Diffrence in Jacketed and Total Metal Jacket?

[Petro_58]

typically you have three (or four) types of bullets when it comes to load data: Metal Jacketed, Lead, Plated and sometimes you'll see separate data for Frangible bullets.

again, typically your lead loads will be the "softest", then plated (usually close to lead but maybe a bit higher depending upon the lead load (mainly if it's a gas check design)), then the jacketed loads. Sometimes you'll see different loads for frangible loads and sometimes separate loads for "non lead" bullets (like Barnes) as they will have a very different load than a similar weight bullet (because of the lack of lead in the design).

as for the TMJ- usually it's referred to as Total Metal Jacket, sometimes it refers to Truncated Cone design. Ask what you are getting if you are considering buying bullets from someone. or look at it. Normally the companies that sell "plated" bullets don't refer to them as anything but "plated" but I could be wrong. Jacketed usually refers to a full metal jacket that's swaged to the core vs. a metal that's plated to the bullets via solution

FMJ usually has a lead exposed base, while TMJ is totally encapsulated lead so there's less chance of lead getting into the air from firing the weapon, etc.

TMJ usually refers to Total Metal Jacket, TC is Truncated Cone not the Same Thing. Some Indoor ranges require TMJ bullets to prevent lead particules getting in the air. FMJ's usually have the base exposed. TC or Truncated Cone is a Type of Bullet Form like HP-Hollow Point, FP-Flat Point, RN-Round Nose etc.

TMJ

TC

 

[Chuckdog]

TMJ usually refers to Total Metal Jacket, TC is Truncated Cone not the Same Thing. Some Indoor ranges require TMJ bullets to prevent lead particules getting in the air. FMJ's usually have the base exposed. TC or Truncated Cone is a Type of Bullet Form like HP-Hollow Point, FP-Flat Point, RN-Round Nose etc.

TMJ

TC

I concur with this. The TMJ is something you'll see more often now with more and more indoor ranges requiring for air quality reasons.

A full metal jacket traditionally still has exposed lead at the base.

I wish companies would list a key with their abbreviations and acronyms now. There's too many for me to keep straight! Sometimes, even with the keys I'm still left scratching my head?

 

[Petro_58]

Getting back to the OP's question, Most of the time your TMJ round will load right along with your FMJ charts. Now that being said, if it's PLATED then your usually loading above cast loads, short of FMJ Max loads. So your Plated Max is around Mid-Range FMJ. Again watch for Over Pressure signs as you Normally would. I haven't loaded any 147gr for the 9mm yet, I've been Loading 115's and 124gr.

 

[Chuckdog]

Plated bullets that I'm familiar with are soft swagged lead. They have a thin copper or similar plating to cut down on bore fouling. They are still very soft, and should be used as you would any other swagged bullet. If pushed too hard they can deform and run pressures up quickly.

The hard cast lead bullets, are alloy mixed lead that are cast, not soft cut/swagged bullets. They, when mixed with the proper alloys can shoot virtually as clean as jacketed bullets in many of my pistols. I've loaded cast bullets in my .454 Casull's and .44 mags that would challenge any jacketed bullet without leading. I use them exclusively in my target pistols. I recommend following the bullet manufacture's recommendations for safe velocities. As those here that cast their own know, there are major differences in the hardness of some cast bullets. If they're too hard, they can actually shatter, too soft and they can run pressures up considerably and lead a barrel something terrible.

Jacketed bullets have a true jacket of copper or similar material that have a soft lead or other core. These jackets are designed to keep bores lead free, supports higher velocities, and aid in penetration. Again follow the manufacturers' velocity ratings for bullets, as they aren't all created equally.

I've got to get to work now, but we likely need to add a "description", "keys" and "acronym" post in the sticky.

I typed this quickly guys, so help fix my errors, and add what I've left out. CD

 

[spamcastle]

I've only been loading the Berrys Plated 115 and 124 plated as well. The 147's are a new breed for me. I figured why not give them a shot and see how I like them. Just want to make sure I'm loading them correctly. I'll stick to loading them to lead cast specs from the loading manual and just pick up a new powder for my heavier bullets.

 

[Clarke123]

Assuming that it is a FLAT NOSED projectile, a TMJ in 147 GR for 9mm it is amost certainly a truncated-cone / flat-nose projectile ...
Insomuch that the 147GR is at the upper end of projectile weights for a 9mm, OAL is a major consideration ... as is powder charge consistency.

One important check is the projectile diameter; most quality plated projectiles are the same diameter as full metal jacketed projectiles (usually .355). Lead projectiles are usually
a thousandth larger in diameter (.356) so that they will properly seal the projectile into the barrel without "blow-by" and resultant "key-holing".

The OAL for truncated cone projectiles is tricky in that the flat nose confuses some people: I would always use what is recommended in the loading mauals as a guide.

My Lyman's #49 shows a starting load of 3.5 and a maximum load of 4.3 Grains of 231 for the FMJTC 147 Grain Projectile loaded to an OAL of 1.115"
They don't list 231 as a recommended charge for the cast lead version of this projectile, but they do show WSF for both loads with a starting load of 3.4 / 3.5 Grains,
that is essentially identical to the starting load weight recommended for 231 in the FMJTC projectile.

I know that this sounds confusing, but I (like you) have noticed a lot of projectile types being sold that have little to no loading data available out there (so, why not send them a clear message: Don't buy them?!)