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Discussion Starter · #1 · (Edited)
I'm setting up rifles for a couple of friends and mine is ready to go. I'm looking for suggested moderate loads using 10X or 322 and the 110 Accubonds. All the barrels are ARP or Bison Armory. Thinking maybe 29gr of 322. Not sure about 10X?? Need to load mag length for shortest mag.
 

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I am loading 28.5 grain H322 and would not go above that in my AR. I have killed 2 deer so far with the 110 accubond And very happy with it performance. I am getting about 2560 fps from a 16” barrel
 

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Discussion Starter · #3 ·
Thanks Scoony.....I will use that as an upper limit initially and see what my brass looks like.
 

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My hunting load with the 110 Accubond and 110 Prohunter are both 28.9 gr of H322 in an arp barrel. Of course work up to the load
 

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Discussion Starter · #5 · (Edited)
So made 15 rounds each of load with 322 and 2200.

H322 are 3 each at 28, 28.2, 28.4, 28.6, and 28.8
AA2200 are 3 each at 27.4, 27.7, 28, 28.3 and 28.6
All loaded to the cannelure on the Accubond.

I've shot SSA 110 TAC loads in the rifle without issue so these seem pretty reasonable from all my reading here. The TAC loads will certainly flatten their primers.
I think 2600 fps with the 110 Accubond should be an easy mark to hit in the 18" bbl.
 

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Discussion Starter · #6 · (Edited)
I hope some of you guys with way more experience than I have with the 6.8 will chime in on the results I got this morning shooting the test loads above. I got some interesting results. The rifle is a Bison armory upper 18" mid-length gas system 1:11 with I believe 6 groves. Hard to tell the grove count just looking down the barrel....it might be 4.

As a starting data point I shot 3 rounds or SSA 110gr OTM TAC.
Average 2618fps and rilfe functioned fine. Flat primers with slight firing pin craters.

On my handloads using AA2200, the rifle short stroked with failure to feed and no lock back with all the charges below:
New Hornady brass; 110 Accubond; AA2200; Wolf SRM Primers
27.4 2566 fps
27.7 2605 fps
28.0 2621 fps
28.3 2659 fps
28.6 2686 fps
Velocities higher than I anticipated especially for short stroking. Primers rounded until 28.6 where they were "slightly" flattened. And mean slightly. My .223 service rifle loads are flatter. Wolf SRMs are fairly tough.

The rounds using H322 functioned better but much lower velocities.
New Hornady Brass; 110 Accubond; H322; Wolf SRM Primers
28.0 2480 fps Fed rounds no lock back
28.2 2509 fps Functioned and locked back
28.4 2524 fps Functioned and locked back
28.6 2539 fps Functioned and locked back
28.8 2550 fps Functioned and locked back

Primers rounded across the board.

All had very slight cratering of the firing pin strike, the AA2200 more pronounced than the H322. But very slight.
I believe the bolt is a standard ARP in a YHM nickle boron carrier.

I then fired some rounds I had loaded up a few years ago using the 110TSX and 28 - 30grs in 0.5 increments of H322 in new SSA brass. Fired three rounds each at 28, 28.5 and 29 grains then noticed that almost all had splits at the shoulder neck junction. I then fired 5 rounds of 120SSTs over 27gr of H322 also in then new SSA brass that I loaded back about the same time. These also split at the should-neck junction. None of the splits extended to the case mouth. I've never seen the like and it was all with the SSA brass. None of the Hornady cases for the loads I did this week and fired today were split.

I also fired 3 rounds of the Fed Fusion 115gr MSR and they all short stroked...no feed and no lock back. Velocity average for those was 2588.

I can't explain any of it. I guess I can go higher with the AA2200. Split case pics are below.
71285


71286
 

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I'm setting up rifles for a couple of friends and mine is ready to go. I'm looking for suggested moderate loads using 10X or 322 and the 110 Accubonds. All the barrels are ARP or Bison Armory. Thinking maybe 29gr of 322. Not sure about 10X?? Need to load mag length for shortest mag.
I use only 10x for my 110gr AB loads.

My pet load is 28.5 grs of 10x loaded at mag length. no pressure signs.

mine is a-

S&B Brass

#41 primer

ARP 18" barrel, w/ adjustable gas block.
 

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Discussion Starter · #8 · (Edited)
Thanks Backwoodsshooter. I will get around to trying 10X but I have a lot more AA2200 on hand. Mainly right now I don't quite understand my rifle having cycling issues with the AA2200 loads at the velocities i was getting. The primers looked okay so I think I can go up and get to 2700+ with 2200 and the 110 Accubond. And the split cases on those old reloads is a real mystery.
 

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The split cases are a known problem with SSA brass produced by Nosler depending on the date of manufacture. Shortly after Nosler bought SSA, the quality of their brass went down the tubes and a high percent of case necks splitting was the norm for a while. From the lack of complaints lately, it seems like they have finally gotten it under control, but I don't know when yours was produced.

It is normal to get much better velocity with AA2200 than the H322, but usually it comes with the price of less consistency and sometimes some cycling challenges. As I am sure you know, cycling is dependent on a lot more factors than velocity.
 

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Discussion Starter · #11 · (Edited)
Thanks Chopperdrvr. I didn't know that about SSA cases after Nosler got involved. I did note they looked pretty thin in the neck. I am quite aware of the cycling factors from shooting service rifle matches. For example IMR8208 is a great powder for .223 service rifle but is known to cause short stroking in some guns. Not usually to the point of not feeding, but not locking back the bolt which is an issue in rapid fire strings. The pressure curve at the gas port is critical for function. Sometimes changing carriers or gas tubes will fix it, sometimes not. I was surprised the Federal Fusion 115 MSR loads wouldn't cycle.
 

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IMO, you can go higher with both AA2200 and H322. It's disappointing that Federal loads are weak. I've only got one AR that will cycle them, and it's overgassed.
 

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Discussion Starter · #13 · (Edited)
Thanks Bedlamite.... That's my assessment of the brass and primers too. I would not call any of the loads I tested even warm. I will be trying some additional loads using the highest of the ones I tried as my new starting point. If I can go up a couple to a few tenths and get reliable cycles with the AA2200 load I'll be very happy with them.
 

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I have a set up very similar to yours... 18” barrel, 11” twist, using Accubond 110’s exclusively. I also use 322 exclusively, now.

When I built my rifle, I had some assistance from a gunsmith who is also a trainer for national teams. One of his specialties is the 6.8mm (although I don’t think any of his teams compete with this set-up). Anyway, we built my barrel (of course) from wilson tube and assisted in helping me build my loads. We started at 27.5 and worked up to 29.0 in 0.1 grain increments. I saw some very interesting results...

At about 27.5 gr, my groups at 100 yards were spread up and down about an inch and a half. At 27.6, they seemed closer, but more narrow spread (spread was more up and down; tighter left to right). At 27.7, even narrower and tighter all around. By 27.9, the spread was roughly 1/2”, but the spread was like the letter “i”; up and down only. At 28.0 grains. I hit the same holes on several occasions, but the up/down spread had disappeared. At 28.1, the bullets started spreading sideways. The more we moved up from there, and by the time we got to 28.5, the spread was big again.

We went all the way up to 29.0, but I never got the tightest, most consistent group as w/ 28.0 gr. I learned a lot that day, as he explained the resonant frequency of barrels and where the nodes and peaks of those waves are affected by the bullet weight and powder type / amount.

I now load everything the same, and have focused on mastering the one load .... on this rifle.
 

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Discussion Starter · #15 ·
ejbragg...why do you use 322 exclusively?? The accuracy and velocity I was getting with the AA2000 loads were all better than almost all the H322 loads. After the function failures with the AA2200I ended up swapping bolts and gas tubes. The bolt in that rifle had a tail that measured 0.0249-0.2495 and there was quite a it of gas leakage around the tube at the gas block. I used blue locktite on the tube and around the gas port. I'll retest with the AA2200 loads at the higher end and maybe with some hotter H322 loads. I would use an H322 load if I can get one to hit 2600fps and have reasonably good accuracy. The goal is hog hunting accuracy.
 

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ejbragg...why do you use 322 exclusively?? The accuracy and velocity I was getting with the AA2000 loads were all better than almost all the H322 loads. After the function failures with the AA2200I ended up swapping bolts and gas tubes. The bolt in that rifle had a tail that measured 0.0249-0.2495 and there was quite a it of gas leakage around the tube at the gas block. I used blue locktite on the tube and around the gas port. I'll retest with the AA2200 loads at the higher end and maybe with some hotter H322 loads. I would use an H322 load if I can get one to hit 2600fps and have reasonably good accuracy. The goal is hog hunting accuracy.
Honestly, I did not test out the AA2200 powder. I went by the extensive research of others on this forum. The consensus seemed to point toward highest (accurate) velocities from AA2200, but finest accuracies (with slightly lower velocities) with H322. I tried out the latter and decided to go that route. Also, my gunsmith was an influence. He used to be a military sniper and he seemed more interested in accuracy than velocity. Ultimately, I should have tested the AA powder myself, since every rifle is different. Guess I got in a hurry.

The main point is tracking your own rifle’s performance with very small powder increments.
 

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Discussion Starter · #17 · (Edited)
Another variable some very good service rifle shooters adjust is seating depth. The 75-77 grain bullets are the norm for highpower XTC and with 2.260 (really around 2.250) as a max, a lot of guys see the best accuracy seating back to 2.235 or so. As you indicate, it is about finding the load the lets the bullet exit the barrel at the optimal spot of the barrels harmonics.
 

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Discussion Starter · #18 ·
Last update to this thread as it was supposed to be about loading the 110 AB and has shifted to more of a function issue. I loaded up some rounds of each H322 at 29 and AA2200 at 28.8. Good velocities for hunting with either and functioned well in the rifle we built with the 18" ARP barrel. This one also functioned with the Federal MSR 115 Fusions and was giving right at 2600 FPS with them. My rifle with 18" Bison bbl still wouldn't function with AA2200 and now stopped functioning with the H322 loads. Mine does function with the Hornady 120SSTs. We're going on a hog hunt this week so I'm leaving well enough alone and my buddy will use the Fusions and I'll use the SSTs. After this hunt I'm going to disassemble this rifle and go through it carefully. I had already sealed the gas block and tube with blue loctite. But I think the bolt carrier is leaky as hell judging by the powder/carbon around the gas key. From a reloading the AB perspective I'm good and I really appreciate of the responses here!! It is pretty easy to hit 2700fps with 2200 and 2600fps with H22 without really flattening primers. With the shortages in components I wanted to get to good loads without using a lot of my limited supply of the ABs.
 

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Discussion Starter · #19 ·
I will add that I did discover that the bolt nickel boron bolt carrier I used doesn't have staked gas key bolts (and that company apparently doesn't stake them) and when i took the gas key off I discovered there was no sealant around the gas holes. i applied blue loctite and reassembled and will test again later.
 

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Are you saying your rifle doesn’t feed correctly? And you’ve sealed the gas block? I think you’re saying “sealed” as from around the outside perimeter, right? Not as in prevented the gas block from passing the gas back to the bolt.(?)
 
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