A30 Barrels and my Chamber is Tall

[pbcrisp]

Previous thread and discussion of using alternative brass source here: blackholeweaponry.proboards.com/thread/2707/american-30-using-nosler-brass

I got two A30 barrels in the mail a few months ago. These were clearance barrels from True Sporting Arms. I think I got the very last two they had. 16"Length, Standard Profile, Carbine Gas, 5/8x24, 1:8.5 twist.

I only JUST got my second 6.8SPC BCG in the mail today, and a batch of 300 Starline Cases. These are the actual 6.8SPC cases, not the 6.8-Basic. 33c per for the real 6.8 cases, and no annealing...theoretically.

I have about 10 once-fired Hornady cases to check headspace and set up my dies. I am using Hornady 30 Herrett dies.

New 6.8SPC brass and once-fired 6.8SPC brass both drop right in the chamber.
I took one of those cases and used the 'cream-of-wheat' method and some HP38 to blow the shoulder forward and get something to start with. I was hoping I had a 'no-fire-form' chamber. Alas, this is not the case. (do I get extra credit for using the word 'alas' and adding in a pun in the same sentance?)

Using a 9mm case as a 'case comparator' I have almost a 0.020" difference between regular 6.8SPC brass and brass that is sized to my chamber. (keep in mind, these dimensions are really only valid for me, as no one else has the exact same 9mm case that I am using)

A fired case from my chamber measures 2.126" - 2.128"
A piece of 6.8SPC brass measures 2.106" - 2.108"
I cant just neck-up the brass and fire it, I'd be asking for case-head separation. Probably not on the first firing, but I would be shortening brass life in that area.

I have a few options:

1) Cream-of wheat fire-forming.
I dont really think this will work well. I have 300 cases to do, and I dont know that I can get fully formed shoulders without uping the pressure high enough to case the same problem that a simple neck-up would cause. (see above issue with case-head separation). This also involves a bit of a mess. I havent installed the gas-system on the uppers yet due to the potential for cereal clogs.

2) Seat a bullet out long and use it to set headspace.
I dont mind this one as much. Seat the bullet long, so it jams into the lands and holds the case back against the bolt. I think this method is a little less precise in an auto-loader vs. bolt gun. But, at least involves shooting bullets, instead of making a cereal mess.

3) Neck up to 35-cal and then neck down to 30-cal, creating a false shoulder. I dont have a .338 expander or I'd try that. This involves working the brass much more than the other methods, but is reliable, and can potentially be used to make 'full-load' ammo.

Which would YOU do?

[GLSHOOTER]

You have a challenge!!

First thing let's do is talk apples to apples. Zero your calipers to eliminate the extra length using the 9 MM. That way no matter what we use in the 9 MM area while there wil be a slight difference we can at least be in the same ball park.

Co f W will work but as you mention it is a pain. The second would work but costs you components same as #3 but is inconsistent. I would do #3.

Greg

[pbcrisp]

9mm brass casing that I am using has been resized using Lee 9mm dies...first set of dies in my collection.
Measures 0.752" in length. Calipers zero'd using this case for the measurements described below.

New 6.8 SPC Starline brass measures 1.356"

Fired brass from both of my chambers measures between 1.373" - 1.374"

I am making false shoulder brass using method #3 described above, setting the shoulder at ~1.372"

Ive made and fired about 50 rds so far, doing 'fire-forming' while also doing some load development work.

I think I'll be bumping the shoulder back about 0.004 - 0.006" for actual hunting ammo. Favoring reliable chambering.

[GLSHOOTER]

Sounds like you have a good handle on it. Looking forward to your accuracy results.

Greg

[pbcrisp]

I'm into load development while making brass.

I have Hodgdon Leverevolution, Benchmark, and CFE BLK.

Using 150 grain flat nose soft points, which I happen to have ~150 in an old box, I was able to hit 2300 FPS using CFEBLK. With 28.0 grains of CFE BLK, I hit 2330-2340 FPS. This is really starting to get hot, and I think 27.8 grains might be my max. That should get me back to 2300.

LVR only hit ~2050-2100 fps. Benchmark got me to about 2200. There just is not enough room in the case for LVR or BM. This is with un-fired, false shoulder brass. I might be able to fit another grain in the case now that they are fired.

I am prepping for a Hog Hunt in Georgia next week, so I dont have too much time to wander around yet. I also have done zero accuracy work thus far. Purely function and pressure monitoring while also recording Chrono results. I was getting a little bit of mis-feed, but this was due letting the brand new BCG and upper run too dry during break in.

Any advice for running the Hornady 135 FTX? Should I stick with CFE BLK? Or, should I see if Benchmark will work.

-PB

[GLSHOOTER]

I'll pull my records tomorrow. I have a pistol match in the AM. I've got something that will work.

Greg

[GLSHOOTER]

Jan 25, 2019 18:04:38 GMT -8 pbcrisp said:

I'm into load development while making brass.

I have Hodgdon Leverevolution, Benchmark, and CFE BLK.

Using 150 grain flat nose soft points, which I happen to have ~150 in an old box, I was able to hit 2300 FPS using CFEBLK. With 28.0 grains of CFE BLK, I hit 2330-2340 FPS. This is really starting to get hot, and I think 27.8 grains might be my max. That should get me back to 2300.

LVR only hit ~2050-2100 fps. Benchmark got me to about 2200. There just is not enough room in the case for LVR or BM. This is with un-fired, false shoulder brass. I might be able to fit another grain in the case now that they are fired.

I am prepping for a Hog Hunt in Georgia next week, so I dont have too much time to wander around yet. I also have done zero accuracy work thus far. Purely function and pressure monitoring while also recording Chrono results. I was getting a little bit of mis-feed, but this was due letting the brand new BCG and upper run too dry during break in.

Any advice for running the Hornady 135 FTX? Should I stick with CFE BLK? Or, should I see if Benchmark will work.

-PB

I haven't shot either CFE BLK or the BM stuff. I've shot a bunch of RL10 in a 130 and would go with 31.0-31.6. 31.6. On a 130 it got me 2808. With a 150 I used 35.0 of LEVER and got 2398. ALL IN a 20"

Greg

[pbcrisp]

I have to ask: How you stuffed 35 grains of LVR under a 150 grain bullet?

I was able to cram 32+ grains into un-fired brass, and I just tried 35 grains in a fired case. Serious bullet deformation from the seating die as the bullet compressed the powder.
That round (I only loaded 1) went 2170 over the chrono.

I am using a flat nose soft point bullet, seated so that it is the same depth in the casing as the Hornady 150 Soft Point 3031 will be loaded to 2.290"

Leverevolution:

LVR    29.0 grains   1950 fps

LVR    31.1 grains   2180 fps (I think this chrono reading might have been off)

LVR    31.8 grains   2000 fps 

LVR    32.6 grains   2000 fps (poor cycling due to dry BCG)

BenchMark:

BM    29.0 grains    2070 fps

BM    29.8 grains    2140 fps

BM    30.8 grains    2240 fps (highly compressed - deformed bullet from seating pressure)

CFE BLK:

CFE    25.0 grains    2170 fps

CFE    26.0 grains    2160 fps (I think this chrono reading might have been off)

CFE    27.0 grains    2270 fps

CFE    28.0 grains    2340 fps

CFE    28.5 grains    UNK (pretty warm)

CFE    29.0 grains    UNK (too hot, wrecks brass)

I also have a bunch of 165 gas checked cast lead bullets.  I was given a bin full of about 750 bullets a few years ago from a 30-30 reloader.  This is why I have a bunch of flat nose 150's.  Ive shot 100+ of the 165 gas checked lead bullets over 28.0 grains of LVR.  These go 1760 over the chrono, cycle and lock back just fine, and dont seem to be leading the barrel.  I have two brand new uppers that I am trying to get rounds through for function check...while I am doing brass forming...while I am doing load work.  I ran 100 of these 165 grain bullets through upper #2 today, and it ran real well.





As always, thanks for the help. BHW barrels are of course nice. I think the support here on the forum is an added bonus that kicks it up a notch.

[GLSHOOTER]

Tapping and vibrating let me put 35.5 in mine. Sated a Hornady 150 Interlock to 2.295. 90% of my load work ups were at 100% or higher density. Compressing with this one was no problem. RL1200 looked promising up to 30.5 at 2362. in a 16" barrel. AA 2230 at 32.0 gave me 2367 with excellent groups out of the 16". AA 2015 really roared at 30.5 going 2495.

Remember all these capaites are different thanks to components. ALL my load workups were with FEDERAL BRASS. It is thinner than much of it that is out there. Also a lot of my work was done at 80+ temps up. I use a Hornady seater BTW.

Greg

[pbcrisp]

Further load work with CFE BLK:

123 grain Varmeggedon bullet - these are actually .310 bullets sized using a Lee push-through sizer to .308
CFE 29.9 grains 2630 fps
I was quite pleased with this speed, but I had 1/10 shots go a bit faster - I think I had it jammed into the lands.


I have also shot the 135 Hornady FTX bullet.
CFE 28.5 grains 2540 fps.
I think I can push this JUST a bit faster...tbd.

I have loaded some of the Hornady 150 grain 3031 soft points.
CFE 28.5 grains 2340 fps.
This is one of my planned hunting loads at this point.


Still waiting to do some accuracy testing, but its super cold here currently.

[rfd]

I know I'm late to the party, but here are the results I'm having.

I hit on the neck up to 35 solution some time ago. It allows me to make usable ammo for first firing, whether target or game. As soon as I cycle through my first batch of brass however, I will anneal.

The shoulders aren't as well defined as I think they should be after firing. I use Starline brass

when it comes to loads, I've had great success with AA2200. Using Speer 150 grain hotcore flat-base spire points and up to 30.2 grains of that powder, I get a consistant 2420 fps from my suppressed 18 inch barrel. At that level, you WILL need an adjustable gas system. Accuracy has been less than MOA. No excessive flattened primers. 30 grains give 2390. The usual caution : that is MY barrel and lot of powder. Started at 27.5 grains and 2.285 OAL. Modern 30-30 indeed!