With the exception of the armor piercing of the api, is there any real different in the two bullets? Like the blue tip have more   incendiary  mix in them?
Anything to know about the two?

I have heard and read that the strictly incendiary ones DO have more of the compound in them and make a noticeably bigger reaction. However, I'm not an expert and have no actual first hand knowledge of whether this is true or not

I am trying to figure out if it is worth getting the blue tips when I have a bunch of the silver api

All of the above.

The incendiary came in 3 varieties during WW2.  Was only produced from 1942 to about 44.  It was the biggest secret military project of the US until the Manhattan project came along.  They had several groups working feverishly trying to work out the problems.  Came down to finally adopting all 3 designs to get something out to the troops.  Most common is the boattail design that came from Frankford Arsenal, loaded by TW, SL, FA, DM, etc.  (A very wide knurled bullet cannelure)  But both Remington and Utah came up with their own designs.  RA was a flat base (1 very small knurled or smooth bullet cannelure), Utah, semi-boattail.  Can't tell them much apart loaded into cases except by headstamp, although UT eventually also started producing the FA design.  Both the RA and UT variants were known as "M1 Alternate" if you find them with the packaging, which would be a major score.

Despite all the work, they never, fully, worked all the kinks out of the designs, so that, to this day, firing Blue tips can sometimes result in a "muzzle burst" where the bullet detonates after leaving the barrel, right in midair.  (propellant gas plasma migrating into the bullet initiating detonation, or internal components setback on ignition initiating the det chain.)  Just an FYI as a potential hazard.  Happened to me only once out of hundreds of fired rounds.  Others have seen and reported this as well over the years.

One other tidbit.  Not sure the connection, but the blue tips, if still loaded as an original round, has a high incidence of green grunge, looks like white, green or blue mold oozing from the case mouth, sometimes around the primer.  Compared to other WW2 production which can also be vulnerable, I've seen 10x more blue tips this way than any other load.  Must have something to do with the powder used in that specific loading over the others.  If you see that happening (any bullet type), forget shooting it.  Even the components aren't usable, so tear down is a waste of time as well.  See previous VHP Magazine articles I've done about the phenomena.

Keith, Any chance we can get a link to the article your talking about. I'm curious as to what this condition on/in the bullet looks like so I can avoid shooting or buying ammunition with this issue. Thanks

VHP magazine goes only to members of the Fifty Caliber Shooters' Assn.   www.fcsa.org

Back issues are available to members.  List of back issues is in the FCSA suppliers directory.

But if you see something around the case mouth or primer that doesn't look like it belongs there, that's it.  Colored blue, white, or green, looks somewhat like mold or the stuff you see forming on car battery terminals.  Pretty distinct, can't miss it when it happens.  Nothing subtle about it.

Keith. You did give some good information. But referencing a publication that only a few people can access was not much help and the other post looks more like an ad for v.h.p.  I looked into FCSA and it wasn't for me as I am sure others find it the same.

It is my understanding that the blue tip incendiary has twice the incendiary compound than the API does.  I've loaded and fired just a few with no issues but the idea of an ignition inside an expensive rifle does bother me some.

"Keith. You did give some good information. But referencing a publication that only a few people can access was not much help and the other post looks more like an ad for v.h.p. I looked into FCSA and it wasn't for me as I am sure others find it the same."

?     Don't know what to tell you.  

You asked what I thought was a legitimate question, I answered.

If you didn't want an answer, why did you ask the question?

Better yet, ask the question, then tell us what the correct answer is.  Save us some time.

I've flicked the "ignore" switch for you.  I won't bother you further by reading any more of your posts.  

An old video from the BH board back in the day...
An 82a mag dump with an aerial burst of a blue-tip...
M1 blue tip air burst..

The blue tips I've seen for sale are 2X + the money vs the API. Both will start fires. I can see the Blue tips larger puff of smoke being fun but the cost always kept me from buying it.

The Blue Tips have 34 grains of IM11 incendiary mix while the M8 API has 15 grains of IM11. Story is that the Blue Tips were too sensitive and ignited on the skin of enemy planes not doing enough damage and not igniting fuels. The M8 API's were less sensitive and penetrated the surface and ignited inside and causing more damage and fires internally in the enemy planes. This from military data I've seen. The Blue Tips can and do sometimes ignite or airburst shortly after leaving the barrel. I've only seen one do this with a big bang maybe 15 feet from the muzzle with the core of the bullet hitting near the target about 100 yards downrange. You need to make sure the base of the Blue Tip bullets has the lead seal intact and also I've had a very few that the steel insert was loose inside. You could lightly shake it and feel the loose core moving inside. I've read that a bad lead base seal could let hot powder gas ignite the incendiary mix in the tips plus a loose core could cause an airburst. Blue Tips-bigger bang and flash, more expensive. Keith is the expert and historian!

So the blue tip has just a mild steel core or something different? Is it the same size as a fmj core or smalller to allow more powder mix?

Thanks for the information. This is all very infinitive.

I did learn some from Keith's post and sure he is very knowledgeable. It is great that he is teaching us what he knows. The only thing rubed me wrong was the reference to v.h.p. and knowing not every one has access to it and making things look like an ad for it.

From what is being posted here I am gathering that it might be cool to have a few rounds of it just to have. But not much since in just buying it to shoot up.

I'm guessing that this is the Blue mold like stuff on bullets your talking about?
Any concern if it just appears to be on the projectile? Could it be tumbled/cleaned off?
Thanks

I shot thousands of rounds of factory loaded(not reloads) API. I gotten air bursts from S&B(spainish). With some cans producting none and other cans 20 out of 100 air bursting.

There are some available on GB right now for .50 each.  Not a bad price.  I'd buy some if I was in the market.

I don't know much about the construction of Blue tips but I can tell you they will set off a propane tank and still have enough projectile mass to poke a hole out the bag side of the tank.

O yea, it set the propane off nicely too.

You have to be very careful with these things.  A friend of mine shot some into his wooded backstop hill.  Well you know how the ground is in wooded areas, its like 4 inches of rotten leaves and crap before you get to dirt.  Blue tips set that layer of rotten leave crap on fire.  Like it smoldered all day and he had to sit out there all day putting out fires.  He didn't do that again either.

Found this pic on the web. linkSo i took a screen shot of it. Seems like the blue incendiary doesnt have a hardened steel core. The OP of the pic says he fired a Blue tip and a API. The API went threw but the blue tip didnt. I wish someone would open up a blue tip to see if the core is a standard fmj or is it smaller.

I'm curious about that. A normal  FMJ will go through mild steel thicker than that. I have seen some get stuck in thinner steel. Those were probably lighter loads and/or hit a spot where the structure of the steel was different.

I would assume the core is smaller if this page is correct. It says that the M1 incendiary has 34 grains of explosive. Subtract that from 647 grains total and you have 613 grains of metal.

link

If I had some blue tips, I'd try one against the 5/8" steel plate I have. Standard FMJ will go through 600 yards away which is the furthest I've shot at it.

The blue tip incendiary does not have a core penetrator like ball, AP, or API. It has a lead base plug, steel tube with incendiary mix in the tube and out to the tip. A drawing of a sectioned Blue Tip can be seen in the Army Ammunition Data Sheets for small arms ammunition TM43-0001-27.http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCEQFjAAahUKEwi4gYLylubGAhWJ0IAKHcaGBXA&url=http%3A%2F%2Fwww.ar15.com%2Fcontent%2FwebPDF%2FTM43-0001-27.pdf&ei=kA-rVbj5JYmhgwTGjZaABw&usg=AFQjCNEeLeaxPfnoeeaz5CUgepQpwPSdkw

 Don't use load data from this data sheet for loading your 50 cal !!!

Thanks for the info. Thats been the most detail if seen on them. Took a screen shot for others to see it.