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I've been loading longer than mag length on the 6.8mm for almost 5 years now so I was excited to get one of H's 22" Valkyrie barrels with longer than SAMMI freebore and apply what I have learned. I have modified magazines and receivers to allow COALs out to 2.410". I wanted to shoot the 95 SMK in the Valkyrie which is longer than mag length in a SAMMI chamber to begin with so I wanted that extra freebore the "Varmint" version provided.

The primary reason for loading long is better accuracy potential because you can seat the bullet right off the lands. A side benefit is that, by doing so, you increase cases capacity. That doesn't mean you can load to higher pressures but it does give you more case volume which you might be able to use for more powder if the mag length COAL was below max chamber pressure. I plan to explore both these potential benefits with this 3R barrel.

Brass. I am not a fan of Federal brass. Starline has been good brass in the 6.8mm but has the least case capacity. I want as much case capacity as I can get to plan on using Hornady brass since S&B has not plans to produce Valkyrie brass in the near term. Hornady brass is hard to get right now because their production is going to produce 88 ELD Match ammo. So I bought some Federal 75 TMJs to break the barrel in with and Hornady 88 ELD for comparison with 90 and 95 SMKs that I will reload. The Federal 75 TMJ as lightly crimped and easily slipped out of the brass. The Hornady 88 ELD had more neck tension. Note the crimp marks on the bullet in the picture are from the collet bullet puller.

I have some RE17 to develop handloads for the 90/95 SMK. Sierra has released load data for the Valkyrie which can be found at the link below. Reloading in pulled cases begins tomorrow.

https://sierrabullets.files.wordpress.com/2018/03/224-valkyrie1.pdf

Below is a picture of the 4 bullets I plan to shoot in this initial go. The first task was to determine distance to the lands. I pulled a 75 TMJ from its Federal case, deprimed it, and cut a slit in the neck. This allows a bullet to slide freely back into the case when pushed into the chamber. I used a dental tool to hook the rim and pull the case back out. Below are the distance to the lands I measured with my barrel. COALs for the seated bullet will be at least 0.010" shorter than these values. You will need to measure your specific barrel because it will be different. I expect these numbers to increase slightly once I have fired, resized brass with the shoulders pushed back 0.003". Initial measurements indicate that just a windowed mag from CavityBackBullets can accommodate the 90 SMK without having to modify the receivers.

75 TMJ 2.220"
88 ELD 2.380" (bullet shank was to the bottom of the case neck)
90 SMK 2.352" (bullet shank was to the bottom of the case neck)
95 SMK 2.390" (boat-tail is at the bottom of the shoulder)

Not shown
69 SMK 2.227" (bullet shank was only 1/2 way down the case neck)
77 SMK 2.235" (bullet shank was to the bottom of the case neck)
75 A-Max 2.363"


Those interested in loading longer than mag length can find the related 6.8mm information at this thread.
 

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Discussion Starter #2
Federal 75 grain Total Metal Jacket (TMJ)

Here is a close-up picture of the powder Federal uses in their 75 TMJ. Charge weight varied from 28.6 to 28.8 grains.
 

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Discussion Starter #4
wash, I'm taking the path of least resistance right now. I'll see how the Hornady brass works first. Once Redding comes out with their production bushing die, I might consider reforming 6.8 S&B brass which will likely be a multi-step process.
 

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Discussion Starter #6 (Edited)
Hornady 88 grain ELD-Match

Here is a close-up picture of the powder Hornady uses in their 88 ELD Match ammunition. Charge weight was 24.6 grains (average of 2).
 

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Discussion Starter #7 (Edited)
224 Valkyrie Initial Handloads

I have the initial rounds loaded to establish a reference baseline for further load development. I've been pulling the Federal TMJ rounds for brass to get me started except for pulling three 88 ELD bullets to load. Walmart had the Federal 75 TMJ for less than $10 a box so it gets me started. I would recommend a light to medium crimp for these bullets but I haven't found the Lee Collet Crimp Die available for this caliber yet. Because the neck tension is low, I will be hand feeding these. The start of the ogive is evident from the reflections off the bullets and shows the amount of freebore this barrel has.

75 A-Max 28.3gr 2.353" COAL Federal
88 ELD 26.8gr 2.370" COAL Hornady
90 SMK 26.8gr 2.342" COAL Federal
95 SMK 26.1gr 2.380" COAL Federal
 

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Wow, .244 Valkyrie.

I thought .224 was a bit too over bore and went with TAC 6 and .243 bullets, now you're one-upping me.
 

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I haven't really been following this too much but has anyone shot or tested the federal fusion 100gr bt hunting ammo yet? Probably not as high of a bc on the fusion bullets but was wondering about minimum expansion thresholds on such a heavy/small bullet.
 

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Discussion Starter #11
Rats! Thanks, bj. I corrected one of the photos but the first one has been more than 24 hours. Sorry if this caused confusion.
 

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Discussion Starter #12
I haven't really been following this too much but has anyone shot or tested the federal fusion 100gr bt hunting ammo yet? Probably not as high of a bc on the fusion bullets but was wondering about minimum expansion thresholds on such a heavy/small bullet.
THM, I saw where Federal did a press release last November that they were doing a 100 grain hunting bullet but the one they are producing is a 90 grain Fusion. Maybe their plans have changed. I've tested the 62gr Fusion and will soon be doing the 75gr Fusion. The 62 had excellent expansion - more than double caliber at 200 yards. I wouldn't expect the 90 grain to expand any less with the benefit of deeper penetration.
 

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Originally it was supposed to be a 100gr fusion. Then I thought they ditched it due to twist rates/accuracy issues

I just saw a company selling the 100gr fusion online and they claim to have 457 in stock for $22.46/ea
Maybe it's a misprint?
 

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Discussion Starter #14 (Edited)
Modifications for Loading Long

You can always hand-load single rounds that are longer than mag length to see if any benefits you would gain are worth it. If positive, the first step to loading longer than mag length for auto-loading vice single feed is to cut out the front of the magazine. This allows COALs up to about 2.36” COALS or longer and could vary depending on your receiver and magazines. I've done this modification on my 6.8mm for hunting situations were I’m not concerned about reloading magazines and can insert the mag in controlled conditions. The cut-out doesn’t go below the lower receiver’s magazine well, can be long enough to hold up to 12 rounds, and the mag’s side-walls still remain stiff.

CavityBackBullets.com now stocks 10-round PRI magazines modified to load longer than mag-length COAL. They are professionally manufactured and available in 6.8mm as well as 5.56/.223 (shown on the right below).

To load even longer COALs, you can widened the center groove in the front of the mag well by taking your time with hand tools to be wide enough to accommodate double stacked rounds or have it expanded by a machine shop . You will also need to use a rat-tail file to add grooves leading up to the upper receiver feed ramps to match. These modification to the upper and lower receivers allow for COALs of 2.41”. Note, I place soft velco on the front of my ASC mag followers to improve the bolt locking back on the empty mag.
 

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Discussion Starter #15 (Edited)
Initial Range Results

These rounds were shot to establish an initial baseline. I don’t expect muzzle velocities to get any faster than this. I may even turn them down a notch. I would also recommend that you be more cautious with the Sierra load data than I was.

The range I ended up shooting at did not allow FMJs so the 75 TMJ was not fired. The temperature in the shade was not less than 101F which may be why Hornady’s factory 88 ELD-Match were about 25 fps faster than they advertise from a 24” test barrel. Velocities of the hand-loads were 75 to 100 fps faster than the Sierra load data. You can see where the primers were flattened some (they still have some roundness) but there were no craters or swipes. The shiny brass case walls were coming out a bit cloudy which can be an indication of the chamber pressure still being a bit high at extraction. Pressure will be lower with resized brass with the shoulder only bumped back 0.003 to 0.004". I could have turn down the adjustable gas block a click or two more. I was 2½ turns open but have a light-weight bolt carrier and plan to try a light-weight buffer, also.

Update: Saw a guy on youtube measure his new Federal Brass rounds and they were only 0.003" shorter than his chamber. I'm used to as much as 5x that amount on some new brass in my 6.8mm. So measured my brass (22" ARP with ARP bolt). It was exactly the same 0.003" difference between new Federal rounds and my chamber (very consistent). New Horady Brass was 0.004" to 0.006" shorter. I'm not sure resized brass will drop chamber pressure that much with such a tight fit with new brass.

So why might these velocities be faster than expected. First, this was the first time I’ve used RE17 and the powder could have some temperature sensitivity being as hot as it was. I’ll have to track this in future range sessions. Second, Sierra lists their test barrel as 1:8 twist which should generate less pressure than a barrel with 1:6.5 twist. Third, loading long creates more case capacity which can reduce pressure but these were 0.010” off the lands which can generate higher pressure than a bullet with a longer jump. There may be other factors.

Has anyone else used the Sierra load data and what were your results?
 

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Discussion Starter #16 (Edited)
Down-Range Results

The 75 A-Max and 88 ELD-M were shot first at 100 yards. The remaining rounds were shot at 200 yards. The ELD-M factor ammo’s 4-shot group was a touch over 1 MOA. I must have thrown one of the 90 SMK shots. Dedicated load development should tighten all these groups but it was nice to see the 95 SMK print ½ MOA without even trying. There is good potential here.
 

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Xman, So these were shot with the ARP 22 inch Valkyrie?

I just got my 8 boxes of factory 88 Hornady ELD-M factory ammo. Want to see how it shoots out of my 7 twist 24 inch barrel as well as my ARP barrel.

Unfortunately not shooting during the monsoon/ flooding here in Lost Wages. To get to the range at the base of a mountain you have to go through a deep flood channel, road on either side is above the roof of my Navigator. LOL

Even when it's pouring it's been over 102 and when it's not raining the heat is going up to 114. I sure wouldn't want to leave a loaded magazine out in the sun. That might put some stress on my Superbolt.

You are doing a GREAT work here!
 

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Discussion Starter #19 (Edited)
Second Range Session

Made a quick trip to the range at noon. Temp was 98F. No big changes from the first session except 95 SMKs were 50 fps faster after getting a handful of rounds down the tube and a good cleaning. ELD-M ammo was very consistent and keep a 1 moa group or better. Shot the Federal 75 TMJ for the first time which was very close to the advertised velocity. For a simplistic performance comparisons, shot some 75 OTM PPU out of my 24" .223. The Valkyrie was 250 fps faster. I will have some BC number after the next range session. The 88 ELD-M is very closed to advertised. The 95 SMK isn't being stabilized enough with the 1:6.5 to achieve its advertised BC. The ELD-M and SMKs velocity decay are essentially the same. I'll have to figure out a way to do some long range testing to see if the 95 SMK's BC increases as it becomes more stable down-range. I don't want to post the BC quite yet as I need to include a known bullet in the mix to establish a known baseline. 35 bullets down the tube so far. As it stands, the factory Hornady 88 ELD-M ammo is supersonic out past 1300 yards.
 

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Discussion Starter #20 (Edited)
Powder vs Velocity Ladder - Sierra Load Data

I've loaded up a variety of powders with 88 ELD, 90 SMK, and 95 SMK in new Hornady brass to do some powder vs velocity ladders to define performance boundaries at get a peek at accuracy potential. I've only shot R17 so far and the initial results are faster than the Sierra data but appear to be higher pressure (Sierra used 1:8 twist instead of 1:6.5). R17 fills the case well. W760 was compressed and I couldn't fit their max charge in even with a longer than mag length COAL. The other powders still had some case capacity left. I am anticipating that AR Comp and Varget may do a bit better than listed (testing will show).

While I'm waiting for the opportunity to get back to the range, I made a powder vs velocity graph of the Sierra load data as a reference to compare range results with. Gray is 90 SMK data and black is 95 SMK data. Interesting that Varget and TAC with the 90 SMK are twins.
 

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