term TMJ until Speer/ATK obtained trademark and they changed to CMJ). Bullet below is Complete Metal Jacket (CMJ) sold by Montana Gold Bullets showing copper disk covering the lead base (Linked post explains various bullet types/constructions) - https://www.thehighroad.org/index.php?threads/alliant.870830/page-3#post-11559838

Compare the 155 gr Montana Gold FMJ bullet with exposed lead base and 180 gr CMJ bullet with copper disk covering lead base

 

[Dane R. Marley]

Thanks Everyone. I am going to load them as FMJ Bullets with some Longshot.

Here is a better picture of the base with the copper cap over the lead.

 

[mcb]

Thanks Everyone. I am going to load them as FMJ Bullets with some Longshot.

Here is a better picture of the base with the copper cap over the lead.

Good picture, definitely looks like a CMJ/TMJ bullet with the jacket material cap over the lead back. Load them up like FMJ and have fun!

 

[Dane R. Marley]

Thanks Everyone!

 

[Walkalong]

My guess is they are jacketed bullets with disk covering the lead base but if you want to be sure, hammer the bullet to see if they are plated or jacketed.

Hornady "encapsulated" bullets, so jacketed, with either a copper or jacket material disc on the bottom.

.45 & 9MM encapsulated bullets from Hornady.

 

[FROGO207]

For future reference you could sacrifice 1 bullet and cut it in half lengthwise to see how thick the jacket is. I have done this in the past when unsure of estate sale lots ID. Looks like you found your answer already though. Folks here are the best.

 

[Dane R. Marley]

For future reference you could sacrifice 1 bullet and cut it in half lengthwise to see how thick the jacket is. I have done this in the past when unsure of estate sale lots ID. Looks like you found your answer already though. Folks here are the best.

I was thinking about cutting one in half. I did make a mental note to bring my Dremel Tool home from a house that I am rehabbing to do some surgery.

 

[lordpaxman]

That’ll work. If you have access to a bandsaw or jigsaw, sandwich the bullet between a couple pieces of wood and cut away. Wood blades do non-ferrous metals pretty well.