The new AR.....

[RBHarter]

So I'm loading for a couple of ARs ,a M4 style 556 and an A2 style 6.8.
The 223 is a no brainer even with cast bullets there's about 15 pages of data at hand in 6 books and comparable data on line the bbl is slow enough to hit 2700 with checked WW and fast enough for 70 gr if I wanted to go that heavy. The 65 gr 22-55 clone is fine but that needs some polish. I noted that even the factory loads looked flat but I haven't shot a lot of factory loads in the last 20 years.

Enter the 6.8 little to no data 1 powder on the Aliant and Hogdon pages per bullet no data in my newest book (2008) and my notes from the 7x6.8 with the 1-8 twist . The good news is that this rifle is the 1-11 twist an is long throated in the SPCII chamber load data for the 120 gr SST says 28 gr of 10x and the 7x6.8 mildcat shot the papered 135 gr up to 24 no problem. At 24.2 it spiked and blew cases around the primer.
So I started at 25 and worked up with a long COAL and the 120 SST at 26 it's not pretty and the Chrony. ..it probably lied too. Anyway below are primer and case pictures . I'm sure there is something amiss ,like I'm way over for this combination in this rifle . 1 picture of primers and 1 of the cases. It looks like the chamber was sand blasted almost.

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[Maximumbob54]

I'm not reloading for my 6.8 yet but I will keep watch of what you figure works or not.

[RBHarter]

There's lots of data on 68forums.com but they're a different group probably 1/3 of the regular posters are commercial builders and push the envelope quite a bit. They mostly shoot the small primer brass also .

It is a good resource for the "advanced" reloader but could get a new guy in trouble pretty quick. I will be getting a couple of new sizers and probably go paper patch for this 1 but I'll try gas checks 1st. That $30/100 for bullets is just suckling the fun out of this 1.
I have some H322 and RL 10X ,the twist is too slow to make the W857 ,IMR4350 or either of the 4831s work (heavier cast bullets) so I will add a couple more powders to the menu and hopefully get lucky with the 27-130 fp from RCBS. I've read good reports about 4198 and 4895 , not top speeds but good function and accuracy. I have an extra day of this week and next so I will probably start lower and do a better break down and work up with both powders.

[Maximumbob54]

not top speeds but good function and accuracy.

I have yet to ever find a load that was top speed that included both function and accuracy. All I ever seem to find is two of the three but never all three. So I always settle for function and accuracy since loss of those kind of mean nothing if it's just a zippy load.

[RBHarter]

It is said that the typical powders 2200,H322,RL 10X give higher speeds with the good accuracy or so they say. I'm very aware of speed being 2nd to little groups. "I have this 06'. ....." there is 2 gr of 4350 between the 4" closing to 5 touching and 8" growing just barely inside the load windows.

[RBHarter]

Some info about the 6.8 rifle.
It is a Blackthorne products kit assembled with an Aero precision stripped lower. It's has mid length gas and a 16 in bbl advertised as 1-11 it slugged just over .277 . It's hard for me to crowd the stock enough to get into the scope ,a work in progress I guess, I have the highest mounts available local and they suit my Miss as is.

The Chrony was uncooperative today, but it rained last night and the damsel flys are thick today along with every other flying bug in the desert. I did get good values on a box of Federal 115 gr FMJ at 2650 fps. Those went into a 75 yd clump of about soft ball proportions ,eyeballed as a cumulative group of 4" .

Vitals
80-85 degrees
Humidity 40% in the gravel pit
Next to no air moving
3 shot steps
Remington brass
CCI LRP 200
Hornady 120 SST
OAL 2.295 to fit the AR Stoner magazines
21.0 to 23.5 in half gr steps of RL10x
None of these showed a real stand out set or any real growing or shrinking groups.
22.0 was probably about as good as it is going to get without some chassis work.

The melonite bbl finish on the bbl as predicted elsewhere smoothed out as the shooting progressed. For those not familiar with it it is a hot process that falls into what is nitriding combined with a black parkerized finish. Almost a matte black chrome. Anyway it is a case hardening process that also gives corrosion protection. In just a couple of shots but the chamber took about 25 to be smooth enough to only be marking the shoulders a little in the fireform areas.

I have the. 277 gas checks and the. 279 sizer die so I will start working a cast load for this, the 27-130 is shorter than the jacketed 120 and should shoot pretty even out to 200 yd. Loosing the fps is a pretty small issue in this case from jackets to cast as the 120s will go about about 2300 and I should be able to get 2200 with the cast at 135 gr.

[RBHarter]

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I loaded a few rounds to work up a load for the 27-130 FP . Among the challenges presented ,my newest load data book is 2008 and the manufacturer sites have little helpful data I did find some data in a note book for a 130 gr SP from sSpeer. Not totally helpful but but better than an eye poke . The next thing is that this boolit tips in at 136-7 gr with check and lube . This is a challenge not because of the length not stabilizing it is shorter than the 120. It is rather that I have no in between powders and this gas gun won't be happy with such a light boolit and 4350 or 4831 let alone W857.

Now if this picture will up load , a 27-130 with a Federal factory 115 gr FMJ and loose with Hornady 120SST . They occupy the same case space and unfortunately seating is dictated by the top band in this rifle .

Hopefully I'll get to shoot in the morning and be able to add some group and speed data.

[Ranch Dog]

It will be interesting to hear how the cast bullet did. I usually don't like a cast bullet to extend beyond the base of the neck but this rule is hard to live by with short necked cartridges.

[RBHarter]

I'm not crazy about it ,but the x39 suffered no I'll effects with a 200gr spire point shaped bullet paper patched . The 223 works ok too. While these will be pushing jacketed loads as a needed evil I think if the curves all get together and the near maximum capacity of the case should make for a powder "wad" to get the base into the neck. That being the general theory of slow powder heavy cast success. .. .......
Unfortunately it is the bullet and chamber shape that have the check below the neck not magazine length these load at about 2.15 while the Magazine will allow 2.3 . NOE has a design that ran as a group buy about a year ago that basically dropped the top band an shortened the check shank allowing a 2.2-2.29 OAL .

I read a write up yesterday about a guy shooting a 900 fps 6.8 load with a 200 gr custom round nose I would describe half jacket . In truth it is probably a 140 or 150 270 jacket with an exposed lead nose about .3 in long .

[RBHarter]

Well the cast is going to work out .
It's a little slower than I had hoped but there is still plenty of room to work on up.

The 27-130 FP for today weighed 136.5 at 5 rounds each load.
H4198
CCI 41
FEDERAL brass

20.0 1889-1923 with core speeds bringing it to 1915 average .
20.5 1934- 1978 and an average 1950.

Groups were good at 35 yd high and left. This AR is very cant sensitive (probably something to do with sights being 2" above the bore) . The groups seem to be closing . Speer lists 22.3 as a maximum load with their 130 SP so without to much worry I will proceed on up. I need to hit 2150 for legal reasons according to the Strelok calculator. It will give me the 100yd 1000 ftlb level needed here . I'm inspired.