Where would demil 220gr .30" OTFB bullets come from?

[dbooksta]

I've gotten some interesting demil'ed bullets from American Reloading, but they can never tell me their origins.

I've been using 220gr OTFB bullets (attached) for subsonics and (not surprisingly) they're just as accurate as premium BTHP pills. But I can't figure out what mil-spec cartridge they might have been pulled from: AFAIK, .30-06 never used open-tips and .300WM was always loaded with boat-tails. Anyone know what might have used these OTFBs?

 

[NukeMMC]

.300 bo
Just because things aren't in common issue doesn't mean they haven't either been tested or used by certain "r&d" units

 

[FLIGHT762]

This ^^^^^^^^^^^^^^^^^^^ Take a look at the cannelure. That will tell you what it came from. See if it fits OAL for a .300 Blackout. It probably does.

I have a bunch of .308" 180 grain FMJ F/B Military type bullets W / cannelure I picked up somewhere 3+ decades ago. I still haven't figured out what these were used for. They work great in the M1-A.

 

[bfoosh006]

Good question... I know the current Mk248 is 220gr OTM.... Apparently some was also developed for the .300BK ...for the "Low Visibility Carbine"

Follow the link... page 20 mentions..."220gr Subsonic flat base w/ cannelure ( Late 2012 ) " and page 21 shows a fully loaded 800rd Ammo can of it.


Hopefully the below link works... third time a charm ?

https://ndiastorage.blob.core.usgovc...590Silvers.pdf

 

[bfoosh006]

I noticed the meplat tip of the 125gr .308 bullet on page 14 is very similar to the photo you posted. .... Nosler ?

 

[dbooksta]

Ah ha: Good finds! I don't doubt that for subsonics the flat base doesn't hurt ballistics significantly, but it doesn't help, and it's still an open-tip bullet. Is it so much more expensive to put a boat-tail on such a bullet that it could be cheaper to produce flat bases (even given that the 220gr open-tip boat-tails are produced in large quantity)? Or could there be some other benefit to the flat base in 300BLK? (For subs it's not a powder volume problem: there is room to spare even with a BTHP seated to just 2.15".

 

[MtnCreek]

Flat base is shorter. A flat base would be easier to stabilize vs a boat tail.

 

[bfoosh006]

Flat base is shorter. A flat base would be easier to stabilize vs a boat tail.

and .... remember... you are probably buying the pulldowns from the experimental ammo ....

 

[bfoosh006]

I thought I recognized that meplat....http://bulletin.accurateshooter.com/2015/09/pointing-basics-how-to-use-a-bullet-pointing-die-system/ .... helps increase the BC

 

[dbooksta]

Flat base is shorter. A flat base would be easier to stabilize vs a boat tail.

Would make sense, except it's the same length as a 220gr SMK (see photo here).

I do believe it's from a subsonic 300BLK run: Seating to the cannelure results in COAL of about 2.15", which was Remington's preferred subsonic length.

Still curious what possible advantage the flat base provides....

 

[NukeMMC]

I can look it up but I would have to guess it would have to do with the velocity of the bullet being <1200fps and no transonic wave being produced then the boat tail stability efficiency is negated or even makes it unstable at subsonic velocity.

I have seen 190SMKs from M14s going thru the targets sideways at 1000 with no supersonic crack.

 

[spife7980]

The flat base loses a bit of the bc at distance compared to a boat tail but it is easier to make a flat base uniform than a boat tail which is why so many short range bench rest shooters use flat base bullets. Accuracy up close. Plus its cheaper.