Is it the 5.56 or .223 version? Federal seems to make a variety of different T3 loads for various LE contracts. Aside from the XM556FBIT3 that's 5.56, I've also seen XM556FBIT3M (.223 pressure), XM223T3HSPB (.223), and XM556SBCT3 (5.56).Quote:
Originally Posted by TGS
The stuff I have is XM556FBIT3M, with 223 listed below that.Quote:
Originally Posted by DiscipulusArmorum
No idea why they don't just call it XM223FBIT3. :confused:
We very well might have various forms to the FBIT3 floating around depending on what year it was bought.
What's different about the HSPB and SBCT3?
Thanks!Quote:
Originally Posted by TGS
Regarding the differences among those various SKUs, I don't know anything beyond what I've been able to piece together from publicly available gov contracts and a few tidbits from other sources.
The HSPB load was in use by ICE. I would bet it's the same as the .223 spec FBI load, just with a different SKU due to packaging (instead of 20rd boxes, it's loaded on stripper clips in 30rd cardboard sleeves, 900rds to a case if the TargetSports description is accurate.)
I can't find reference to SBCT3 in any official sources, but I've seen speculation that it's a 5.56 spec load optimized for the 11.5" guns that the FBI has standardized on (I guess SBC could stand for "short barreled carbine"?) or just a different SKU for non-FBI sales.
Does anyone have any resources on the effectiveness of loads like Gold Dot or Barnes TSX out of barrels as short as 4.5"? I would assume that there would be little to no effective expansion, but I'm curious if there has been any documented testing of barrels that short. Other than getting the most compact package possible but staying in a mainstream calber I'm just not seeing the benefits, yet there are several companies now offering such things.
The estimated 4.5" barrel velocities and expansion thresholds for most loads do not look very encouraging.Quote:
Originally Posted by MandoWookie
https://www.ar15.com/forums/ar-15/Up...el-/16-721162/
http://ballisticsbytheinch.com/223rifle.html
Yeah, even at the muzzle it looks like most loadings would fail, making it an exercise in sound and fury over substance.Quote:
Originally Posted by Velo Dog
I know you'll see it in the other thread where you posted the same questions, but for people coming along later...
https://pistol-forum.com/showthread....35#post1062735