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Discussion Starter · #1 ·
Does anyone reload .223 (.224) Rem using 75GR HPBTs? The 556 loves heavier bullets and functions flawlessly using either 75GR Hornady or Privi Partizan Match (factory loaded) ammo.

I'm trying to develop some accurate reloads using both Hornady and Partizan 75GR HPBT bullets. Despite numerous online searches (to include this forum), I’ve found little info (recipes) for the Sig 556's fast 1 in 7 twist - 16" barrel. Nearly all printed guides list the Hornady 75GR HPBT with longer barrels. Does anyone have any starter recipes or online links they’d be willing to share? My starter loads will be based on:

Rifle: Sig 556
Barrel: 16”
Twist: 1 in 7
Bullets: Hornady 75GR HPBT Match
Privi Partizan 75GR HPBT Match
Primers: CCI 400
CCI 41
Brass: PMC Military (once fired)
Lake City Military (-10%) (once fired)
Powder: ?
Grains: ?
OAL: ?
Data Source: ?
 

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The 2009 7th Edition Hornady Reloading Manual has complete Service Rifle loads for the Hornady 75 grain BTHP for use in autoloaders (AR platforms) with a 1:7 twist.

Order that manual for yourself.

I just ordered some Hogdon BL-C(2) powder to take advantage of reloading the above mentioned bullets after learning what I read in that Hornday Manual.

Your right NOT to follow reloading data for bolt action .223 or slower rate of twist though.....
 

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Discussion Starter · #5 ·
Thanks SkyPup. That's what I was looking for. Strange that nobody is loading for the Privi Partizan 75grainer. It's almost identical to the Hornady but considerably cheaper.
 

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SkyPup said:
RamShot also has some good AR type 1:7 twist loads listed too:

http://www.ramshot.com/powders/loadguide/Ramshot_V4.2.2.pdf
I just got a keg of TAC in, so I'll commence loading up some Hornady 75gr pills tomorrow. Don't have a load developed yet, but am using the arfcom reloading recipe thread for some guidance.

Tried using Varget, but it didn't look like it was going to work very well. TAC is considerably cheaper, anyway. ...And by many accounts, is better for this application.
 

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FWIW...

The following formula appears to show promise, and hasn't yet blown up my rifle:

75gr Hornady BTHP
23.6gr TAC (max load, according to Ramshot)
COL 2.263" +/- ~.004" (variation caused by typical variation in projo length)
IMI once-fired brass, trimmed to min length, polished/reamed/chamfered
WSR primers (the old kind)

Was testing over a chronograph, which I shot. :lol: So, will have to try it again next time after receipt of replacement parts from the manufacturer. Will shoot for accuracy at that time. I anticipate velocity to be ~2650 fps (slightly faster than TAP FPD) in a 16" barrel.

No signs of excessive pressure were witnessed. The spent primers looked pristine; no unusual report or recoil noticed. Temp was around 63 degrees or so.

The next range trip will be switching over to the new style WSR primers, and adding a collet-type crimp. Few people would recommend WSR primers for this application, but it was what I had on hand. Will be switching over to Wolf SRM's after a few more range trips.
 

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man, any of you reloaders live in Ga? :roll:
 

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Rifle: Sig 556
Barrel: 16”
Twist: 1 in 7
Bullets: Hornady 75GR HPBT Match
Primers: CCI 400
Brass: Remington .223 fired once
Powder: Hodgdon BLC-2
Grains: 24.7 (max is 25.2)
OAL: 2.250"
Full Length Resize with RCBS X-Die
Data Source: Hornaday Service Rifle 2008 Manual


Okay, I loaded up my first .223 rounds as listed above and am going to try them out tomorrow. My only question is that the Hornady 75 grain BTJHP bullets do not have a channelure and I did not crimp them.

Question is this going to be okay in a semi-auto? I'm hoping the bullets do not get pushed back down into the shell during the loading process.
Overall length is 2.250"

I also noted that my Federal XM-193 5.56mm and Prvi M855 5.56mm cases could NOT be reloaded as the primer hole is too small for the primers I'm using....apparently only .223 cases can be reloaded without reaming out the primer pockets on the mil-spec ammo.
 

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Question is this going to be okay in a semi-auto? I'm hoping the bullets do not get pushed back down into the shell during the loading process.
Overall length is 2.250"

I also noted that my Federal XM-193 5.56mm and Prvi M855 5.56mm cases could NOT be reloaded as the primer hole is too small for the primers I'm using....apparently only .223 cases can be reloaded without reaming out the primer pockets on the mil-spec ammo.
As far as not putting a crimp in, you should be GTG, given the size of the 556's feed ramp. I've used non crimped bullets with no set back issues.

Most Mil-Spec 5.56 will have a crimped in primer. The quick and cheap fix is to get a hand reaming tool from your local gun/reloading shop.

Please post the results of your loads. I'm kinda anxious to see how they came out for you.
 

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WOW, I am extremely impressed with my very first .223 reloading project.

Here is the load:

Rifle: Sig 556
Barrel: 16”
Twist: 1 in 7
Bullets: Hornady 75GR HPBT Match
Primers: CCI 400
Brass: Remington .223 fired once
Powder: Hodgdon BLC-2
Grains: 24.7 (max is 25.2)
OAL: 2.250"
Full Length Resize with RCBS X-Die
Data Source: Hornaday Service Rifle 2008 Manual

And here is the result of the first Eleven Rounds.

Every one was super smooth and flawless, virtually no smoke whatsoever. The accuracy and power appear to be very good. Only problem encounted was recovering my spent casings out in the woods when the SIG flinged them out 15-20 feet (although none of the cases were bent or banged up and all the spent primers looked fine)

Eleven rounds from 50 yards using Eotech 512 from sitting position in about 1.5 inch diameter (I had the Eotech sight zeroed at 50 yards to be one inch high using Prvi 5.56mm 62 grain M855 steel green-tip mil-spec ammo):



Here is my reloading bench:



All in all I am very pleased and next project will be working this up as a Hog Hunting round and firing it at 100 yards through my other SIG 556 with the Burris 1-4X Extreme Tactical Scope for accuracy. 8)

Most likely I will go to 25.0 grains of BLC-2 and stick with that in the future if all is well..

LebbenB, thank you so much for helping me getting started on this, it took awhile to gather all the componets but now I am good to go for at least another 4,000 rounds or so..... :wink:
 

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That's a good looking group, Skypup! And you're welcome, though thanks aren't really necessary. I'm just sharing what little I know.
 

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My Magpul magazine now has 30 freshly made 75 grain Hornaday reloads in it and I've been following a huge boar's track now for over two weeks, haven't seen him yet, just where he has been, but when I do get an eyeball on him, I'll post some pics of the results!!! :wink:
 

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Ah Ha, reloading is great fun! 8)

I moved up to 25.0 grains of BLC-2 and it works just perfect. My 556 has never run as fine as this with any kind of ammo before.

I loaded up 250 rounds individually and rezeroed my scope for bullseye at 50 yards ( as it was shooting over two inches higher than the M-855 62 grain ammo I had previously zeroed it in with).

Now it shoots right on the money over and over again like nobody's business.

I'll try some 100 yard and 250 yard targets next weekend if the weather is good. And if a hog happens to be standing adjacent to my target, so be it, another dead zombie swine in the works!

So glad to have such an awesome hunting round dialed in and also functions as a supreme target round too! 8)

Thanks again to all for getting me going, my 556 absolutely loves these rounds.....
 

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I just wanted to leave a comment about the new RCBS "X-Dies".

So far, I really like this rifle die.

You first deprime the cases and then clean the cases in the vibrator. Then you set the die to full-length resize each case.

Then, instead of trimming the cases to 1.750, you trim them to 1.730 and then resize them again and set the die down onto the case and keep it that way.

After doing this on my first 30 rounds, I have shot them three times and reloaded again without any further case trimming!

The reason is works is after the initial trim to standardize case lengths, the X-Die allows repeated full-length resizing without the case length exceeding the maximum ANSI specification. Routine trimming after each sizing is eliminated. A precision mandrel in the X-Die limits growth of the case without shortening it or causing metal build-up in the neck.

http://www.rcbs.com/downloads/instructions/XDieProductInstructions.pdf

I didn't know if this was going to work for me, but after loading the same cases four times now, I know it works great!
 

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I just loaded up another experiment for this weekend-

Ran out of WSR primers, so have now started using the Wolf Small Rifle Magnum primers.

I've also loaded up some trial rounds that are .2 gr over the manufacturer's max charge (TAC powder). Various anecdotal evidences suggest that the max load of 23.6gr for a 75 BTHP may be a bit overly conservative, particularly with a 5.56 chamber vice .223. Sierra, for instance, suggests 24.0 grains of TAC for their 77gr BTHP.

If I'm still alive afterwards, I'll post the chrono results.
 

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I am loading various loads to see where accuracy diminishes due to excessive velocity. I will post data after I get to the range.
 
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