New guy here...not new to reloading though

[arklatexgeo]

Morning gents...
I have just returned to the fine world of reloading and I find myself in need of a little knowledge. I am reloading for three different rifles right now and I found something that is new (to me...not the world) and this forum looked like the best place to ask.

I have a Winchester Model 70 300 Win Mag that I reload quite a bit for. I found a good deal on some sabots for it. After looking around online, the reloading data for this sort of load is scarce at best and all seems to come from the same source that rose up in the late 1960s. I am SURE there is better data than that out there.

Also, I just finished building a 300 AAC Blackout and I want to do some subsonic rounds for it. The most popular powder for this seems to be A1680...which I can't locate ANYWHERE. I saw a few loads using H4198 and Berger 210gr match bullets. Anyone else got a load that will function? I am shooting with a 16" stainless barrel, 1:8 twist, carbine gas tube system, and Phantom flash hider all attached to a 556 Tactical upper receiver.

Lastly, for comparisons, what loads are you guys using for 223? I started using a load with a 55-gr HPBT and H110 powder. Any suggestions? This is feeding a standard Colt AR15-A2 HBAR.

Thanks in advance!

 

[FLIGHT762]

Morning gents...
Lastly, for comparisons, what loads are you guys using for 223? I started using a load with a 55-gr HPBT and H110 powder. Any suggestions? This is feeding a standard Colt AR15-A2 HBAR.

Thanks in advance!

H-110 is NOT a powder suitable for the 223 Remington / 5.56 NATO. H-110 was developed for use in the .30 M-1 Carbine and is used in magnum pistol cartridges. I's much too fast burning for the .223 Remington. H-110 is a ball powder and using it in the 223 Remington could be disastrous.

Consult a reloading manual or go to the "Reloading Depot" on this forum to the "223- 5.56 Stickey" for 223 Remington loads.

 

[arklatexgeo]

Wow!!! Glad I haven't Done it yet. The H110 seemed like one of the go-to powders on some of the other forums. It seemed to be pretty highly regarded for the 300 BLK round.

Those rounds are primed and I was going to charge them and seat them tonight. WOW!!! Talk about good timing!

 

[GSluzenski]

H-110 is one of the powders for Supersonic rounds in the 300 BLKOUT. It is not however, for the 5.56/.223. All similarities end with the use of the same case to form the 300 BLKOUT. Recommend a good relaoding manual. Welcome!

 

[arklatexgeo]

I just picked the hobby back up and do need a new manual. I was just grabbing loads off the internet to try them out. REALLY glad I didn't try to load those up for the 223. I would really hate to have blown up my HBAR. I have a couple pounds of Varget that I know will work in the 223. Any pet loads there? I had a look at the 223/5.56 sticky. Just wondering of there were any that just stand out as great.

I knew the H-110 was good for the 300 BLK. I got some H4198 to load up some subs too.

 

[arklatexgeo]

Had a great 4th of July weekend. Ended up loading up a bunch of 300 AAC Blackout subs. I used the following components:
Berger 210-gr HPBT Match Grade
Rem 7-1/2 Primers
LC Brass, TL 1.360"
Hodgdon H4198
COAL 2.250"
Air temp 91 F

I loaded these up in 0.1-gr intervals starting from 11.5 gr and worked downward to 10.5 gr. The end result was a 11.1-gr load under these bullets that was consistently subsonic and cycled the action with a mean velocity of 1016.33 FPS and a SD of 12.097. The shot velocities were:
1030 fps
1007 fps
1012 fps

I had some at lower charge weights that registered as subsonic around 990 FPS but they weren't cycling reliably so they won't be repeated. The 11.1-grain rounds still had a pretty good POP even though they were registering as subsonic. I am sure this was due to the fact that we were shooting under an overhang at the range and the muzzle blast resonated. The last time I shot this rifle with supersonics out on the open, it barely had any sound at all. Am I missing something here or is my resonation theory correct?

I have another range date this weekend and my plan is to load up 10 of each starting at 11.2 grains and working down to 10.9 grains of H4198 until I get a really good read on what these can do in terms of sound and ballistics/accuracy. Anyone have any suggestions? Does it sound like I am on the right track here?