Loading 5.56 for short barrel

[Capt. mike]

Probably going to go dust off the presses and load up some 5.56 for a 10.5 AR upper.

Before I had just been loading for a 1-9 SS 16" and mainly was just using whatever powder I could find and going a hair over published .223 loads for 55gr FMJ.

Ive used IMR 4064, IMR4198, CFE223, and BL-C(2)

From my lee and hodgdon recipes cfe223 has the best velocity in a 50gr and is right behind varget for 55gr. This is a rifle recipe for a 24" barrel.

I also have a pistol recipe from hodgdon that is for a 15" barrel
this has varget at 2972 and bl-c(2) at 2816
also has H4198 (not IMR4198 which I still have a pound of) at 2719

the IMR4198 is the fastest rifle powder that I have and its nice as it calls for 20.4grs compared to the 27.5 for cfe or varget. Since this is for a 10.5 inch Im thinking that the 4198 would probably be getting about the same velocity in the short barrel as its burning quicker than the other slower powders.

I basically just want to load something that is optimizes for the shorter barrel that I can push a little on the hot side. Yeah I know 300blk works great for short barrels but thats what the vz58 and the AK are for. Oh yeah Im not worried about these being sub MOA just want to hold minute of beer can at 50 yards. I saw where the bbti guys chronoed remington UMC .223 55gr at 2616 in a 10" so I feel like with the right powder and loading it a little hotter I can get up to 27-2800 fps any thoughts?

[Rumbler]

I'll do a little reading, but my intuition at this moment is telling me "probably H110/W296"


But it could well turn out to be 800-x.

You propose a tough nut to crack because it is not just a velocity issue. It is not even a gross pressure issue. Dwell time figures into this heavily as well, so you gotta get all three right if you want reliable function . . . . on more than just one single shot . . . ever.

[Capt. mike]

I ran some 55 FMJ over 28grs of CFE223 all ran fine
Also had a few 55grs with 21grs of IMR4198 all cycled fine too.
Only hiccup was a hornady factory 55gr .223 but It may have been a mag issue. I tested with a mag of tula 55gr and that worked ok too.

[Evil_McNasty]

Do people still use those pigtail coil looking gas tubes on their pistol builds?

[Capt. mike]

I have seen them before but that sounds retarded, all the issues with pressure and dwell time is the gas port diameter and length its drilled at on the barrel, just making the tube longer by pig tailing it can only reduce pressure by putting more volume and heat loss in the tube. Unless it was for 16"s with carbine length gas that were "overgassed" and they wanted to soften the pulse.

[Capt. mike]

Does anybody know of a site with any good information about this, every thing I can find says you'll shoot your eye out, to drive hybrid cars and to stop smoking.

[Rumbler]

I've been doing some research on this.

To summarise what I have learned: "For long term reliable ar pistol functionality buy a 300 BLK". Every bit of data I can find for 5.56 pistol at the velocity the bullet needs to perform to specification is razor edge thin in terms of safety. +,- 1/10gr carries a warning to let someone you don't like test it first.

No shit.


. . and this from a guy that spent a couple of hours this morning putting 48.5gr of H110 under 240 grain pistol bullets.

[Capt. mike]

Well I had a 10" blk barrel but ended up getting rid of it. It was a pistol gas system that I guess is required for a 10-12". I know the 300 does better ballistically in a short barrel over 5.56 thats pretty clear, but given a fmj bullet out of either a 125-150 bullet out of a 300 isn't going to fragment either and the cost of components goes way up. I know you can buy ammo but its not at the price range yet that I can pile up enough ammo to be comfortable.

In a 10.5 upper green tip 62gr m855 runs 2612fps at 4 meters from the muzzle. Most people agree green tip frags above 2700 and may frag down to 2500. If you can get 2600 from a 62gr I feel like a 55-53-50 gr is gonna be in the frag zone up close and while expensive, ive seen some of those new barrier blind bullets that are made for 8" barrels. I know except for the bullets, barrel, and loading equipment most everything is the same but I just cant justify another caliber when I already have another AR and can use the ammo in both. I have plenty of rifles if I need a rifle, this is just a pistol and I don't expect it to perform the same as one of my rifles.

I completely agree, especially in a short barrel, the 300 is a better round ballistically, its also much more flexible especially if your running a can. But for me Im not sure its the best choice. Im more concerned with having ammo that pokes holes and runs than have a better round that I will have a finite supply thats not available. I like the idea that the 5.56 is still a bullet thats super sonic out a few hundred yards even out that short barrel and there is something to be said about cover fire and just because a bullet doesn't fragment in FBI ballistics gel doesn't mean bones don't explode violently when hit by bullet. I just think if it really did suck that bad why are special forces, DEA, and Navy boarding teams using the 10.3" Mk 18

[Rumbler]

I just think if it really did suck that bad why are special forces, DEA, and Navy boarding teams using the 10.3" Mk 18

I understand.

But you should do some reading. The organizations you mention are not using 5.56 ammo you can buy on the open (legal) market. At least not at this time.

. . and remember that is the same logic folks use to justify the 9mm as a defensive cartridge, despite virtually every reputable source in existence labeling it "marginal at best".

Uncle stopped issuing small arms based on their actual effectiveness long ago.

It probably sounds like I am "arguing" my point, but really I am not. To each their own and I am fine with that. My interest (here) is in the discrimination of information and the furtherance of all our thought processes.

[polebarn]

"Uncle stopped issuing small arms based on their actual effectiveness long ago."

Around 1962?