View Full Version : Is primer varnish a mil-spec feature?
M193 is supposed to be ammo that's mil spec. Correct me if I'm wrong, but that's what the "M" stands for, as we've traditionally seen on the Federal Lake City M193 ammo.
I understand the "M" spec includes crimped primers, but doesn't that spec also include a little spot of varnish over the primer, to keep out moisture? American Eagle's ammo has it. The reason I'm asking is that Winchester's white box 5.56 with "M193" on the front doesn't have this. Neither does Frontier's M193. If the "M" spec is supposed to include primer varnish, that means these companies are blatantly mislabeling their ammo.
Have you pulled down the Winchester? Sometimes the bullet and primer sealants are hard see externally.
Have you pulled down the Winchester? Sometimes the bullet and primer sealants are hard see externally.
No, I haven't. I did notice that on the Federal M193 you can clearly see the sealant - it's a reddish color around the edge of the primer. I tried scraping off a little piece of it on some Winchester ammo with a razorsharp needle point, nothing.
M193 is often used loosely to describe 55 gr FMJBT W/C loaded to M193 velocities. I suppose you could argue that they mis-label the ammo, but most shooters who buy frontier or Win White box know they're getting blaster ammo.
I looked up this ammo on Winchester's website. They have a few different white box/USA ammos. They have one marked 5.56 (no M193 markings) with a nominal velocity of 3240. Then they have one marked with M193 at 3180 fps. Weird.
Like markm said...companies can sometimes play fast and loose with the M193 label. You could call Winchester.
M193 is a military specification. Not just the “m”.
The spec is quite detailed and covers more than just, for example the 55g fmjbt w/c. The thickness of the jacket is quite a bit different than the 55g fmjbt you find in most 223rem Ammo. Ie the likelihood of fragmentation may be substantially different between some 55g fmjbt and a real m193 projectile.
Of course, there’s little to stop mfg from loosely using the term, other than their reputation.
I wouldn’t be surprised to find xm193 that lacked sealant.
I wouldn’t be surprised to find xm193 that lacked sealant.
I've definitely found that in both the pocket and the neck. I pull down almost any sort of "M193" variant in order to use the brass to make good ammo. I have a dedicated bullet pulling press on my bench.
The spec is quite detailed and covers more than just, for example the 55g fmjbt w/c. The thickness of the jacket is quite a bit different than the 55g fmjbt you find in most 223rem Ammo. Ie the likelihood of fragmentation may be substantially different between some 55g fmjbt and a real m193 projectile.
Of course, there’s little to stop mfg from loosely using the term, other than their reputation.
.
PPU, I think it is, makes a 55gr ball load they call “M193”, and headstamp it as such. I doubt that it would be comparable to real M193.
What is the difference in jacket thickness? And why? I feel like I’ve heard this before, but I don’t know the whole story.
What is the difference in jacket thickness? And why? I feel like I’ve heard this before, but I don’t know the whole story.
Jacket thickness would affect fragmentation. Anyone still using M193 for defense (instead of an OTM or Bonded) is nuts in my opinion, so who it shouldn't really matter.
Jacket thickness would affect fragmentation. Anyone still using M193 for defense (instead of an OTM or Bonded) is nuts in my opinion, so who it shouldn't really matter.
Yes, but are commercial FMJ jackets thicker, or thinner, or is it random? I would expect thinner jackets to both cost less and be more precise, but I also suspect that some FMJ uses thicker jackets, but I don’t know why they do.
I agree that using ball for defense is sub-optimal.
No idea. I'm sure it varies between manufacturers. Could be that mil jackets are thicker for more penetration, and like you say, commercial thinner to save money.
55 gr FMJ are such bad projectiles, I almost never shoot them.
I have a bunch of pull downs but they're in storage. next time I am by there i'll grab a few and take a pic to compare. the mil bullets will have a much thinner jacket than commercial.
I think people have sectioned bullets before to compare construction, but that was years back when M193 was something worth owning.
Getting wrapped up in a 55 gr FMJ bullet's construction is fruitless. The bullet isn't good for much more than short/medium range practice.
I think people have sectioned bullets before to compare construction, but that was years back when M193 was something worth owning.
Getting wrapped up in a 55 gr FMJ bullet's construction is fruitless. The bullet isn't good for much more than short/medium range practice.
Truth
If you have nothing else, any .223/5.55 FMJ beats a service pistol round. If you have a choice, any .223/5.56 FMJ is a poor performer compared to a good bonded or solid copper bullet.
FWIW, primers seal pretty well in new cases anyway. We had that discussion here in the not too distant past.
Andy
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.